Significance and approaches of microbial bioremediation in sustainable development

Abstract

Microorganisms like bacteria, yeast, or fungi have the capabilities to degrade or transform hazardous chemicals like benzene, toluene, polychlorinated biphenyls (PCB), dioxins, etc. into nontoxic or less toxic substances, known as microbial bioremediation. It has been used for treating contaminated water and soil. It involves the promotion of growth of specific microflora which is local to that contaminated sites. Various approaches can be used for promoting the growth of microflora like incorporation of nutrients and addition of electron acceptors molecules or controlling temperature and moisture. Contaminants play the role of nutrients for microorganisms in bioremediation. Generally it involves biodegradation and biotransformation which convert the hazardous substances to non-hazardous or less-hazardous form with the production of carbon dioxide or methane, water, and biomass. Microorganisms which are considered for bioremediation are Actinobacteria, Alcaligenes, Flavobacterium, Mycobacterium, Mycococcus, Nitrosomonas, Penicillium, Phanerochaete, Pseudomonas, Serratio, Trametes, and Xanthobacter. Many petroleum hydrocarbons like benzene, toluene, and O-xylene (BTX) have been biodegraded by Pseudomonas putida MHF7109. Pseudomonas nitroreducens PS-2 has been found useful for bioremediation of pesticide chlorpyrifos. Cow dung microflora has been found for bioremediation for benzene. Treatment technologies are being used; still organic pollutants are existing in the soil and water beyond their normal limit; hence bioremediation along with recombinant DNA technology can be a significant tool to remove toxic substances.