Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, West Bengal, India.
J Biotechnol. 2011 Mar 10;152(1-2):9-15. doi: 10.1016/j.jbiotec.2010.12.014. Epub 2010 Dec 23.
The present study investigates the effect of pH and intermediate products formation on biological hydrogen production using Enterobacter cloacae IIT-BT 08. Initial pH was found to have a profound effect on hydrogen production potential, while regulating the pH 6.5 throughout the fermentation was found to increase the cumulative hydrogen production rate and yield significantly. Modified Gompertz equation was used to fit the cumulative hydrogen production curves to obtain the hydrogen production potential P, the hydrogen production rate R and lag phase λ. At regulated pH 6.5, higher H(2) yield (3.1molH(2)mol(-1) glucose), specific hydrogen production potential (798.1mL/g) and specific rate of H(2) production (72.1mLL(-1)h(-1)g(-1)) were obtained. The volatile fatty acid profile showed butyrate, ethanol and acetate as the major end metabolites of fermentation under the operating pH conditions tested; however, their pattern of distribution was pH dependent. At the optimum pH of 6.5, the acetate to butyrate ratio (A/B ratio) was found to be higher than that at any other pH. The study also investigates the effect of sodium ions on biohydrogen production potential. It was also found that sodium ion concentration up to 250mM enhanced the hydrogen production potential; however, any further increase in the metal ion concentration had an inhibitory effect.
本研究考察了 pH 值和中间产物形成对肠杆菌 cloacae IIT-BT 08 生物制氢的影响。初始 pH 值对产氢潜力有深远影响，而在发酵过程中调节 pH 值至 6.5 被发现可显著提高累积产氢率和产率。采用修正的 Gompertz 方程拟合累积产氢曲线，得到产氢潜力 P、产氢速率 R 和迟滞期 λ。在调节 pH 值至 6.5 时，可获得更高的 H 2 产率（3.1molH 2 mol -1 葡萄糖）、特定产氢潜力（798.1mL/g）和特定产氢速率（72.1mLL -1 h -1 g -1 ）。挥发性脂肪酸谱表明，在测试的操作 pH 值条件下，丁酸、乙醇和乙酸是发酵的主要末端代谢物；然而，它们的分布模式是 pH 值依赖性的。在最佳 pH 值 6.5 时，发现乙酸与丁酸的比例（A/B 比）高于任何其他 pH 值。该研究还考察了钠离子对生物制氢潜力的影响。还发现，钠离子浓度高达 250mM 可增强产氢潜力；然而，金属离子浓度的进一步增加会产生抑制作用。
