Conversion from gaseous sources like carbon dioxide and hydrogen. In a previous study, autotrophy was lost when RNF-complex genes were disrupted, although glycolysis still allowed for heterotrophy. Additionally, it was demonstrated that nitrate supplementation might remove the energy restriction during autotrophy, leading to increased cellular growth and ATP output. Here, we deleted the putative RNF regulator gene rseC, the putative nitrate reductase gene cluster, and the RNF complex-encoding gene cluster rnfCDGEAB using CRISPRCas12a. The entire loss of autotrophy caused by the deletion of either rnfCDGEAB or rseC may be recovered by plasmid-based complementation of the lost genes. We noticed a transcriptional inhibition of the RNF-gene cluster in the rseC-deletion strain during autotrophy, and we looked into the distribution of the rseC gene across Acetogenic bacteria. We contrasted the autotrophic and heterotrophic development of our three deletion strains with either ammonium or nitrate in order to investigate nitrate reduction and its relationship to the RNF complex. During autotrophy but not during heterotrophy, the rnfCDGEAB and rseC deletion strains failed to decrease nitrate as a metabolic activity in non-growing cultures. While the nitrate reductase deletion strain was unable to reduce nitrate, it was nevertheless able to grow in all of the test conditions. Our findings show how crucial the rseC gene is for autotrophy and also help us understand how nitrate reduction is related to energy metabolism.
