Alginate Extraction from Natural Resources Based on Legal Requirements: An Incentive for Sustainable Development

Abstract

Biodiversity is the expansive range of life on the Earth and the natural patterns formed by it, shaped by natural processes and the influence of human beings. This diversity comprises a large array of plants, animals, and microorganisms. Thus, natural resources are essential to humanity’s economic and social development; moreover, there is a spreading granting that biological diversity is a global asset of high benefit to all generations. The purpose of this chapter is to compile information on the use of native species for alginate extraction, with a focus on sustainable development in order to comply with legal requirements, particularly on the Brazilian Biodiversity Law. The chapter addresses issues on sustainable strategies aimed at the traceability of species and the reduction of biopiracy caused by the inappropriate use of biodiversity. Thus encouraging sustainable development through legal and sustainable exploitation of native species. Furthermore, an overview will be presented on the use of alginate extracted from different species of algae that can be used as a value-added product in different industrial sectors. Finally, providing a global legal framework and recommendations for action on the use of genetic heritage and biodiversity conservation will be a contribution of the presented chapter.

1. Introduction

Most of the Earth’s biodiversity is present in the countries of the southern hemisphere, mainly in Africa, Asia, and South America. Brazil is considered one of the largest countries in the world in terms of land area, occupying almost half of South America. That said, it is also a country that has a sovereign biodiversity of species, which is distributed in six terrestrial biomes and three marine ecosystems. Associated with the illegal exploitation of genetic resources and the lack of benefit sharing, the loss of biodiversity is progressively increasing, especially in what is related to new patterns of consumption, urbanization, and biotechnological development. Due to the serious consequences of biodiversity loss, this theme has been growing in the international spotlight [1].

Inappropriate exploitation of biodiversity has consequences for the supply of natural resources, negatively impacting the environment. Ecosystems have a slow recovery period or may not recover at all. Since natural resources are limited, it is essential to contribute to sustainable development, which refers to a process that leads to a better condition of life, while reducing environmental impacts. The improper exploitation of natural resources leads to environmental degradation. However, for the use of natural resources to be carried out in a sustainable manner, there is a need for regulations and laws, with the purpose of stimulating society, the scientific community, and companies to adopt environmentally friendly technological development practices [2].

With the purpose of promoting technological development based on sustainable guidelines, the food, textile, cosmetics, and pharmaceutical industries spare no effort in the search for species that can be extracted from alginate. Alginate is a natural biopolymer that can be synthesized from algae species. Due to the high quantity of alginate that can be found in algae, and the gelling, viscosity, and stability characteristics, it has become an attractive product of great commercial interest, as it is a natural and innovative option with the possibility of application in various industrial sectors [3].

Thus, in order to ensure sustainable development, conserve the country’s genetic heritage, enable the traceability of species, combat biopiracy, as well as ensure the fair and equitable sharing of benefits, Law No. 13,123/2015, which came into force on 17 November 2015, establishes rules for the access to genetic heritage and/or associated traditional knowledge, the remittance and sending of samples abroad, as well as the economic exploitation of finished products or reproductive material and the respective sharing of benefits arising from the access [4]. Actions aimed at minimizing human threats to biodiversity are of the utmost urgency. In response to the environmental crisis, most countries sign international agreements and treaties, pass laws, and commit to measures aimed at protecting biodiversity [5].

In this context, environmental laws assume a pivotal role in advancing sustainable development by ensuring the protection and conservation of the environment, effectively harmonizing economic growth with the preservation of natural resources. These laws are indispensable for cultivating a salubrious environment for current and future generations, guiding both corporate and individual practices toward heightened sustainability standards within the framework of sustainable development. Intrinsically connected to biodiversity conservation and the promotion of sustainability, well-crafted environmental legislation fosters practices that mitigate adverse impacts on ecosystems, guaranteeing the preservation of species and habitats. Concurrently, conservation endeavors contribute to the resilience of ecosystems in the face of challenges such as climate change and environmental degradation. The continual refinement of environmental laws is paramount, particularly given the evolution of industrial and technological practices. Confronting new environmental threats necessitates periodic updates and revisions to ensure the ongoing effectiveness and comprehensiveness of these laws. Moreover, it is imperative to contemplate innovative approaches and incentives to nurture sustainable practices, facilitating a seamless transition toward a more environmentally conscious economy. In summary, environmental laws serve as indispensable pillars for sustainable development, supplying a legal framework for environmental conservation and sustainability. Their ongoing enhancement is imperative for addressing emerging challenges and maintaining a wholesome equilibrium between human activities and the preservation of the planet.

2. Seaweeds and Brazilian biodiversity

The relationship between biodiversity and marine algae is inherently complex and crucial for the sustainability of marine ecosystems. Marine algae play multifaceted roles that contribute significantly to coastal biodiversity and the balance of marine ecosystems. In this context, Brazil stands out not only for its rich terrestrial biodiversity but also for marine diversity, particularly in tidal zones where algae play a fundamental role. The country hosts a remarkable variety of marine algae, with recent data indicating the presence of 539 species of macroalgae. This diversity includes 116 species of green algae (Chlorophyta), 359 of red algae (Rhodophyta), and 64 of brown algae (Phaeophyceae), along with an abundance of microscopic algae, primarily diatoms [6].

