Open access peer-reviewed chapter

Biorefinery System of Lignocellulosic Biomass Using Steam Explosion

Written By

Chikako Asada, Sholahuddin and Yoshitoshi Nakamura

Submitted: 21 May 2021 Reviewed: 24 May 2021 Published: 14 June 2021

DOI: 10.5772/intechopen.98544

From the Edited Volume

Cellulose Science and Derivatives

Edited by Arpit Sand and Sangita Banga

Chapter metrics overview

468 Chapter Downloads

View Full Metrics

Abstract

Recently, plant biomass has been attracting attention due to global warming and the depletion of fossil fuels. Lignocellulosic biomass (i.e., wood, straw, and bagasse) is attracting attention as an abundant renewable resource that does not compete with the food resources. It is composed of cellulose, hemicellulose, and lignin and is a potential resource that can be converted into high-value-added substances, such as biofuels, raw materials for chemical products, and cellulose nanofibers. However, due to its complicated structure, an appropriate pretreatment method is required for developing its biorefinery process. Steam explosion is one of the simplest and environmentally friendly pretreatments to decompose lignin structure, which converts cellulose into low-molecular-weight lignin with high efficiency. It has received significant attention in the field of not only biofuel but also biochemical production. Steam explosion involves the hydrolysis of plant biomass under high-pressure steam and the sudden release of steam pressure induces a shear force on the plant biomass. Moreover, it is a green technology that does not use any chemicals. Thus, a steam explosion-based biorefinery system is highly effective for the utilization of lignocellulosic into useful materials, such as ethanol, methane gas, antioxidant material, epoxy resin, and cellulose nanofiber.

Keywords

  • steam explosion
  • biorefinery
  • lignocellulosic
  • environmentally friendly
  • conversion

1. Introduction

The agricultural and forestry sectors produce the maximum amount of lignocellulosic biomass waste with minimum utilization. Moreover, many abundant crops, such as bamboo, weed, and shrubs, are not utilized optimally. Recently, lignocellulosic biomass has been widely used for burning fuel, such as gasification through the palletization process; however, the burning pathway in this process could only result in heat and a minimum amount of byproduct. Thus, the process of obtaining byproducts from lignocellulosic biomass requires considerable improvement. The utilization pathway of renewable sources for biofuels has been improved through the second generation of biofuels obtained from nonfood resources. However, the biofuel production process still results in potential waste that could have been used for obtaining another product. This opens up possibilities for the total conversion of biomass into biomaterials, pharmaceuticals, and raw chemicals with minimum waste.

Lignocellulosic biomass contains three main sources of core materials that can be developed into more valuable products: lignin, cellulose, and hemicellulose. Lignin performs biological functions such as providing mechanical support for resistance to various stresses and water transport. It is a highly irregular polymer of phenol subunits. Phenol is a derivative of the organic molecule benzene that exhibits high stability with the alcohol functional group. Lignin has recently become a promising raw material that can be converted into various products, such as biopolymer-based products (i.e., lignin-epoxy resin (LER), polyphenols sources, antioxidants, and various chemicals (i.e., 5-hydroxymethyl furfural (HMF) and furfural). Meanwhile, cellulose is a promising raw material for second-generation biofuel and has been widely used as a source of biomaterials, such as cellulose nanofiber (CNF), which can change the dominancy of conventional fillers for composites and performs other functions in biomedical and other industries. Hemicellulose has long been used as a source for monosaccharides, such as xylose, which can produce xylitol, and various biochemicals.

Lignocellulosic biomass is difficult to treat, wherein the dominance of lignin carbohydrate-complex (LCC) causes the recalcitrance of the separation process. Steam explosion is an environmentally friendly physiochemical pretreatment widely used for lignocellulosic biomass, which only uses water. This section illustrates the biorefinery process of obtaining lignocellulosic biomass from various sources and provides information on developments made in the use of steam explosion pretreatment to convert lignocellulosic biomass into value-added products, such as various biofuels, derivative methane gas, biopolymers, raw material, biochemical, and polyphenol.

Advertisement

2. Steam explosion pretreatment

In 1926, the steam explosion was introduced to efficiently process lignocellulosic biomass into fibers [1, 2], and in 1932, Babcock was patented as the first method for producing sugar and alcohol from wood chips under high pressure and temperature with varying retention time, where the chips were suddenly discharged through a slotted port and an explosion was generated [3]. Steam explosion pretreatment is still being extensively used and increasing the scope of lignocellulosic biomass utilization.

Steam explosion is classified as a psychochemical pretreatment that can change a compound and chemical structure. The autohydrolysis mechanism involved in steam explosion facilitates mechanical cutting and fiber defibrillation, which hydrolyze some of the cell-wall components and release acid in the process. The structural components are broken by the diffusion process under the induced pressure and heat that penetrate the recalcitrant of the cell wall; furthermore, the pressure released in the explosion process separates the fibers through sudden evaporation of the condensed moisture. As shown in Figure 1, during the steam explosion pretreatment, the biomass changes the main route as follows: lignin to low-molecular-weight lignin (LML) and polyphenols; cellulose to glucose; and hemicellulose to acetic acid, glucose, xylose, and other monosaccharides. Glucose, mannose, and galactose continue to be converted into HMF, and levulinic acid, xylose, and arabinose continue to be converted into furfural and formic acid.

Figure 1.

Route changes in the steam-exploded lignocellulosic compound.

Advertisement

3. Conversion concept

Various conversion concepts using steam explosion have been introduced to obtain lignocellulosic byproducts, such as raw materials and biochemicals, as described in Figure 2. Generally, lignin is converted into LML and polyphenols, curing agent, and LER; holocellulose is converted into CNF and biofuels, such as ethanol and biogas; and hemicellulose is converted into monosaccharides and their derived products.

Figure 2.

Conversion scheme for the main routes of steam-exploded lignocellulose.

3.1 Green conversion

To meet the current requirements of obtaining environmentally friendly byproducts, green conversion has been introduced. This has emphasized the need of a biorefinery method that can reduce the amount of waste generated by using the sustainable development goal (SDG) program, which reduces the environmental impact of global warming. Steam explosion pretreatment is considered environmentally friendly because it only uses pressure and water. To obtain a green conversion, various green biorefinery processes have been proposed, which produce minimum waste and reusable chemicals during the process. For example, for the conversion of lignocellulosic biomass into raw materials and biofuels, green conversion using steam explosion has been extensively reported. Ethanol production from lignocellulosic biomass follows a basic pathway: steam explosion–enzymatic saccharification–ethanol fermentation under varying steaming times and pressures with various additional methods, such as the combination of steam explosion with other pretreatments; reduction of the fermentation inhibitor, various enzymes, and their dosages; and the hydrolysis and fermentation process. Another biorefinery process for obtaining cellulose and hemicellulose byproducts, such as monosaccharides, uses the basic methods of enzymatic saccharification and combination pretreatment for ethanol production.

3.2 Total biorefinery

The total biorefinery concept for lignocellulosic biomass has been introduced to maximize the amount of byproduct produced from each biorefinery process and reduce waste production. A conventional biorefinery focuses on only one product from lignocellulosic biomass, such as derived products of cellulose, hemicellulose, or lignin. The waste generated from a conventional biorefinery contains a potential raw material, which is wasted into effluents; for example, the waste generated from lignocellulosic biomass ethanol production still contains lignin, which could have been used as lignin-derived products.

Asada [4] introduced a waste reduction system to obtain more useful products through steam explosion pretreatment, followed by water and methanol extraction. They used a water-soluble material for the purification process to obtain monosaccharides and oligosaccharides and methanol-soluble lignin for the resinification process to obtain LER. The two solid residues (i.e., hollocellulose and klason lignin) were used to obtain antibacterial violet pigment or lactic acid and activated carbon, respectively. The antibacterial violet pigment was produced using the enzyme saccharification process to obtain the monosaccharide content, followed by lactic acid fermentation using Lactobacillus plantarum and Janthinobacterium lividum. The waste generated from enzymatic saccharification (i.e., klason lignin) was processed into activated carbon through carbonization in a furnace at 500°C under a nitrogen gas atmosphere. Hongzang [5] examined the steam explosion-based total biorefinery process, followed by washing with water and alcohol extraction. They used a water-soluble material for the fermentation process and purified an alcohol-soluble material to obtain LML. The solid residue generated from the alcohol extraction was subjected to the pulping process, with cellulose as the final product. Asada [6] subjected Japanese cedar (Cryptomeria japonica) to steam explosion pretreatment followed by water extraction and methanol extraction. They used all residues obtained from each process to obtain the potential products; for example, they used the water-soluble material from water extraction for obtaining antioxidant resources by examining the antioxidant activities. Furthermore, the methanol-soluble lignin obtained from methanol extraction produced LER through epoxy resin synthesis and the hollocellulose obtained from the solid residue of methanol extraction was used for ethanol production using simultaneous saccharification and fermentation process (SSF). In another study, Asada [7] subjected cedar (Cryptomeria japonica), eucalyptus (Eucalyptus globulus), and bamboo (Phyllostachys pubescens) to steam explosion pretreatment, which produced raw materials by the continuous biorefinery process. They used water extraction, which produced a water-soluble material rich in polyphenol content; the residue obtained from this process was used to continue the methanol extraction with LML as the raw material, and finally, enzymatic saccharification with glucose as the raw material was performed using the residue obtained from methanol extraction. LML was subjected to epoxy resin synthesis to produce LER. In another study, Asada [8] reported the steam explosion-based total biorefinery process for lignocellulosic biomass, followed by water extraction and acetone extraction, to produce a phenolic compound as an antioxidant, followed by acetone extraction, which produced LML. This LML was converted into LER and a curing agent. The residue obtained from the acetone extraction was used to convert hollocellulose (cellulose and hemicellulose) into CNF, with the cured epoxy resin as an end product. The final product of LER, curing agent, CNF was producing the cured epoxy resin.

