Abstract
Growth characteristics and cell composition of Alcaligenes eutrophus under limitation of gaseous substrates were evaluated in a chemostatically controlled continuous culture. Yield coefficients, especially YH2, and cell composition varied conspicuously with the change of growth limiting gas from hydrogen to oxygen. In O2-limitation, YH2 was 1.5 times higher than that in H2-limitation but the content of protein in cell decreased. With feeding the gas-mixture containing H2:O2:CO2=3:1:0.4, simultaneous limitation of three gases was suspected to occur. With this feeding ratio of gases, highest productivity of cell mass and efficient utilization of gaseous substrates were obtained.