The coastal waters of Brazil serve as a habitat for endemic species such as Laminaria brasiliensis (Phaeophyceae) and Dictyurus occidentalis (Rhodophyta), whose preservation is fundamental for maintaining marine biodiversity. However, the analysis of collections over time reveals significant challenges, especially in urban areas like Santos, São Paulo, where increasing pollution levels have contributed to the decline of crucial groups such as Chlorophyta, Rhodophyta, and Phaeophyceae [6].

Understanding and conserving this rich algae biodiversity in Brazil is essential not only for the health of marine and terrestrial ecosystems but also for maintaining environmental balance in the face of contemporary challenges such as pollution, climate change, and species traceability [6].

Definitely in art. 2 of the Convention on Biological Diversity (CBD), as “the variability of living organisms from all sources, including transitional waters, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part.” biodiversity is considered an important natural resource, both for its environmental importance and for its medical results. However, there are benefits that result from the use of this resource, and its conservation is directly linked to the policy that the country has adopted in relation to its heritage, that is, its biodiversity (CBD) [7].

Being a fertile field for obtaining raw materials for use in various fields [8], the lack of regulation for access to biodiversity intensifies disputes between countries that accessed this wealth indistinctly without any kind of care [9] related to the preservation of species and the integrity of heritage of the country, not ensuring present and future population the right to a balanced environment [10].

Brazil, having the greatest biodiversity, is one of the countries with the greatest perspectives for the economic exploitation of its native species due to the expressive number of species, the excellent climatic and edaphic conditions, and the great water potential [11]. This great genetic variety has a high strategic and economic value in areas of development such as pharmaceuticals and medicine [12, 13] due to a great variety of metabolites and substances that present biological and pharmacological activities with therapeutic potential [14].

The Brazilian coastline has a great biodiversity of marine macroalgae species, which have been investigated in detail under the chemical aspect of their compounds. The interest in studying different algal polysaccharides is centered on two main aspects: the search for phycocolloids of national origin with gelling or viscous properties, comparable to those of imported polymers, and the search for new bio-actives aimed at treating diseases considered to be major health problems [15].

Marine macroalgae have been used in oriental food for many years. Still restricted, a change of scenery is taking place, and these species are also being incorporated into Western food, due to the benefits arising from the consumption. In Brazil, research related to macroalgae has gained importance for bringing results that demonstrate high nutritional levels and antioxidant and antimicrobial activity [16, 17].

3. Plant polysaccharides

Algae are found worldwide and the base of the food chain, serving as a source of nutrients for a variety of aquatic organisms. They are considered important photosynthetic organisms and represent an important source of biological compounds commonly used in industry. They can be classified into two large groups: macroalgae, which can be seen with the naked eye, and microalgae, which need a microscope to be observed [18].

The most abundant groups of macroalgae belong to green algae (Chlorophyta), which produce chlorophyll a and b as pigment; red algae (Rhodophyta), with phycoerythrin, and brown algae (Phaeophyceae), those that produce a xanthophyll pigment called fucoxanthin [19, 20].

Agarans and carrageenans are obtained from red algae, which is composed of a linear chain formed by β-D-galactose units linked 1 → 3 (A unit) to α-D/L-galactose linked in the positions 1 → 4 (unit B) arranged in the form of a repeating unit (AB). The α-D-galactose units in the disaccharide can be biologically converted into the anhydrous 3,6 derivatives by the elimination of sulfate groups at position 6. Carrageenans differ from agarans in that they have the B unit in the form of α-D-galactose and are found in Chondrus, Gigartina, Kappaphycus, Eucheuma, Meristotheca and Solieria species (Rhodophyta). While the agarans, in the species Gracilaria, Gelidium, and Pterocladiella (Rhodophyta) [21].

Extracted from brown algae species (Phaeophyceae), the alginates are such as Macrocystis, Ascophyllum, Laminaria, Ecklonia, and Sargassum. This polysaccharide has a linear structure of mannuronic (M) and guluronic (G) acids, and the distribution of M and G blocks in the structure as well as the M/G ratio strongly influence its properties in solution [21].

3.1 Alginic acid

This acidic polysaccharide is a polyuronide consisting of β-D-mannuronic and α-L-guluronic acid units linked through (1 → 4) bonds. The proportion and distribution along the chain of the polymer varies according to the species [22].

The characterization, through chemical methods, such as partial acid hydrolysis, purification of the blocks and methylation of the carboxy-reduced polymer, as well as spectroscopic techniques, allowed us to determine that alginate from Sargassum stenophyllum, which has 21% yield, has a molar ratio between mannuronic (M) and guluronic (G) acid units of 1:1. These units are distributed throughout the polymer in the form of M blocks (5%) and G blocks (25%) with degrees of polymerization of 20 and 64, respectively, in addition to a high percentage of hybrid blocks (MG, 70%). The determination of the chemical structure of alginates is of fundamental importance for its proper application in different sectors of industry since alginates rich in mannuronic acid have viscous properties and those rich in guluronic acid are more gelling [23].

