Biotechnology – A Pathway to Bioremediation
The advent of biotechnology is prominent. Gone are the winds of insipid excitement and permanent are the forces of renovation that contain historic achievements. The use of microbes that have inhabited the earth for millions of years, for bioremedial techniques illustrates the fact that natural history paves a way for present development. Bioremediation of toxic metals from groundwater is an advantage that biotechnology has provided for human health. Arsenic is a toxic metal that can be removed from water by arsenic oxidizing bacteria. The bacteria are used for oxidation of Arsenite As(III) to As(V), that can be easily separated from the water. Many heterotrophic bacteria oxidize As(III) to detoxify their immediate environment. On the contrary, some bacteria behave as agents that use As(III) as electron donors. Various molecular markers have been identified to recognize bacteria with potential arsenic oxidizing activity such as 16s rRNA, aioA, arsB and others. By oxidizing the more toxic Arsenic As (III) to less toxic As(V) and concomitantly gaining energy, such bacteria have an appreciable ecological advantage over their counterparts. The As oxidase gene has been characterized by bacteria. A study has confirmed that the As oxidase gene is a very ancient gene. In certain ways, Arra and As oxidase have been found to be similar.
Classical technologies are efficient in removal of As(V) but not As(III). There are also cost intensive. Here Biotechnology counters the problem. Biocolumn reactors with immobilised bacterial cells have been used. A novel cost effective biocomposite- granules of cement coated with cysts of certain cyanobacteria has been studied The composite has been proven to remove 96% arsenic. Many such biocolumns or devices have been made that harness the ability of bacteria to remove As(III) and As(V). The efficiency of these has been very high. Thus techniques of biotechnology have been effectively used to clean drinking water from arsenic. Similar approaches have been taken for remediation of other toxic metals like cadmium, excessive Iron and others. Biotechnology is critically involved in the maintenance of human health.