Physico-chemical properties of 16 PAHs as classified by USEPA.
Abstract
The genus Mycobacterium has the ability to degrade various environmental pollutants including polycyclic aromatic hydrocarbons (PAHs). Mycobacterium has an ability to withstand adverse environmental conditions and it has been considered for future bioremediation applications for the removal of PAH contaminants from crude oil–polluted sites. The degradation of PAHs using a cost-effective laboratory microcosm system was discussed. The various conditions such as environmental habitat, degradation behavior, enzymatic mechanisms, and ecological survival are thoroughly discussed in this chapter. Based on the above study, Mycobacterium has proved to be a better candidate in bioremediation of PAH-contaminated sites.
Keywords
- mycobacterium
- PAHs
- microcosm
- bioremediation
1. Introduction
As a result of anthropogenic activities, toxic chemicals have become ubiquitous contaminants of soils and groundwater worldwide. Thus, they are omnipresent in the environment due to rapid industrialization, urbanization, and modernization. This type of pollution is now being taken seriously by various industries, governments, environmental agencies, and non-governmental organizations. They are now always looking for an eco-friendly and cost-effective approach toward the removal of emerging environmental contaminants. Consequently, biodegradation is recognized as an efficient, economic, and versatile alternative to physico-chemical treatment of oil contaminants. Hence, microbial biodegradation plays a crucial role in the removal of polycyclic aromatic hydrocarbons (PAHs) specifically actinobacteria, which are a group of diverse bacteria, having the ability to degrade a wide range of organic compounds particularly hydrophobic compounds as PAH polychlorinated biphenyls (PCB), BTEX, pesticides, and so on [1]. Members of the genus
These compounds are persistent in environment due to high hydrophobicity and high stereochemical stability. They are known to possess mutagenic, genotoxic, and carcinogenic properties, causing deleterious effects on plants, aquatic organisms, animals, and humans. In contrast to low molecular weight (LMW) PAHs that can be degraded by various microorganisms (bacteria, actinobacteria, etc.), enrichment culture methods with HMW PAHs as sole sources of carbon and energy often lead to the isolation of
The goal of this chapter is to provide an outline of the current knowledge about biodegradation of PAHs using
2. Calligraphy
2.1. Polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that are widely distributed in the environment. PAHs is a predominant term describing hundreds of individual chemical compounds containing two or more fused aromatic rings and are known to persist or accumulate in the environment. PAHs in the soil have recently become a matter of great concern due to their potential toxicity, mutagenicity, and carcinogenicity. Therefore, 16 PAH compounds have been identified by the United States Environmental Protection Agency (USEPA) as priority pollutants [3, 4]. They are ubiquitous compounds that are formed either naturally during thermal geological reactions, fossilization, and biological reactions or anthropogenically during mineral production, combustion of fossil fuels, refuse burning, forest and agricultural fires, and so on. On the basis of physical and chemical properties of PAHs, they are classified into two groups: low molecular weight (LMW PAHs, including 2–3 rings) and high molecular weight (HMW PAHs, including four or more rings). Table 1 shows the physico-chemical properties of 16 PAHs as a number of benzene rings, vapor pressure, aqueous solubility, and octanol-water partitioning coefficient (Kow) values. Therefore, LMW PAHs are greatly more soluble and volatile as compared to HMW PAHs due to their higher hydrophobicity than the LMW PAHs [5]. The Kow values also reflect the hydrophobicity of the PAHs. These properties regulate the environmental behavior of PAHs. Therefore, HMW PAHs are persistent in the environment specifically in soil due to their high hydrophobicity.
