초록
Production of bio-hydrogen from stale rice was conducted in an aerobic digester. It was applied 3 types of pressure control range to the digester, they are (0-3/3%), (0-2/3%), (0-1/3%) of maximum pressure during the production of bio-hydrogen in mesophilic (35<SUP>o</SUP>C) condition which is equal to (0-10 psi), (0-6 psi), (0-3 psi), and as small as possible pressure in the digester. This research shows that the optimum pressure control range to increase total gas production is (0-2/3%) or (0-6 psi), with total production of 19 liters biogas.