Advertisement

4. Biofuels

Biofuels face competition with other food resources such as wheat, grain, corn, cassava, and palm oil. To address this issue, researchers started evaluating other renewable resources that do not face this competition. The second generation of biofuels is obtained from unutilized biomass and biomass waste resources, which are abundantly available. The biomass waste generated from agricultural and forestry sectors, such as burning fuel or dumping of disposal waste, commonly ends up with minimum utilization. Moreover, the unutilized biomass, such as weed, grass, and bamboos, can be converted into biofuels. The second-generation biofuels have been widely introduced with various biorefinery processes, including steam explosion pretreatment for bioethanol and biogas production.

4.1 Ethanol

The second-generation ethanol production is highly dependent on the availability of cellulose and hemicellulose from LCC. Steam explosion is an effective pretreatment for breaking LCC into cellulose and hemicellulose, which can be readily converted into ethanol. This pretreatment is widely used because of its ability to break LCC into cellulose and hemicellulose obtained from the conversion of lignocellulosic biomass into ethanol. The general routes for ethanol production via steam explosion pretreatment are described in Figure 3. Nakamura [9] converted rice straw into ethanol through steam explosion, followed by water extraction and enzymatic saccharification and fermentation. They reported 86% theoretical ethanol production from the substrate by using steam explosion and Trichoderma viride cellulase or Meicelase and Aspergillus aculeatus cellulase or Acucelase, using Pichia stipites. Sasaki [10] converted wood chips and acorns of Quercus acutissima into acetone, butanol, ethanol (ABE) by steam explosion pretreatment, followed by direct conversion using the separate hydrolysis and fermentation (SHF) and SSF methods. The SSF method yielded 100% ABE conversion rate, with 0.112 g/L/h ABE productivity for 196 h of incubation time with 60 g/l concentration of the initial substrate. In another study, Sasaki [11] subjected the pruned branches of pear trees to steam explosion pretreatment, followed by SSF, to produce ethanol. They compared the steam-exploded substrates with and without water and methanol extraction in terms of the amount of ethanol produced. The result showed that the SSF with water and methanol extraction achieved 76% of the theoretical production with 99.7% of glucose recovery, whereas the sample not subjected to methanol and water extraction majorly produced sugar and no ethanol. This result was attributed to fermentation inhibitors contained in the substrate as compound fractions obtained from steam explosion pretreatment.

Figure 3.

Production routes for ethanol produced from steam explosion.

Table 1 shows the steam explosion-based ethanol production methods. The most significant problem incurred in ethanol production using steam explosion pretreatment is the yield of a fermentation inhibitor as a derived product of steam explosion. Ando [24] identified the influences of an aromatic monomer in steam explosion on ethanol production via Saccharomyces cerevisiae, which could be reduced by washing the inhibitors with a solvent, converting them into inactive compounds using biological or chemical methods, improving the steam explosion conditions to minimize the inhibitor formation, and screening for yeasts that resist the inhibitors. Asada [19] used the SSF method for spent of shitake mushroom medium for evaluating the effect of reducing the formation of fermentation inhibitors with and without water extraction. They reported 87.6% of theoretical ethanol yield, which produced 15.9 g ethanol from 100 g substrate. In another study, Asada [15] used steam explosion, followed by water extraction, in comparison with mechanical grinding with a ball mill, for converting disposable chopstick obtained from aspen into ethanol. This resulted in 20 FPU/g samples, and the continuous fermentation using the SSF method resulted in 520 and 598 mg-glucose/g-dry samples from grinding and steam explosion pretreatment, respectively. This method yielded 79% of theoretical ethanol production with 241 mg-ethanol/g-dry. In addition, Scholl [20] used steam explosion pretreatment for converting the elephant grass Pennisetum purpureum under various pressures and steaming times, followed by vacuum draining and washing with water to remove the inhibitor material and enzymatic saccharification using cellulase and xylanase obtained from P. echinulatum. Thereafter, the fermentation process was continued using Saccharomyces cerevisiae as the steam-exploded elephant grass, followed by water washing and using cellulose enzymes with 10 FPU/g total solid having 4 wt% substrate concentration, which did not result in a feasible production (110.45 μl/g). To overcome the toxicity of phenolic compounds obtained from the steam-exploded substrate, which act as an inhibitor for ethanol production, various treatments have been reported, such as the use of laccase produced from Coriolopsis rigida and Trametes villosa. The detoxification by laccases considerably improves the ethanol fermentation, which in turn reduces the toxic effect on S. cerevisiae [18]. Asada [17] converted cedar into ethanol by using steam explosion pretreatment in comparison with water and methanol extract, followed by the use of the simultaneous saccharification, detoxification, and fermentation (SSDF) method combined with the detoxification process using U. thermosphaericus A1 as a biological fermentation inhibitor degrading agent to degrade the inhibitory material produced from the steam explosion pretreatment. They concluded that the fermentation inhibitor degradation in low concentration was necessary to produce ethanol from steam-exploded lignocellulosic biomass, where the steam-exploded cedar produced glucose alone due to the saccharification end product.

BiomassPretreatmentPressures (MPa)Steaming time (min)Inhibitors removalMethod*Enzyme and/or microorganismAchievement (Glucose or ethanol yields)References
SaccharificationFermentationOther
PotatoSteam explosion0.51 to 3.0410n/aBS, SSFA. AwamoriS. cerevisiae87%[12]
Rice strawSteam explosion3.0 to 4.00.5 to 10n/aES, SHFAcucelase, MeicelsePichia stipitis86%[9]
Domestic wasteSteam explosion0.5 to 2.53n/aES, SSFA. awamori, Trichoderma viride NBRC 31327S. cerevisiaen/a[13]
Japanese cedarSteam explosion, organosolv2.5 to 4.55n/aES, SSFMeicelsen/a84.4%[14]
Aspen chopsticksSteam explosion2.0 to 3.05Water extractionES, SSFMeicelse[15]
Sawdust wasteSteam explosion2.5 to 5.55Water & Methanol ExtractionES, SSFMeicelase, Trichoderma viride,
β-glucosidase
S. cerevisiae81%[16]
Japanese cedarSteam explosion3.5 to 5.55 & 10Water extraction, Biological detoxificationES, SSF, SSDFMeicelaseS. cerevisiae BA11U. thermosphaericus A188%, 74%[17]
Q . acutissimaSteam explosion3.55Water & Methanol ExtractionES, SSF, SHFGlutase-AN, Cellic CTec 2C. acetobutylicum NBRC 13948100%[10]
Pear treesSteam explosion2.5 to 3.55Water & Methanol ExtractionES SSFCellic CTec 2Kluveromyces marxianus NBRC 177776%[11]
Japanese cedarSteam explosion4.53Water & Methanol ExtractionES, SSFMeicelase, Trichoderma viride,
β-glucosidase
S. cerevisiae70%[6]
Wheat strawSteam explosionn/an/an/aES, FermentationLaccasen/aC. rigida & T. villosan/a[18]
Sawtooth OakSteam explosion1.0 to 3.05Water extractionSSFMeicelaseS. cerevisiae AM1287.6%[19]
Elephant grassSteam explosion1.27 to 2.056 to 10Vacuum dring, Water washingES, FermentationP. echinulatum S1M29S. cerevisiae CAT-1n/a[20]
Lemon peelSteam explosion0.65n/aSSF, SHFPectinase, Cellulase, β-glucosidase (Novozym 188)S. cerevisiae CECT 1329n/a[21]
Brassica napusSteam explosion, H2SO4, CaOn/an/an/aES, FermentationCellulases, XylanaseS. cerevisiae90–93%[22]
BagasseSteam explosion1.57 to 3.531 to 10Water extractionES, FermentationMeicelase, AcucelasePichia stipitis CBS 5773n/a[23]

Table 1.

Steam explosion-based ethanol production methods.

BS: Biological saccharification, ES: Enzymatic saccharification, SHF: Separate hydrolysis and fermentation, SSF: Simultaneous saccharification and fermentation, SSDF: Simultaneous saccharification, detoxification, and fermentation.


