Continuous culture of Mycobacterium avium limited for ammonia.

Previous investigations demonstrated the utility of a cell-cycle technique for physiologic studies of lipid metabolism in Mycobacterium avium. Such a culture technique was not suitable for enzymic analyses. Therefore, continuous culture of M. avium was attempted. A modified culture medium, limited for ammonia nitrogen, was used to culture the organism at dilution rates of 0.08 to 0.175 per h. Measurements of colony-forming units, isotope incorporation, and cell protein during extended incubation times demonstrated that the organism was in steady state. Cells harvested from continuous culture had levels of glutamate synthase that increased proportionately to the dilution rate.