biodegradation of malathion by serratia marcescens isolated from arvandkenar region, iran

as a result of the global use of pesticides, various ecosystems have been contaminated in the world. biodegradation rate is mainly affected by isolation of efficient bacteria and determination of optimal biodegradation conditions. malathion degrading bacteria were isolated from agricultural soil of arvandkenar, iran. to optimize the biodegradation of malathion by the isolated strain, the effect of four parameters (i.e. temperature, salinity, nh4cl and k2hpo4) was evaluated considering protein concentrations at different times. the remaining malathion in the mediums was measured using gas chromatography method. a gram-negative bacterium strain bna1 with malathion biodegrading ability was isolated from the soil sample which showed 99% similarity to serratia marcescens. optimum biodegradation condition was determined to occur at temperature = 30 ˚c, salinity = 0 %, nh4cl = 0.25 g.l-1and k2hpo4 = 0.25 g.l-1. biodegradation efficiency of 65% was obtained in the above-mentioned condition. in conclusion, the results revealed that the significant capability of bna1 to utilize malathion. obviously, the isolated strain may be considered an important tool on bioremediation of pesticide-contaminated soil.