Sr. no. | PAH | No. of rings | Mr | Melting point (°C) | Boiling point (°C) | Water solubility (mg L−1) | Vapor pressure (Pa) | K |
---|---|---|---|---|---|---|---|---|
1 | Naphthalene | 2 | 128.17 | 80.6 | 218 | 31 | 10.4 | 3.37 |
2 | Acenaphthene | 3 | 154.21 | 95 | 279 | 3.47 | 3.0 × 10 | 3.92 |
3 | Acenaphthylene | 3 | 152.20 | 93.5–94.5 | 265 | 3.93 | 8.93 × 10 | 4.07 |
4 | Fluorene | 3 | 166.22 | 116 | 295 | 0.190 | 8.0 × 10−2 | 4.18 |
5 | Anthracene | 3 | 178.23 | 217.5 | 340 | 0.0434 | 1.0 × 10−3 | 4.54 |
6 | Phenanthrene | 3 | 178.23 | 99.5 | 340 | 1.18 | 2.0 × 10 | 4.57 |
7 | Fluoranthene | 4 | 202.26 | 110.8 | 375 | 0.265 | 1.23 × 10−3 | 5.22 |
8 | Pyrene | 4 | 202.26 | 156 | 404 | 0.013 | 6.0 × 10−4 | 5.18 |
9 | Benz[a]anthracene | 4 | 228.29 | 159.8 | 437.6 | 0.014 | 2.8 × 10−5 | 5.91 |
10 | Chrysene | 4 | 228.29 | 255.8 | 448 | 0.0018 | 5.70 × 10 | 5.86 |
11 | Benzo[k]fluoranthene | 5 | 252.31 | 215.7 | 480 | 0.00055 | 7.0 × 10−7 | 6.04 |
12 | Dibenz[a,h]anthracene | 5 | 278.35 | 266 | 524 | 0.0005 | 1.33 × 10 | 7.16 |
13 | Benzo[a]pyrene | 5 | 252.31 | 176.5 | 495 | 0.0038 | 1.40 × 10−8 | 6.25 |
14 | Indeno[1,2,3-cd]pyrene | 6 | 276.34 | 162.5 | 536 | 0.0620 | 1.0 × 10−10 | 6.58 |
15 | Benzo[b]fluoranthene | 6 | 252.31 | 167 | 357 | 0.0012 | 6.67 × 10 | 6.57 |
16 | Benzo[g,h,i]perylene | 6 | 276.34 | 278.3 | 500 | 0.00026 | 1.39 × 10−8 | 7.10 |
Generally, the rate of degradation of PAHs is inversely proportional to the number of rings in PAH molecule [6]. LMW PAHs, such as naphthalene, fluorene, phenanthrene, and anthracene, are more easily degraded and usually utilized as the model PAHs for further understanding the degradative mechanisms on the HMW PAHs. HMW PAHs are more persistent in the environment as they exhibit higher hydrophobicity and toxicity [7] than LMW PAHs.
With increase in the number of benzene rings, PAH solubility decreases while hydrophobicity increases. The Kow values of the 16 PAH priority pollutants are in the range from 3.37 to 6.5, which is generally considered moderate-to-higher lipophilic (Table 1). Thus, PAHs tend to adsorb onto organic fractions in soil sediment and biota and are also accumulated in the food chain [8].
2.2. Characteristics of Mycobacterium
The genus
Mycobacteria are high G + C-containing genera; they possess many properties that make them good candidates for application in bioremediation of soils contaminated with organic pollutants.
Strain | Compound degraded | Source | Reference |
---|---|---|---|
pyrene | PAH-contaminated farmland soil, China | Zeng et al., [19] | |
Phenanthrene, pyrene, fluoranthene | PAHs-contaminated soil | Johnsen et al., [38] | |
Phenanthrene, pyrene, fluoranthene | Crude oil-contaminated sand, Spain | Vila et al., [21] | |
benzo[a]pyrene, pyrene, fluoranthene, and phenanthrene | Hennessee et al., [39] | ||
CP1/CP2/CFt2/CFt6 | Naphthalene, phenanthrene, anthracene, acenaphthene, fluorene, pyrene, fluoranthene, | Creosote-contaminated soil, Spain | López et al. [32] |
S65 | Phenanthrene, pyrene, fluoranthene | Soil contaminated with jet fuel, Quebec | Sho et al. [40] |
pyrene, fluoranthene, phenanthrene, and fluorene | Pagnout et al., [20] | ||
1B | Phenanthrene, pyrene, fluoranthene | Manufactured gas plant-contaminated soil, Australia | Dandie et al. [41] |
MHP-1 | Pyrene | Contaminated soil sample, Japan | Habe et al. [42] |
Pyrene, Fluoranthene, Phenanthrene | Manufactured gas plant site, Iowa | Bogan et al., [15] | |
Fluoranthene, Phenanthrene | Oil-contaminated soil, India | [3, 4] |
3. PAH biodegradation using Mycobacterium
3.1. Mycobacterium degradation ability
Our laboratory has worked on degradation of HMW PAHs as pyrene and fluoranthene using
Many
The ability of the soil microbial community to degrade hydrocarbons depends on the number of microbes and its catabolic activity.
