BIOAUGMENTATION OF BACILLUS SUBTILIS FOR THE DEGRADATION OF MONOCROTOPHOS IN AGRICULTURAL SOIL FROM KARNATAKA, INDIARAMYA N. AND P.K. MAHESHWARAbstract Monocrotophos is a highly potent organophosphate insecticide. It is preferred by most of the farming communities. But this insecticide is non-biodegradable by natural processes and hence accumulates in the environment. Therefore, an efficient Bacillus strain capable of degrading monocrotophos was isolated from the agricultural soil from Mysuru district, Karnataka, India. 25 isolates of Bacillus subtilis were isolated from 45 agricultural soil samples. All the isolates were subjected to degradation studies through agar well diffusion method and high performance liquid chromatography method. One among 25 isolates was chosen as the test isolate, based on the results of degradation studies. Further, the isolate was sequenced with species-specific primers for 16S rRNA gene amplification. With this confirmation the isolate was submitted to GenBank. Also the sequence was compared with other bacterial sequences obtained from Gen Bank database BLAST program to construct a phylogenetic tree. The bacterial isolates from the present study exhibited profound capabilities to degrade monocrotophos at a concentration as high as 1000 mg/l in the minimal salt medium. The residue analysis of the insecticide revealed that the isolates could degrade 75% of monocrotophos after the treatment with bacterial inoculants. The present study has revealed the ability of B. subtilis to utilize monocrotophos insecticide as its nutrient source which can tolerate up to 1000 mg/l of monocrotophos, leading to its degradation. Thus, the present bacterial strain can be used for the bioremediation of monocrotophos contaminated agricultural soils. |