IMPACT OF CHLORPYRIFOS ON BACILLUS CEREUS OP3 SOIL BACTERIA ISOLATED FROM RHIZOSPHERE

Abstract

Chlorpyrifos is a pesticide belongs to organophosphate group and widely used in Indian agriculture. The evaluation of chlorpyrifos removal from the soil using pesticide degrading bacteria will help in the resilience of soil fertility. Bacteria capable of degrading chlorpyrifos were isolated from chlorpyrifos-treated agricultural soil. The degradation of chlorpyrifos by a potential isolate was determined using FTIR and quantified using the molecular extinction coefficient in an ELISA reader. GC-MS was used to analyze the chlorpyrifos degradation metabolites. Additionally, the effect of chlorpyrifos exposure on genomic DNA and total protein content was determined. A total of 174 bacterial colonies were isolated, of which only 40 bacterial colonies were pesticide tolerant in 100ppm chlorpyrifos. Among them, only three isolates (OP3, OP5, and OP7) demonstrated tolerance above 100ppm. Within five days of incubation, OP3 demonstrated tolerance to chlorpyrifos concentrations up to 300ppm and 47 percent of chlorpyrifos was removed. By 16S rRNA sequencing, potential OP3 isolates were identified as Bacillus cereus OP3. FTIR spectra confirmed that B. cereus degraded chlorpyrifos, with 92.4 percent of chlorpyrifos degraded. In GC-MS analysis, metabolites such as MNitroaniline and 4-Methyl-2-{(4-Nitrophenyl)Thio}Pyrimidine were detected. Chlorpyrifos overexposure alters the total protein content of exposed cells and induces DNA breaks. As a result, it is concluded that B. cereus is able to degrade chlorpyrifos and the excessive use of pesticides make some changes in the soil bacteria. Overexposure of chlorpyrifos leads to an increase in total protein content and induce DNA strands breaks in pesticide degrading Bacillus cereus.