Alginates with different molecular weights, viscosity and ratios of M and G units were obtained from Sargassum vulgare, which inhibited tumor cell growth in vivo [24, 25]. Alginate from the brown seaweed Laminaria brasiliensis was characterized structurally [26]. Although the M/G molar ratio is similar to that of Sargassum stenophyllum, the polymerization of the G blocks is lower (=20). The physicochemical properties presented by alginates depend both on the M/G ratio and on the percentage and size of the constituent blocks, which justifies a detailed study of the chain structure of alginates isolated from different species of brown algae for commercial use [24, 25].

4. Alginate sources

Some compounds with therapeutic properties, produced by algae, are soluble polysaccharides, such as alginates and carrageenans, and sulfate polysaccharides, such as fucoidan, carotenoids, polyunsaturated fatty acids, vitamins, tocopherols and phycocyanin’s [27, 28, 29], differing, between groups, in according to their physiology and photosynthetic pigments they produce [30]. Each group also has a different mineral content from the others, as well as protein and fiber content [31, 32].

Marine macroalgae, whose body is represented by a thallus, are aquatic plants without vascularization; most are benthic, that is, they live adhered to a substrate and are autotrophic [33, 34]. Brown algae, from Phaeophyceae, make up the most studied group and are commonly used in human food [35]. They can also be used as a complement to feed, in the cosmetic area, as sources of chemical products such as alginates [31, 32].

Because they are organisms exposed to environmental conditions of high luminosity and considerable concentrations of oxygen and carbon dioxide, algae have defense mechanisms against free radicals, thus forming an important source of natural antioxidants [36, 37]. Antioxidants are compounds that prevent the formation of reactive oxygen species that are accumulating between cells and causing oxidative stress. This, in turn, causes deregulation in cellular metabolism, reflecting at molecular, protein, and DNA levels [38].

Extracted both from species of brown algae, where it makes up the structure of the cell wall and intracellular spaces, promoting rigidity and, at the same time, flexibility, and extracellularly covering some bacterial species [39], due to its unique properties in the food, cosmetic, pharmaceutical, textile and of paper, alginate has become a product of commercial importance [40], as mentioned in Table 1. Among its pharmacological potential, the antioxidant characteristic of alginate has been relevant, due to its mechanisms and properties in helping serious illnesses [42], also conferring properties of texture to food, such as thickening, adhesion, emulsification, gelling or bulking [40].

	Industry type	Applications/function
	Food	Ice cream production: prevent crystallization and shrinkage, resulting in a homogeneous product; Salad dressings: stabilizers to prevent phase separation; Mayonnaise: stabilizers to avoid phase separation; Fruit analog: artificial cherries using a colored and flavored solution of alginate in sugar.
	Drinks	Beers and juices: stabilizes the foam and keeps the constituents of the mixture in suspension.
Alginate	Textile	Improves the performance of inks used in printing processes, favoring the adherence and deposition of these materials on fabrics.
	Paper	Improved printing.
	Bioactive films	Food cover.
	Medical	Drug release excipients, smart dressings, gastric reflux prevention formulations, and dental impression materials.

Table 1.

Main applications of alginate.

Source: Adapted from Puscaselu et al. [41].

Despite being applied in a wide range of areas, Brazil imports all of its demand for alginate [43]. In 2017, the country imported around US$10.8 million worth of alginic acid from Chile, China, Norway, and Italy [44]. This dependence can be reduced through the national production of alginate from Sargassum spp., illustrated in Figure 1, which is abundant on the Brazilian coast, respecting the laws and regulations [45].

Figure 1.

Sargassum sp. (image from personal archive).

Regarding algae of the Phaeophyceae class, according to the Reflora Virtual Herbarium—Plants of Brazil system, there are 49 genera cataloged as native to Brazil; among these, 102 species and 16 varieties [46]. The main species that produce alginate of industrial interest are part of the genera Laminaria and Sargassum, as listed in Table 2, with their species and geographic distribution, among other aspects.

