Biodegradation of Isofenphos-Methyl by Using Isolated and Mixed Cultures of Lactobacillus sp.M1 and Micrococcus sp.M2

摘要

As one of the most widely used organophosphorus insecticides, isofenphos-methyl (IM) is usually detectable in the environment. In this paper, biodegradation of IM in aqueous environment by bacteria isolated from contaminated soil has been studied. Based on the physiological and biochemical characteristics tests results and 16SrDNA gene sequence analysis, two strains were identified respectively as Lactobacillus sp. M1 and Micrococcus sp. M2. They could utilize IM as the sole carbon source and nitrogen source during their growth period. The degradation rates of IM by strains M1 and M2 were 90.84% and 91.76%, respectively. The strain W1 and W2 were mixed culturing proportionately. Under optimal conditions (pH 6.0-8.0, temperature 30 , and ℃ glucose addition 1.0 g/L), the degradation rate of IM with 300 mg/L reached to 93.80% in 72 h by the mixed bacterium. The mixed bacterium also showed the better degradation stability than single strain. This study could be lain a foundation for the further study on microbial degradation and bioremediation of organophosphorus pesticide contaminated soil.