4.2 Biogas

Figure 4 shows the cellulose conversion into methane gas. The methanogenic reaction of cellulose or other forms of carbohydrates through the hydrolysis process yields monosaccharides, which are fermented to produce acetic acid, hydrogen, and CO2 [25]. From the fermented products, acetolactic methanogenesis converts the acetic acid and hydrogenotrophic methanogenesis converts the hydrogen and CO2; the conversion process includes reforming the acetic acid, hydrogen, and CO2 into methane [26]. Steam explosion pretreatment has been widely used for biogas production. Take [27] subjected Japanese cedar chips to 4.51 MPa steam explosion for 5 min for optimal methane production. Kobayashi [28] used bamboo to produce methane by 3.53 MPa steam explosion (243°C) using the sludge obtained from sewage treatment for microbial seed under mesophilic condition (37°C), which resulted in 80% theoretical yield with 423 ml obtained from 1 gr of cellulose and hemicellulose for 25 days of total cumulative production. Mulat [29] combined steam explosion pretreatment for lignocellulosic biomass and bioaugmentation using Caldicellulosiruptor bescii, which enhanced the methane production under thermophilic conditions by 140% in 50 days with low dosages of Caldicellulosiruptor bescii inoculum (2–5%). Sholahuddin [30] subjected rice husk to a combination of steam explosion pretreatment at 2.52 MPa and 224°C followed by water extraction and activated cow dung as the inoculum without co-digestion, at 37°C. This yielded 96.1% of stochiometric prediction of methane production with 199 ml/g of total solid, which contained 41% of cellulose only for 22 days, and all the liquid and solid residues were used as the substrate. Steam explosion pretreatment was also used for grass, such as reed, which can be used as a potential raw material for biogas because of its abundance. Lizasoain [31] subjected reed biomass (Phragmites australis) for biogas feedstock to steam explosion under various temperatures, pressures, and steaming times, where the 200°C and 15 min combination increased the methane yield by 85% compared to the untreated samples. Furthermore, Dererie [32] used oat straw for combined biogas and ethanol production with steam explosion pretreatment and other chemical treatment; as per the result, the residue of ethanol fermentation from steam-exploded oat straw produced higher methane than that produced by unfermented steam-exploded oat straw. They concluded that the fermentation ethanol process acts as an additional pretreatment for methane production.

Figure 4.

Cellulose conversion into methane gas.

Methane production from lignocellulosic feedstock through steam explosion pretreatment provides a wide spectrum of total conversion. Methane is converted not only from cellulose and hemicellulose but the aromatic lignin fractions also contribute to the methane production. Moreover, steam explosion facilitates better anaerobic digestion by disrupting the lignin structure [33], which can be converted into methane. However, the anaerobic degradation of the aromatic compound incurs several difficulties in the degradation process [34], and several studies have reportedly observed anaerobic lignin degradation [35, 36]. The aromatic lignin heteropolymers mainly comprise two monolignols, which are methoxylated to various degrees: synapyl and coniferile alcohols; these monolignols are fused into lignin in the unit syringyl (S) and guaiacyl (G) forms, respectively [37]. The depolymerized monomeric unit of lignin (i.e., S) is converted into vanillin and the G unit is converted to syringaldehyde [38]. Syringaldehyde can produce a high methane yield [19, 24, 39]. Barakat [40] demonstrated the combination of xylose and the lignin fraction, such as aromatic compounds syringaldehyde and vanillin; cellulose and hemicellulose fractions, such as HMF; and furfural and xylose. The combination of xylose and syringaldehyde yielded the highest methane production, followed by the combination of xylose and furfural compared with xylose alone.

Advertisement

5. Cellulose- and hemicellulose-derived products

The cellulose- and hemicellulose-derived products by steam explosion pretreatment, such as monosaccharides, antibacterial, lactic acid, D-lactic acid, xylose, xylitol, HMF, and furfural, have been widely introduced in many studies. The production of monosaccharides as a raw material derived from cellulose- and hemicellulos-based products, such as glucose conversion, has been reported. Fernandez [41] reported the use of steam explosion for whole olive stones to enhance the enzymatic hydrolysis for conversion of cellulose into sugar. Dai [42] used steam explosion, in comparison with hydrothermal pretreatment, to convert bamboo (Bambusa stenostachya) into monosaccharides, such as glucose xylose and arabinose and furfural. Asada [4] reported the production of lactic acid and antibacterial through enzymatic saccharification followed by the fermentation process, and as a result, approximately 0.53 g/l where the lactic acid from glucose produced approximately 0.7 g/l from 1 g/l glucose. This result was attributed to the inhibition of the fermentation process of soluble lignin from the substrate of enzymatic hydrolysate. The antibacterial violet pigment was produced by the same process of enzymatic hydrolysate, where glucose decreased in line with the rapid cell growth, with the maximum growth occurring within 20 h. After the cell growth was stopped, the antibacterial was produced as a secondary metabolite and reached the maximum condition within 30 h, where the culture color changed into deep violet. Sasaki [43] used steam-exploded sugarcane bagasse to produce D-lactic acid by comparison with and without water extraction. They used meicelase for enzymatic saccharification and Lactobacillus delbrueckii NBRC 3534 for D-lactic acid fermentation; according to the result, the glucose conversion rate for water-extracted hydrolysate (49.9%) was found to be higher than that obtained without extraction (36.4%). In terms of the rate of conversion from glucose to D-lactic acid, D-lactic acid production was escalated more by the water extraction treatment (90%) than that without the extraction (66.6%). This result was attributed to the water extraction, which was decreased by fermentation inhibitors such as HMF and furfural. Macros [44] used wheat straw to produced xylose and glucose by the steam explosion pretreatment followed by warm water wash and enzymatic hydrolysis, which used a combination of accellerase and xylanase (accellerase-XC and XY), which exhibits multiple enzyme activities, such as exoglucanase, endoglucanase, hemicellulose, and β-glucosidase. As a result, 87% and 27% increases were observed in the hemicellulose conversion into glucose and xylose, respectively. Liu [45] used simultaneous and co-fermentation for improving the xylose production by steam explosion, followed by SHF and SSCF methods. S cerevisiae IPE002 was used for both fermentation methods, which could convert. The glucose and xylose production reached 100.4 and 25.1 g/l concentrations, respectively. Wang [46] used corn straw to produce xylitol by acid impregnation, followed by steam explosion without detoxification; as a result, xylene hydrolysate with a high amount of xylose production and simultaneous glucan production were observed. The medium of Candida tropicalis produced a maximum yield of 35.6 g/l for xylitol in 38 h fermentation with 0.94 g/l h productivity.

Advertisement

6. Biomaterials

The lignocellulosic biomaterial has the potential to be used as a raw material for developing a new renewable and environmentally friendly product. The steam explosion pretreatment is a highly recommended pretreatment to obtain more valuable raw materials in the biorefinery process due to its effective breaking process, which yields lignin, cellulose, and hemicellulose byproducts. The lignocellulosic biomaterial can be used in various fields, such automobiles, medical, pharmaceutical, food packaging, beverage cans, electronics, composite industries, and the aerospace industry. The lignocellulosic biomaterials such as LER as biopolymers exhibit valuable properties, such as low moister absorption, good mechanical and electrical properties, and high chemical and thermal resistance. CNF is widely known as a raw material that exhibits good optical and mechanical properties, low thermal expansion coefficient, and high specific area. The basic properties of the raw material of lignocellulosic make it a promising raw material.

6.1 CNF

CNF is a promising biomaterial material that has advantageous characteristics beside those of optically transparent functional material [47], same as plastic (i.e., high gas barrier properties [48], biodegradability, light weight, high strength, ultrafine fibers, large specific surface area, low thermal expansion, characteristic viscosity in water, and environmentally friendly biomaterials, which can be used for cosmetic, biomedical, and pharmaceutical products [49, 50, 51], nanocomposites for industrial products [52], and filters that have large surface area for collecting small dust particles [53]). Table 2 lists an extensively reported substrate developer for CNF resources; wood and nonwood biomass is the most potential CNF resource owing to the considerable abundant waste generated from the wood industry and agricultural waste.

BiomassPretreatmentConditionDelignificationNanosizerReferences
Pressure (MPa)Steaming time (min)
Abaca (Musa textilis)Steam explosion0.1315Water, HomogenizerOxidation[54]
Japanese cedarSteam explosion3.0 to 4.05 to 15Water, Acetone, Bleaching (NaClO2), NaOHGrinder[55]
Yerba mateSteam explosion0.1560Water, Hydrogen peroxide, WaterOxalic acid[56]
Sugarcane bagasseSteam explosion1.3 to 1.95 to 15Water, Immersed hydrogen peroxide, NaOHHigh-speed agitation, High pressure homogenization[57]
Wheat strawSteam explosion32Water, Microwave alkali hydrolysis, NaOHMicrofluidization[58]
CorncorbsAlkaline steam explosionn/an/aNaOH, Bleaching (NaClO2)High-speed agitation, Ultrasonication[59]
Pineapple leafAlkaline steam explosion0.1360NaOH, Acetic acid, Bleaching (NaClO2), Oxalic acid, KMnO4High speed mechanical stirring[60]
Sugarcane bagasseAlkaline steam explosion0.1300NaOH, Hydrogen peroxide, Water, HClUltrasonication[61]
Sugar beet pulpSteam explosion2.435Hydrogen peroxide, WaterHigh-speed agitation, Ultrasonication[62]
Banana fibersAlkaline steam explosion0.1360NaOH, Acetic acid, Bleaching (NaClO2), Oxalic acid, KMnO4High speed mechanical stirring[63]
Abaca (Musa textilis)Steam explosion0.1315HNO3, NaNO2, NaSO3, Water, Hydrogen peroxideHydrolyzed H2C2O4, Homogenization[64]
Palm Oil Empty Fruit BunchesSteam explosion210Sodium hydroxide, Water, Bleaching (NaClO2)Grinder[65]
Wheat strawalkaline steam explosion0.1240NaOH, Immersed hydrogen peroxide, HCl, Ultrasonicator, WaterHomogenizer[66]
Sugarcane bagasseSteam explosion1.1 to 1.5n/aCatalyzed hydrothermal NaOH, Bleaching, Hydrogen peroxide, WaterHigh-speed agitation, Ultrasonication[67]
White poplarSteam explosion2.5 to 3.51 to 5Bleaching (NaClO2), Acetic acidGrinder[8]
Rice strawSteam explosionn/an/aNaOH, Immersed hydrogen peroxideTEMPO-oxidized[68]

Table 2.

