IMPORTANCE: Our study elucidates the crucial role of electron flow and redox balancing mechanisms in improving ethanol yields from renewable biomass. We delve into the mechanism of electron transfer, highlighting the potential of key genes to be leveraged for enhanced ethanol production in anaerobic microbial species. We suggest by genetic investigation the existence of a novel Ferredoxin:NADP+ Oxidoreductase (FNOR) reaction, comprising HfsD, HydAB, and NfnAB enzymes, as a promising avenue for achieving balanced stoichiometry and efficient ethanol synthesis. Our findings not only advance the understanding of microbial metabolism but also offer practical insights for developing strategies to improve bioenergy production and sustainability.