Species	Synonym	Subspecies/variety/form	Life form	Geographic distribution
Laminaria abyssalis A. B. Joly & E. C. Oliveira	No synonyms are currently included in AlgaeBase	—	Aquatic-Benthos	Espírito Santo and Rio de Janeiro
Sargassum acinarium (Linnaeus) Setchell	Fucus acinarius Linnaeus	—	Aquatic-Benthos	Bahia
Sargassum cymosum C. Agardh	No synonyms are currently included in AlgaeBase	Sargassum cymosum var. esperi Grunow, Sargassum cymosum var. nanum E. de Paula & E.C. Oliveira	Aquatic-Benthos	Alagoas, Bahia, Ceará, Paraíba, Pernambuco, Rio Grande do Norte, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Rio Grande do Sul e Santa Catarina
Sargassum filipendula C. Agardh	Sargassum affine J. Agardh	Sargassum filipendula f. subcirerea Grunow	Aquatic-Benthos	Bahia, Ceará, Paraíba, Pernambuco, Piauí, Rio Grande do Norte, Sergipe, Espírito Santo, Rio de Janeiro, São Paulo e Santa Catarina
Sargassum furcatum Kützing	Sargassum vulgare f. furcatum (Kützing) J. Agardh	—	Aquatic-Benthos	Bahia, Espírito Santo, Rio de Janeiro, São Paulo e Santa Catarina
Sargassum hystrix J. Agardh	Carpacanthus spinulosus Kützing	Sargassum hystrix var. spinulosum (Kützing) Grunow	Aquatic-Benthos	Alagoas, Bahia, Ceará, Maranhão, Paraíba, Pernambuco, Rio Grande do Norte, Sergipe, Espírito Santo e Rio de Janeiro
Sargassum lendigerum (Linnaeus) C. Agardh	Fucus lendigerus Linnaeus, Sargassum cymosum var. lendigerum (Linnaeus) Grunow	—	Aquatic-Benthos	Pernambuco, Espírito Santo e Rio de Janeiro
Sargassum liebmannii J. Agardh	No synonyms are currently included in AlgaeBase	—	Aquatic-Benthos	Bahia e Pernambuco
Sargassum natans (Linnaeus) Gaillon	Fucus natans Linnaeus, Sargassum bacciferum (Turner) C. Agardh	—	Aquática-Plankton	Pará
Sargassum platycarpum Montagne	Carpacanthus platycarpus (Montagne) Kützing	—	Aquatic-Benthos	Bahia, Pernambuco, Rio Grande do Norte, Sergipe, Espírito Santo e Rio de Janeiro
Sargassum polyceratium Montagne	Carpacanthus polyceratius (Montagne) Kützing	—	Aquatic-Benthos	Alagoas, Bahia, Paraíba, Pernambuco, Rio Grande do Norte e Rio de Janeiro
Sargassum ramifolium Kützing	Sargassum cymosum var. ramifolia (Kützing) Grunow	—	Aquatic-Benthos	Espírito Santo, Rio de Janeiro, São Paulo e Santa Catarina
Sargassum stenophyllum C. Martius	Sargassum cymosum var. stenophyllum (C. Martius) Grunow	—	Aquatic-Benthos	Bahia, Ceará, Pernambuco, Rio Grande do Norte, Espírito Santo, Rio de Janeiro, São Paulo, Paraná e Santa Catarina
Sargassum vulgare C. Agardh		Sargassum vulgare var. laxum Mertens ex Martius, Sargassum vulgare var. tenuifolium C. Agardh, Sargassum vulgare var. foliosissimum (J.V. Lamouroux) C. Agardh, Sargassum vulgare var. nanum E.J. Paula	Aquatic-Benthos	Alagoas, Bahia, Ceará, Paraíba, Pernambuco, Piauí, Rio Grande do Norte, Sergipe, Espírito Santo, Rio de Janeiro, São Paulo, Paraná e Santa Catarina

Table 2.

Main native species of Brazil producing alginate.

Alginate was characterized at the end of the nineteenth century and is currently obtained from brown algae, according to Table 3, from coastal regions [40]. It is a molecular polysaccharide that is high weight, composed of α-L-guluronic acid (G) and β-D-mannuronic acid (M) bonds, as shown in Figure 2, which interacts with ions metals by cation exchange mechanisms [48]. It can react with divalent ions forming a gel or with polyvalent ions forming crosslinks, as shown in Figure 3. The physical properties of the molecule depend on the proportion and size of the G blocks in the alginate chain [49].

Colloid	Species
Alginate	Laminaria hyperborea
	Turbinaria conoides
	Dictyopteris delicatula
	Saccharina japonica
	Lobophora varieegata
	Himanthalia elongata
	Sargassum wightii
	Sargassum tenerrimum

Table 3.

Main species of alginate-producing brown algae, according to all the literature consulted for this work.

Figure 2.

Chemical structure of alginate. Source: Adapted from Fang et al. [47].

Figure 3.

Polymeric chain representation from the G and M blocks of the alginate structure.

Alginate is an acid that is insoluble in water at room temperature and soluble at elevated temperatures. Therefore, the sodium, calcium, and potassium salts present, being soluble in water, are commonly used in the different areas of industry. Sodium alginate is the main one used in many applications, and it becomes insoluble through the addition of divalent cations, resulting in gels or films. These are not thermo-reversible when high concentrations of calcium are used; however, when exposed to low concentrations, they can become thermo-reversible [39].