CNF production via steam explosion pretreatment.

Before isolating CNF, it is necessary to break the recalcitrant of the compact-structure LCC from wood and nonwood lignocellulose biomass before it is used as a CNF source. There are several treatments to break the LCC; in this study, steam explosion pretreatment is recognized as a promising method to obtain CNF due to its effectiveness in the biorefinery process and being considered as environmentally friendly.

After wood or non-wood lignocellulosic biomass is treated with steam explosion, two main routes have been proposed, as described in Figure 5. The first route is the use of the extraction process to separate the other compounds that could be used as other biomaterials, such as LML and polyphenols, by water, methanol, or acetone extraction as part of the delignification process. Then, the lignin still attached to hollocellulose is separated by the bleaching process. Several bleaching agents are available in the market, such as alkaline peroxide, sodium hypochlorite, and sodium chlorite, which are separated by filtration to obtain holocellulose, which is a raw material used for CNF. Hollocellulose can be directly processed to obtain CNF by using the grinding treatment [55, 69, 70, 71], high-pressure homogenization [57, 72, 73, 74], acid hydrolysis [54, 56], enzymatic hydrolysis [41, 75], and ultrasonication [67, 76, 77]. The second route is the bleaching process followed by TEMPO-mediated oxidation to isolate the CNF [68].

Figure 5.

CNFs produced from steam explosion-based general route biorefinery.

6.2 Biopolymers

The production of biopolymers through steam explosion pretreatment is a potential and feasible biorefinery process that can produce various polymer raw materials, such as a curing agent and lignin resin, and byproducts, such as LER and composite material [78]. A biodegradable polymer obtained from renewable resources has recently attracted attention as a substitute for hegemony petroleum-based polymers, which support the SDG program to reduce the effect of global warming. LER production from steam-exploded lignocellulosic biomass has been extensively reported. Lignocellulosic biomass is a potential resource for epoxy resins derived from lignin and hemicellulose (i.e., lignin-based epoxies, furfural-based epoxies, and phenolic and polyphenolic epoxies). Lignin-based epoxies include depolymerized organosolv lignin [79], depolymerized hydrolysis lignin [80], LER, which acts as both a curing agent and a resin [4, 6, 7, 81, 82, 83, 84], diglycidyl ether of vanillyl alcohol/IPDA, diglycidyl ether of methoxyhydroquinone, diglycidyl ether of vanillic acid [85], and vanillin-based epoxies [86]. Furfural-based epoxies include furan diepoxide and bis-furan di-epoxide furan monoepoxide, 2,5-Bis[(2-oxiranylmethoxy)methyl]-furan [87], 1,4-Bis[(2-oxiranylmethoxy)methyl]-benzene [88], 5,5-Methylenedifurfurylamine (DFDA) and 5,5-Ethylidenedifurfurylamine (CH3-DFDA) [89], diglycidyl ester of 2,5-furandicarboxylic acid, 2,5-Furandicarboxyli acid, and bis(prop-2-enyl)furan-2,5-dicarboxylate [90]. The phenolic and polyphenolic epoxy resins include catechin-based (such as glycidyl ether of catechin [91], glycidyl ether of green tea extract [92], glycidyl ether of heat dried green tea extract, and glycidyl ether of freeze-dried green tea [83]) or gallic acid-based (such as gallic acid epoxidized, tannic acid epoxidized, vanillic acid epoxidized [93, 94, 95], tri- and tetra-glycidyl ethers of gallic acid [96], cardanol epoxidized [97], cardanol novolac epoxy [98], cardanol [99], and tannic acid [95]). The hard segment of lignin can provide stiffness as a lignin-cured copolymer, which can significantly affect the properties of the copolymer [78]. The curing agent allows the main adhesive to form a net or three-dimensional structure to increase the cohesive strength of the adhesive layer, which is commonly formed by acid anhydrides, amines, sulfurs, and macromolecules [100].

Figure 6 describes the main route of lignin epoxy resin (LER) production by steam explosion-based biorefinery process. The steam-exploded substrate is subjected to the extraction process by water–methanol/acetone [4, 7, 8, 82] or direct methanol/acetone extraction under various temperatures and extraction times for water extraction. The extraction process provides LML after the evaporation process. The next step is resin synthesis using LML, which can be performed using various methods, such as a two-step reaction: epichlorohydrin catalyzed by tetrabutylammonium bromide (TBAB) to open the epoxy ring and the reaction with sodium hydroxide to reconstruct the hydrogen chloride [82]; lignin is reacted with epichlorohydrin and NaOH aqueous solution is added at 110°C, followed by the washing process, to deprive the NaOH to obtain LER [4]; lignin is reacted with epichlorohydrin and continue to use tetramethylammonium chloride (TMAC) by heated and flowed under nitrogen (N2). This reaction is simpler than TBAB in order to syntheses the epoxy resin, and continue to epoxy ring reconstructed, after that the methyl ethyl ketone (MEK) solvent was used during the ring closure reaction and also for wash out the NaCl as by product of ring closure reaction [7, 8]. The curing process uses various curing agents, such as biological curing agents, epoxy resin, or chemical curing agent, to obtain cured LER through various processes. The cured process includes various biological or conventional curing agents.

Figure 6.

Main routes for the conversion of lignocellulose to biopolymers by steam explosion pretreatment.

LER synthesized from bamboo by steam explosion pretreatment was used for toxicity examination with human breast cancer estrogen-sensitive MCF cells. Here, the LER was synthesized from methanol-soluble lignin/LML and subjected to the epoxy reaction by melting the LML with a combination of epichlorohydrin and NAOH; then, the NaCl was produced from water extraction and evaporated to obtain epoxidized lignin. The LER production was continued by reacting with dimethyltyramine used as the curing agent. The epoxidized lignin is considered safe for the toxicity effect of epoxy resin because no proliferative MCF cells are produced, which indicates the absence of endocrine-disruption activity [4]. The epoxy resin syntheses produced an LER, which can act as an epoxy resin, a curing agent, or a copolymer to produce cured epoxy resin. Sasaki [82] introduced an LER that can be used as both an epoxy resin and a curing agent, and used epoxidized lignin resin from bamboo produced through a two-step reaction with catalysis transfer method by adding bamboo lignin to TBAB-catalyzed epichlorohydrin and releasing the hydrogen chloride to reconstruct the epoxy ring in the presence of sodium hydroxide. Asada [7] produced an LER that can be used as both a curing agent and an epoxy resin, which was evaluated by the synthesis of cured epoxy resin. The LER was synthesized by dissolving LML, followed by a catalyzed process, to open the epoxy ring and detaching the hydrogen chloride used TMAC. After the separation process, continue to be dissolved with MEK as a solvent to obtain LER by the washing process and vacuum-drying.

Advertisement

7. Antioxidant resources

LCC was broken down and degraded by steam explosion. The degradation of lignin [101, 102] and its compounds [103] resulted in a complete conversion of lignin to phenolic compounds, which is also an important raw material for the production of antioxidants and drugs [101]. The depolymerization was performed through the rupture of ether and destruction of C − C bonds connecting the phenylpropane units. This method produced low-molecular-weight monomer phenols, such as 2-methoxyphenols (guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-vinylguaiacol, 4-propylguaiacol, eugenol, isoeugenol, vanillin, acetovanillone, and 2-propiovanillone), 2,6-dimethoxyphenols (syringol, 4-methylsyringol, 4-allylsyringol, syringaldehyde, and acetosyringone), dihydroxybenzenes (catechol, 3-methylcatechol, 4-methyl-catechol, 3-methoxycatecho, and hydroquinone), and phenolsyringaldehyde [6, 104, 105, 106, 107, 108, 109, 110], which are comparatively easy to identify through the separation and chromatographic identification [111].

