Optimization of Enzymatic Gas‐Phase Reactions by Increasing the Long‐Term Stability of the Catalyst
Optimization of Enzymatic Gas‐Phase Reactions by Increasing the Long‐Term Stability of the Catalyst
复制标题
通过提高催化剂的长期稳定性来优化酶促气相反应
DOI：
10.1021/bp034334e
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发表时间：
2004
影响因子：
2.9
通讯作者：
Jochen Büchs
中科院分区：
文献类型：
--
作者：
Clara Ferloni;Matthias Heinemann;W. Hummel;T. Daussmann;Jochen Büchs
酶的气相反应通常在连续反应器中进行，因此需要非常稳定和活性的催化剂才能在成本效益的水平上进行这种转化。本文研究了由短乳杆菌（LBADH）的固体醇脱氢酶催化气态苯乙酮还原为对构象纯(R)‐1‐苯乙醇，并将其固定在玻璃微珠上。最初，在40°C和0.5水活度的反应条件下，催化剂的半衰期为1天。结果表明，观察到的活性下降是由于酶本身（LBADH）的降解，而不是由于共固定的辅助因子NADP的降解。通过在酶固定前向细胞提取物中添加蔗糖，催化剂制备的半衰期（在40°C下）增加了40倍。在连续气相反应器中，在不同温度（25-60℃）下制备了稳定催化剂。在50℃下，连续反应前80 h的时空产率达到107 g/L/d。
Enzymatic gas‐phase reactions are usually performed in continuous reactors, and thus very stable and active catalysts are required to perform such transformations on cost‐effective levels. The present work is concerned with the reduction of gaseous acetophenone to enantiomerically pure ( R)‐1‐phenylethanol catalyzed by solid alcohol dehydrogenase from Lactobacillus brevis (LBADH), immobilized onto glass beads. Initially, the catalyst preparation displayed a half‐life of 1 day under reaction conditions at 40 °C and at a water activity of 0.5. It was shown that the observed decrease in activity is due to a degradation of the enzyme itself (LBADH) and not of the co‐immobilized cofactor NADP. By the addition of sucrose to the cell extract before immobilization of the enzyme, the half‐life of the catalyst preparation (at 40 °C) was increased 40 times. The stabilized catalyst preparation was employed in a continuous gas‐phase reactor at different temperatures (25–60 °C). At 50 °C, a space‐time yield of 107 g/L/d was achieved within the first 80 h of continuous reaction.