Fawzy I. Eissa; Hend A. Mahmoud; Osama N. Massoud; Khaled M. Ghanem and Ibrahim M. Gomaa( 2014). Biodegradation Of Chlorpyrifos By Microbial Strains Isolated From Agricultural WastewaterJournal of American Science 2014;10(3)
Abstract: Biodegradation of chlorpyrifos in mineral salt liquid (MSL) medium under different environmental factors such as pH of media, temperature and different concentrations of pesticide were investigated to optimize the conditions for biodegradation of chlorpyrifos by microbial strains. Isolating the microbial strains for identifying those having high chlorpyrifos degradation capability in liquid culture was undertaken as well. Out of thirteen microbial isolates from agricultural wastewater samples collected from different pesticides-polluted locations in Egypt, three isolates were only capable of degrading chlorpyrifos and utilizing it as a sole source of carbon and phosphorus. Isolates’ biomass and chlorpyrifos degradation were found to be optimum at 30 °C and pH 7 (for bacteria and actinomycete), and pH 6 for fungi. These strains were identified as Bacillus sp. SMF5, Penicillium sp.F09-T10-1 and Streptomyces thermocarboxydus strain A-B based on morphological and biochemical tests as well as 16S rDNA analysis. It was also confirmed that biodegradation potential of the microbial isolates influenced by a range of abiotic factors such as pH of media, temperature and different concentrations of the tested pesticide. The rate of degradation for chlorpyrifos was faster in all inoculated samples relative to the corresponding control. Results showed also that chlorpyrifos was degraded faster by bacteria than fungi followed by actinomycete compared to its respective uninoculated water after 28 days. The dissipation of chlorpyrifos was coinciding with increasing biomass growth in chlorpyrifos contaminated water. Thus, the results from the present study confirmed that the newly isolated chlorpyrifos-degrading isolates can be successfully used for bioremediation of chlorpyrifos-contaminated water.
Keywords: (Chlorpyrifos, bioremediation, biomass, water.)
