The Study Of Soybean Herbicide Degrading Bacteria

Pendimethalin is a broad-spectrum and selective dinitrobenzene herbicide, and thedegradation of pendimethalin is mainly biodegradation and light degradation in theenvironment. There have been some reports about degrading bacteria of pendimethalin athome and abroad, but degradation rate of degrading bacteria should be improved. In this study,pendimethalin degrading fungi were isolated from soil which was sprayed with pendimethalin,and researched the degradation characteristics and application of the strain. Methods for thepreparation and application of microbial preparation were provided the experimental basis andtheoretical basis.Firstly, the study determined the extraction method andtest condition of HPLC,withpetroleum ether as extraction agent, and extract pendimethalin from the fungi culture solutionby separating funnel. Secondly, the pendimethalin degrading fungi were isolated byenrichment culture from soil, and identifying the strains by characteristic of colonies and thethe evolutionary tree. Thirdly, the degradation rate to pendimethalin was affected by mediumculture and growth conditions such as pH, temperature, and sucrose and pendimethanlinconcentration. Besides,the effect of efficient degradation strains in the soil was studied.With petroleum ether as extraction agent, extract pendimethalin from the fungi culturesolution by separating funnel, and detect with HPLC. Analytical column, C18column(4.6×150mm,5μm); Column temperature,30℃; mobile phase, methanol-water (85:15); flowrate:1mll/min; UV detection wavelength:238nm. The6pendimethalin degrading fungi wereisolated by enrichment culture from soil, in these fungi, only the degradation rate ofpendimethalin by strain Qsun-1is75.21%, and Qsun-6was identified as Aspergillustubingensi by DNA identification. The ideal growth of strain Qsun-6and a higher degradationrate to pendimethalin could be gained at additional carbon source about1%,30℃, pH6.0,and0~200mg·L-1of pendimethalin. Pendimethalin is poison for radish growth, but afterQsun-6degradating, the harm caused by pendimethalin was significantly reduced theinhibition rate of seed germination was10%, decreased40%,21d after germination, the growth inhibition rate was4.57%, decreased33.64%. Qsun-3was identified as Aspergillusoryzae by DNA identification, although Qsun-3has a high tolerance for pendimethalin, butthe degradation rate and the treatment effect of soil which was sprayed with pendimethalin areworse than Qsun-6.