Chemical Engineering Laboratory, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña (UDC), 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 (UDC), Rúa da Fraga 10, E-15008, La Coruña, Spain.
J Environ Manage. 2019 Jul 15;242:515-521. doi: 10.1016/j.jenvman.2019.04.093. Epub 2019 May 7.
Clostridium kluyveri was used for chain elongation of C2C4 fatty acids in stirred tank bioreactors. The influence of different electron acceptors (acetic acid, butyric acid and the mixture of both) on C6 fatty acid production was evaluated in presence of ethanol using similar molar alcohol/acid ratios around 3.5. Bottle batch assays without pH regulation and with only acetic acid as electron acceptor yielded a final C6 fatty acid concentration of 6.8 ± 0.6 g L. Then, pH-regulated bioreactors were operated at constant pH of 6.8. Under such conditions, the maximum growth rate was 0.039 h obtained using acetic acid and butyric acid as electron acceptors, whereas the lowest growth rate was 0.010 h with only butyric acid as electron acceptor. The maximum growth rate with acetic acid only, was similar, though slightly lower, as with the mixture of C2C4 fatty acids. Besides, the maximum productions of hexanoic acid were 11.8 g L, 13.1 g L and 21.2 g L using, respectively, acetic acid, butyric acid and the mixture of both acids as electron acceptors. Thus, the use of a mixture of acetic acid and butyric acid in presence of ethanol for chain elongation, at constant pH, proved to be efficient for hexanoic acid production.
利用克利夫兰梭菌（Clostridium kluyveri）在搅拌罐生物反应器中对 C2C4 脂肪酸进行链延伸。在乙醇存在的情况下，使用类似的摩尔醇/酸比约 3.5，评估了不同电子受体（乙酸、丁酸和两者的混合物）对 C6 脂肪酸生产的影响。在没有 pH 调节且仅使用乙酸作为电子受体的瓶批实验中，最终 C6 脂肪酸浓度为 6.8±0.6 g/L。然后，在恒定 pH 值为 6.8 的 pH 调节生物反应器中进行操作。在这些条件下，使用乙酸和丁酸作为电子受体时的最大生长速率为 0.039 h，而仅使用丁酸作为电子受体时的最低生长速率为 0.010 h。仅使用乙酸时的最大生长速率虽然略低，但与 C2C4 脂肪酸混合物相似。此外，分别使用乙酸、丁酸和两者的混合物作为电子受体时，己酸的最大产量分别为 11.8 g/L、13.1 g/L 和 21.2 g/L。因此，在乙醇存在下，使用乙酸和丁酸的混合物在恒定 pH 值下进行链延伸，被证明是生产己酸的有效方法。
