Clostridium tyrobutyricum is a promising microbial cell factory to produce biofuels. In this study, an uptake hydrogenase (hyd2293) from Ethanoligenens harbinense was overexpressed in C. tyrobutyricum and significantly affected the redox reactions and metabolic profiles. Compared to the parental strain (Ct-WT), the mutant strain Ct-Hyd2293 produced ~34% less butyrate, ~148% more acetate, and ~11% less hydrogen, accompanied by the emerging genesis of butanol. Comparative transcriptome analysis revealed that 666 genes were significantly differentially expressed after the overexpression of hyd2293, including 82 up-regulated genes and 584 down-regulated genes. The up-regulated genes were mainly involved in carbohydrate and energy metabolisms while the down-regulated genes were distributed in nearly all pathways. Genes involved in glucose transportation, glycolysis, different fermentation pathways and hydrogen metabolism were studied and the gene expression changes showed the mechanism of the metabolic flux redistribution in Ct-Hyd2293. The overexpression of uptake hydrogenase redirected electrons from hydrogen and butyrate to butanol. The key enzymes participating in the energy conservation and sporulation were also identified and their transcription levels were generally reduced. This study demonstrated the transcriptomic responses of C. tyrobutyricum to the expression of a heterologous uptake hydrogenase, which provided a better understanding of the metabolic characteristics of C. tyrobutyricum and demonstrated the potential role of redox manipulation in metabolic engineering for biofuel productions.

酪丁酸梭菌是生产生物燃料的有前途的微生物细胞工厂。在这项研究中，从哈氏乙醇杆菌中摄取的氢化酶（hyd2293）在酪丁酸梭菌中过表达，并显着影响氧化还原反应和代谢特性。与亲本菌株（Ct-WT）相比，突变菌株Ct-Hyd2293产生的丁酸酯减少约34％，乙酸盐减少约148％，氢气减少约11％，同时伴随出现丁醇。对比转录组分析显示，hyd2293过表达后，666个基因明显差异表达包括82个上调基因和584个下调基因。上调的基因主要参与碳水化合物和能量代谢，而下调的基因几乎分布在所有途径中。研究了涉及葡萄糖转运，糖酵解，不同发酵途径和氢代谢的基因，该基因表达的变化表明了Ct-Hyd2293中代谢通量的重新分布机制。摄取氢化酶的过表达将电子从氢和丁酸酯重定向到丁醇。还确定了参与能量节约和孢子形成的关键酶，并且它们的转录水平普遍降低。这项研究证明了酪丁酸梭菌的转录组反应异源摄取氢化酶的表达，可以更好地了解酪丁酸梭菌的代谢特征，并证明氧化还原操纵在生物燃料生产代谢工程中的潜在作用。