Efficient Biocatalysis with Immobilized Enzymes or Encapsulated Whole Cell Microorganism by Using the SpinChem Reactor System
Efficient Biocatalysis with Immobilized Enzymes or Encapsulated Whole Cell Microorganism by Using the SpinChem Reactor System
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DOI：
10.1002/cctc.201300599
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发表时间：
2013-12
期刊：
影响因子：
4.5
通讯作者：
Hendrik Mallin;Jan Muschiol;Emil Byström;U. Bornscheuer
中科院分区：
文献类型：
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作者：
Hendrik Mallin;Jan Muschiol;Emil Byström;U. Bornscheuer
如今，生物催化是用于有机化合物和药物的手性结构单元的酶促合成、用于调味品和香料工业的化合物、大宗化学品的生产以及用于食品工业的脂质的改性的既定方法。生物催化与使用过渡金属催化剂的经典（不对称）化学路线相比具有很强的竞争力，特别是与酶发现和蛋白质工程的新方法相结合，如最近在药物西格列汀的合成中所示。酶的成本效益应用，特别是用于合成廉价产品，需要固定化生物催化剂（或包封整个细胞），以提高其长期稳定性5]并促进其重复使用。与此同时，生物催化剂的固定化应该能够使用已建立的反应器设置，如固定床反应器（FBR），而不是简单的搅拌罐反应器（STR，图1）。6]FBR例如用于通过使用脂肪酶催化剂大规模生产化妆品领域的手性胺或润肤剂酯。然而，FBR遇到了几个缺点，这些缺点取决于例如反应器中的长度、直径和粒度、流速、柱内的压降、反应物和pH梯度以及长期使用后的失活特征。相比之下，操作上更简单的STR遇到载体的机械挑战，这导致生物催化剂材料的磨损和包封的全细胞的严重损坏，此外固定化生物催化剂的再循环相当费力。在此，我们已经研究了用于应用固定化酶和包封的全细胞的替代设置的使用。该SpinChem反应器（SCR; SpinChem是Nordic ChemQuest AB，Ume，Sweden的注册商标）使得能够同时搅拌和液体通过填充颗粒床的有效渗滤，这通过中空搅拌装置来实现，该中空搅拌装置允许固体反应室位于搅拌元件本身内部。SCR可以被看作是标准篮式反应器的演变。10]篮式反应器（英语：Basket reactor）是由Carberry于1964年首次提出的一种装置，其中四个篮在一个井内旋转，用于气体/固体反应。这个概念后来由Mahoney等人在1978年发展为“环形转篮反应器”。然而，在SpinChem反应器中，固相（例如固定化酶）存在于搅拌元件本身中多达四个单独的隔室中，这与篮式反应器相比提供了更大的混合和灵活性。图1.顶部：所研究的三个反应器设置的示意图。底部：SpinChem装置的照片（回流冷却器和氧气供应仅用于BVMO反应）。
Nowadays, biocatalysis is an established method for the enzymatic synthesis of chiral building blocks for organic compounds and pharmaceuticals, compounds for the flavor and fragrance industry, the production of bulk chemicals, and the modification of lipids for the food industry. Biocatalysis has become highly competitive with classical (asymmetric) chemical routes that use transition-metal catalysts, especially in combination with new methods for enzyme discovery and protein engineering, as recently shown for the synthesis of the drug Sitagliptin. The cost-effective application of enzymes, in particular for the synthesis of cheap products, requires immobilization of the biocatalyst (or the encapsulation of whole cells) to enhance their long-term stability 5] and facilitate their reuse. At the same time, immobilization of the biocatalyst should enable the use of established reactor setups, such as fixed-bed reactors (FBRs), instead of simple stirred-tank reactors (STRs, Figure 1). 6] FBRs are used, for instance, for the large-scale production of chiral amines or emollient esters for the cosmetic sector by using lipase catalysts. However, several disadvantages are encountered with FBRs, which depend on, for example, the length, diameter, and particle size in the reactor, the flow rate, the pressure drop within the column, and reactant and pH gradients, as well as inactivation profiles after extended use. In contrast, the more operationally simple STR encounters mechanical challenges for the carrier, which results in abrasion of the biocatalyst material and severe damage of encapsulated whole cells beside the fact that the recycling of the immobilized biocatalyst is rather laborious. Herein, we have investigated the use of an alternative setup for the application of immobilized enzymes and encapsulated whole cells. This SpinChem reactor (SCR; SpinChem is a registered trademark by Nordic ChemQuest AB, Ume , Sweden) enables the simultaneous stirring and efficient percolation of a liquid through packed particle beds, which is implemented by a hollow stirring device that allows the solid reaction chamber to be located inside the stirring element itself. The SCR can be seen as an evolution of the standard basket reactor. 10] The basket reactor, first published by Carberry in 1964, is a setup in which four baskets rotate inside a well for gas/solid reactions. This concept was later developed as the “annular spinning basket reactor” by Mahoney et al. in 1978. However, in the SpinChem reactor, the solid phase (such as an immobilized enzyme) is present in the stirring element itself in up to four separate compartments, which provides greater mixing and flexibility compared to the basket reactors. Figure 1. Top: Schematic representation of the three reactor setups that were investigated. Bottom: Photograph of the SpinChem device (reflux cooler and oxygen supply only for BVMO reaction).