Biodegradation of carbendazim and oxyfluorfen by autochthonous bacterial cultures
Loading...
Date
2017-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
To meet the food requirement of burgeoning human population, pesticides have become indispensible part of modern agriculture however their intensive use has led to contamination of air, water, soil and disruption of bio-geochemical cycles. Reports on groundwater contamination and its effect on human health have attracted attention all around. In the present study biodegradation of Carbendazim and Oxyfluorfen by two indigineous bacterial cultures (A1 and BI) has been undertaken. The bacterial isolates, able to tolerate ~ 400 ppm, of pesticide(s) were recovered from a rice field and characterized. Based on 16S rDNA sequencing A1 and BI were identified as Bacillus methylotrophicus and Streptomyces sp. respectively. Biodegradation of chemo-pollutants requires the production of extracellular enzymes like laccase, esterase, aldehyde dehydrogenase, phosphotriesterase etc. Presence of laccase enzyme was observed in both the isolates and the level of enzyme was 3.8 and 5.24 Uml-1, respectively for A1 and BI. Laccase is a polyphenol oxidase and found responsible for degradation of complex aromatic compounds. Presence of Esterase enzyme was observed in BI which was confirmed by amplification of EST gene and amplicon of size 1000bp was obtained. In vitro biodegradation of both the pesticides was determined by HPLC analysis and it was found that A1 degraded Carbendazim and Oxyfluorfen upto 86.35 and 81.33% respectively in 15 days. BI culture degraded Carbendazim and Oxyfluorfen upto 77.25 and 79.75% respectively in 15 days. GC-MS analysis of the intermediates of pesticides produced by A1 culture during biodegradation in broth revealed that the culture was able to degrade complex aromatic structures to simpler aliphatic low molecular weight compounds that confirmed the biodegradation of both the pesticides.
Description
Keywords
null