Continuous-Flow Asymmetric Synthesis of (3R)-3-Hydroxyl-5-hexenoates with Co-Immobilized Ketoreductase and Lactobacillus kefir Dehydrogenase Integrating Greener Inline Microfluidic Liquid-Liquid Extractors and Membrane Separators
Continuous-Flow Asymmetric Synthesis of (3R)-3-Hydroxyl-5-hexenoates with Co-Immobilized Ketoreductase and Lactobacillus kefir Dehydrogenase Integrating Greener Inline Microfluidic Liquid-Liquid Extractors and Membrane Separators
复制标题
使用共固定化酮还原酶和开菲尔乳杆菌脱氢酶连续流动不对称合成 (3R)-3-羟基-5-己烯酸酯，集成更环保的在线微流体液体萃取器和膜分离器
DOI：
10.1021/acssuschemeng.1c01419
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发表时间：
2021-06-25
影响因子：
8.4
通讯作者：
Chen, Fener
中科院分区：
文献类型：
--
作者：
Hu, Chen;Huang, Zedu;Chen, Fener
由酮还原酶（KRED）和开菲尔乳杆菌脱氢酶（LkADH）组成的双酶体系能有效地将3-氧代-5-己烯酸转化为（3R）-3-羟基-5-己烯酸，但其游离状态下稳定性差、回收困难、重复使用性差，阻碍了其实际应用。本工作采用包埋法将KRED/LkADH共固定于聚乙烯醇（PVA）颗粒中，所得KRED/LkADH@PVA不仅具有最高的催化活性，而且具有良好的上级物理和机械稳定性。值得注意的是，观察到KRED/LkADH@PVA可以循环至少6个连续循环，并且其最大耐受底物浓度是游离KRED/LkADH的2.34倍。随后通过将KRED/LkADH@PVA加载到与内联微流体液-液萃取和膜分离单元耦合的固定床反应器中来开发更绿色的连续流工艺。模型底物3-氧代己-5-烯酸叔丁酯可以在连续流动过程中在10 min停留时间内完全转化为（3R）-3-羟基-5-己烯酸叔丁酯，这提供了93%的分离产率，具有优异的立体选择性（> 99.9%ee）和22.03 g L-1 h（-1）的时空产率（即，528.72 g L-1 day（-1））。实现了31.1的低工艺质量强度值。
The dual-enzyme system composed of Ketoreductase (KRED) and Lactobacillus kefir Dehydrogenase (LkADH) is powerful in converting 3-oxohex-5-enoates into (3R)-3-hydroxyl-5-hexenoates, but its practical applications are hindered by low stability, difficult recovery, and poor reusability in the free state. In this work, KRED/LkADH was co-immobilized into polyvinyl alcohol (PVA) particles via the entrapment approach as the resulting KRED/LkADH@PVA not only exhibited the highest catalytic activity but also had superior physical and mechanical stability. Notably, it was observed that the KRED/LkADH@PVA could be recycled for at least six consecutive cycles, and its maximum tolerable substrate concentration was 2.34 times as high as that of the free KRED/LkADH. A greener continuous-flow process was subsequently developed by loading the KRED/LkADH@PVA into a fixed bed reactor that was coupled with inline microfluidic liquid-liquid extraction and membrane separation units. The model substrate tert-butyl 3-oxohex-5-enoate can be completely transformed into tert-butyl (3R)-3-hydroxyl-5-hexenoate in 10 min residence time in the continuous-flow process, which afforded a 93% isolated yield with excellent stereoselectivity (>99.9% ee) and a space time yield of 22.03 g L-1 h(-1) (i.e., 528.72 g L-1 day(-1)) after 24 h of continuous operation. A low value of process mass intensity of 31.1 was achieved.