Department of Botany and Microbiology, University of Oklahoma, 770 Van Vleet Oval, Norman, Oklahoma 73019.
Appl Environ Microbiol. 1989 Apr;55(4):977-83. doi: 10.1128/aem.55.4.977-983.1989.
The effects of organic acid anions on the growth of Syntrophomonas wolfei was determined by varying the initial concentration of the acid anion in the medium. The addition of 15 mM acetate decreased the growth rate of a butyrate-catabolizing coculture containing Methanospirillum hungatei from 0.0085 to 0.0029 per hour. Higher initial acetate concentrations decreased the butyrate degradation rate and the yield of cells of S. wolfei per butyrate degraded. Inhibition was not due to the counter ion or the effect of acetate on the methanogen. Initial acetate concentrations above 25 mM inhibited crotonate-using pure cultures and cocultures of S. wolfei. Benzoate and lactate inhibited the growth of S. wolfei on crotonate in pure culture and coculture. Lactate was an effective inhibitor of S. wolfei cultures at concentrations greater than 10 mM. High concentrations of acetate and lactate altered the electron flow in crotonate-catabolizing cocultures, resulting in the formation of less methane and more butyrate and caproate. The inclusion of the acetate-using methanogen, Methanosarcina barkeri, in a methanogenic butyrate-catabolizing coculture increased both the yield of S. wolfei cells per butyrate degraded and the efficacy of butyrate degradation. Butyrate degradation by acetate-inhibited cocultures occurred only after the addition of Methanosarcina barkeri. These results showed that the metabolism of S. wolfei was inhibited by high levels of organic acid anions. The activity of acetate-using methanogens is important for the syntrophic degradation of fatty acids when high levels of acetate are present.
通过改变培养基中酸阴离子的初始浓度来确定有机酸阴离子对Syntrophomonas wolfei 生长的影响。添加 15 mM 乙酸使含有 Methanospirillum hungatei 的丁酸盐分解共培养物的生长速率从 0.0085 降至 0.0029 每小时。较高的初始乙酸浓度降低了丁酸的降解率和 S. wolfei 细胞的产率每降解 1 摩尔丁酸。抑制不是由于反离子或乙酸对产甲烷菌的影响。初始乙酸浓度高于 25 mM 抑制了纯培养和 S. wolfei 共培养的丙酸盐利用。苯甲酸盐和乳酸盐抑制了 S. wolfei 在纯培养和共培养中对丙酸盐的生长。乳酸盐在浓度大于 10 mM 时是 S. wolfei 培养物的有效抑制剂。高浓度的乙酸和乳酸盐改变了丙酸盐分解共培养物中的电子流，导致形成的甲烷减少，而丁酸和己酸增加。将利用乙酸的产甲烷菌 Methanosarcina barkeri 包含在产甲烷的丁酸盐分解共培养物中，增加了每降解 1 摩尔丁酸盐的 S. wolfei 细胞的产率和丁酸盐降解的功效。仅在添加 Methanosarcina barkeri 后，受乙酸抑制的共培养物才开始降解丁酸盐。这些结果表明，高水平的有机酸阴离子抑制了 S. wolfei 的代谢。当存在高浓度的乙酸盐时，利用乙酸的产甲烷菌的活性对于脂肪酸的协同降解很重要。
