Biodegradation study of -hexachlorocyclohexane using selected bacteria isolated from agricultural soil

Abstract

Bacterial isolates RP-1, RP-3 and RP-9 were isolated from agricultural soil using enrichment culture technique and screened pos. for lindane degrdn. RP-1, RP-3 and RP-9 were found to utilize and degrade higher concns. (100 ppm) of lindane. RP-1 and RP-3 showed 69.5 and 65 % lindane degrdn. after 10 days of inoculation where as RP-9 degraded 62% of lindane after 15 days. The estd. Cl- ion release was 49, 42 and 39 mg/mL, resp. for the three bacterial isolates. Gas chromatog. was used for anal. of metabolite formed during lindane degrdn. and different parameters of degrdn. kinetics were calcd. using first order kinetic equation. A drastic decrease in degrdn. rate was obsd. at initial lindane concns. higher than 200 mg/l in the mineral media. The calcd. half-life periods for RP-1, RP-3 and RP-9 were found to be 3.85, 2.77 and 4.00 days, resp. All three isolates showed max. degrdn. activity at: incubation period; 10-15 days, incubation temps.; 30°C, pH; 7.0, shaking speed 120 rpm, initial substrate concn.; 100 mg/l. Galactose and succinate enhanced the degrdn. rate up to 10% whereas maltose, lactose and xylose decreased the degrdn. level up to 40%. Addn. of glucose as a co-substrate was found highly favorable for enhancement of lindane degrdn. [on SciFinder(R)]