Abstract
The most dominant factor influencing the oxidation-reduction potentials (E) in the cultured system was oxygen tension. E was an useful index to express the degree of oxygen supply in place of dissolved oxygen (PL) under a limited oxygen supply. The conversion of microbial products caused by the change in oxygen supply was clearly analyzed by the use of E value. Bacillus subtilis excreted lactic acid at the E value -220mV, 2, 3-butyleneglycol at -195mV and acetoin at -160mV as the main product. E also gave the significant information concerning the changes in cell's respiration. Cyanide at the concentration of 10-5M, azide at 10-3M and 2, 4-dinitrophenol (DNP) at 10-2M inhibited cell respiration causing the decrease in E and the increase in PL, and DNP at 0.4×10-3M promoted oxygen uptake of the cells causing the decrease in both E and PL.