Steam explosion pretreatment for antioxidant examination for biomass has been extensively reported. Asada [8] subjected white poplar to steam explosion pretreatment on a total biorefinery system and obtained 76 mg-catechin equiv./g-dry steam-exploded white poplar. Kurosumi [104, 112] used S. palmata from the leaf, stem, rhizome, and root of bamboo grass to examine its antioxidant compounds by steam explosion pretreatment followed by hot water extraction at 98°C for 2 h and methanol extraction. They examined the antioxidant activity of water-soluble material, methanol-soluble material, and its residue, which yielded a higher phenolic compound with a concentration of 217.41 mg/g from the leaf part, and expressed the antioxidant activity through butylated hydroxyanisole, which yielded 142.81 mg/g of radical scavenging activity from the leaf part. Noda [113] subjected raw garlic to steam explosion followed by water extraction to examine its antioxidant activity and obtained 0.135 g/l of EC50 with 80.8 mg/g of phenolic compounds. Subsequently, Noda [107] examined the garlic husk in comparison steam explosion with microwave irradiation followed by water extraction, and found that the value of EC50 was decreased, which was expressed as an increase in the radical scavenging activity. This is in line with the dramatically increased amount of phenolic compounds. Sui [114] examined the tea waste by steam explosion and observed a 20% improvement in the antioxidant capacity and OH, O2, and ferric reducing antioxidant power (FRAP) radical scavenging activity of tea extracts. Romero [115] used olive leaves for obtaining the antioxidant by steam explosion pretreatment, and obtained 1950 mg of antioxidant from 100 g of olive leaves. Gong [116] used barley bran to determine the phenolic compounds and antioxidant activities with steam explosion followed by methanol extraction, and as a result, the total soluble phenolic content of 1686.4 gallic acid equivalents mg/100 g with 2983 TEAC mg/100 g of DW was obtained by the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid method for scavenging activity and 13.45 mmol FeSO4·L−1·g −1 was obtained using FRAP. Chen [117] used steam-exploded wheat to examine the antioxidant activity and antiproliferation on HepG2 cells by ultrasonic extraction with 80% methanol, followed by washing with phosphate buffer solution. They obtained 423.335 ± 19.94 mg/ml EC50 and concluded that the cellular and antiproliferation activities were enhanced. Furthermore, Li et al. [110] subjected the bran of buckwheat to steam explosion followed by the extraction process using 80% chilled acetone and a purification process to remove any lipid and other fractions. They examined the phenolic composition, antioxidant activity, and ability to inhibit the proliferation of HepG2 and Coca-2 cells, as well as their cytotoxicity, which resulted in 28.32 ± 0.91 and 13.18 ± 0.81 mg RE/g DW total phenolic and flavonoid, respectively. The antioxidant activity was expressed by oxygen radical absorbance capacity, which resulted in 1120.33 ± 41.43 μmol TE/g DW, and it can against the HepG2 and Caco-2 cells by antiproliferative activity. In addition, the effect of antioxidant extraction for ethanol production under the effect of saccharification and fermentation process has also been reported (e.g., [118, 119, 120]), which suggests that the scavenging activity cannot increase with the phenolic compounds. Asada [6] subjected softwood to steam explosion followed by water and methanol extraction. The water-soluble material obtained from water extraction as an antioxidant resource yielded 10.4 ± 2.52 min/μg/ml (AAPH-induced linoleic acid oxidation). This value is one-fifth that of Trolox, where the expectation was that the polyphenol compounds, such as phenylpropanoids and flavonoids, contained in water-soluble materials exhibit an antioxidative activity equal to that of Trolox. However, the result was below expectation, which is attributed to the impurities, and thus, the softwood must be purified before being examined for antioxidant activities.

Advertisement

8. Conclusions

The steam explosion pretreatment for lignocellulosic biomass biorefinery is an environmentally friendly process and can produce a wide range of products. This system aims to obtain an effective biorefinery to identify potentialities used in all sectors, including biomedical, aviation, energy, electronics, and environment. The previously reported studies on this topic have already provided several biorefinery systems based on steam explosion pretreatment for lignocellulosic biomass. Even though the scope is beyond that of the present review, it is necessary to perform the economical calculation and life cycle assessment analysis. Further studies must be conducted as most of the abovementioned lignocellulosic biomass byproducts have not yet been produced at a commercial production level and require a transition from academic assumptions to industry assumptions.

Advertisement

Acknowledgments

The authors gratefully acknowledge the financial supports provided by a Grant-in-Aid for Young Scientists (A) (Grant No. 17H04717) and a Grant-in-Aid for Scientific Research (A) (Grant No. 20H00664) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.

