Role of Biotechnology in Bioremediation

Introduction

Environmental pollutants are now the major global concern due their undesirable recalcitrant and xenobiotic compounds. A variety of polycyclic aromatic hydrocarbons (PAHs), chlorinated and nitro-aromatic compounds and xenobiotics, were depicted to be highly toxic, mutagenic and carcinogenic for all living organisms in the earth. A number of microorganisms are considered to be the best suitable candidates among all living organisms to remediate most of the environmental contaminants into the natural biogeochemical cycle due to their diversity, versatility and adaptability in adverse conditions. These microorganisms exhibit a remarkable range of contaminant degradable capacity that can proficiently restore the natural environmental conditions. However, some contaminants have been shown to be uncommonly recalcitrant, i.e. microorganisms neither metabolize nor transform them into certain other nontoxic metabolites. As a result, it may be more productive to discover new catabolic pathways that might lead towards complete mineralization of these toxic pollutants. Due to complexity of microbial physiology which allows response and adaptability to various internal and external stimuli, the perfect knowledge of mechanisms of microbial degradation pathways is quite incomplete. (Fulekar, 2007).

Bioremediation, a biological process mediated by microorganisms, is now considered to be one of the most sustainable approaches to degrade and detoxify environmental contaminants. Though bioremediation approach has been used at varying degrees for more than 60 years, for example petroleum land farming, it historically has been implemented as a very ‘black box’ engineering solution where amendments are added and the pollutants are degraded (Chakraborty, Wu, & Hazen, 2012). This approach is often successful but practically admiration of less result as desirable, i.e., instead of degradation of the contaminant, even production of more toxic daughter products is found. The key to successful bioremediation is to trap up the naturally occurring catabolic potential of microorganisms to effectively catalyze transformations of environmental pollutants. Small scale experiments using distinct microbial consortia in the laboratory is an immense starting point in providing crucial initial indication of the bioremediation process within definite control condition. However In situ bioremediation in real execution is a complex phenomenon involving more than one contaminant and simultaneously mediated by different microorganisms involving different metabolic pathways, across geochemical gradients, geophysical and hydrological complexities (Purohit, 2003).