Abstract: (R)-mandelic acid is a useful chiral synthon for the production of various pharmaceutical. In order to prepare (R)-mandelic acid from rac-mandelic acid, Brevibacterium sp. CCSYU10011 was screened from various microorganisms, of which the resting cells could convert the racmate to (R)-isomer. The process of bioconversion showed that the microorganism asymmetricly degraded (S)-mandelic acid from the racemate and (R)-mandelic acid was maintained. The factors affecting biotransformation efficiency were investigated, including temperature, pH, substrate concentration and cell biomass. Under the optimal conditions, 48.7% yield and 99% enantiomeric excess value were obtained.

Key words: (R)-mandelic acid, asymmetric degradation, resting cell, Brevibacterium sp.

摘要： 以外消旋扁桃酸为底物，筛选出一株短杆菌Brevibacterium sp. CCSYU 10011，该菌能转化外消旋扁桃酸为(R)-扁桃酸. 用全细胞转化法研究发现，其转化过程是不对称降解过程，即选择性降解了(S)-扁桃酸，进而获得(R)-扁桃酸. 考察了温度、pH、底物浓度及细胞量等因素对(S)-扁桃酸降解的影响，转化结束后，收率为48.7%，对映体过量值(e.e.)可达99%.

关键词: (R)-扁桃酸, 不对称降解, 全细胞转化, Brevibacterium sp.