The alginate extraction process essentially comprises five steps, namely acidification, alkaline extraction, solid/liquid separation, precipitation, and drying. In the acidification step, the seaweed is immersed in a bath of sulfuric acid for several hours to convert the insoluble alginate salts (Ca(Alg)2; Mg(Alg)2) present in the cell walls into alginic acid. The next stage is alkaline extraction, where the acidified seaweed is placed in a solution of sodium carbonate. The previously insoluble alginic acid is converted into soluble sodium alginate, which transfers to the aqueous phase. It takes several hours to achieve maximum extraction. Algae residues are separated from the sodium alginate solution using flotation/flocculation and filtration. Sulfuric acid or calcium chloride is then added to precipitate the alginates. The final product is pressed and dried through heating. Different alginate salts can be prepared by reacting alginic acid with the appropriate base [50, 51]. When alginate is added to an aqueous solution, it swells, increasing its viscosity. The solution’s viscosity and the strength of the formed gel depend on temperature, pH, and the presence of metal cations [52].

Various alginate salts and their combinations influence different parameters. The matrices exhibited a greater ability to swell in neutral environments (pH 6.8) than in acidic conditions. pH changes from 6.8 to 1.2 affected polymer hydration and the rheology of the alginate gel due to the interconversion of carboxylate anions (sodium alginate) to free carboxyl groups (alginic acid) with an increasing concentration of hydrogen ions [53, 54].

4.1 Seaweed alginate vs. bacterial alginate

Although the cell wall of brown algae has much in common with the cell wall of higher plants, alginic acid is found in all known Phaeophyceae species and is absent in other plant tissues. However, it is synthesized by bacteria such as Pseudomonas spp. and Azotobacter vinelandii, as a capsular polysaccharide and differs from alginic acid present in algae only by being more acetylated [39].

Brown algae containing alginate grows on rocky beaches or in areas of ocean with clear, rocky bottoms. They are found at high tide or centurion along the beach, at a depth of less than 38 m, the limit for sunlight penetration. Among all Phaeophyceae species, some are used as a commercial source of alginate, the giant seaweed Macrocystis pyrifera, which grows abundantly on the coasts of North and South America, being the main one [39].

The variability in the structures of the chain blocks, such as molecular weight, proportion, and relative distribution of the two monomers, M and G, along the molecule, and acetylation have an influence on the physicochemical properties of compost and the biological basis for this variability is therefore of scientific and practical importance. Alginates produced by bacteria and mannuronate residues from bacterial alginates are acetylated at the O-2 and/or O-3 positions. Therefore, alginates have significant differences for the industry and its applications. Like the species of Laminaria, Ecklonia, and Aschophyllum nodosum, they produce alginates with different proportions of polyguluronic acid, related to M. pyrifera, in their structure, thus resulting in different functionalities of this compound [39].

The production of alginic acid is concentrated in the cultivation of brown algae; however, the structure of the monomer residue blocks is similar in alginates produced by seaweed and synthesized by the bacteria A. vinelandii. According to Gorin and Spencer, the specific rotation of bacterial sodium alginate is very close to the rotation of sodium alginate derived from algae, thus suggesting that the glycosidic configurations are similar [55]. In contrast, all Pseudomonas alginates, although they have G monomers, do not have sequences of these monomers, that is, they do not have G blocks [56, 57].

4.2 Alginate extraction

There are several factors that influence the composition of an extract, and one of them is the extraction method [58]. The literature demonstrates several different methods and protocols that can be applied according to the objective of each research. Table 4 lists two main methods of extracting bacterial alginate, from Azotobacter vinelandii, and from algae such Sargassum cymosum, as illustrated in Figure 3.

Reference	Extraction methods for obtaining alginate		Species
Garcia-Cruz et al. [59]	Bacterial alginate extraction	Culture of Azotobacter vinelandii in PCA slant tubes; transfer in depletion to slanted PCA tubes; keep in an oven at 30°C for 24 h; transfer cells to production medium; Incubate on a rotary orbital shaker for 24 h at 30°C at 200 rpm; standardize the inoculum in a spectrophotometer at an optical density of 0.5 at 620 nm; place the inoculum in new production medium; incubate on a rotary orbital shaker at 30°C for between 72 and 96 h at 200 rpm; centrifuge the fermented broth at 8000 g for 15 minutes at 4°C; separate into supernatant and cells. supernatant: precipitate in three volumes of ethanol and discard the supernatant. The precipitated alginate is dried in a vacuum tube at 55°C until constant weight; calculate yield. The fermented broth cells: dry in a vacuum oven at 55°C until constant weight; determine cell growth (g).	Azotobacter vinelandii
Mchugh et al. [60]	Seaweed alginate extraction	Separate 6 g of seaweed of the Sargassum cymosum species, immersed in ethanol; shake in a shaker for 3 h at 250 rpm; repeat twice; dry the seaweed overnight in an oven at 40°C and, the dried product, submit to the acid treatment, which consisted of adding distilled water and adding 0.1 M hydrochloric acid to pH 2.0, at 45°C for 110 min, under stirring at 250 rpm; wash samples with distilled water and optimize the extraction conditions: add 2% sodium carbonate, until reaching the desired pH (pH 8, 9 and 10), at different times (90, 195 and 300 min), at temperatures of 50, 65, and 80°C, under stirring. Filter the solution repeatedly until impurities are removed. To separate the sodium alginate, add ethanol (1:2, v/v) to the solution to precipitate the desired product, which was separated by centrifugation (3000 rpm) and dried in an oven at 45°C for 15 h.	Sargassum cymosum C. Agardh.

