Sodium Alginate Entrapped Baker's Yeast Asymmetric Catalytic Synthesis Of (s) - (+) -1 - Phenyl - 2 - Propanol,

(S)-(+)-1-Phenyl-2-propanol can be used as building block for the synthesis of amphetamine hydrochloride,(R)-Selegiline,cathepsin K and Benzodiazepine.The reduction of phenylacetone or resolution of(R,S)-(+)-1-phenyl-2-propanol was catalyzed by chemical catalyst,enzyme and microorganism.But microbial reduction of phenylacetone by immobilized bake's yeast has been rarely mentioned in the literature.In this study,the asymmetric reduction of phenylacetone to(S)-(+)-Phenyl-2-propanol catalyzed by immobilized bake's yeast was studied.Determing their appearance in the bioreduction of phenylacetone by bake's yeast.The gas chromatogram(GC)was applied to detect the conversion of phenylacetone.(S)-(+)-Phenyl-2-propanol was characterized by IR and ~1HMNR.Enantiomeric excess(e.e.)was determined by specific optical rotation.At first,the asymmetric reduction of(S)-(+)-Phenyl-2-propanol by free bake's yeast was investigated when phenylacetone was chosen as the substrate.The effects of reaction conditions,such as substrate concentration,reaction time,reaction temperature,pH value and glucose concentration,on the reaction were investigated.The optimized reaction condition was as below:concentration of phenylacetone 3.28g/L,reaction time 22h,reaction temperature 25℃,pH 6.5 and glucose concentration 15g/L.The conversion of phenylacetone and e.e.of(S)-1-phenyl-2-propanol were 61.6%and 90.4%.The immobilization conditions about the best technological parameters were studied such as the concentration of sodium alginate and calcium chloride,immobilized temperature,concentration of cells and so on.The concentration of glutaraldehyde and cross-link time were also studied.The results showed that sodium alginate and calcium chloride had the same the concentration of 3%,concentration of cells 20%,immobilized time 4h,temp.at 30℃,concentration of glutaraldehyde 1.5%and cross-link time 2h.At last,the asymmetric reduction of(S)-(+)-Phenyl-2-propanol by immobilized bake's yeast was investigated when phenylacetone was chosen as the substrate.The effects of reaction conditions,such as substrate concentration,concentration of cells,bead diameter,shaker rotation,pH value,reaction temperature and reaction time,on the reaction were investigated.The optimized reaction condition was as below: concentration of phenylacetone 5.74g/L,concentration of cells 1.5g,bead diameter 1.5mm to 2.0mm,shaker rotation 200r/min,pH7.5,reaction temperature 30℃and reaction time 24h.The conversion of phenylacetone and e.e.of(S)-(+)-Phenyl-2-propanol were 62.5%and 90.7%.But the conversion of phenylacetone and e.e.of(S)-(+)- Phenyl -2-propanol were 55.9%and 89.7%by free bake's yeast.So immobilized bake's yeast had higher conversion of phenylacetone and e.e. of(S)-(+)-Phenyl-2-propanol than free bake's yeast.Immobilized bake's yeast maintains high catalysis after consecutive use 3 times.It showed that the asymmetric reduction of phenylacetone to (S)-(+)-Phenyl-2-propanol can be catalyzed by free bake's yeast and immobilized bake's yeast.However,the conversion of phenylacetone and e.e.of(S)-(+)-Phenyl-2-propanol were higher when phenylacetone was catalyzed by immobilized bake's yeast.Moreover,it had higher stability and can stand higher concentration of phenylacetone.