The metabolism of sugar and malic acid byLeuconostoc oenos: effect of malic acid, pH and aeration conditions

摘要

The co‐metabolism of sugars byLeuconostoc oenoswas studied under different environmental conditions. Under aerobic conditions, growth and sugar metabolism were poorer than under CO2or N2atmosphere and acetic acid accumulated to a larger extent. Glycerol was found in the aerobic cultures while erythritol was detected under N2or CO2. When medium conditions make growth difficult (low pH, aerobic conditions, low nutrients), sugars were only slightly metabolized and growth was very slow while malic acid was rapidly and completely degraded, leading to an increase in theyATP. Aeration effects on the malic acid degradation rate depended on the nutrients and carbon source in the medium. Malic acid clearly stimulated bacterial growth, allowing an increase in the molar growth yields and ATP production. The results suggest that under adverse conditions cells are not able to grow and malic degradation supplies additional energy productio