Nath Kaushik, Kumar Anish, Das Debabrata
Fermentation Technology Laboratory, Department of Biotechnology, Indian Institute of Technology, Kharagpur.
Can J Microbiol. 2006 Jun;52(6):525-32. doi: 10.1139/w06-005.
Fermentative hydrogen production was carried out by Enterobacter cloacae DM11, using glucose as the substrate. The effects of initial substrate concentration, initial medium pH, and temperature were investigated. Results showed that at an initial glucose concentration of 1.0% (m/v), the molar yield of hydrogen was 3.31 mol (mol glucose)(-1). However, at higher initial glucose concentration, both the rate and cumulative volume of hydrogen production decreased. The pH of 6.5 +/- 0.2 at a temperature of 37 degrees C was found most suitable with respect to maximum rate of production of hydrogen in batch fermentation. Activation enthalpies of fermentation and that of thermal deactivation of the present process were estimated following a modified Arrhenius equation. The values were 47.34 and 118.67 kJ mol(-1) K(-1), respectively. The effect of the addition of Fe(2+) on hydrogen production was also studied. It revealed that the presence of iron (Fe(2+)) in the media up to a concentration of 20 mg L(-1) had a marginal enhancing effect on total hydrogen production. A simple model developed from the modified Gompertz equation was applied to estimate the hydrogen production potential, production rate, and lag-phase time in a batch process, based on the cumulative hydrogen production curves, using the software program Curve Expert 1.3.
阴沟肠杆菌DM11以葡萄糖为底物进行发酵产氢。研究了初始底物浓度、初始培养基pH值和温度的影响。结果表明，当初始葡萄糖浓度为1.0%（m/v）时，氢气的摩尔产率为3.31 mol（mol葡萄糖）⁻¹。然而，在较高的初始葡萄糖浓度下，氢气产生的速率和累积体积均下降。发现在37℃温度下pH值为6.5±0.2时，对于分批发酵中氢气的最大产生速率最为合适。根据修正的阿伦尼乌斯方程估算了本工艺发酵的活化焓和热失活的活化焓。其值分别为47.34和118.67 kJ mol⁻¹ K⁻¹。还研究了添加Fe²⁺对产氢的影响。结果表明，培养基中浓度高达20 mg L⁻¹的铁（Fe²⁺）对总产氢量有轻微的增强作用。基于累积产氢曲线，使用软件程序Curve Expert 1.3，应用从修正的Gompertz方程开发的简单模型来估算分批过程中的产氢潜力、产率和滞后期时间。
