Study On Producing Enantiopure (R,R)-3-Phenylglycidiol By Biotransformation

Using 3-phenylglcidol as substrate and the sole carbon, we screened hundreds of bacteria and fungus strains with epoxide hydrolases from kinds of soil samples collected from many place.4 strains showed high enantioselectivity toward the epoxide 3-phenylglcidol. A fungi with best enantioselectivity was further studied and identified as Aspergillus fumigatus based on morphology and ITS sequence, which named A. fumigatus ZJUTZQ160.Then, the fermentation conditions for A. fumigatus ZJUTZQ160 were investigated based on single factor experiments, including carbon source, nitrogen source, metal ions, time for fermentation and the initial pH of medium, which influence the biomass, enzyme activity, e.e.s value and E value. The best result were obtained under the following condition: glucose 25 g/L, soybean flour 14g/L, NH4NO3 lg/L, K2HPO4·3H2O 1.0 g/L, KCl 0.5 g/L, MgSO4·7H2O 1.23 g/L,30℃, pH 4.0,60 h. In this contidion, the reaction rate of the substrate was 70.63%, the e.e.s and the E were 94.02% and 7.2, both of them increased 11.0% and 8.9%, respectively.Afterward, the conditions for kinetic resolution of racemic 3-phenylglcidol by A. fumigatus ZJUTZQ160 were studied including the initial pH, co-solvents, initial substrate concentration, bioconversion time and so on. It showed the best resolution conditions as follows:racemic PG (10mmol/L) in DMSO (4%) was hydrolyzed in 2mL KPB (0.1 M, pH7.2) using wet mycelium of A. fumigatus ZJUTZQ160 (1.0 g) at 30℃ for 10 h. It gave the best e.e.s value 99.9% and E value 19.07 under the best resolution condition. The research on substrate specificity of this enzyme showed that this fungi showed low enantioselectivity toward cinnamyl alcohol expoxide analogs.