Ex situ and in situ biodegradation of lindane by Azotobacter chroococcum

This study was undertaken to investigate the potential of Azotobacter chroococcum for degrading lindane. Ten cultures were screened for lindane degradation by a chloride estimation method and the best A. chroococcum culture JL 102 was selected for further studies. This strain was subjected to a lindane-tolerance experiment and based on the results obtained, 10 and 100 ppm of lindane were selected to study the potential of the A. chroococcum strain for ex situ and in situ biodegradation of lindane. The organism was grown in 2 different media viz. Jensen's broth and soil extract broth and ex situ lindane degradation was studied for a period of 6 days. Maximum degradation of lindane was recorded at 10 ppm concentration. The degradation was higher in Jensen's medium, compared to the soil extract broth. A pot culture experiment was conducted using both sterile and non-sterile soils supplemented with 10 ppm lindane to study in situ degradation potential of this strain for a period of 8 weeks. In both the conditions (sterile and non-sterile), the organism exhibited increased degradation over the days with maximum degradation observed on the 8th week of incubation. It could degrade most of the applied lindane by the end of the study period.