초록
Elevated temperatures (52, 60 and 65 <SUP>o</SUP>C) were used to enrich hydrogen producers on cellulose from cow rumen fluid. Methanogens were inhibited with two different heat treatments. Hydrogen production was considerable at 60 <SUP>o</SUP>C with the highest H<SUB>2</SUB> yield of 0.44 mol-H<SUB>2</SUB> mol-hexose<SUP>-1</SUP> (1.93 mol-H<SUB>2</SUB> mol-hexose-degraded<SUP>-1</SUP>) as obtained without heat treatment and with acetate and ethanol as the main fermentation products. H<SUB>2</SUB> production rates and yields were controlled by cellulose degradation that was at the highest 21%. The optimum temperature and pH for H<SUB>2</SUB> production of the rumen fluid enrichment culture were 62 <SUP>o</SUP>C and 7.3, respectively. The enrichments at 52 and 60 <SUP>o</SUP>C contained mainly bacteria from Clostridia family. At 52 <SUP>o</SUP>C, the bacterial diversity was larger and was not affected by heat treatments. Bacterial diversity at 60 <SUP>o</SUP>C remained similar between heat treatments, but decreased during enrichment. At 60 <SUP>o</SUP>C, the dominant microorganism was Clostridium stercorarium subsp. leptospartum.