Department of Environmental Engineering, Kyungpook National University, Daegu 702-701, Korea.
J Microbiol Biotechnol. 2012 Mar;22(3):400-6. doi: 10.4014/jmb.1108.08009.
To improve the hydrogen yield from biological fermentation of organic wastewater, a co-culture system of dark- and photo-fermentation bacteria was investigated. In a pureculture system of the dark-fermentation bacterium Clostridium butyricum, a pH of 6.25 was found to be optimal, resulting in a hydrogen production rate of 18.7 ml-H₂/l/h. On the other hand, the photosynthetic bacterium Rhodobacter sphaeroides could produce the most hydrogen at 1.81 mol-H₂/mol-glucose at pH 7.0. The maximum specific growth rate of R. sphaeroides was determined to be 2.93 h⁻¹ when acetic acid was used as the carbon source, a result that was significantly higher than that obtained using either glucose or a mixture of volatile fatty acids (VFAs). Acetic acid best supported R. sphaeroides cell growth but not hydrogen production. In the co-culture system with glucose, hydrogen could be steadily produced without any lag phase. There were distinguishable inflection points in a plot of accumulated hydrogen over time, resulting from the dynamic production or consumption of VFAs by the interaction between the dark- and photofermentation bacteria. Lastly, the hydrogen production rate of a repeated fed-batch run was 15.9 ml-H₂/l/h, which was achievable in a sustainable manner.
为提高有机废水生物发酵产氢效率，采用混合发酵工艺，对发酵产氢细菌进行了研究。纯种丁酸梭菌（Clostridium butyricum）发酵体系的最适 pH 值为 6.25，产氢速率为 18.7 ml-H₂/l/h。而光合细菌球形红假单胞菌（Rhodobacter sphaeroides）在 pH 值为 7.0 时产氢量最大，为 1.81 mol-H₂/mol-葡萄糖。以乙酸为碳源时，R. sphaeroides 的最大比生长速率为 2.93 h⁻¹，显著高于葡萄糖或挥发性脂肪酸（VFAs）混合物。乙酸最有利于 R. sphaeroides 细胞生长，但不利于产氢。在以葡萄糖为基质的混合发酵体系中，氢气可以稳定产生，没有迟滞期。随着时间的推移，积累的氢气曲线有明显的拐点，这是由于黑暗发酵细菌和光合发酵细菌之间的相互作用，导致挥发性脂肪酸的动态产生或消耗。最后，重复分批补料运行的产氢速率为 15.9 ml-H₂/l/h，可实现可持续产氢。
