Biotechnological Potentials of Microbe Assisted Eco-Recovery of Crude Oil Impacted Environment

Globally, the environment is facing a very challenging situation with constant influx of crude oil and its derivatives due to rapid urbanization and industrialization. The release of this essential energy source has caused tremendous consequences on land, water, groundwater, air and biodiversity. Crude oil is a very complex and variable mixture of thousands of individual compounds that can be degraded with microbes with corresponding enzymatic systems harboring the genes. With advances in biotechnology, bioremediation has become one of the most rapidly developing fields of environmental restoration, utilizing microorganisms to reduce the concentration and toxicity of various chemical pollutants, such as petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, phthalate esters, nitroaromatic compounds and industrial solvents. Different remediation methods have been introduced and applied with varied degrees of success in terms of reduction in contamination concentration without considering ecotoxicity and restoration of biodiversity. Researchers have now developed methods that consider ecotoxicology, environmental sustainability and ecorestoration in remediation of crude oil impacted sites and they are categorized as biotechnological tools such as bioremediation. The approach involves a natural process of microorganisms with inherent genetic capabilities completely mineralizing/degrading contaminants into innocuous substances. Progressive advances in bioremediation such as the use of genetically engineered microbes have become an improved system for empowering microbes to degrade very complex recalcitrant substances through the modification of rate-limiting steps in the metabolic pathway of hydrocarbon degrading microbes to yield increase in mineralization rates or the development of completely new metabolic pathways incorporated into the bacterial strains for the degradation of highly persistent compounds. Other areas discussed in this chapter include the biosurfactant-enhanced bioremediation, microbial and plant bioremediation (phytoremediation), their mechanism of action and the environmental factors influencing the processes