Excretion of metabolites by hydrogen bacteria II. Influences of aeration,pH, temperature,and age of cells

Summary The effects of the aeration rate, the pH value, the temperature of the culture medium and of the age of cells on the excretion of metabolites by mutant strains of Alcaligenes eutrophus were studied. With lactate or gluconate as substrates, ethanol, 3-hydroxybutanoate, succinate, cis-aconitate, 2-oxo-3-methylbutanoate and 2-oxoglutarate were excreted, each at a distinct low aeration rate. Maximum concentrations of metabolites were found at pH 7.0 at 30°C when ammonia was growth limiting and the carbon substrate was present in excess. Excretion occurred only by viable intact cells.