BIOCATALYTIC MINERALIZATION OF THE INSECTICIDE 1α, 2, 3β, 4α, 5α, 6β- HEXACHLOROCYCLOHEXANE (γ-HCH) IN PESTICIDES

Abstract

Naturally occurring compounds have been used as pesticides since decades. That time of pesticides were most liable sulphurous rock, red pepper, extracts of tobacco, salt, and etc. Though the execution of the synthetic pesticides was a blessing for the world, yet the same has turned into a curse due to the heavy usage by people ultimately leading to their accumulation in the environment and taking its way in to the food web. We tried to investigate the negative effects of lindane on major food crop (wheat) in laboratory. We have found that mean shoot length decreased to 2.93 cm in 50 ppm lindane as compared to 10.2 cm in control. The corresponding mean root length were 0.86 cm and 10.64 cm indicating very heavy deleterious effect of increasing concentration of lindane on the development of wheat seedling even-though the percentage germination in 10, 20, and 50 ppm were very near to that of control (98%) while the percentage in 5 ppm was 84 % indicating heavy loss in the germination ability of seeds at low concentrations even though the mean root and shoot length were comparatively higher than the other concentrations. Many of the synthetic pesticides have been shown to persist in nature and their degradation is either very slow (longer half- life) or negligible. Most of the pesticide remained unused and entered into the ecosystem. These excessive pesticide residues accumulate in the biosphere and create ecological stress. Soil and water are the ultimate sinks for the excessive pesticides. Microbial degradation involves the use of microbes to detoxify and degrade environmental contaminants. The study on co-metabolic mineralization of organochlorine pesticide (lindane) was undertaken for this project. We isolated morphologically four different strains of bacteria by enrichment technique and designated them as LRN1, LRN2, LRN3 and LRN4 respectively. These four strains viz. LRN1, LRN2, LRN3 and LRN4 were able to individually act on lindane co-metabolically thereby reducing the initially added concentration to approximately 80% in a very short period of 5 days under aerobic conditions. Co-metabolism is the best applicable bioremediation methods and the use of consortium is a promising approach .Our 4 strains may be constituted into a defined consortium and applied to the contaminated sites for efficient treatment. Further studies need to be conducted to optimize the conditions and investigate the enhanced efficiency of these four strains individually and in combinations to develop best remediation technologies.