树脂原位吸附促进高浓度底物不对称氧化还原合成(S)-苯基乙二醇

Enhancement of asymmetric redox efficiency for (S)-1-phenyl-1,2-ethanediol synthesis at high substrate concentration by in situ resin adsorption

以近平滑假丝酵母(Candida parapsilosis)全细胞为催化剂,考察了添加吸附树脂对不对称氧化还原外消旋苯基乙二醇制备(S)-苯基乙二醇(S-PED)的影响。通过树脂吸附性能考察,筛选出一种对底物有较快吸附速率和较大吸附量的树脂NKAⅡ,在反应体系中加入一定量NKAⅡ树脂,可以显著降低底物和产物对反应过程的抑制,提高反应的初始底物浓度。结合树脂对底物的吸附量和菌体反应的最适底物浓度,建立了树脂添加量随底物浓度变化的关系式,通过此公式添加树脂将溶液中底物产物总浓度控制在最适水平,从而实现高初始浓度底物、快速度反应。在40 g/L初始底物浓度转化体系中加入0.74 g树脂,平衡2 h后,反应108 h,产物S-PED的ee值和产率分别为98.1%和88.5%,产物浓度达到35.4 g/L。

The effect of addition of absorbent resin on the preparation of （S）-1-phenyl-1,2-ethanediol （S-PED） from racemate by stereoinversion was investigated, with whole cells of Candida parapsilosis as catalyst. To increase the substrate concentration in reaction, absorbent resin NKA Ⅱ was selected, which had a relatively high adsorption amount and velocity to both substrate and product. By adding NKA Ⅱ adsorption resin in the reaction system, substrate and or product inhibition was mitigated, and the initial substrate concentration was thus increased. According to adsorption capacity and optimal substrate concentration of reaction, a formula was established about the resin addition amount along with the change of substrate concentration. According to the formula, the PED concentration in aqueous phase could be controlled at a best level. Thus, high substrate concentration and high reaction speed could be achieved. Then 0.74 g NKAⅡ adsorbent resin was added to the system at an increased substrate concentration of 40 g/L with a pre-adsorption for 2 h before reaction. When reacting for 108 h under optimized conditions, the optical purity arid yield of （S）-enantiomer reached 98.1% and 88.5% respectively, with the product concentration of 35.4 g/L.