Study Stenotrophomonas Maltophilia NJ2 In Transforming Imidacloprid To 5-hydroxy Imidacloprid

Biotransformation and biocatalysis technology have the characters of high efficiency, diversity, specialty of substrate, regioselectivity, chemical selectivity, enantiomorph selectivity. So it is praised with "the third wave of biotechnology" as followed medicine biotechnology and agriculture biotechnology. In this paper, we used microbial transformation method to isolate and screen microorganism which could efficiently transform neonicotinoid insecticide IMI to 5-hydroxy IMI, then 5-hydroxy IMI was further hydrolyzed under acid conditions to produce the highly insecticidal olefin IMI.Through enrichment culture using IMI as sole nitrogen source, a strain named NJ2 was isolated from the soil .Resting cells of NJ2 can transform IMI into a polar product by HPLC analysis. The transformated product extracted with organic solvent and re-crystallization was identified as 5-hydroxy IMI by using LC-MS/MS and NMR analysis. This strain was identified as Stenotrophomonas maltophilia on the basis of the physiological tests with ATB Expression system (ID32 STREP) (BioMerieux Vitek) and the analysis of 16s rDNA sequence.The fermention and resting cells transformation conditions of strain NJ2 were examined. Optimization of carbon sources showed glucose and maltose were the optimal carbon sources for growth, and maltose and malic acid were the optimal carbon sources for the transformation activity, acetic acid and ethanol were the optimal carbon source for specific activity. Optimization of nitrogen sources showed that peptone was the optimal nitrogen source for growth, beef extract and yeast extract were the optimal nitrogen sources for the transformation activity, corn steep was the optimal nitrogen source for specific activity.A very remarkable feature was that transformation of IMI by NJ2 was promoted by some carbohydrates and organic acids such as maltose, sucrose, malic acid, among which sucrose was the most effective effector for the activity in resting cells transformation, and the transformation activity reached the highest at 5% concentration of sucrose. But addition of sucrose in LB didn't effect on the enzyme activity. The concentration of sucrose was decreased in the progress of the transformation, and the biomass didn't increase. We guess that bacterias use the sucrose to provide deoxidized hydrogen. So...