ABSTRACT
The pathways of carbon metabolism in bacteria can be profoundly affected by the environment, as manifest by the availability and type of carbon and nitrogen sources and inorganic ions, by pH, and by the partial pressure of oxygen. Automatic control of pH is an essential requirement for investigation of carbon metabolism because of the profound effect of pH on metabolic pathways. When Pseudomonas aeruginosa was grown in a mineral salts medium with citrate or succinate as the sole carbon source, or in peptone medium, the principal enzymes of glucose metabolism were severely repressed. The accumulation of carbon reserve materials such as polyglucoses and lipids in microbial cells generally has been associated with the establishment of a nutrient limitation in the presence of an excess of the carbon and energy source. The nutrient limitation potentiating the deposition is the nitrogen source.
