[Cooperation of mixed culturing bacteria in the hydrogen production by fermentation]

In order to discuss the cooperation of H2-producing fermentation bacteria (HPFB) in mixed culture, a batch test fed with glucose and complex organic substance (starch, beef, PEP and peptone) respectively, was conducted to investigate the effects of mixed culture on H2-producing ability. For the systemic and accurate analysis, three kinds of the mixed culture were use to this batch test. It included that the mixed culture with five strains of HPFB (B49, H1, LM12, LM11 and B51), B49 and three stains of non-HPFB (L10, Bacteroide 3-2, Sporobacterl), and B49 and hydrogen producing sludge. The results showed that the cooperation of mixed culturing bacteria was conditional on the substrates. When fed with glucose, which were easily utilized by HPB, the H2-producing ability of HPB was restrained because of the competition on the co-substrate between HPB and other fermentation bacteria, and it was quite difficult for the cooperation of mixed culturing bacteria to be performed. When fed with complex organic substance, the H2-producing ability of HPB was enhanced via the cooperation of mixed culturing bacteria. Furthermore, a strategy was put forward, that is, different kind of HPB cultures could be adopted according to the difference of substrates.