Zeinat Kamal M., Nashwa A.H. Fetyan A., Mohamed A. Ibrahim, Sherif El-Nagdy( 2008). Biodegradation and Detoxification of Malathion by of Bacillus Thuringiensis MOS-5.Australian Journal of Basic and Applied Sciences, 2(3): 724-732, 2008 ISSN 1991-8178
Abstract: Efficiency of a strain of B. thuringiensis MOS-5 (Bt), isolated from agricultural waste water near Berket El-Sabaa Egypt contaminated with organophosphorus insecticide, for degradation of malathion was investigated. It was able to utilize malathion as a sole carbon and energy source and to degrade it cometabolically. In a minimal salt medium supplied with 250 mg 1-1 malathion ether alone or incombination with glucose or yeast extract MOS-5 caused 99.32% reduction in malathion after 30 days. Addition of glucose (5 g l-1) and yeast extract (0.5 g l-1) increased the growth rate 104 and 105 fold, respectively, compared to malathion alone. Results of HPLC, gas chromatography/ mass spectrometry (GC/MS) and infrared spectroscopic analysis revealed that one malathion-derived compound mal-monocarboxylic acid (MMA) was producted after three days. Two additional malathion derivatives, mal-dicarboxylic acid (MDA) and unidentified mal-x were detected after 7 days. MMA and MDA were the major degrading compounds. Esterase activity involved in malathion degradation was also determined in culture filtrate of MOS-5. Results indicated that esterase activity was two folds more in the presence of yeast extract compared to glucose. These results indicate that Bt MOS-5 may consider as highly potential candidate in the biodegradation of organophosphorus in contaminated soil.
Keywords: (Degradation of malathion, cometabolism, esrase .)
