Bacillus megaterium WZ009催化合成(R)-4-氯-3-羟基丁酸乙酯和(S)-3-羟基-γ-丁内酯

以外消旋4-氯-3-羟基丁酸乙酯为唯一C源的富集培养筛选得到一株菌株WZ009,经16S rDNA测序鉴定为巨大芽胞杆菌(Bacillus megaterium)。B.megaterium WZ009静息细胞可以立体选择性催化(S)-4-氯-3-羟基丁酸乙酯水解和脱氯反应得到光学纯的(R)-4-氯-3-羟基丁酸乙酯(e.e.≥99%)和(S)-3-羟基-γ-丁内酯(e.e.≥95%)。笔者对B.megaterium WZ009不对称催化反应影响因素(温度、pH、中和剂、底物浓度、时间进程以及细胞重复利用)进行优化研究,确定了该反应体系最优条件:底物浓度200 mmol/L,中和剂氨水,pH 7.2,40℃反应12 h,转化率达到50.6%,底物对映体过量值为99.6%。该生物催化合成(R)-4-氯-3-羟基丁酸乙酯和(S)-3-羟基-γ-丁内酯过程具有良好的工业化应用前景。

Synthesis of ethyl-（R）-4-chloro-3-hydroxybutyrate and（S）-3-hydroxy-γ-butyrolactone by being catalyzed by resting cell of Bacillus megaterium WZ009

A new strain WZ009 was isolated by enrichment culture with ethyl-4-chloro-3-hydroxybutyrate as the only source of carbon. Strain WZ009 was identified as Bacillus megaterium by 16 S rDNA gene sequencing. The resting cell of B. megaterium WZ009 catalyzed stereoselective hydrolysis and dechlorination of ethyl-（S）-4-chloro-3-hydroxybutyrate,obtained high optical active ethyl-（ R）-4-chloro-3-hydroxybutyrate（ e. e. ≥ 99%） and（ S）-3-hydroxy-γ-butyrolactone（ e. e. ≥ 95%）. The catalytic characteristics of B. megaterium WZ009 were studied. The optimal conditions were obtained as follows：substrate concentration 200 mmol /L,reaction temperature 40 ℃,pH 7. 2,neutralizing agent NH3·H2O and reaction time 12 h. Under the above-mentioned conditions,the conversion was 50. 6% with e. e.99. 6%. The biocatalysis synthesis of ethyl-（ R）-4-chloro-3-hydroxybutyrate and（ S）-3-hydroxy-γ-butyrolactone has a bright industrialization future.