[Kamat2010]

The restoration, maintenance and protection of the environment with the help of biological agents, which includes both the living organisms and their components along with the physical, chemical and engineering processes is known as Environmental Biotechnology. Industrial Microbiology also plays an important role in the preservation of the environment. Hence, in many cases, Microbiology and environmental Biotechnology go hand in hand and both are interdependent on each other.

Environmental Biotechnology is mainly concerned with the removal and treatment of the wastes, solid or liquid, from various sources like the industrial, domestic, municipal, or agricultural. The main part is in the conversion or degradation of the xenobiotic compounds, which are released into the environment by the wastewater streams of industries. The ever-increasing population has caused the disposal of different types of wastes into the environment. This has resulted in the pollution of both land and water environment. Due to the seriousness of the issue of pollution of the water bodies, various steps are being taken for the treatment of the wastes. The wastes from domestic and commercial sources are treated to make them chemically and biologically harmless by nitrification and removal of suspended and dissolved harmful compounds. These types of treatment not only prevent the spread of epidemic water-borne diseases, but also the pollution of potable water supplies, land and water contamination, etc. Various types of analysis of the water sources are done like the Biological oxygen demand (BOD), Chemical Oxygen Demand (COD), total suspended solids (TSS), total solids (TS), etc to determine the polluting strength of the wastes and after proper analysis, the type of treatment to be done is determined.

In the present times, the treatment of the wastewater has become one of the major applications of biotechnology. The industrial wastewater is more polluted than the domestic sewage. The different options for the treatment of the wastewater are:

a) Biological, which includes various aerobic and anaerobic processes,
b) Chemical, which includes electrochemical processes, coagulation, etc,
c) Physical, which includes sedimentation, etc

In most of the cases, all the three methods are employed for the treatment of the wastewater. The wastewater first undergoes primary treatment involving sedimentation followed by secondary treatment involving biological process with microbes. The aerobic treatment of the wastewater involves the bringing into contact of the wastewater with the aerobes and oxygen, which gives rise to excess biomass and CO2 in the process, thereby reducing the efficiency of the process. The anaerobic treatment involves the interaction of the facultative and the obligate anaerobic organisms, thereby producing methane, CO2, etc with very less formation of new cells and hence biomass.

Composting is another method used for the processing of solid organic wastes by microorganisms. The solid wastes are converted to humified product used for increasing the fertility of the soil by a sequence of microbial processes including fermentation. Xenobiotics are compounds that are not recognised by the microorganisms and hence remain in native form in the environment, as they are not degraded easily. They remain so due to their complex structures and absence of one or more steps in the sequence of biodegradation including the formation of toxic intermediates. However, extensive research in the present times has made possible the biodegradation of the xenobiotics by the formation of genetically engineered microorganisms, which can degrade them and treatment with immobilized enzymes for degradation.

The other process of removing the toxic solid wastes in the land and water is bioremediation. Bioremediation involves the utilization of the indigenous microorganisms by enhancing their growth by the addition of specific nutrients in the soil and water in order to detoxify the wastes present in situ. Biomining or the mineral leaching with the use of microorganisms to extract minerals from tough, low-grade ores, sludges, and wastes is also a major advancement in environmental biotechnology. The use of genetically engineered microorganisms yields their better resistance to temperature, pH, etc thereby making the process much easier. The microbes are now being used for the desulphurization of the fuels like coal thus helping largely in the prevention of formation of pollutants like SO2, which are formed during the burning of coal. The generation of genetically engineered microorganisms for use as bioinsecticides is also a major turning point, thereby reducing the use of chemicals as insecticides, which may cause pollution indirectly. Thus, major advances in environmental biotechnology with the use of microbiology are proving to be a boon for the welfare of the living community of the environment.