References

  1. 1. Mason WH. Process and apparatus for disintegration of wood and the like. US: US Patent; 1586159, 1926. p. 6
  2. 2. WH M. appartus for and process of explosion fibration of lignocellulose material. US; 1655618, 1928
  3. 3. Babcok L. Method for producing fermentable sugars and alcohol from wood. US; 1855464, 1932
  4. 4. Asada C, Nakamura Y, Kobayashi F. Waste reduction system for production of useful materials from un-utilized bamboo using steam explosion followed by various conversion methods. Biochemical Engineering Journal. 2005;23(2):131-137
  5. 5. Hongzhang C, Liying L. Unpolluted fractionation of wheat straw by steam explosion and ethanol extraction. Bioresource Technology. 2007;98(3):666-676
  6. 6. Asada C, Sasaki C, Uto Y, Sakafuji J, Nakamura Y. Effect of steam explosion pretreatment with ultra-high temperature and pressure on effective utilization of softwood biomass. Biochemical Engineering Journal. 2012;60:25-29. Available from: http://dx.doi.org/10.1016/j.bej.2011.09.013
  7. 7. Asada C, Basnet S, Otsuka M, Sasaki C, Nakamura Y. Epoxy resin synthesis using low molecular weight lignin separated from various lignocellulosic materials. International Journal of Biological Macromolecules. 2015;74:413-419. Available from: http://dx.doi.org/10.1016/j.ijbiomac.2014.12.039
  8. 8. Asada C, Sasaki C, Suzuki A, Nakamura Y. Total Biorefinery Process of Lignocellulosic Waste Using Steam Explosion Followed by Water and Acetone Extractions. Waste and Biomass Valorization. 2018;9(12):2423-2432. Available from: http://dx.doi.org/10.1007/s12649-017-0157-x
  9. 9. Nakamura Y, Sawada T, Inoue E. Enhanced ethanol production from enzymatically treated steam-exploded rice straw using extractive fermentation. Journal of Chemical Technology and Biotechnology. 2001;76(8):879-884
  10. 10. Sasaki C, Kushiki Y, Asada C, Nakamura Y. Acetone-butanol-ethanol production by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) methods using acorns and wood chips of Quercus acutissima as a carbon source. Industrial Crops and Products. 2014;62:286-292. Available from: http://dx.doi.org/10.1016/j.indcrop.2014.08.049
  11. 11. Sasaki C, Okumura R, Asada C, Nakamura Y. Steam explosion treatment for ethanol production from branches pruned from pear trees by simultaneous saccharification and fermentation. Bioscience, Biotechnology and Biochemistry. 2014;78(1):160-166
  12. 12. Kobayashi F, Sawada T, Nakamura Y, Ohnaga M, Godliving M, Ushiyama T. Saccharification and alcohol fermentation in starch solution of steam- exploded potato. Applied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology. 1998;69(3):177-189
  13. 13. Nakamura Y, Sawada T. Ethanol production from artificial domestic household waste solubilized by steam explosion. Biotechnology and Bioprocess Engineering. 2003;8(3):205-209
  14. 14. Yamashita Y, Sasaki C, Nakamura Y. Effective enzyme saccharification and ethanol production from Japanese cedar using various pretreatment methods. Journal of Bioscience and Bioengineering. 2010;110(1):79-86. Available from: http://dx.doi.org/10.1016/j.jbiosc.2009.12.009
  15. 15. Asada C, Kita A, Sasaki C, Nakamura Y. Ethanol production from disposable aspen chopsticks using delignification pretreatments. Carbohydrate Polymers. 2011;85(1):196-200. Available from: http://dx.doi.org/10.1016/j.carbpol.2011.02.020
  16. 16. Asada C, Sasaki C, Nakamura Y. High Concentration Ethanol Production from Mixed Softwood Sawdust Waste. Waste and Biomass Valorization. 2019;10(2):433-439
  17. 17. Asada C, Sasaki C, Takamatsu T, Nakamura Y. Conversion of steam-exploded cedar into ethanol using simultaneous saccharification, fermentation and detoxification process. Bioresource Technology. 2015;176:203-209. Available from: http://dx.doi.org/10.1016/j.biortech.2014.11.039
  18. 18. Jurado M, Prieto A, Martínez-Alcalá Á, Martínez ÁT, Martínez MJ. Laccase detoxification of steam-exploded wheat straw for second generation bioethanol. Bioresource Technology. 2009;100(24):6378-6384. Available from: http://dx.doi.org/10.1016/j.biortech.2009.07.049
  19. 19. Asada C, Asakawa A, Sasaki C, Nakamura Y. Characterization of the steam-exploded spent Shiitake mushroom medium and its efficient conversion to ethanol. Bioresource Technology. 2011;102(21):10052-10056. Available from: http://dx.doi.org/10.1016/j.biortech.2011.08.020
  20. 20. Scholl AL, Menegol D, Pitarelo AP, Fontana RC, Filho AZ, Ramos LP, et al. Ethanol production from sugars obtained during enzymatic hydrolysis of elephant grass (Pennisetum purpureum, Schum.) pretreated by steam explosion. Bioresource Technology. 2015;192:228-237
  21. 21. Boluda-Aguilar M, López-Gómez A. Production of bioethanol by fermentation of lemon (Citrus limon L.) peel wastes pretreated with steam explosion. Industrial Crops and Products. 2013;41(1):188-97. Available from: http://dx.doi.org/10.1016/j.indcrop.2012.04.031
  22. 22. Deng J, Zhu X, Chen P, He B, Tang SW, Zhao W, et al. Mechanism of lignocellulose modification and enzyme disadsorption for complete biomass saccharification to maximize bioethanol yield in rapeseed stalks. Sustainable Energy and Fuels. 2020;4(2):607-618
  23. 23. Asada C, Nakamura Y, Kobayashi F. Chemical characteristics and ethanol fermentation of the cellulose component in autohydrolyzed Bagasse. Biotechnol. Biopro. Eng. 2005;10(4):346-352
  24. 24. Ando S, Arai I, Kiyoto K, Hanai S. Identification of aromatic monomers in steam-exploded poplar and their influences on ethanol fermentation by Saccharomyces cerevisiae. Journal of Fermentation Technology. 1986;64(6):567-570
  25. 25. Anukam A, Mohammadi A, Naqvi M, Granström K. A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency. Processes. 2019;7(8):504
  26. 26. Kotsyurbenko OR, Chin KJ, Glagolev M v., Stubner S, Simankova M v., Nozhevnikova AN, et al. Acetoclastic and hydrogenotrophic methane production and methanogenic populations in an acidic West-Siberian peat bog. Environmental Microbiology. 2004;6(11):1159-1173
  27. 27. Take H, Andou Y, Nakamura Y, Kobayashi F, Kurimoto Y, Kuwahara M. Production of methane gas from Japanese cedar chips pretreated by various delignification methods. Biochemical Engineering Journal. 2006;28(1):30-35
  28. 28. Kobayashi F, Take H, Asada C, Nakamura Y. Methane production from steam-exploded bamboo. Journal of Bioscience and Bioengineering. 2004;97(6):426-428
  29. 29. Mulat DG, Huerta SG, Kalyani D, Horn SJ. Enhancing methane production from lignocellulosic biomass by combined steam-explosion pretreatment and bioaugmentation with cellulolytic bacterium Caldicellulosiruptor bescii. Biotechnology for Biofuels. 2018;11(1):1-15. Available from: https://doi.org/10.1186/s13068-018-1025-z
  30. 30. Sholahuddin, Nakamura Y, Asada C. Effect of Activated Cow Dung as Inoculum on Methane Production of Steam-Exploded Rice Husks. Waste and Biomass Valorization. 2021; Available from: https://doi.org/10.1007/s12649-021-01365-6
  31. 31. Lizasoain J, Rincón M, Theuretzbacher F, Enguídanos R, Nielsen PJ, Potthast A, et al. Biogas production from reed biomass: Effect of pretreatment using different steam explosion conditions. Biomass and Bioenergy. 2016;95:84-91
  32. 32. Dererie DY, Trobro S, Momeni MH, Hansson H, Blomqvist J, Passoth V, et al. Improved bio-energy yields via sequential ethanol fermentation and biogas digestion of steam exploded oat straw. Bioresource Technology. 2011;102(6):4449-4455. Available from: http://dx.doi.org/10.1016/j.biortech.2010.12.096
  33. 33. Yue ZB, Liu RH, Yu HQ , Cheng HZ, Yu B, Harada H, et al. Enhanced anaerobic ruminai degradation of bulrush through steam explosion pretreatment. Industrial and Engineering Chemistry Research. 2008;47(16):5899-5905
  34. 34. Fuchs G, Boll M, Heider J. Microbial degradation of aromatic compounds- From one strategy to four. Nature Reviews Microbiology. 2011;9(11):803-816. Available from: http://dx.doi.org/10.1038/nrmicro2652
  35. 35. Yan L, Yue Z, Yu H. Microscale Analysis of in Vitro Anaerobic Degradation of Lignocellulosic Wastes by Rumen Microorganisms Microscale Analysis of in Vitro Anaerobic Degradation of Lignocellulosic Wastes by Rumen Microorganisms. 2015;42:276-281
  36. 36. Ko JJ, Shimizu Y, Ikeda K, Kim SK, Park CH, Matsui S. Biodegradation of high molecular weight lignin under sulfate reducing conditions: Lignin degradability and degradation by-products. Bioresource Technology. 2009;100(4):1622-1627. Available from: http://dx.doi.org/10.1016/j.biortech.2008.09.029
  37. 37. Chen F, Dixon RA. Lignin modification improves fermentable sugar yields for biofuel production. Nature Biotechnology. 2007;25(7):759-761
  38. 38. Vivekanand V, Olsen EF, Eijsink VGH, Horn SJ. Effect of different steam explosion conditions on methane potential and enzymatic saccharification of birch. Bioresource Technology. 2013;127:343-349. Available from: http://dx.doi.org/10.1016/j.biortech.2012.09.118
  39. 39. Healy JB, Young LY. Anaerobic biodegradation of eleven aromatic compounds to methane. Applied and Environmental Microbiology. 1979;38(1):84-89
  40. 40. Barakat A, Monlau F, Steyer JP, Carrere H. Effect of lignin-derived and furan compounds found in lignocellulosic hydrolysates on biomethane production. Bioresource Technology. 2012;104:90-99. Available from: http://dx.doi.org/10.1016/j.biortech.2011.10.060