3.2. Microcosm study
Soil microcosm is an approach to study microbial interactions with organic pollutants, in controlled and reproducible environmental conditions. Laboratory microcosms permit measuring of biodegradation and mineralization (CO2 production) rates and can be used to study the effect of bioaugmentation and biostimulation on bioremediation process [22, 23]. Dave et al. [23], in our laboratory have constructed an efficient microcosm system for the enhancement of soil bioremediation process, which resulted in the improvement of HMW PAH degradation in simulated soil conditions (Figure 2). Addition of glucose, Triton X-100, and beta-cyclodextrin in presence of chrysene resulted in enhanced biodegradation of LMW and HMW PAHs up to six rings. In our previous study (unpublished work), we conducted a microcosm experiment in the laboratory using
3.3. Bacterial enzymatic routes
In the aerobic degradation, cytochrome P-450 monooxygenases are complex multicomponent systems present generally in fungi and are like the bacterial aromatic ring dioxygenases. These enzymes are generally membrane bound and have broad substrate specificities. PAH is converted into arene oxide by addition by one atom of molecular oxygen by the monooxygenase (Figure 3), while the other atom is reduced to water.
The bacterial aerobic degradation of PAHs is generally initiated by the action of multicomponent dioxygenases that can catalyze the incorporation of both atoms of oxygen and two electrons from NADH to form
Majority of dioxygenase enzymes were studied with Gram-negative bacteria but certain reports are also on gram-positive bacteria, specifically actinobacteria [25]. Silva et al. [26] reported that
Figure 3 represents the major routes for the degradation of PAHs by various enzyme systems. Among these, degradation of PAHs by dioxygenase-dehydrogenase enzyme system is commonly used by bacteria. Bacterial genera, capable of degrading PAHs commonly, include species of
3.4. Biotransformation by Mycobacterium species
Many
4. Conclusion
Organic pollutants such as PAHs, PCB, and pesticides are resistant to degradation and are predominantly present in the environment; thus, they cause severe toxicological effects on humans as well as marine biota. Therefore, there has been growing interest in mycobacterial strains as potential bioremediation agents and as important components of indigenous PAH and other xenobiotic compound degradation. Various researchers reported the use of
Acknowledgments
Authors are thankful to Department of Science and Technology, Government of India, New Delhi, for providing SERB-National Post-Doctoral Fellowship (PDF/2016/003007) and Gujarat State Biotechnology Mission (GSBTM), Gandhinagar, Gujarat, for financial assistance to carry out this research.
References
- 1.
Pizzul L, Sjögren Å, del Pilar Castillo M, Stenström J. Degradation of polycyclic aromatic hydrocarbons in soil by a two-step sequential treatment. Biodegradation. 2007; 18 (5):607-616 - 2.
Kanaly RA, Harayama S. Biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by bacteria. Journal of Bacteriology. 2000; 182 (8):2059-2067 - 3.
Dudhagara DR, Rajpara RK, Bhatt JK, Gosai HB, Dave BP. Bioengineering for polycyclic aromatic hydrocarbon degradation by Mycobacterium litorale : Statistical and artificial neural network (ANN) approach. Chemometrics and Intelligent Laboratory Systems. 2016b;159 :155-163 - 4.
Dudhagara DR, Rajpara RK, Bhatt JK, Gosai HB, Sachaniya BK, Dave BP. Distribution, sources and ecological risk assessment of PAHs in historically contaminated surface sediments at Bhavnagar coast, Gujarat, India. Environmental Pollution. 2016a; 213 :338-346 - 5.
Juhasz AL, Naidu R. Bioremediation of high molecular weight polycyclic aromatic hydrocarbons: A review of the microbial degradation of benzo[a]pyrene. International Biodeterioration & Biodegradation. 2000; 45 (1):57-88 - 6.
Cerniglia CE. Biodegradation of polycyclic aromatic hydrocarbons. Biodegradation. 1992; 3 (2-3):351-368 - 7.
Sutherland TB, Rafii F, Khan AA, Cerniglia CE. Mechanisms of polycyclic aromatic hydrocarbon degradation. In: Young LY, Ceiniglia CE, editors. Microbial Transformation and Degradation of Toxic Organic Chemicals. New York: Wiley-Liss; 1995. pp. 269-306 - 8.
Latimer J, Zheng J. The sources, transport, and fate of PAHs in the marine environment. In: PAHs: An Ecotoxicological Perspective. Wiley; 2003. pp. 9-23 - 9.
Floyd MM, Tang J, Kane M, Emerson D. Captured diversity in a culture collection: Case study of the geographic and habitat distributions of environmental isolates held at the American type culture collection. Applied and Environmental Microbiology. 2005; 71 (6):2813-2823 - 10.
Stahl DA, Urbance JW. The division between fast-and slow-growing species corresponds to natural relationships among the mycobacteria. Journal of Bacteriology. 1990; 172 (1):116-124 - 11.
