Metabolic Versatility of acetogens in syngas Fermentation: Responding to varying CO availability.

Syngas fermentation using acetogenic bacteria offers a promising route for sustainable chemical production. However, gas-liquid mass transfer limitations and efficient co-utilization of CO and H₂ pose significant challenges. This study investigated the kinetics of syngas conversion to acetate by Acetobacterium wieringae and Clostridium species in batch conditions under varying initial CO partial pressures (19 - 110 kPa). A. wieringae strains, exhibited superior growth in all gas compositions, with a maximum growth rate of 0.104 h^-1. The distinct CO, H₂, and CO₂ consumption patterns revealed metabolic flexibility and adaptation to varying syngas compositions. Notably, A. wieringae strains and C. autoethanogenum achieved complete CO and H₂ conversion, with C. autoethanogenum also exhibiting net CO₂ uptake. These findings provide valuable insights into the distinct metabolic capabilities of these acetogens and contribute to the development of efficient and sustainable syngas fermentation processes.