Thermodynamic, Sulfide, Redox Potential, and pH Effects on Syngas Fermentation

摘要: Thermodynamic, Sulfide, Redox Potential, and pH Effects on Syngas Fermentation Peng Hu Department of Chemical Engineering Doctor Philosophy Recently, work in ethanol production is exploring the fermentation syngas (primarily CO, CO2, H2) following gasification cellulosic biomass. The by clostridium microbes utilizes Wood-Ljungdahl metabolic pathway. Along this pathway, intermediate Acetyl-CoA typically diverges to produce ethanol, acetic acid, and/or cell mass. To develop strategies for process optimization, a thermodynamic analysis was conducted that provided detailed understanding favorability reactions. Thermodynamic identification potentially limiting steps. Once these reactions were identified, further additional insights into ways which reaction conditions could be adjusted improve product yield as well minimize effect such bottlenecks. In way, enhance formation effectively formed. A regarding electron utilization suggested it would unlikely H2 utilized favor CO when both species are present. Therefore, conversion efficiency products will sacrificed during since some make electrons at expense mass formation. Furthermore, showed difference production, acetate conversion, varying conditions, different redox potential levels. These differences then incorporated strategy optimize desired product, bioreactor design, decrease amount by-product Based thermodynamics analysis, experiments with experimental performed. results sulfide concentration media changed. order assess effects variability, controlled sulfide, potential, designed indicated factors play key roles growth, distribution. had phases. For example, growth much better pH=5.8 than pH=4.5. However, rate pH=4.5 pH=5.8. involving controlling phases applied production. This significant how can affect process.