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Bacillus sp. DL-2 was isolated from the deep sea of the Western Pacific and further utilized as novel biocatalysts to efficiently asymmetrically hydrolyze (±)-1-phenylethyl acetate. After the optimization of hydrolytic reactions, chiral chemicals (R)-1-phenylethanol and (S)-1-phenylethyl acetate were obtained with high optical purities (96% and 99.8%, respectively). Our research is about the asymmeric hydrolysis of (±)-1-phenylethyl acetate using whole-cell biocatalysts. In addition, the optical purity of (S)-1-phenylethyl acetate generated through the kinetic resolution of (±)-1-phenylethyl acetate using the whole-cells of Bacillus sp. DL-2 was the highest report so far. Using the whole cells of deep sea bacterium Bacillus sp. DL-2 as the biocatalysts is an environmentally friendly method and will play critical roles in industrial asymmetric synthesis.

Chiral 1-phenylethanol and its ester derivative are important chiral chemicals in diverse industries and the preparation of those optically pure enantiomers is of great importance. One bacterium, Bacillus sp. DL-2, whose extracellular proteases could efficiently asymmetrically hydrolyse (±)-1-phenylethyl acetate, was isolated from the deep sea of the Western Pacific. After the immobilization of extracellular proteases and the optimization of enzymatic reactions, (R)-1-phenylethanol was prepared with the enantiomeric excess (e.e.) being 97% and the yield being 41%, respectively. The optimal resolution reaction condition for the preparation of (R)-1-phenylethanol using immobilized extracellular proteases was found to be 5-mM (±)-1-phenylethyl acetate, 360 mg/mL immobilized extracellular proteases, pH 6.5, and 20 °C for 2 h. (S)-1-phenylethyl acetate was generated through enzymatic kinetic resolution with the e.e. being as high as 99% and the yield being 71%, respectively. The optimal resolution reaction condition for the preparation of (S)-1-phenylethyl acetate was found to be 2.5-mM (±)-1-phenylethyl acetate, 440 mg/mL immobilized extracellular proteases, pH 7.5, and 35 °C for 10 h. Our report is the first report about the kinetic resolution of (±)-1-phenylethyl acetate using proteases and the enantio-preference of the proteases was found to be the same as those of most other esterases/lipases. Also notably, the optical purity of (S)-1-phenylethyl acetate generated through kinetic resolution using the proteases of Bacillus sp. DL-2 was the highest report so far. Proteases from deep-sea Bacillus sp. DL-2 are new contributions to the biocatalyst library for the preparation of valuable chiral alcohols and chiral esters through kinetic resolution.

A novel esterase EstC10 from Bacillus sp. CX01 isolated from the deep sea of the Western Pacific Ocean and the functionalities of EstC10 was characterized. At present, the reports about the kinetic resolution of racemic methyl 2-chloropropionate were quite rare. So we developed deep-sea microbial esterase EstC10 as a novel biocatalyst in the kinetic resolution of racemic methyl 2-chloropropionate and generate (R)-methyl 2-chloropropionate with high enantiomeric excess (>99%) after the optimization of process parameters such as pH, temperature, organic co-solvents, surfactants, substrate concentration and reaction time. Notably, the optimal substrate concentration (80 mmol/L) of esterase EstC10 was higher than the kinetic resolution of another esterase, Est12-7 (50 mmol/L). The novel microbial esterase EstC10 identified from the deep sea was a promising green biocatalyst in the generation of (R)-methyl 2-chloropropionate as well of many other valuable chiral chemicals in industry.