Acetobacterium woodii utilizes the Wood‐Ljungdahl pathway for reductive synthesis of acetate from carbon dioxide. However, A. woodii can also perform non‐acetogenic growth on 1,2‐propanediol (1,2‐PD) where instead of acetate, equal amounts of propionate and propanol are produced as metabolic end products. Metabolism of 1,2‐PD occurs via encapsulated metabolic enzymes within large proteinaceous bodies called bacterial microcompartments. While the genome of A. woodii harbours 11 genes encoding putative alcohol dehydrogenases, the BMC‐encapsulated propanol‐generating alcohol dehydrogenase remains unidentified. Here, we show that Adh4 of A. woodii is the alcohol dehydrogenase required for propanol/ethanol formation within these microcompartments. It catalyses the NADH‐dependent reduction of propionaldehyde or acetaldehyde to propanol or ethanol and primarily functions to recycle NADH within the BMC. Removal of adh4 gene from the A. woodii genome resulted in slow growth on 1,2‐PD and the mutant displayed reduced propanol and enhanced propionate formation as a metabolic end product. In sum, the data suggest that Adh4 is responsible for propanol formation within the BMC and is involved in redox balancing in the acetogen, A. woodii.

中文翻译：

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Adh4，一种醇脱氢酶，控制产乙酸细菌木醋杆菌中细菌微隔室内的醇形成

木本醋杆菌利用Wood-Ljungdahl途径从二氧化碳还原合成乙酸盐。但是，木柴还可以在1,2-丙二醇（1,2-PD）上进行非产乙酸的生长，在该代谢中，产生等量的丙酸酯和丙醇代替乙酸盐，从而成为代谢终产物。1,2-PD的代谢通过被包裹在称为细菌微区隔的大型蛋白质体内的代谢酶发生。虽然伍德木球菌的基因组包含11个编码推定的醇脱氢酶的基因，但BMC封装的生成丙醇的醇脱氢酶仍未鉴定。在这里，我们显示了A. woodii的Adh4是在这些微隔室内形成丙醇/乙醇所需的醇脱氢酶。它催化NADH依赖的丙醛或乙醛向丙醇或乙醇的还原，并主要用于在BMC中循环利用NADH。的去除ADH4从基因A.伍氏醋酸杆菌基因组中导致生长缓慢上1,2-PD和突变显示的缩小丙醇和增强丙酸形成作为代谢的最终产物。总而言之，数据表明Adh4负责BMC中丙醇的形成，并参与了乙酸原曲霉A. woodii中的氧化还原平衡。