The chitinolytic bacterium Clostridium paraputrificum strain M-21 produced 2.2 and 1.5 mol hydrogen gas from 1 mol N-acetyl-D-glucosamine (GlcNAc) and ball-milled chitin equivalent to 1 mol of GlcNAc, respectively, at pH 6.0. In addition, strain M-21 efficiently degraded and fermented ball-milled raw shrimp and lobster shells to produce hydrogen gas: 11.4 mmol H-2 from 2.6 g of the former and 7.8 mmol H-2 from 1.5 g of the latter. Hydrogen evolution from these shell wastes were enhanced two fold by employing acid and alkali pretreatment. Waste from the starch industry was also converted to hydrogen. When C. paraputrificum M-21 was cultivated on ball-milled chitin and bah-milled shrimp shells for 14 and 12h, respectively, chitinases ChiA and/or ChiB were detected as the major chitinase species in the supernatant of the cultures, suggesting that they play a critical role in the degradation of chitinous materials.