Table 4.

Methods for extracting bacterial alginate from Azotobacter vinelandii and algae from Sargassum cymosum C. Agardh.

However, the methods have basic procedures, being the conversion of insoluble alginate into alginic acid [55]. This conversion occurs in the acid pre-treatment, a step carried out in the conventional extraction, commonly using hydrochloric acid, which also contributes to the increase in yield and removal of some contaminants such as fucoidans, laminarins, amino acids, and polyphenols. The addition of sodium carbonate to the solution, at a controlled time and temperature, will allow the precipitation of sodium alginate in its soluble form [61].

The original brown color of alginate extracted from brown seaweed can cause rejection and dissatisfaction in the industrial market. Therefore, it is necessary to use bleaching agents, such as sodium hypochlorite. However, the use of hypochlorite and other chlorine salts has been a matter of concern, as these compounds are considered precursors in the formation of compounds that are harmful to health due to their high carcinogenic potential [62, 63].

The conventional approach to alginate production involves a multi-stage process. Essentially, fresh algae are washed, dried, and ground into powder. Subsequently, the algae biomass is soaked in water for rehydration, to which various chemicals are added to eliminate undesirable compounds in the algae. Next, an acid or alkaline pre-treatment is applied to break down the plant’s cell wall, followed by sodium carbonate extraction to obtain water-soluble alginate from the seaweed biomass matrix. There are three precipitation routes to recover alginate from solution, namely the sodium alginate route, the calcium alginate route and the alginic acid route, with the final product generally isolated in the form of sodium alginate. On the other hand, with a focus on sustainable development, more environmentally friendly ways of obtaining alginate have been explored. Several greener technologies have been developed and implemented in the field of biopolymer extraction. Some of these technologies, such as ultrasound-assisted extraction, microwave-assisted extraction, enzyme-assisted extraction, and extrusion-assisted extraction, can be employed in the extraction of alginate from brown seaweed, thereby increasing extraction efficiency, reducing energy consumption and minimizing waste generation, as mentioned in Table 5 [64].

Extraction technique	Description
Ultrasound-assisted extraction	Regarded as an emerging extraction method with minimal solvent requirements, eco-friendly characteristics, straightforward handling, and a rapid extraction rate. It can be employed in conjunction with other unconventional extraction techniques, such as microwave-assisted extraction.
Microwave-assisted extraction	Widely utilized for extracting active compounds from natural materials. Considered one of the most efficient extraction methods in comparison to traditional approaches. In the process of microwave-assisted extraction, microwave radiation is utilized to expedite the extraction rate by swiftly and effectively heating the solvent. It is hypothesized that the heat generated by microwaves causes the water within seaweed cells to evaporate, resulting in increased pressure on the cell wall. This effectively induces the rupture of the cell wall, subsequently releasing intercellular compounds into the extraction solvent.
Enzyme-assisted extraction	Gaining increasing attention due to being an environmentally friendly, non-toxic, and expeditious process. Enzymes specifically react with a designated substrate, preserving the integrity of the target products within the biomass matrix. Enzyme-assisted extraction proves particularly useful for extracting alginate and other polysaccharides from brown algae, targeting celluloses and proteins using enzymes such as cellulases and proteases (e.g., Alcalase).
Extrusion-assisted extraction	A thermomechanical process traditionally employed in the production of starchy foods. Recently, this extrusion technology has been applied to extract alginate from the brown seaweed Sargassum cristaefolium.

Table 5.

Greener extraction methods of alginate. Source: Adapted from Saji et al. [64].

In general, as conventional processes have been investigated for more than a century, the technology is relatively mature, although innovations are still needed to further improve process efficiency. On the other hand, green extraction processes offer promising and environmentally friendly options, but their industrial applications have yet to be demonstrated on an industrial scale [64].

5. Innovation from genetic resources

The concept of innovation, in general, includes the process from the creation of new ideas to their implementation and propagation. Innovation is also considered very important with regard to sustainability. In recent times, attention has focused on the use of bio-based natural compounds in different industrial sectors of application. Bio-based natural compounds, or those derived from plants, microorganisms, and animal resources, have several advantages (such as biocompatibility, availability, non-toxicity, and biodegradability) [65, 66, 67]. Due to their unique properties, such as biodegradable properties, biopolymers are gradually replacing synthetic ones. Among the biopolymers is alginate (NaC₆H₇O₆), a group of polysaccharides that have been of great interest. Resulting from the depletion of renewable sources for obtaining resources, the adoption of sustainable practices also highlights the use of bioproducts for sustainable development. Alginate is widely used and has numerous usage features in biomedicals, food, agricultural, chemicals, cosmetics, pharmaceuticals, adsorbent, and water treatment industries, among many other industrial sectors [68, 69]. Innovation is needed with regard to the social and ecological benefits of the sustainable use of natural resources. Seaweeds, in turn, play an important role in maintaining ecological balance, as well as their potential for sustainable cultivation and biotechnology make them a very significant resource for innovative strategies related to technological development [70].

