Biological hydrogen production has attracted more and more attention in recent years because of its ability to produce hydrogen energy while also addressing concerns on environment and fossil fuel replacement. A creative bacteria immobilization method for hydrogen fermentation was studied. Anaerobic granular sludge was proposed as the immobilized hydrogen producing bacteria to be used in hydrogen fermentation after methanogenic activity of the granules was eliminated in the pretreatment process with the chloroform. Immobilized hydrogen production with chloroform treated granule was examined, and the biological hydrogen production was combined with methane production for efficient use of volatile fatty acid. The microbial community changes inside the granules during the chloroform treatment and continuous culture were analyzed. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake, UT 11/4-9/2007).