PURPOSE: To provide a new bacterium which can develop excellent ability to produce hydrogen gas under increased hydrogen partial pressure and can maintain the hydrogen-producing ability on the surfaces of cereals in its spore form and is useful for effective utilization of waste or refuse.

CONSTITUTION: Soybean cake produced in China barned in a silo is subjected to repeated enrichment culture anaerobically at 35°C using GAM bouillon (pH7.3), then the colony is formed with a roll tube and cell bodies are selectively picked up from the colony and is cultured to determine the hydrogen generation by chromatography. In the meantime, the amount of the cell bodies are determined by measuring the turbidity of the filtrate from the culture mixture spectroscopically and the bacterium capable of producing a large volume of hydrogen gas is separated to give Clostridium butyricum SC-E1 (FERM P-14790) which can manifest the high hydrogen gas-producing ability. This bacterium strain can stably maintain the ability to produce hydrogen gas on the surface of cereal grains in the spore form without deterioration for a long period of time.