Enzymes responsible for acetate oxidation intrinsic to acetic acid bacteria belonging to genus Acetobacter

筛选出几株乙酸菌，属于醋酸杆菌属，表现出强烈的乙酸氧化，并在乙酸氧化的微生物方面进行了研究。当所有可用的碳源和能源耗尽，只有乙酸留在具有稳定期的后期时，细菌开始消耗积累在培养基中的乙酸用于醋发酵。它们生长迅速，出现第二个稳定期，并观察到典型的双相生长曲线。来自第一生长期的细胞是耐酸性的，而来自第二生长期的细胞转变为酸敏感的。然而，没有明显的乙酸氧化发生时，可氧化的乙醇和其他可用的碳源仍然留在培养基中。此外，在允许乙酸积累超过4.5%的醋醪中没有观察到明显的乙酸氧化。有一个门槛 关于我们 在乙酸浓度中，因为大多数选择的菌株在乙酸积累的最终浓度小于3.7%时氧化乙酸。当仅给予乙酸作为唯一的碳源和能量源时，生物体在很长的滞后时间后最终使用乙酸。通过添加少量容易使用的能量源，如乙醇，缩短了滞后时间。从酶学分析来看，在与乙酸生成乙酰辅酶A有关的酶中，只有乙酰辅酶A合成酶活性增加较多，而乙酸激酶和磷酸转乙酰酶的活性变化不明显。当乙酸消耗时，异柠檬酸裂解酶和苹果酸合成酶的酶活性也显著增加。这些结果表明，乙酸通过乙酰辅酶A合成酶转化为乙酰辅酶A，以将乙酸盐置于TCA循环以及乙醛酸循环中，从而允许细菌在乙醇耗尽后在乙酸上快速生长。结合生长试验和积累的酶学数据，强烈建议在第二生长期出现与生长期不同的生理特性。少

Several strains of acetic acid bacteria belonging to the genus Acetobacter, showing strong acetate oxidation, were screened and their microbiological aspects in acetate oxidation were investigated. When all available carbon and energy sources were exhausted and only acetic acid remained in the late that had stationary phase, the bacteria started to consume the acetic acid that had been accumulated in the culture medium for vinegar fermentation. They grew rapidly, showing the second stationary phase and a typical biphasic growth curve was observed. The cells from the first growth phase were acid tolerant, while the calls from the second growth phase turned over to become acid senritive. However, no distinct acetate oxidation took place when oxidizable ethanol and other available carbon sources still remained in the culture medium. Moreeover, no apparent acetate oxidation was observed in vinegar mash in which more than 4.5% of acetic acid was allowed to accumulate. There was a threshold … More in acetate concentration since the most selected strains oxidized acetate when the final concentration of acetic acid accumulated was less than 3.7%. When only acetic was administrated as the sole carbon and energy sources, the organisms finally used acetic acid after a long lag time. The lag time was shortened by the addition of a small amount of readily usable energy source, such as ethanol. From enzymatic analysis, only acetyl-CoA synthetase increased much among the enzymes concerning acetyl-CoA formation from acetate, whole the enzyme activities of acetate kinase and phosphotransacetylase were not changed significantly. The enzyme activities of isocitrate lyase and malate synthase also increased significantly in the cells when acetate was consumed. These results indicate that acetic acid is converted to acetyl-CoA by acetyl-CoA synthetase to put acetate into the TCA cycle as well as to the glyoxylate cycle allowing the bacteria to grow rapidly on acetic acid after ethanol exhaustion. Taking together with growth experiments and enzymatic data accumulated, it was strongly suggested that calls different in physiological characteristics from the growth phase emerged in the second growth phase. Less