- Email: [email protected]
Biosurfactant—Enhanced bioremediation of hydrophobic pollutants
Journal of Biotechnology 136S (2008) S678–S707
Contents lists available at ScienceDirect
Journal of Biotechnology journal homepage: www.elsevier.com/locate/jbiotec
Abstracts
VII-5 Bioremediation
VII5-O-002 Risks and benefits of biological cleaning of the environment polluted with halogenated compounds
ies, microbial analysis including characterization and identification of major microbial species. Aerobic versus anaerobic approaches for decontamination are described, their advantages and disadvantages are discussed.
Katerina Demnerova a,∗ , Martina Macková a , Katerina Jecna a , Hana Stiborova a , Petra Lovecka a , Vlasta Dudková a , Jana Zlámalíková a , Tomas Macek a,b
Acknowledgement
a
The work was sponsored by the grants TANDEM FT – TA 4/101, MSM 6046137305 and MSMT NPVII 2B08031.
ICT Prague, Fac. Food and Bioch. Technology, Department of Biochemistry and Microbiology, Technická 3, 166 28 Prague, Czech Republic b Institute of Organic Chemistry and Biochemistry, CAS, Department of Natural Products, Flemingovo n. 2, 166 10 Prague, Czech Republic E-mail address: [email protected] (K. Demnerova). For several decades, significant efforts have been devoted to the study of the biodegradation of organic pollutants. Unfortunately, in many cases, these compounds are persistent in nature. Various aspects need to be studied to obtain a detailed overview of biodegradation processes in the environment and to optimize and predict the performance of degrading microorganisms in situ. The astonishing diversity of microbial capabilities to degrade organic compounds and the variability of site-specific conditions make it difficult to predict the rate and extent at which different pollutants may be degraded in different environments. Biodegradation of most priority pollutants generally results in products of lesser toxicity. Nevertheless, there are some noteworthy exceptions where a pollutant is biotransformed to a product of higher toxicity. Different approaches were designed to monitor and remove contamination from the environment including biological ones. However, bioremediation in many cases failed to meet the expectations raised by many technology salespeople because of a number of limiting factors. These include a lack of essential nutrients, insufficient access of the microorganisms to sorbed contaminants or unfeasible thermodynamics. In the Czech Republic there are still many places contaminated with persistent xenobiotics of industrial and agricultural origin. Beside polychlorinated biphenyls, there is a new class of halogenated compounds polybrominated diphenyl ethers (PBDEs) often referred as the new PCBs. These compounds are used as fire retardants in electronics, plastics, car upholstery, furniture, and cables. PBDEs are also very persistent and tend to bioaccumulate in wildlife and human tissue. As a last example of halogenated compounds there is a large group of halogenated pesticides like DDT. The present study describes experience from our studies dealing with monitoring of contaminated sites, toxicity versus analytical stud-
0168-1656/$ – see front matter
doi:10.1016/j.jbiotec.2008.07.1572 VII5-O-004 Biosurfactant—Enhanced bioremediation of hydrophobic pollutants Swaranjit Singh Cameotra MTCC & Gene Bank, An IDA, IMTECH, Chandigarh 160036, India E-mail address: [email protected]. Biosurfactants are surface-active compounds synthesized by a wide variety of microorganisms. They are molecules that have both hydrophobic and hydrophilic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures—lipopeptides, glycolipids, neutral lipids and fatty acids. They are non-toxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs), crude oil sludge and pesticides can be toxic, mutagenic and carcinogenic compounds that pollute the environment. They are released to the environment as a result of spillage of oil and by-products of coal treatment processes. The low water solubility of these compounds limits their availability to microorganisms, which is a potential problem for bioremediation of contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of pollutants has potential applications in bioremediation. doi:10.1016/j.jbiotec.2008.07.1573
Contents lists available at ScienceDirect
Journal of Biotechnology journal homepage: www.elsevier.com/locate/jbiotec
Abstracts
VII-5 Bioremediation
VII5-O-002 Risks and benefits of biological cleaning of the environment polluted with halogenated compounds
ies, microbial analysis including characterization and identification of major microbial species. Aerobic versus anaerobic approaches for decontamination are described, their advantages and disadvantages are discussed.
