Chwa Jun-Won, Kim Wook Jin, Sim Sang Jun, Um Youngsoon, Woo Han Min
Clean Energy Research Center, Korea Institute of Science and Technology, Seongbuk-gu, Seoul, Korea.
Green School (Graduate School of Energy and Environment), Korea University, Seongbuk-gu, Seoul, Korea.
Plant Biotechnol J. 2016 Aug;14(8):1768-76. doi: 10.1111/pbi.12536. Epub 2016 Feb 16.
Capture and conversion of CO2 to valuable chemicals is intended to answer global challenges on environmental issues, climate change and energy security. Engineered cyanobacteria have been enabled to produce industry-relevant chemicals from CO2 . However, the final products from cyanobacteria have often been mixed with fermented metabolites during dark fermentation. In this study, our engineering of Synechococcus elongatus PCC 7942 enabled continuous conversion of CO2 to volatile acetone as sole product. This process occurred during lighted, aerobic culture via both ATP-driven malonyl-CoA synthesis pathway and heterologous phosphoketolase (PHK)-phosphotransacetylase (Pta) pathway. Because of strong correlations between the metabolic pathways of acetate and acetone, supplying the acetyl-CoA directly from CO2 in the engineered strain, led to sole production of acetone (22.48 mg/L ± 1.00) without changing nutritional constraints, and without an anaerobic shift. Our engineered S. elongatus strains, designed for acetone production, could be modified to create biosolar cell factories for sustainable photosynthetic production of acetyl-CoA-derived biochemicals.
将二氧化碳捕获并转化为有价值的化学品旨在应对环境问题、气候变化和能源安全等全球性挑战。工程改造的蓝细菌已能够利用二氧化碳生产与工业相关的化学品。然而，在黑暗发酵过程中，蓝细菌产生的最终产物常常与发酵代谢物混合在一起。在本研究中，我们对聚球藻PCC 7942进行工程改造，使其能够将二氧化碳持续转化为挥发性丙酮作为唯一产物。该过程通过ATP驱动的丙二酰辅酶A合成途径和异源磷酸酮醇酶（PHK）-磷酸转乙酰酶（Pta）途径在光照有氧培养过程中发生。由于乙酸盐和丙酮代谢途径之间存在强相关性，在工程菌株中直接从二氧化碳供应乙酰辅酶A，导致仅产生丙酮（22.48 mg/L±1.00），而不改变营养限制，也无需厌氧转变。我们设计用于生产丙酮的工程改造聚球藻菌株可以进行改造，以创建生物太阳能电池工厂，用于可持续光合生产乙酰辅酶A衍生的生物化学品。