Primm TP, Lucero CA, Falkinham JO. Health impacts of environmental mycobacteria. Clinical Microbiology Reviews. 2004; 17 (1):98-106 - 12.
Cerniglia CE. Recent advances in the biodegradation of polycyclic aromatic hydrocarbons by mycobacterium species. In: The Utilization of Bioremediation to Reduce Soil Contamination: Problems and Solutions. Netherlands: Springer; 2003. pp. 51-73 - 13.
Leys NM, Bastiaens L, Verstraete W, Springael D. Influence of the carbon/nitrogen/phosphorus ratio on polycyclic aromatic hydrocarbon degradation by Mycobacterium andSphingomonas in soil. Applied Microbiology and Biotechnology. 2005;66 (6):726-736 - 14.
Uyttebroek M, Vermeir S, Wattiau P, Ryngaert A, Springael D. Characterization of cultures enriched from acidic polycyclic aromatic hydrocarbon-contaminated soil for growth on pyrene at low pH. Applied and Environmental Microbiology. 2007; 73 (10):3159-3164 - 15.
Bogan BW, Lahner LM, Sullivan WR, Paterek JR. Degradation of straight-chain aliphatic and high-molecular-weight polycyclic aromatic hydrocarbons by a strain of Mycobacterium austroafricanum . Journal of Applied Microbiology. 2003;94 (2):230-239 - 16.
Cheung PY, Kinkle BK. Mycobacterium diversity and pyrene mineralization in petroleum-contaminated soils. Applied and Environmental Microbiology. 2001; 67 (5):2222-2229 - 17.
Haritash AK, Kaushik CP. Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): A review. Journal of Hazardous Materials. 2009; 169 (1):1-15 - 18.
McLellan SL, Warshawsky D, Shann JR. The effect of polycyclic aromatic hydrocarbons on the degradation of benzo [a] pyrene by Mycobacterium sp. strain RJGII-135. Environmental Toxicology and Chemistry. 2002;21 (2):253-259 - 19.
Zeng J, Lin X, Zhang J, Li X. Isolation of polycyclic aromatic hydrocarbons (PAHs)-degrading Mycobacterium spp. and the degradation in soil. Journal of Hazardous Materials. 2010;183 (1):718-723 - 20.
Pagnout C, Rast C, Veber AM, Poupin P, Férard JF. Ecotoxicological assessment of PAHs and their dead-end metabolites after degradation by Mycobacterium sp. strain SNP11. Ecotoxicology and Environmental Safety. 2006;65 (2):151-158 - 21.
Vila J, López Z, Sabaté J, Minguillón C, Solanas AM, Grifoll M. Identification of a novel metabolite in the degradation of pyrene by Mycobacterium sp. strain AP1: Actions of the isolate on two-and three-ring polycyclic aromatic hydrocarbons. Applied and Environmental Microbiology. 2001;67 (12):5497-5505 - 22.
Arias L, Bauzá J, Tobella J, Vila J, Grifoll M. A microcosm system and an analytical protocol to assess PAH degradation and metabolite formation in soils. Biodegradation. 2008; 19 (3):425-434 - 23.
Dave BP, Ghevariya CM, Bhatt JK, Dudhagara DR, Rajpara RK. Enhanced biodegradation of total polycyclic aromatic hydrocarbons (TPAHs) by marine halotolerant Achromobacter xylosoxidans using triton X-100 and β-cyclodextrin–a microcosm approach. Marine Pollution Bulletin. 2014;79 (1):123-129 - 24.
Labana S, Kapur M, Malik DK, Prakash D, Jain RK. Diversity, biodegradation and bioremediation of polycyclic aromatic hydrocarbons. In: Environmental Bioremediation Technologies. Springer Berlin Heidelberg; 2007. pp. 409-443 - 25.
Shumkova ES, Solyanikova IP, Plotnikova EG, Golovleva LA. Degradation of para-toluate by the bacterium Rhodococcus ruber P25. Microbiology. 2009;78 (3):376-378 - 26.
Silva ASD, Jacques RJS, Andreazza R, Bento FM, Roesch LFW, Camargo FADO. Properties of catechol 1, 2-dioxygenase in the cell free extract and immobilized extract of Mycobacterium fortuitum . Brazilian Journal of Microbiology. Porto Alegre, RS, Brazil: Department de Solos, Universidade Federal do Rio Grande do Sul. 2013;44 (1):291-297 - 27.
Harayama S. Polycyclic aromatic hydrocarbon bioremediation design. Current Opinion in Biotechnology. 1997; 8 (3):268-273 - 28.
