Metatranscriptomic insights into the microbial electrosynthesis of acetate by Fe2+/Ni2+ addition

As important components of enzymes and coenzymes involved in energy transfer and Wood-Ljungdahl (WL) pathways, Fe2+ and Ni2+ supplementation may promote the acetate synthesis through CO2 reduction by the microbial electrosynthesis (MES). However, the effect of Fe2+ and Ni2+ addition on acetate production in MES and corresponding microbial mechanisms have not been fully studied. Therefore, this study investigated the effect of Fe2+ and Ni2+ addition on acetate production in MES, and explored the underlying microbial mechanism from the metatranscriptomic perspective. Both Fe2+ and Ni2+ addition enhanced acetate production of the MES, which was 76.9 λ Acetate microbial electrosynthesis was enhanced by Fe2+ and Ni2+ addition. λ Fe2+ and Ni2+ addition caused small changes in genus-level microbial composition. λ Genes expression of hydrogenase was increased with Fe2+ and Ni2+ addition. λ Fe2+ improved methyl and Ni2+ improved carboxyl branch expression of WL pathway.