产氢菌对沼气发酵的生物强化作用

Biotechnological Intensification of Biogas Fermentation by Hydrogen Producing Bacteria

在以猪粪为底物的沼气发酵系统中,投加产氢菌Clostridium sp.WY-1与Clostridium sp.WW-5混合后离心的菌体,加入量以两株菌的混合菌液计,分别为发酵液总体积的2%、4%、8%、16%,30℃下发酵30 d,研究产氢菌投加对产甲烷系统的生物强化效应.结果表明,2%、4%、8%、16%四种不同投加量均能提高甲烷总产量,累积甲烷产量比对照分别增加6%、11%、4%、3%,其中投加量4%增加最高;而对甲烷浓度无明显提高.在发酵前3 d,各组中均能检测到少量的氢气,投加产氢菌各组中d 2的氢气含量均比对照高,d 3对照组、2%和4%组检测不出氢气,但8%、16%组仍有极少量氢气存在.总挥发性有机酸在发酵过程中总体趋势是不断下降,发酵前20 d投加产氢菌组的总挥发性有机酸含量均比对照组高.投加产氢菌各组中产氢菌和产甲烷菌的数量与对照组相比均有所增加,而投加量4%组中产氢菌和产甲烷菌的数量比投加2%、8%和16%中的产氢菌和产甲烷菌的数量高.

In order to study the biotechnological intensification of hydrogen producing bacteria （HPB）, two HPBs isolated by our laboratory, Clostridium sp. WY-1and Clostridium sp. WW-5, were introduced into the methane fermentation system with pig manure as substrate. Besides the control without HPB addition, four levels of the mixture of the two HPBs were applied in this trial, i.e. 2%, 4%, 8% and 16% of HPB mixture in the fermentation liquid. The mixtures of the liquid were fermented for 30 days at 30 ℃. Results showed that the accumulative methane production of 2%, 4%, 8% and 16% of the HPB treatments were 6%, 11%, 4% and 3% respectively higher than that of the control, but methane concentration was not enhanced significantly. It suggested that 4% of HPB was the optimal proportion. H2 was detected during the first three days in all five groups. On the second day the H2 content of 2%, 4%, 8% and 16% of HPB treatment was higher than that of the control; on the third day H2 was detected in the 8% and 16% of HPB treatments, but not in the control, 2% and 4% groups. The amount of volatile fatty acid （VFA） was decreasing during the fermentation period in all five groups, with the concentration of VFA of all HPB treatments higher than that of the control in the first 20 days. The amounts of HPB and MPB in 2%, 4%, 8% and 16% HPB treatments were both higher than those of the control; and the highest amount of the two types of bacteria was detected in the 4% HPB treatment. Fig 7, Tab 3, Ref 15