Acetic acid Bacteria Carbohydrate utilization

The reason for the inefiiciency of these bacteria in utilizing amino acids is not definitely known however, it seems probable, as is the case with some of the carbohydrate-fermenting rumen bacteria (8, 33), that these materials are not transported effectively into the cell. It seems probable that, in their adaptation to the natural habitat, their abilities to utihze proteins and amino acids were of little survival value and were lost. It is well known that amino acids are present in very small amounts in extracellular fiuid of rumen contents while relatively high concentrations of ammonia and acetate and other volatile acids including 2-methylbutyrate are present (8). A similar condition probably exists in sludge although the volatile acids are usually present in lower concentration than in the rumen. 

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