Considering the high potential of obtaining alginate from algae, added to the sustainable exploitation of natural resources in order to increase economic benefits, it is essential to seek ways to minimize environmental impacts. Moreover, it is possible to apply life cycle assessment (LCA) techniques to quantify the sustainability associated with technological development. The LCA methodology can measure the benefits associated with alginate production activities and obtain value-added products until their final destination. Thus, the LCA methodology, which is considered a “cradle-to-grave” methodology, can assess the life cycle of a process or product from the extraction of raw materials to the end of its useful life. Moreover, to carry out innovative processes within legal requirements, it is necessary to analyze the environmental laws in force in the countries of origin of the species in question because both the activities of use of the species itself, as well as the activities of use of products derived from its metabolism, can be framed in environmental laws and have legal implications if there is no compliance with the requirements laid down in law [71].

Technological innovation can be used as a strategy with the purpose of achieving sustainable development, which has played a very important role in the economy in recent years. It is noteworthy that despite the positive impact of innovation on environmental issues, it is not in fact sufficient to offset the negative impacts previously caused. This fact may indicate the need to enable complementary measures to achieve sustainable development [72].

6. Regularization and conservation: Brazilian biodiversity law

Biodiversity refers to the extent of a variety of resources within a natural system encompassing an extensive range of plants, animals, and microorganisms, as well as the genes they contain and the ecosystems that are made up of them. Biodiversity includes genetic differences within each species and the variety of ecosystems. In each ecosystem, living things form a community, interacting with each other [73]. The Earth possesses a unique feature: the possibility for life to exist. Millions of people and millions of other organisms such as plants, animals, protozoa, and fungi inhabit planet Earth. It is a fact that human actions have contributed to the devastation of biodiversity at a worrying rate. This loss of biodiversity affects the functioning of ecosystems and the ability to provide resources to society. In recent years, remarkable progress has been made toward understanding how biodiversity loss affects society and encouraging sustainable development [74].

The use of the term biodiversity first occurred in the 1980s, in a scenario of scientific-political initiatives impacting society for the richness of life on Earth and for issues aimed at environmental conservation. It emerged officially in 1992 and was formally enshrined in international policy when the United Nations Convention on Biological Diversity (CBD) came into force in 1993. Brazil has competitive advantages over other countries of the globe in relation to its biodiversity, which allows the development of science and technology from research with its natural resources. Brazil, in turn, stands out in the creation of norms and public policies with the purpose of guaranteeing scientific prosperity based on sustainable development. Thus, Law No. 13.123/2015 has as its main objective to minimize the bureaucracy regarding access to genetic heritage and associated traditional knowledge. Law 13.123/2015, also known as the Brazilian Biodiversity Law, and its regulations are some of the instruments used by Brazil to achieve the goals established by the Convention on Biological Diversity (CBD), also relating to the Nagoya Protocol. These legal frameworks establish guidelines for access to biodiversity and associated traditional knowledge. In other words, it establishes the guidelines and recommendations for commercial relations between the country that provides genetic resources and the one that will eventually use these resources [75].

CBD was the first global treaty on biodiversity that came into force in 1993 and was ratified by Brazil in 1994. CBD provides for the need for a benefit-sharing mechanism and control of access to genetic heritage, guaranteeing nations’ autonomy to deal with access to their genetic heritage. But points out that it would be unfair for the holders of this heritage not to obtain any kind of return on the commercial exploitation of their resources. The Nagoya Protocol was created by the CBD at its tenth meeting, which took place in 2010 in Nagoya, Japan, and came into force in 2014. Brazil ratified the Nagoya Protocol in 2021, joining 130 other countries [76].

Law 13.123/2015 on access to Brazilian Biodiversity regulates the conduct of research and development with species originating or belonging to the Brazilian biodiversity and the sharing of benefits arising from this access. This Law has its origin associated with the most important international treaty for the protection of biodiversity, the Convention on Biological Diversity. Through Provisional Measure No. 2.186 of 2001, Brazil was a pioneer in regulating the rights and obligations associated with access to genetic heritage, associated traditional knowledge, and benefit sharing with respect to biodiversity. In order to legally facilitate access to genetic heritage and reduce bureaucratic obstacles to research and technological development, the Provisional Measure (which was in force since 2001) was replaced by Law 13.123/2015 [77]. Figure 4 presents the interaction between the use of species belonging to Brazilian Biodiversity and legal requirements.

Figure 4.

Legal requirements related to sustainable development practices.

