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Enzymatic Degradation of Monocrotophos by Extracellular Fungal OP Hydrolases

Jain, Rachna, Garg, Veena
Applied biochemistry and biotechnology 2013 v.171 no.6 pp. 1473-1486
Macrophomina, Aspergillus niger, Fusarium incarnatum, hydrolases, thin layer chromatography, molecular weight, monocrotophos, culture media, Penicillium, Aspergillus flavus, fungi
The present study explores the potential of extracellular fungal organophosphate (OP) hydrolase for the degradation of monocrotophos. Extracellular OP hydrolases were isolated and purified from five different fungal isolates viz. Aspergillus niger (M1), Aspergillus flavus (M2), Penicillium aculeatum (M3), Fusarium pallidoroseum (M4), and Macrophomina sp. (M5) by AmSO₄precipitation, dialysis, and G-100 chromatography. M3 showed highest percentage yield of 68.81 followed by 55.41 % for M1. Each of the purified enzyme fraction constituted of two different subunits of 33- and 67-kDa molecular weight. Optimum enzyme fraction (150 μg ml⁻¹) rapidly degraded monocrotophos within 120 h in phosphorus-free liquid culture medium (CZM) with Kdₑgof 0.0368, 0.0138, 0.048, 0.016, 0.0138, and 0.048 day⁻¹and half-life of 0.79, 2.11, 0.6, 1.8, and 2.11 days for M1, M2, M3, M4, and M5, respectively. The results were further confirmed by high performance thin layer chromatography and Fourier transform infrared which indicate the disappearance of monocrotophos by hydrolytic cleavage of vinyl phosphate bond. The overall order of enzymatic degradation was found to be P. aculeatum > A. niger > F. pallidoroseum > A. flavus = Macrophomina sp. Hence, the study concludes that extracellular OP hydrolases efficiently degraded monocrotophos and could be used as a potential candidate for the detoxification of this neurotoxin pesticide.