Department Solar Materials, Helmholtz Centre for Environmental Research-UFZ, Leipzig, 04318, Germany.
Biotechnol J. 2020 Nov;15(11):e2000127. doi: 10.1002/biot.202000127. Epub 2020 Sep 9.
It is known that Synechocystis sp. PCC 6803 carrying a partial deletion of the succinate dehydrogenase (Synechocystis_∆sll1625) secretes succinate during aerobic cultivation with continuous illumination and in the presence of CO . Maximal succinate titers of 2 mM (236 mg L ) are reported. CO is identified as a crucial parameter for product formation, however, a detailed characterization of different cultivation conditions is still missing. Here the focus is on further reaction engineering to improve the photoautotrophic production of succinate using Synechocystis_∆sll1625. Therefore the impact of light availability, illumination regimes, nutrient availability, and external pH on product formation are investigated. Results obtained in this study reveal the importance of these parameters on the formation of succinate and cultivation with light/dark cycles increases the succinate concentration to 3 mM (354 mg L ) after 28 days of cultivation. Furthermore, cultivation in unbuffered medium under ambient CO conditions even doubled the final succinate titer to 4 mM (472 mg L ) after 28 days. Taking biomass concentrations into account, a maximal yield of succinate on biomass of 215 mg g is achieved, which is the highest so far reported for the production of succinate utilizing Synechocystis as host organism.
已知携带琥珀酸脱氢酶（Synechocystis_∆sll1625）部分缺失的集胞藻 sp. PCC 6803 在有氧培养条件下，连续光照并存在 CO 的情况下分泌琥珀酸。报道称，琥珀酸的最大产量为 2mM（236mgL）。CO 被确定为产物形成的关键参数，但不同培养条件的详细特征仍不清楚。在这里，我们专注于进一步的反应工程，使用 Synechocystis_∆sll1625 来提高琥珀酸的光自养生产。因此，研究了光可用性、光照制度、营养物质可用性和外部 pH 值对产物形成的影响。本研究的结果表明了这些参数对琥珀酸形成的重要性，并且光照/黑暗循环的培养将琥珀酸浓度提高到 28 天后的 3mM（354mgL）。此外，在环境 CO 条件下的未缓冲培养基中培养甚至将最终琥珀酸产量提高到 28 天后的 4mM（472mgL），增加了一倍。考虑到生物量浓度，在生物质上实现了琥珀酸的最大产率为 215mg g，这是迄今为止利用集胞藻作为宿主生物生产琥珀酸的最高产量。
