Events and Hazards in Biotransformation of Contaminants

In the past few decades, wastewater disposal has raised substantial environmental concerns for natural water reservoirs. Naturally occurring decomposer organisms develop the ability to degrade or transform complex organic and inorganic substances into simpler or less toxic substances. The practice of releasing unprocessed industrial effluents has transpired hazardous or toxic effects on the local ecosystem and diversity. In these circumstances, microbial activities play a vital role in the sustenance of the environment. Several studies have shown that microorganisms of diverse forms like bacteria, archaea, fungi, etc. are capable of biodegradation/biotransformation. These processes involve enzymatic degradation, stabilisation of degraded molecules, immobilisation and eradication of a wide range of organic and inorganic contaminants from the wastewater that are toxic to the ecosystem. Biodegradation and biotransformation are receiving great attention lately. Microbial processes have been developed and are being used on the industrial scale for degradation/transformation of contaminants such as textile dyes, sewage waste, petroleum wastes, chemical pesticides, and heavy metals. Environmental biotechnology consistently emphasises biodegradation methods that seek sustainable degradation of organic and inorganic pollutants. Uses of carefully selected and/or genetically engineered microorganisms for metabolic degradation of recalcitrant pollutants have been reported. Introduction of genetically modified microorganisms in wastewater treatment set up a new manifesto towards sustainable biodegradation. This chapter proffers the microbial diversity that manifests degradation and transformation of a wide variety of pollutants. The chapter also emphasises the classes of pollutants and diversified microorganisms that play roles in the degradation or transformation process.