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The effect of the redox potential on the by-production of acetic acid by Bacillus licheniformis grown in a chemostat has been studied.It was demonstrated that B.licheniformis produced acetic acid when it was grown at a low growth rate, low oxygen supplies, and low redox potentials.

The influence of CO2 on the information of alpha-amylase by Bacillus subtilis NCIB 8646 growing in continuous and batch cultures was investigated. Different levels of CO2 examined in the batch cultures stimulated the formation of alpha-amylase, with the highest activity being obtained using 6% CO2 (v/v). The additions of CO2 inhibit the growth and division of vegetative cells of B. subtilis when CO2 is present in a concentration of more than 3% (v/v). In chemostat cultures, air containing 8% CO2 (v/v) increased the specific enzyme productivity almost three times over the control, without affecting the cell growth. An attempt is made to correlate the obtained results with the alesis.

The specific ethanol productivity with Saccharomyces cerevisiae grown aerobicly in a chemostat was found to be highly dependent on the ratio of intracellular to extracellular potassium concentration through variations in the energy consumption used for maintenance of the concentration gradient of potassium across the cell membrane. The specific ethanol productivity progressively rose from 0 to 20 mmol h(-1) g(-1) cell dry matter at a growth rate of 0.17 h(-1) when the ratio of intracellular to extracellular potassium concentration was increased from 10 to 80. The ethanol production under potassium limited growth conditions was caused neither by a reduction in the specific respiratory activity nor by variations in the potassium content in cell dry matter. Results which strongly that ethanol production under potassium limited growth conditions is brought about by changes in the ratio of pyruvate oxidase to pyruvate decarboxylase activity through changes in the intracellular pyruvate concentration are presented.

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