Contracted but effective: production of enantiopure 2,3-butanediol by thermophilic and GRAS Bacillus licheniformis
Contracted but effective: production of enantiopure 2,3-butanediol by thermophilic and GRAS Bacillus licheniformis
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简约但有效：嗜热和 GRAS 地衣芽孢杆菌生产对映体纯 2,3-丁二醇
DOI：
10.1039/c6gc01023g
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发表时间：
2016-01-01
期刊：
影响因子：
9.8
通讯作者：
Xu, Ping
中科院分区：
文献类型：
--
作者：
Ge, Yongsheng;Li, Kun;Xu, Ping
通过化学方法生产具有手性基团的化学品很有吸引力，但实施起来困难。光学活性的2,3 - 丁二醇（2,3 - BD）能提供两个手性基团，在不对称合成中具有特殊应用。然而，从不可再生资源化学合成2,3 - BD成本高昂，且会产生三种立体异构体的混合物。因此，通过绿色生物技术途径生产对映纯的2,3 - BD是非常理想的。在这项工作中，我们引入了一个“筛选、分析、突变和评估（SAME）”流程，以2,3 - BD为目标分子来获得用于生产手性化学品的高效微生物。地衣芽孢杆菌MW3是一种公认安全（GRAS）的嗜热菌株，首先被选作一种有潜力的宿主。然后研究了地衣芽孢杆菌MW3中2,3 - BD立体异构体形成的机制。两种立体特异性的2,3 - BD脱氢酶（BDHs），即2R,3R - BDH（由gdh编码）和内消旋 - BDH（由budC编码），被确定分别负责（2R,3R）- 2,3 - BD和内消旋 - 2,3 - BD的生产。构建了两种代谢工程菌株，地衣芽孢杆菌MW3（ΔbudC）和地衣芽孢杆菌MW3（Δgdh），分别用于生产（2R,3R）- 2,3 - BD和内消旋 - 2,3 - BD。发酵42小时后，地衣芽孢杆菌MW3（ΔbudC）合成了123.7 g/L的（2R,3R）- 2,3 - BD；而地衣芽孢杆菌MW3（Δgdh）在32小时后合成了90.1 g/L的内消旋 - 2,3 - BD。由于它们的高产率和生物安全性，这些经过工程改造的地衣芽孢杆菌菌株在对映纯（2R,3R）- 2,3 - BD和内消旋 - 2,3 - BD的商业生产中可能具有潜力。这种精简但有效的“筛选、分析、突变和评估（SAME）”流程可能作为生产其他手性化学品的一种替代方法。
The production of chemicals with chiral groups through chemical methods is attractive but difficult to perform. Optically active 2,3-butanediol (2,3-BD) can provide two chiral groups and has special applications in asymmetric synthesis. However, the chemical production of 2,3-BD from nonrenewable resources is expensive to perform and results in a mixture of three stereoisomeric forms. Enantiopure 2,3-BD production through green biotechnological routes is thus rather desirable. In this work, we introduced a “SAME” (Screening, Analysis, Mutation, and Evaluation) process to achieve efficient microbes for chiral chemicals’ production using 2,3-BD as a target molecule. Bacillus licheniformis MW3, a GRAS and thermophilic strain, was firstly selected as a promising host. The mechanism of stereoisomer formation of 2,3-BD in B. licheniformis MW3 was then investigated. Two stereospecific 2,3-BD dehydrogenases (BDHs), 2R,3R-BDH (encoded by gdh) and meso-BDH (encoded by budC), were identified to be responsible for the production of (2R,3R)-2,3-BD and meso-2,3-BD. Two metabolically engineered strains, B. licheniformis MW3 (ΔbudC) and B. licheniformis MW3 (Δgdh), were constructed for the production of (2R,3R)-2,3-BD and meso-2,3-BD, respectively. After 42 h of fermentation, 123.7 g L−1 (2R,3R)-2,3-BD was synthesized using B. licheniformis MW3 (ΔbudC); while 90.1 g L−1meso-2,3-BD was synthesized after 32 h using B. licheniformis MW3 (Δgdh). Because of their high levels of production and biosecurity, these engineered B. licheniformis strains might have potential in the commercial production of enantiopure (2R,3R)-2,3-BD and meso-2,3-BD. The contracted but effective “SAME” process might serve as an alternative method for other chiral chemicals’ production.