Whole‐Cell Teabag Catalysis for the Modularisation of Synthetic Enzyme Cascades in Micro‐Aqueous Systems
Whole‐Cell Teabag Catalysis for the Modularisation of Synthetic Enzyme Cascades in Micro‐Aqueous Systems
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DOI：
10.1002/cctc.201300880
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发表时间：
2014-04
期刊：
影响因子：
4.5
通讯作者：
Jochen Wachtmeister;Andre Jakoblinnert;Justyna K. Kulig;H. Offermann;D. Rother
中科院分区：
文献类型：
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作者：
Jochen Wachtmeister;Andre Jakoblinnert;Justyna K. Kulig;H. Offermann;D. Rother
结合酶以形成多步酶级联具有巨大的潜力，可以用高原子效率和生态效率的合成策略取代现有的化学路线，以及获得新产品，特别是具有多立体中心的产品。然而，用于设置适当的反应条件和工艺模式的简单解决方案和工具几乎不可用。使用充满整个电池的茶袋具有几个优点，例如1）简化催化剂的处理和回收，2）容易组合来自催化剂工具箱的各种催化剂，3）在纯化期间快速测试不同的操作模式，以及4）简化下游处理。其中一个主要优点是冻干的全细胞催化剂可以应用于微水介质中，允许高底物负载（也是水溶性差的底物），同时实现高催化剂稳定性。这在本文中对于从廉价醛开始的合成两步级联到手性1，2-二醇得到了证明。使用荧光假单胞菌苯甲醛裂解酶对两种醛进行碳化，随后用罗尔斯通氏菌属醇脱氢酶进行氧化还原，得到浓度高达339 mM的1-苯基丙烷-1，2-二醇[（1 R，2 R）-PPD]，对映体和非对映体过量> 99%。因此，全细胞催化和茶袋模块化的组合允许廉价，易于应用和有效的催化剂制备，以测试酶组合和最佳反应条件，直至制备规模。通过避免催化剂纯化和固定化，并且与水性体系中的那些相比能够实现高底物负载，可以实现具有非常高的产物浓度的手性二醇的有效生产。
Combining enzymes to form multi‐step enzyme cascades has great potential to replace existing chemical routes with high atom‐efficient and eco‐efficient synthesis strategies as well as to grant access to new products, especially those with multi‐stereogenic centres. However, easy solutions and tools for setting up appropriate reaction conditions and process modes are hardly available. The utilisation of teabags filled with whole cells has several advantages, such as 1) simplified handling and recovery of catalyst, 2) easy combination of various catalysts from catalyst toolboxes, 3) fast testing of different operating modes during cascadation and 4) simplified downstream processing. One of the main advantages is that lyophilised whole‐cell catalysts can be applied in micro‐aqueous media, allowing high substrate loads (also of poorly water‐soluble substrates) and concomitantly enabling high catalyst stability. This was demonstrated herein for a synthetic two‐step cascade towards chiral 1,2‐diols starting from cheap aldehydes. The carboligation of two aldehydes using Pseudomonas fluorescens benzaldehyde lyase and subsequent oxidoreduction with Ralstonia sp. alcohol dehydrogenase yielded 1‐phenylpropane‐1,2‐diol [(1R,2R)‐PPD] in concentrations of up to 339 mM and excellent enantiomeric and diastereomeric excesses >99 %. Therefore, the combination of whole‐cell catalysis and teabag modularisation allows cheap, easy‐to‐apply and efficient catalyst preparation to test enzyme combinations and optimal reaction conditions up to the preparative scale. By circumventing catalyst purification and immobilisation, and enabling high substrate loadings compared to those in aqueous systems, efficient production of a chiral diol with extraordinarily high product concentrations can be achieved.