Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain.
Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, Rúa da Fraga 10, E - 15008 La Coruña, Spain.
Bioresour Technol. 2020 Mar;300:122659. doi: 10.1016/j.biortech.2019.122659. Epub 2019 Dec 20.
Several anaerobic bioconversion technologies produce short chain volatile fatty acids and sometimes ethanol, which can together be elongated to hexanoic acid (C6 acid) by Clostridium kluyveri in a secondary fermentation process. Initiatives are needed to further optimize the process. Therefore, five strategies were tested aiming at elucidating their influence on hexanoic acid production from mixtures of acetic acid, butyric acid and ethanol. pH-regulated bioreactors, maintained at pH 7.5, 6.8 or 6.4 led to maximum C6 acid concentrations of, respectively, 19.4, 18.3 and 13.3 g L. At pH 6.8, yeast extract omission resulted in a decrease of the hexanoic acid concentration to 12.0 g L while the addition of an inorganic carbon source, such as bicarbonate, for pH control, increased the C6 acid concentration up to 21.4 g L. This research provides guidelines for efficient improved production of hexanoic acid by pure cultures of C. kluyveri, contributing to the state of art.
几种厌氧生物转化技术可产生短链挥发性脂肪酸，有时还可产生乙醇，这些物质可在二次发酵过程中被克氏柠檬酸杆菌进一步延伸为己酸（C6 酸）。需要采取措施进一步优化该过程。因此，本研究测试了 5 种策略，旨在阐明它们对从乙酸、丁酸和乙醇混合物生产己酸的影响。在 pH 值分别为 7.5、6.8 和 6.4 的 pH 调控生物反应器中，C6 酸的最大浓度分别为 19.4、18.3 和 13.3 g/L。在 pH 值为 6.8 时，酵母提取物的缺失会导致己酸浓度降低至 12.0 g/L，而添加碳酸氢盐等无机碳源来控制 pH 值则可将 C6 酸浓度提高至 21.4 g/L。本研究为利用克氏柠檬酸杆菌纯培养物高效生产己酸提供了指导，有助于该领域的发展。
