不同底物种类对厌氧发酵产氢的影响

在批式培养试验中以人工配置的废水为原料,以厌氧消化污泥作为天然产氢菌源,通过厌氧生物发酵制备生物氢气,研究了不同底物葡萄糖、蔗糖、麦芽糖、木糖、乳糖对产氢能力的影响,以及生物制氢发酵过程中液相组成的变化,并对产氢动力学和细菌生长动力学进行了分析.结果表明,5种底物中最佳的底物是葡萄糖,氢气含量、累积产氢量和氢气产量最高可达到49.52%、67.21 L/mol、3.23 mol/mol.发酵产氢代谢产物以丁酸和乙酸为主,乙酸的含量占到26.76%～40.49%,丁酸的含量占到37.60%-58.07%.并含有部分丙酸和乙醇,属于丁酸型发酵.丁酸/乙酸比值可作为衡量氢气产生效率的一个指标,比值越大产氢量越高.实验中氧化还原电位均在-300 mV以下,以厌氧为主.Gompertz模型能够很好地拟合其产氢过程和产氢菌生长过程.

Effects of Substrate Species on Fermentative Hydrogen Production

Biohydrogen production by anaerobic sludge was studied by using wastewater as substrate in batch process. Hydrogen production potential of different substrate species, as well as the composition of fermentation product in liquid phase, was studied in the batch culture experiments. The hydrogen production and bacterial growth dynamics were also analyzed. The experiment results demonstrated that the optimal substrate was glucose for hydrogen production. It could be obtained maximum cumulative hydrogen production 67.21 L/mol, hydrogen yield 3.23 mol/mol and hydrogen content 49.52%. The butyrate and acetate were main liquid end products, occupied 26.76%-40.49% of acetate, 37.60%-58.07% of butyrate, implying that it is butyrate-type fermentation. Butyrate/acetate could be used as the indicator for evaluating the effectiveness of H2 production, with that the higher butyrate/acetate, the higher the hydrogen yield. ORP was less than -300 mV during fermentation indicating the experiment was anaerobic. A modified Gompertz model can adequately describe the H2 production and bacterial growth.