Moody JD, Freeman JP, Doerge DR, Cerniglia CE. Degradation of phenanthrene and anthracene by cell suspensions of Mycobacterium sp. strain PYR-1. Applied and Environmental Microbiology. 2001;67 (4):1476-1483 - 29.
Dean-Ross D, Moody J, Cerniglia CE. Utilization of mixtures of polycyclic aromatic hydrocarbons by bacteria isolated from contaminated sediment. FEMS Microbiology Ecology. 2002; 41 (1):1-7 - 30.
Kleespies M, Kroppenstedt RM, Rainey FA, Webb LE, Stackebrandt E. Mycobacterium holderi sp. nov., a new member of the fast-growing mycobacteria capable of degrading polycyclic aromatic hydrocarbons. International Journal of Systematic and Evolutionary Microbiology. 1996;46 :683-687 - 31.
Kweon O, Kim SJ, Jones RC, Freeman JP, Adjei MD, Edmondson RD, Cerniglia CE. A polyomic approach to elucidate the fluoranthene-degradative pathway in Mycobacterium vanbaalenii PYR-1. Journal of Bacteriology. 2007;189 (13):4635-4647 - 32.
López Z, Vila J, Grifoll M. Metabolism of fluoranthene by mycobacterial strains isolated by their ability to grow in fluoranthene or pyrene. Journal of Industrial Microbiology and Biotechnology. 2005; 32 (10):455-464 - 33.
Khan AA, Wang RF, Cao WW, Doerge DR, Wennerstrom D, Cerniglia CE. Molecular cloning, nucleotide sequence, and expression of genes encoding a polycyclic aromatic ring dioxygenase from mycobacterium sp. strain PYR-1. Applied and Environmental Microbiology. 2001; 67 (8):3577-3585 - 34.
Kim SJ, Kweon O, Freeman JP, Jones RC, Adjei MD, Jhoo JW, Edmondson RD, Cerniglia CE. Molecular cloning and expression of genes encoding a novel dioxygenase involved in low-and high-molecular-weight polycyclic aromatic hydrocarbon degradation in Mycobacterium vanbaalenii PYR-1. Applied and Environmental Microbiology. 2006;72 (2):1045-1054 - 35.
Krivobok S, Kuony S, Meyer C, Louwagie M, Willison JC, Jouanneau Y. Identification of pyrene-induced proteins in Mycobacterium sp. strain 6PY1: Evidence for two ring-hydroxylating dioxygenases. Journal of Bacteriology. 2003;185 (13):3828-3841 - 36.
Stingley RL, Brezna B, Khan AA, Cerniglia CE. Novel organization of genes in a phthalate degradation operon of Mycobacterium vanbaalenii PYR-1. Microbiology. 2004;150 (11):3749-3761 - 37.
Guo C, Dang Z, Wong Y, Tam NF. Biodegradation ability and dioxgenase genes of PAH-degrading Sphingomonas andMycobacterium strains isolated from mangrove sediments. International Biodeterioration & Biodegradation. 2010;64 (6):419-426 - 38.
Johnsen AR, Schmidt S, Hybholt TK, Henriksen S, Jacobsen CS, Andersen O. Strong impact on the polycyclic aromatic hydrocarbon (PAH)-degrading community of a PAH-polluted soil but marginal effect on PAH degradation when priming with bioremediated soil dominated by mycobacteria. Applied and Environmental Microbiology. 2007; 73 (5):1474-1480 - 39.
Hennessee CT, Li QX. Effects of polycyclic aromatic hydrocarbon mixtures on degradation, gene expression, and metabolite production in four Mycobacterium species. Applied and Environmental Microbiology. 2016;82 (11):3357-3369 - 40.
Sho M, Hamel C, Greer CW. Two distinct gene clusters encode pyrene degradation in Mycobacterium sp. strain S65. FEMS Microbiology Ecology. 2004;48 (2):209-220 - 41.
Dandie CE, Thomas SM, Bentham RH, McClure NC. Physiological characterization of Mycobacterium sp. strain 1B isolated from a bacterial culture able to degrade high-molecular-weight polycyclic aromatic hydrocarbons. Journal of Applied Microbiology. 2004;97 (2):246-255 - 42.
Habe H, Kanemitsu M, Nomura M, Takemura T, Iwata K, Nojiri H, Yamane H, Omori T. Isolation and characterization of an alkaliphilic bacterium utilizing pyrene as a carbon source. Journal of Bioscience and Bioengineering. 2004; 98 (4):306-308