Katerina Demnerova a,∗ , Martina Macková a , Katerina Jecna a , Hana Stiborova a , Petra Lovecka a , Vlasta Dudková a , Jana Zlámalíková a , Tomas Macek a,b
Acknowledgement
a
The work was sponsored by the grants TANDEM FT – TA 4/101, MSM 6046137305 and MSMT NPVII 2B08031.
ICT Prague, Fac. Food and Bioch. Technology, Department of Biochemistry and Microbiology, Technická 3, 166 28 Prague, Czech Republic b Institute of Organic Chemistry and Biochemistry, CAS, Department of Natural Products, Flemingovo n. 2, 166 10 Prague, Czech Republic E-mail address: [email protected] (K. Demnerova). For several decades, significant efforts have been devoted to the study of the biodegradation of organic pollutants. Unfortunately, in many cases, these compounds are persistent in nature. Various aspects need to be studied to obtain a detailed overview of biodegradation processes in the environment and to optimize and predict the performance of degrading microorganisms in situ. The astonishing diversity of microbial capabilities to degrade organic compounds and the variability of site-specific conditions make it difficult to predict the rate and extent at which different pollutants may be degraded in different environments. Biodegradation of most priority pollutants generally results in products of lesser toxicity. Nevertheless, there are some noteworthy exceptions where a pollutant is biotransformed to a product of higher toxicity. Different approaches were designed to monitor and remove contamination from the environment including biological ones. However, bioremediation in many cases failed to meet the expectations raised by many technology salespeople because of a number of limiting factors. These include a lack of essential nutrients, insufficient access of the microorganisms to sorbed contaminants or unfeasible thermodynamics. In the Czech Republic there are still many places contaminated with persistent xenobiotics of industrial and agricultural origin. Beside polychlorinated biphenyls, there is a new class of halogenated compounds polybrominated diphenyl ethers (PBDEs) often referred as the new PCBs. These compounds are used as fire retardants in electronics, plastics, car upholstery, furniture, and cables. PBDEs are also very persistent and tend to bioaccumulate in wildlife and human tissue. As a last example of halogenated compounds there is a large group of halogenated pesticides like DDT. The present study describes experience from our studies dealing with monitoring of contaminated sites, toxicity versus analytical stud-
0168-1656/$ – see front matter
doi:10.1016/j.jbiotec.2008.07.1572 VII5-O-004 Biosurfactant—Enhanced bioremediation of hydrophobic pollutants Swaranjit Singh Cameotra MTCC & Gene Bank, An IDA, IMTECH, Chandigarh 160036, India E-mail address: [email protected]. Biosurfactants are surface-active compounds synthesized by a wide variety of microorganisms. They are molecules that have both hydrophobic and hydrophilic domains and are capable of lowering the surface tension and the interfacial tension of the growth medium. Biosurfactants possess different chemical structures—lipopeptides, glycolipids, neutral lipids and fatty acids. They are non-toxic biomolecules that are biodegradable. Biosurfactants also exhibit strong emulsification of hydrophobic compounds and form stable emulsions. Polycyclic aromatic hydrocarbons (PAHs), crude oil sludge and pesticides can be toxic, mutagenic and carcinogenic compounds that pollute the environment. They are released to the environment as a result of spillage of oil and by-products of coal treatment processes. The low water solubility of these compounds limits their availability to microorganisms, which is a potential problem for bioremediation of contaminated sites. Microbially produced surfactants enhance the bioavailability of these hydrophobic compounds for bioremediation. Therefore, biosurfactant-enhanced solubility of pollutants has potential applications in bioremediation. doi:10.1016/j.jbiotec.2008.07.1573