Hirokawa Yasutaka, Suzuki Iwane, Hanai Taizo
Laboratory for Bioinformatics, Graduate School of Systems Biosciences, Kyushu University, 804 Westwing, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Laboratory of Plant Physiology and Metabolism, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai, Tsukuba 305-8572, Japan.
J Biosci Bioeng. 2015 May;119(5):585-90. doi: 10.1016/j.jbiosc.2014.10.005. Epub 2014 Nov 7.
Cyanobacterium is an attractive host for the production of various chemicals and alternative fuels using solar energy and carbon dioxide. In previous study, we succeeded to produce isopropanol using engineered Synechococcus elongatus PCC 7942 under dark and anaerobic conditions (0.43 mM, 26.5 mg/l). In the present study, we report the further optimization of this isopropanol producing condition. We then optimized growth conditions for production of isopropanol by the engineered cyanobacteria, including the use of cells in early stationary phase and buffering of the production medium to neutral pH. We observed that shifting of cultures from dark and anaerobic to light and aerobic conditions during the production phase dramatically increased isopropanol production by conversion to isopropanol from acetate, byproduct under dark and anaerobic condition. Under the optimized production conditions, the titer of isopropanol was elevated 6-fold, to 2.42 mM (146 mg/l).
蓝细菌是利用太阳能和二氧化碳生产各种化学品和替代燃料的理想宿主。在之前的研究中，我们成功地利用工程改造的聚球藻PCC 7942在黑暗和厌氧条件下生产了异丙醇（0.43 mM，26.5 mg/l）。在本研究中，我们报告了这种异丙醇生产条件的进一步优化。然后，我们优化了工程蓝细菌生产异丙醇的生长条件，包括使用处于早期稳定期的细胞以及将生产培养基缓冲至中性pH值。我们观察到，在生产阶段将培养物从黑暗和厌氧条件转变为光照和好氧条件，通过将黑暗和厌氧条件下的副产物乙酸盐转化为异丙醇，显著提高了异丙醇的产量。在优化的生产条件下，异丙醇的产量提高了6倍，达到2.42 mM（146 mg/l）。
