定向产S-1-苯乙醇菌株的筛选和发酵

以DL-1-苯乙醇为唯一碳源从土壤微生物中筛选出1株高度立体选择性还原苯乙酮为S-1-苯乙醇的产酶菌株No.XC35-8。对发酵条件进行了优化，考察了多种辅助底物对酶促反应的影响，选取异丙醇进一步研究其对酶促反应的促进作用。结果表明：5g/L葡萄糖为培养基碳源，10g/L胰蛋白胨为氮源，30℃，200r/min振荡培养30h。转化底物苯乙酮体积分数为0.1%，辅助底物异丙醇体积分数为6%，转化24h，底物转化率可达83.4%，产物的对映体过量值(ee值)为99.5%。

Screening and fermentation of a directed S-1-phenyl alcohol-producing strain

Screening of acetophenone reduction microorganisms has been carried out and one special strain was ultimately isolated from the soil when DL-1-phenyl alcohol was used as the only carbon source. This strain No. XC35-8 uses DL-1-phenyl alcohol as a growth inducer and gave high conversion and optical selectivity when it was used to reduce acetophenone to S-1-phenyl alcohol. The culture and reduction reaction parameters were investigated in detail and different co substrates were added in an attempt to improve the conversion. The results showed that the acetophenone conversion with strain No. XC35-8 reached 83.4% while the ee value of S-1-phenyl alcohol was as high as 99.5% when it was cultured for 30 hours at 30℃ with shaking at 200r/min and 0.1% (volume fraction) 1-phenyl alcohol as the inducer, 5g/L glucose as carbon source and 10g/L tryptone as nitrogen source followed by reaction for 24 hours with an acetophenone substrate concentration of 0.1% (volume fraction) with 6% (volume fraction) of 2-propanol as the co-substrate. 