Nutrition and Fermentative Energy Metabolism of the Water Mold Aqualinderella Fermentans

SUMMARY

The water mold Aqualinderella fermentans is facultatively anaerobic, indifferent to oxygen in growth rate and in acid production, and requires high atmospheric levels of CO₂. In the present work several aspects of its nutrition and energy metabolism are examined, in relation to the unusual characteristics mentioned above. A. fermentans requires one of a limited number of carbohydrates as energy source and appears to carry out homolactic fermentation under both aerobic and anaerobic conditions. A. fermentans required lipids, which can be supplied in yeast extract, in wheat-germ oil, or as a mixture of cholesterol and an unsaturated fatty acid. Relatively complex nutritional requirements are indicated by the fact that yeast extract cannot be successfully replaced by a mixture of amino acids and vitamins. These features are regarded as adaptations to anaerobic, fermentative existence in an environment rich in organic substrates. Supplemental CO₂ can be partially replaced by dicarboxylic acids. A growth factor found in pond water has been replaced by calcium ions.