6.1 Biopiracy

Biopiracy is characterized by the unauthorized use of biological resources and traditional knowledge belonging to other countries and their local and indigenous communities without sharing revenues obtained from the economic exploitation of these resources [78, 79]. Biopiracy is not just limited to medical development; it also happens in agriculture and many other industrial sectors. It occurs when researchers or development and research institutions access biological resources without official sanction, mostly from less developed countries or countries that do not have environmental laws for such activities. It is, therefore, a practice against sustainable development and against the genetic heritage of the country. The associated traditional knowledge has been used as a contribution to the pharmaceutical, phytotherapy, cosmetic, and agricultural and biological pesticide industries, among others. Protection of associated traditional knowledge has the potential to improve the performance of the economies of many developing countries by making their biological wealth more commercially available and increasing exports of traditional knowledge-related products. This knowledge is the heritage of indigenous and local communities that are being exploited on a large scale without making a share of the profit [73]. Thus, this exploitation of genetic heritage linked to communities’ traditional knowledge is often used in ways that result in biopiracy. Figure 5 provides a brief description of the biopiracy process and possible damage caused to the country of origin of the species.

Figure 5.

Harms related to the practice of biopiracy.

The practices of biopiracy, are businesses that can involve millions. In this sense, Brazil is one of the biggest targets of biopiracy, due to the interest of other countries in its vast biodiversity. A lot of companies and developed countries make huge profits using the biological properties of native and endemic plants from developing countries; on the other hand, they get nothing in return. The damage and inconvenience that the country is subjected to, related to the practice of biopiracy, knowledge, and bioproducts, until 2017, were evaluated in losses of R$33.3 billion per year. These losses would be linked not only to the illegal trade in plants and animals but also to the monetary loss from not receiving royalties from the patenting of active pharmaceutical and cosmetic ingredients obtained from Brazilian biodiversity and associated traditional knowledge, which, based on these practices, were registered in other countries. As it is considered an illegal activity under the national laws of many countries, the genetic heritage that has been illegally accessed can be used in various innovation processes around the world, and due to the lack of integration of international systems, it is almost impossible to trace raw materials and consequently identify the origin of biopiracy [80]. This practice has been a concern for countries with vast biodiversity, such as Brazil. Meanwhile, it is expected that with legal regulations, international treaties, and conventions, it will be possible to trace the origin of bioprospecting and access to genetic heritage. And thus combat this crime against the conservation and biodiversity of countries.

6.2 Enforcement of the law to access Brazilian genetic heritage

Access to genetic heritage (GH) and/or associated traditional knowledge (ATK) to GH, has been regulated in Brazil since 2001 (through Provisional Measure No. 2.186/2001). Law 13.123/2015 determined significant changes regarding the access to Brazilian Biodiversity, mainly on the rules of sharing benefits obtained for the conservation and sustainable use of biodiversity, the access to technology and technology transfer, the exploitation of products or reproductive material of GH or ATK and the remittance abroad of part or all of the living or dead organism part of GH access. Thus, SISGEN (National System of Genetic Heritage Management), was created by Decree No. 8772/2016, is an electronic system maintained by the executive secretariat of CGEN (Genetic Heritage Management Council) in order to assist the user to register processes of access to GH or ATK, in order to request authorization for access to the country’s GH or ATK, carry out shipment of GH samples abroad, notification of finished product among other provisions set out in Law 13.123/2015 [80].

Therefore, the use of products of the metabolism of living organisms resulting from access to the GH existing in the national territory is within the scope of the legal requirements related to the abovementioned Law. Thus, in order to carry out scientific research and/or economic exploitation, shipment, and access to ATK from organisms that are considered part of the Brazilian PG and/or product of the metabolism of these organisms, it is necessary to register in SISGEN according to the activity to be performed. Otherwise, the user will be subject to the legal implications set forth in the Law, including fines for noncompliance with the legal requirements related to access to the Brazilian GH. Thus, the activities of extraction of alginate, which is considered a product of the metabolism of living organisms, which are obtained or isolated in Brazilian territory, found in situ conditions in the national territory, continental shelf, territorial sea, and exclusive economic zone, are within the scope of Law 13.123/2015, therefore, subject to the legal implications of the country, being essential to register the respective activities in SISGEN, before CGEN [4].

7. Conclusions

Currently, Brazilian algae aquaculture provides the industry with raw materials for various sectors of the industrial economy. Alginate is a polymeric material of biological origin with a wide range of applications already consolidated and with various applications in various industrial sectors. Several other applications have been developed due to biological origin, and it is considered to be safer and more effective than synthetic materials. Thus, it is necessary to analyses the place of origin of the species in question, that is, to be used for the extraction of alginate and its legal framework. Since alginate extracted from algae is considered a product of their metabolism. Therefore, if the extraction species has its origin in Brazil, it is within the scope of Law 13.123/2015 and its implications. Additionally, ongoing research or emerging trends related to alginate applications could be considered potential challenges or areas for improvement in the current algae aquaculture practices, and alginate extraction processes are able to offer a more comprehensive view. It enriches understanding of the significance and potential advancements in Brazilian algae aquaculture and alginate utilization.