Faculty of Chemical, Environmental and Biological Engineering, Dalian University of Technology, Dalian, 116012, People's Republic of China.
Appl Microbiol Biotechnol. 2011 Sep;91(6):1677-84. doi: 10.1007/s00253-011-3509-7. Epub 2011 Aug 7.
The objective of this study was to improve the biological water-gas shift reaction for producing hydrogen (H(2)) by conversion of carbon monoxide (CO) using an anaerobic thermophilic pure strain, Carboxydothermus hydrogenoformans. Specific hydrogen production rates and yields were investigated at initial biomass densities varying from 5 to 20 mg volatile suspended solid (VSS) L(-1). Results showed that the gas-liquid mass transfer limits the CO conversion rate at high biomass concentrations. At 100-rpm agitation and at CO partial pressure of 1 atm, the optimal substrate/biomass ratio must exceed 5 mol CO g(-1) biomass VSS in order to avoid gas-liquid substrate transfer limitation. An average H(2) yield of 94 ± 3% and a specific hydrogen production rate of ca. 3 mol g(-1) VSS day(-1) were obtained at initial biomass densities between 5 and 8 mg VSS(-1). In addition, CO bioconversion kinetics was assessed at CO partial pressure from 0.16 to 2 atm, corresponding to a dissolved CO concentration at 70°C from 0.09 to 1.1 mM. Specific bioactivity was maximal at 3.5 mol CO g(-1) VSS day(-1) for a dissolved CO concentration of 0.55 mM in the culture. This optimal concentration is higher than with most other hydrogenogenic carboxydotrophic species.
本研究的目的是通过利用产甲烷嗜热纯菌株羧甲基氢杆菌来提高生物水煤气变换反应，以生产氢气（H2）。在初始生物量密度从 5 到 20 毫克挥发性悬浮固体（VSS）L（-1）的范围内，研究了特定的氢气产生速率和产率。结果表明，在高生物质浓度下，气液传质限制了 CO 的转化速率。在 100-rpm 搅拌和 CO 分压为 1 大气压的条件下，为了避免气液底物传递限制，最佳的底物/生物质比必须超过 5 mol CO g（-1）生物质 VSS。在初始生物量密度为 5 到 8 毫克 VSS（-1）之间，获得了 94±3%的平均 H2 产率和约 3 mol g（-1）VSS day（-1）的特定氢气产生速率。此外，在 CO 分压从 0.16 到 2 大气压的条件下评估了 CO 生物转化动力学，这对应于 70°C 时溶解 CO 的浓度从 0.09 到 1.1 mM。在培养物中溶解 CO 的浓度为 0.55 mM 时，特定生物活性在 3.5 mol CO g（-1）VSS day（-1）达到最大值。这个最佳浓度高于大多数其他产氢羧基营养物种。
