Programming Integrative Extracellular and Intracellular Biocatalysis for Rapid, Robust, and Recyclable Synthesis of Trehalose
Programming Integrative Extracellular and Intracellular Biocatalysis for Rapid, Robust, and Recyclable Synthesis of Trehalose
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编程整合细胞外和细胞内生物催化以快速、稳健且可回收地合成海藻糖
DOI：
10.1021/acscatal.7b03445
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发表时间：
2018-03-01
期刊：
影响因子：
12.9
通讯作者：
Zhong, Chao
中科院分区：
文献类型：
--
作者：
Jiang, Ling;Song, Xiaogang;Zhong, Chao
我们在此介绍了一种策略，该策略利用并整合了全细胞催化的属性与细胞外固定化酶的增强的稳定性，以可扩展的方式进行快速，稳健，可回收的酶级联反应。本研究采用酶法固定化β-淀粉酶（BA），以大肠杆菌为载体，通过两步连续生物转化酶促反应，以可溶性淀粉为原料催化合成海藻糖。大肠杆菌生物膜卷曲展示技术，在同一细胞内表达海藻糖合酶（TreS）。与基于细胞与分离的BA偶联的策略相比，这种整合策略通过有效地减少BA与细胞内TreS酶的平均距离而使最大海藻糖形成速率增加103.5 +/-18.7%。此外，在相对高的淀粉浓度（10%w/v）下，用15 g/L的工程化细胞，淀粉转化为海藻糖的最大产率高达59.0 +/-1.3%。我们进一步表明，即使在连续8轮生物催化后，海藻糖的生产率和细胞活力的百分比分别保持在89.1 +/- 4.4%和85.2 +/-3.6%。此外，即使在苛刻的条件下，例如，富含大量有机溶剂的溶液中，该策略也表现出极好的操作稳定性。这里展示的策略开辟了将细胞外催化与细胞内反应相结合的研究机会，以快速和稳健地生产各种基于价值的产品。
We herein introduce a strategy that leverages and integrates the attributes of whole-cell catalysis with enhanced stability of extracellular immobilized enzymes for rapid, robust, recyclable enzyme cascade reactions in a scalable fashion. We demonstrated the utility of the integrative strategy for catalytic synthesis of trehalose from soluble starch with two-step sequential bioconversion enzymatic reactions, implemented by coupling the enzymatic immobilization of beta-amylase (BA), based upon E. coli biofilm curli display technique, with intracellular expression of trehalose synthase (TreS) within the same cells. This integrative strategy, compared with a strategy based on cells coupled with isolated BA, enabled a 103.5 +/- 18.7% increase in the maximum trehalose formation rate by efficiently reducing the average distance of BA to intracellluar TreS enzyme. In addition, the maximum yield of starch into trehalose reached as high as 59.0 +/- 1.3% at a relatively high starch concentration (10% w/v) with 15 g/L of engineered cells. We further showed that the productivity of trehalose and the percentages of cell viability remained 89.1 +/- 4.4% and 85.2 +/- 3.6%, respectively, even after 8 continuous rounds of biocatalysis. In addition, this strategy exhibited superb operational stability even under harsh conditions, for example, solutions rich in high amount of organic solvents. The strategy demonstrated here opens up research opportunities of combining extracellular catalysis with intracellular reactions for rapid and robust production of various value-based products.