To investigate novel extremozymes encoded by sequenced metagenes from a microbial community in an extreme environment, we have characterized a recombinant glycosyl hydrolase (rGH) from an uncultured bacterium within the order Chloroflexi. rGH formed insoluble bodies in an Escherichia coli protein expression system. The protein was partially dissolved by a surfactant and was enzymatically characterized. The MW of the monomeric peptide was similar to 62 kDa, and it formed a homodimers in buffer. It was optimally active at 65 A degrees C and from pH 4 to 8. rGH showed hydrolytic activity for alpha-1,1, alpha-1,2 and alpha-1,6 linkages, including isomaltose, but not alpha-1,4 and beta-linkages.