Oliveira Luis, Röhrenbach Simon, Holzmüller Verena, Weuster-Botz Dirk
Department of Energy and Process Engineering, School of Engineering and Design, Chair of Biochemical Engineering, Technical University of Munich, Boltzmannstr. 15, 85748, Garching, Germany.
Bioresour Bioprocess. 2022 Mar 3;9(1):15. doi: 10.1186/s40643-022-00506-6.
Autotrophic syngas fermentation with clostridia enables the conversion of CO, CO, and H into organic acids and alcohols. The batch process performance of Clostridium ragsdalei was studied in fully controlled and continuously gassed (600 mbar CO, 200 mbar H, 200 mbar CO) stirred-tank bioreactors. The final ethanol concentration varied as function of the reaction conditions. Decreasing the pH from pH 6.0-5.5 at a temperature of 37 °C increased the ethanol concentration from 2.33 g L to 3.95 g L, whereas lowering the temperature from 37 to 32 °C at constant pH 6.0 resulted in a final ethanol concentration of 5.34 g L after 5 days of batch operation. The sulphur availability was monitored by measuring the cysteine concentration in the medium and the HS fraction in the exhaust gas. It was found that most of the initially added sulphur was stripped out within the first day of the batch process (first half of the exponential growth phase). A continuous sodium sulfide feed allowed ethanol concentrations to increase more than threefold to 7.67 g L and the alcohol-to-acetate ratio to increase 43-fold to 17.71 g g.
梭菌进行的自养合成气发酵可将一氧化碳、二氧化碳和氢气转化为有机酸和醇类。在完全受控且持续通气（600毫巴二氧化碳、200毫巴氢气、200毫巴一氧化碳）的搅拌罐式生物反应器中研究了拉氏梭菌的分批工艺性能。最终乙醇浓度随反应条件而变化。在37℃下将pH从6.0降至5.5，乙醇浓度从2.33克/升增加到3.95克/升，而在恒定pH 6.0条件下将温度从37℃降至32℃，分批操作5天后最终乙醇浓度为5.34克/升。通过测量培养基中的半胱氨酸浓度和废气中的硫化氢含量来监测硫的供应情况。结果发现，大部分最初添加的硫在分批工艺的第一天（指数生长期的前半段）就被去除了。连续加入硫化钠可使乙醇浓度增加三倍多，达到7.67克/升，醇与乙酸的比例增加43倍，达到17.71克/克。