  41. 41. Fernández-Bolaños J, Felizón B, Heredia A, Rodríguez R, Guillén R, Jiménez A. Steam-explosion of olive stones: Hemicellulose solubilization and enhancement of enzymatic hydrolysis of cellulose. Bioresource Technology. 2001;79(1):53-61
  42. 42. Dai NH, Huynh KTT, Nguyen TAD, Do VVT, van Tran M. Hydrothermal and Steam Explosion Pretreatment of Bambusa stenostachya Bamboo. Waste and Biomass Valorization. 2020;(0123456789). Available from: https://doi.org/10.1007/s12649-020-01299-5
  43. 43. Sasaki C, Okumura R, Asakawa A, Asada C, Nakamura Y. Effects of washing with water on enzymatic saccharification and d-lactic acid production from steam-exploded sugarcane bagasse. Journal of Material Cycles and Waste Management. 2012;14(3):234-240
  44. 44. Marcos M, García-Cubero MT, González-Benito G, Coca M, Bolado S, Lucas S. Optimization of the enzymatic hydrolysis conditions of steam-exploded wheat straw for maximum glucose and xylose recovery. Journal of Chemical Technology and Biotechnology. 2013;88(2):237-246
  45. 45. Liu ZH, Chen HZ. Simultaneous saccharification and co-fermentation for improving the xylose utilization of steam exploded corn stover at high solid loading. Bioresource Technology. 2016;201:15-26. Available from: http://dx.doi.org/10.1016/j.biortech.2015.11.023
  46. 46. Wang W, Ling H, Zhao H. Steam explosion pretreatment of corn straw on xylose recovery and xylitol production using hydrolysate without detoxification. Process Biochemistry. 2015;50(10):1623-1628. Available from: http://dx.doi.org/10.1016/j.procbio.2015.06.001
  47. 47. Nogi M, Yano H. Transparent nanocomposites based on cellulose produced by bacteria offer potential innovation in the electronics device industry. Advanced Materials. 2008;20(10):1849-1852
  48. 48. Fukuzumi H, Saito T, Iwata T, Kumamoto Y, Isogai A. Transparent and high gas barrier films of cellulose nanofibers prepared by TEMPO-mediated oxidation. Biomacromolecules. 2009;10(1):162-165
  49. 49. Xue Y, Mou Z, Xiao H. Nanocellulose as a sustainable biomass material: Structure, properties, present status and future prospects in biomedical applications. Nanoscale. 2017;9(39):14758-14781
  50. 50. Abdul Khalil HPS, Adnan AS, Yahya EB, Olaiya NG, Safrida S, Hossain MS, et al. A review on plant cellulose nanofibre-based aerogels for biomedical applications. Polymers. 2020;12(8)
  51. 51. Amalraj A, Gopi S, Thomas S, Haponiuk JT. Cellulose Nanomaterials in Biomedical, Food, and Nutraceutical Applications: A Review. Macromolecular Symposia. 2018;380(1):1-9
  52. 52. Iwamoto S, Abe K, Yano H. The effect of hemicelluloses on wood pulp nanofibrillation and nanofiber network characteristics. Biomacromolecules. 2008;9(3):1022-1026
  53. 53. Mazzuckelli LF, Methner MM, Eileen Birch M, Evans DE, Ku BK, Crouch K, et al. Identification and characterization of potential sources of worker exposure to carbon nanofibers during polymer composite laboratory operations. Journal of Occupational and Environmental Hygiene. 2007;4(12):D125–D130
  54. 54. Saragih SW, Wirjosentono B, Eddiyanto, Meliana Y. Influence of crosslinking agent on the morphology, chemical, crystallinity and thermal properties of cellulose nanofiber using steam explosion. Case Studies in Thermal Engineering. 2020;22:100740. Available from: https://doi.org/10.1016/j.csite.2020.100740
  55. 55. Suzuki A, Sasaki C, Asada C, Nakamura Y. Production of cellulose nanofibers from Aspen and Bode chopsticks using a high temperature and high pressure steam treatment combined with milling. Carbohydrate Polymers. 2018;194(December 2017):303-10. Available from: https://doi.org/10.1016/j.carbpol.2018.04.047
  56. 56. Dahlem MA, Borsoi C, Hansen B, Catto AL. Evaluation of different methods for extraction of nanocellulose from yerba mate residues. Carbohydrate Polymers. 2019;218:78-86. Available from: https://doi.org/10.1016/j.carbpol.2019.04.064
  57. 57. Hongrattanavichit I, Aht-Ong D. Nanofibrillation and characterization of sugarcane bagasse agro-waste using water-based steam explosion and high-pressure homogenization. Journal of Cleaner Production. 2020;277:123471. Available from: https://doi.org/10.1016/j.jclepro.2020.123471
  58. 58. Liu Q , Lu Y, Aguedo M, Jacquet N, Ouyang C, He W, et al. Isolation of High-Purity Cellulose Nanofibers from Wheat Straw through the Combined Environmentally Friendly Methods of Steam Explosion, Microwave-Assisted Hydrolysis, and Microfluidization. ACS Sustainable Chemistry and Engineering. 2017;5(7):6183-6191
  59. 59. Yang W, Cheng T, Feng Y, Qu J, He H, Yu X. Isolating cellulose nanofibers from steam-explosion pretreated corncobs using mild mechanochemical treatments. BioResources. 2017;12(4):9183-9197
  60. 60. Cherian BM, Leão AL, de Souza SF, Thomas S, Pothan LA, Kottaisamy M. Isolation of nanocellulose from pineapple leaf fibres by steam explosion. Carbohydrate Polymers. 2010;81(3):720-725
  61. 61. Anuradha Rani, Sheetal Monga, Monica Bansal AS. vm. Polymer Composites. 2016;00:000-000:Thermoplastic starch (TPS)/cellulose nanofiber (CN
  62. 62. Yang W, Feng Y, He H, Yang Z. Environmentally-friendly extraction of cellulose nanofibers from steam-explosion pretreated sugar beet pulp. Materials. 2018;11(7)
  63. 63. Deepa B, Abraham E, Cherian BM, Bismarck A, Blaker JJ, Pothan LA, et al. Structure, morphology and thermal characteristics of banana nano fibers obtained by steam explosion. Bioresource Technology. 2011;102(2):1988-1997. Available from: http://dx.doi.org/10.1016/j.biortech.2010.09.030
  64. 64. Saragih SW, Wirjosentono B, Eddyanto, Meliana Y. Thermal and Morphological Properties of Cellulose Nanofiber from Pseudo-Stem Fiber of Abaca (Musa Textilis). Macromolecular Symposia. 2020;391(1):1-5
  65. 65. Supian MAF, Amin KNM, Jamari SS, Mohamad S. Production of cellulose nanofiber (CNF) from empty fruit bunch (EFB) via mechanical method. Journal of Environmental Chemical Engineering. 2020;8(1):103024. Available from: https://doi.org/10.1016/j.jece.2019.103024
  66. 66. Kaushik A, Singh M, Verma G. Green nanocomposites based on thermoplastic starch and steam exploded cellulose nanofibrils from wheat straw. Carbohydrate Polymers. 2010;82(2):337-345. Available from: http://dx.doi.org/10.1016/j.carbpol.2010.04.063
  67. 67. Feng YH, Cheng TY, Yang WG, Ma PT, He HZ, Yin XC, et al. Characteristics and environmentally friendly extraction of cellulose nanofibrils from sugarcane bagasse. Industrial Crops and Products. 2018;111(March 2017):285-91. Available from: http://dx.doi.org/10.1016/j.indcrop.2017.10.041
  68. 68. Wang Z, Qiao X, Sun K. Rice straw cellulose nanofibrils reinforced poly(vinyl alcohol) composite films. Carbohydrate Polymers. 2018;197(June):442-450
  69. 69. Suzuki A, Sasaki C, Asada C, Nakamura Y. Characterization of cellulose nanofiber from steam-exploded Japanese cedar. BioResources. 2017;12(4):7628-7641
  70. 70. Asada C, Seno M, Nakamura Y. Preparation of Biopolymer Composite Using Cedar-Derived Cellulose Nanofibers. Waste and Biomass Valorization. 2021; Available from: https://doi.org/10.1007/s12649-021-01436-8
  71. 71. Asada C, Sasaki Y, Nakamura Y. Production of Eco-refinery Pulp from Moso Bamboo Using Steam Treatment Followed by Milling Treatment. Waste and Biomass Valorization. 2020;11(11):6139-6146. Available from: https://doi.org/10.1007/s12649-019-00847-y
  72. 72. Xiao K, Deng J, Zeng L, Guo T, Gong Y, Yang B, et al. Enhancement of municipal sludge dewaterability by electrochemical pretreatment. Journal of Environmental Sciences (China). 2019;75:98-104. Available from: https://doi.org/10.1016/j.jes.2018.03.007
  73. 73. Kaushik A, Singh M. Isolation and characterization of cellulose nanofibrils from wheat straw using steam explosion coupled with high shear homogenization. Carbohydrate Research. 2011;346(1):76-85. Available from: http://dx.doi.org/10.1016/j.carres.2010.10.020
  74. 74. Panyasiri P, Yingkamhaeng N, Lam NT, Sukyai P. Extraction of cellulose nanofibrils from amylase-treated cassava bagasse using high-pressure homogenization. Cellulose. 2018;25(3):1757-1768. Available from: https://doi.org/10.1007/s10570-018-1686-6
  75. 75. Kumari P, Pathak G, Gupta R, Sharma D, Meena A. Cellulose nanofibers from lignocellulosic biomass of lemongrass using enzymatic hydrolysis: characterization and cytotoxicity assessment. DARU, Journal of Pharmaceutical Sciences. 2019;27(2):683-693
  76. 76. Gea S, Siregar AH, Zaidar E, Harahap M, Indrawan DP, Perangin-Angin YA. Isolation and characterisation of cellulose nanofibre and lignin from oil palm empty fruit bunches. Materials. 2020;13(10)
  77. 77. Shahi N, Min B, Sapkota B, Rangari VK. Eco-friendly cellulose nanofiber extraction from sugarcane bagasse and film fabrication. Sustainability (Switzerland). 2020;12(15):1-15
  78. 78. Asada C, Sholahuddin, Nakamura Y. Lignin as a Coating and Curing Agent on Biodegradable Epoxy Resins. In: Reactive and Functional Polymers Volume One. Springer International Publishing; 2020. p. 195-206
  79. 79. Ferdosian F, Yuan Z, Anderson M, Xu CC. Chemically modified lignin through epoxidation and its thermal properties. J-for. 2012;2(4):11-15
  80. 80. Ferdosian F, Yuan Z, Anderson M, Xu C (Charles). Synthesis and characterization of hydrolysis lignin-based epoxy resins. Industrial Crops and Products. 2016;91:295-301. Available from: http://dx.doi.org/10.1016/j.indcrop.2016.07.020
