Degradation of hexachlorocyclohexane (HCH; α, β, γ and δ) by Bacillus circulans and Bacillus brevis isolated from soil contaminated with HCH

Hexachlorocyclohexane (HCH; α, β, γ and δ) degradation efficiency of acclimatized Bacillus circulans and Bacillus brevis was studied under aerobic conditions on nutrient agar. These bacteria were isolated from HCH contaminated soil and acclimatized to different concentrations of HCH for more than 2 years. Acclimatized bacteria degraded at a significantly high rate not only the α and γ isomers but also the thermodynamically stable β and δ isomers at different concentrations, suggesting their potential for degradation of even the aged residues.