Cover Image |
| |
Authors: | Zhiqiang Wen Rodrigo Ledesma-Amaro Minrui Lu Yu Jiang Shuliang Gao Mingjie Jin Sheng Yang |
| |
Affiliation: | 1. School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, China;2. Department of Bioengineering, Imperial College London, London, UK;3. Huzhou Center of Industrial Biotechnology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Zhejiang, China Shanghai TaoYuSheng Biotechnology Co., Ltd., Shanghai, China;4. Zhejiang Huarui Biotechnology Co., Ltd., Zhejiang, China;5. Huzhou Center of Industrial Biotechnology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Zhejiang, China |
| |
Abstract: | Synthetic microbial communities have become a focus of biotechnological research since they can overcome several of the limitations of single-specie cultures. A paradigmatic example is Clostridium cellulovorans DSM 743B, which can decompose lignocellulose but cannot produce butanol. Clostridium beijerinckii NCIMB 8052 however, is unable to use lignocellulose but can produce high amounts of butanol from simple sugars. In our previous studies, both organisms were cocultured to produce butanol by consolidated bioprocessing. However, such consolidated bioprocessing implementation strongly depends on pH regulation. Since low pH (pH 4.5–5.5) is required for butanol fermentation, C. cellulovorans cannot grow well and saccharify sufficient lignocellulose to feed both strains at a pH below 6.4. To overcome this bottleneck, this study engineered C. cellulovorans by adaptive laboratory evolution, inactivating cell wall lyases genes (Clocel_0798 and Clocel_2169), and overexpressing agmatine deiminase genes (augA, encoded by Cbei_1922) from C. beijerinckii NCIMB 8052. The generated strain WZQ36: 743B*6.0*3△lyt0798△lyt2169-(pXY1-Pthl-augA) can tolerate a pH of 5.5. Finally, the alcohol aldehyde dehydrogenase gene adhE1 from Clostridium acetobutylicum ATCC 824 was introduced into the strain to enable butanol production at low pH, in coordination with solvent fermentation of C. beijerinckii in consortium. The engineered consortium produced 3.94 g/L butanol without pH control within 83 hr, which is more than 5-fold of the level achieved by wild consortia under the same conditions. This exploration represents a proof of concept on how to combine metabolic and evolutionary engineering to coordinate coculture of a synthetic microbial community. |
| |
Keywords: | adaptive laboratory evolution agmatine deiminase cell wall lyases consolidated bioprocessing low pH resistance |
|
|