  81. 81. Chikako Asada KH& YN. Utilization of Steam-Treated and Milling-Treated Lignin from Moso Bamboo as Curing Agent of Epoxy Resin. Waste and Biomass Valorization. 2021
  82. 82. Sasaki C, Wanaka M, Takagi H, Tamura S, Asada C, Nakamura Y. Evaluation of epoxy resins synthesized from steam-exploded bamboo lignin. Industrial Crops and Products. 2013;43(1):757-761. Available from: http://dx.doi.org/10.1016/j.indcrop.2012.08.018
  83. 83. Basnet S, Otsuka M, Sasaki C, Asada C, Nakamura Y. Functionalization of the active ingredients of Japanese green tea (Camellia sinensis) for the synthesis of bio-based epoxy resin. Industrial Crops and Products. 2015;73:63-72. Available from: http://dx.doi.org/10.1016/j.indcrop.2015.03.091
  84. 84. Nakamura Y, Sawada T, Kuno K, Nakamoto Y. Resinification by woody lignin and its characteristics on safety and biodegradation. Journal of Chemical Engineering of Japan. 2001;34(10):1309-1312
  85. 85. Fache M, Auvergne R, Boutevin B, Caillol S. New vanillin-derived diepoxy monomers for the synthesis of biobased thermosets. European Polymer Journal. 2015;67:527-538. Available from: http://dx.doi.org/10.1016/j.eurpolymj.2014.10.011
  86. 86. Wang S, Ma S, Xu C, Liu Y, Dai J, Wang Z, et al. Vanillin-Derived High-Performance Flame Retardant Epoxy Resins: Facile Synthesis and Properties. Macromolecules. 2017;50(5):1892-1901
  87. 87. Cho JK, Lee JS, Jeong J, Kim B, Kim B, Kim S, et al. Synthesis of carbohydrate biomass-based furanic compounds bearing epoxide end group(s) and evaluation of their feasibility as adhesives. Journal of Adhesion Science and Technology. 2013;27(18-19):2127-2138
  88. 88. Hu F, la Scala JJ, Sadler JM, Palmese GR. Synthesis and characterization of thermosetting furan-based epoxy systems. Macromolecules. 2014;47(10):3332-3342
  89. 89. Hu F, Yadav SK, la Scala JJ, Sadler JM, Palmese GR. Preparation and Characterization of Fully Furan-Based Renewable Thermosetting Epoxy-Amine Systems. Macromolecular Chemistry and Physics. 2015;216(13):1441-1446
  90. 90. Deng J, Liu X, Li C, Jiang Y, Zhu J. Synthesis and properties of a bio-based epoxy resin from 2,5-furandicarboxylic acid (FDCA). RSC Advances. 2015;5(21):15930-15939. Available from: http://dx.doi.org/10.1039/C5RA00242G
  91. 91. Nouailhas, H.; Aouf, C.; Le Guerneve, C.; Caillol, S.; Boutevin, B.; Fulcrand H. Synthesis and Properties of Biobased Epoxy Resins. Part 1. Glycidylation of Flavonoids by Epichlorohydrin. J Polym Sci Part A Polym Chem. 2011;49:2261-2270
  92. 92. Benyahya S, Aouf C, Caillol S, Boutevin B, Pascault JP, Fulcrand H. Functionalized green tea tannins as phenolic prepolymers for bio-based epoxy resins. Industrial Crops and Products. 2014;53:296-307. Available from: http://dx.doi.org/10.1016/j.indcrop.2013.12.045
  93. 93. Aouf C, Lecomte J, Villeneuve P, Dubreucq E, Fulcrand H. Chemo-enzymatic functionalization of gallic and vanillic acids: Synthesis of bio-based epoxy resins prepolymers. Green Chemistry. 2012;14(8):2328-2336
  94. 94. Cao L, Liu X, Na H, Wu Y, Zheng W, Zhu J. How a bio-based epoxy monomer enhanced the properties of diglycidyl ether of bisphenol A (DGEBA)/graphene composites. Journal of Materials Chemistry A. 2013;1(16):5081-5088
  95. 95. Mitsuhiro Shibata KN. Preparation and Properties of Biocomposites Composed of Bio-Based Epoxy Resin, Tannic Acid, and Microfibrillated Cellulose. Journal of Polymer Science: Part B: Polymer Physics. 2010;48:425-433
  96. 96. Antonella Tarzia, Jeanette Montanaro, Michele Casiello, Cosimo Annese, Angelo Nacci AM. Synthesis, Curing, and Properties of an Epoxy Resin Derived from Gallic Acid. BioResources. 2018;13(1):632-645
  97. 97. Unnikrishnan KP, Thachil ET. Synthesis and characterization of cardanol-based epoxy systems. Designed Monomers and Polymers. 2008;11(6):593-607
  98. 98. Atta AM, Al-Hodan HA, Hameed RSA, Ezzat AO. Preparation of green cardanol-based epoxy and hardener as primer coatings for petroleum and gas steel in marine environment. Progress in Organic Coatings. 2017;111(June):283-293. Available from: http://dx.doi.org/10.1016/j.porgcoat.2017.06.002
  99. 99. Maffezzoli A, Calò E, Zurlo S, Mele G, Tarzia A, Stifani C. Cardanol based matrix biocomposites reinforced with natural fibres. Composites Science and Technology. 2004;64(6):839-845
  100. 100. Ren YL and S. Adhesives. In: Building Decorative Materials. 2011. p. 325-341
  101. 101. Wahyudiono, Sasaki M, Goto M. Recovery of phenolic compounds through the decomposition of lignin in near and supercritical water. Chemical Engineering and Processing: Process Intensification. 2008;47(9-10):1609-1619
  102. 102. Cheng L, Ye XP, He R, Liu S. Investigation of rapid conversion of switchgrass in subcritical water. Fuel Processing Technology. 2009;90(2):301-311. Available from: http://dx.doi.org/10.1016/j.fuproc.2008.09.009
  103. 103. Wahyudiono, Sasaki M, Goto M. Conversion of biomass model compound under hydrothermal conditions using batch reactor. Fuel. 2009;88(9):1656-1664. Available from: http://dx.doi.org/10.1016/j.fuel.2009.02.028
  104. 104. Kurosumi A, Sasaki C, Kumada K, Kobayashi F, Mtui G, Nakamura Y. Novel extraction method of antioxidant compounds from Sasa palmata (Bean) Nakai using steam explosion. Process Biochemistry. 2007;42(10):1449-1453
  105. 105. Noda Y, Asada C, Sasaki C, Hashimoto S, Nakamura Y. Extraction method for increasing antioxidant activity of raw garlic using steam explosion. Biochemical Engineering Journal. 2013;73:1-4. Available from: http://dx.doi.org/10.1016/j.bej.2013.01.013
  106. 106. Asada C, Suzuki A, Nakamura Y. Antioxidant activity of water extract from bamboo by high-temperature and high-pressure steam treatment. Biomass Conversion and Biorefinery. 2021; Available from: https://doi.org/10.1007/s13399-021-01413-0
  107. 107. Noda Y, Asada C, Sasaki C, Nakamura Y. Effects of Hydrothermal Methods such as Steam Explosion and Microwave Irradiation on Extraction of Water Soluble Antioxidant Materials from Garlic Husk. Waste and Biomass Valorization. 2019;10(11):3397-3402. Available from: http://dx.doi.org/10.1007/s12649-018-0353-3
  108. 108. Bortolomeazzi R, Sebastianutto N, Toniolo R, Pizzariello A. Comparative evaluation of the antioxidant capacity of smoke flavouring phenols by crocin bleaching inhibition, DPPH radical scavenging and oxidation potential. Food Chemistry. 2007;100(4):1481-1489
  109. 109. Liu L, Zhao M, Liu X, Zhong K, Tong L, Zhou X, et al. Effect of steam explosion-assisted extraction on phenolic acid profiles and antioxidant properties of wheat bran. Journal of the science of food and agriculture. 2016;96(10):3484-3491
  110. 110. Li W, Zhang X, He X, Li F, Zhao J, Yin R, et al. Effects of steam explosion pretreatment on the composition and biological activities of tartary buckwheat bran phenolics. Food and Function. 2020;11(5):4648-4658
  111. 111. Kensingtort JKH, S N, Prague KM, Orinda LRS, Volumes S, Orinda EH. Analysis of phenols from lignin depolymerization by capillary gas chromatography. 1989;467(2)
  112. 112. Kurosumi A, Kobayashi F, Nakamura Y. Development of New Extraction Method of Natural Antioxidants from Bamboo Grass. Transactions of the Materials Research Society of Japan. 2007;32(4):1139-1142
  113. 113. Noda Y, Asada C, Sasaki C, Hashimoto S, Nakamura Y. Extraction method for increasing antioxidant activity of raw garlic using steam explosion. Biochemical Engineering Journal. 2013;73:1-4. Available from: http://dx.doi.org/10.1016/j.bej.2013.01.013
  114. 114. Sui W, Xiao Y, Liu R, Wu T, Zhang M. Steam explosion modification on tea waste to enhance bioactive compounds’ extractability and antioxidant capacity of extracts. Journal of Food Engineering. 2019;261:51-9. Available from: https://doi.org/10.1016/j.jfoodeng.2019.03.015
  115. 115. Romero-García JM, Lama-Muñoz A, Rodríguez-Gutiérrez G, Moya M, Ruiz E, Fernández-Bolaños J, et al. Obtaining sugars and natural antioxidants from olive leaves by steam-explosion. Food Chemistry. 2016;210:457-465
  116. 116. Gong L, Huang L, Zhang Y. Effect of steam explosion treatment on barley bran phenolic compounds and antioxidant capacity. Journal of Agricultural and Food Chemistry. 2012;60(29):7177-7184
  117. 117. Chen Y, Zhang R, Liu C, Zheng X, Liu B. Enhancing antioxidant activity and antiproliferation of wheat bran through steam flash explosion. Journal of Food Science and Technology. 2016;53(7):3028-3034
  118. 118. Cruz JM, Domínguez JM, Domínguez H, Parajó JC. Antioxidant and antimicrobial effects of extracts from hydrolysates of lignocellulosic materials. Journal of Agricultural and Food Chemistry. 2001;49(5):2459-2464
  119. 119. Li J, Wu K, Xiao W, Zhang J, Lin J, Gong Y, et al. Effect of antioxidant extraction on the enzymatic hydrolysis and bioethanol production of the extracted steam-exploded sugarcane bagasse. Biochemical Engineering Journal. 2014;82:91-96
  120. 120. Li J, Lin J, Xiao W, Gong Y, Wang M, Zhou P, et al. Solvent extraction of antioxidants from steam exploded sugarcane bagasse and enzymatic convertibility of the solid fraction. Bioresource Technology. 2013;130:8-15

Written By

Chikako Asada, Sholahuddin and Yoshitoshi Nakamura

Submitted: 21 May 2021 Reviewed: 24 May 2021 Published: 14 June 2021