Extracellular production of proteins by microorganisms. Part V. Stimulatory effect of inhibitors of cell wall synthesis on protein production by Bacillus brevis.

Abstract

Mutants of Bacillus brevis No. 47 that grew in synthetic media containing a high concentration of ammonium sulfate were stable and had high protein production. Among various antibiotics tested, inhibitors of cell wall synthesis, such as bacitracin or β-lactam antibiotics, were effective in greatly increasing the accumulation of exoproteins. When 60μg/ml of bacitracin was added to the culture at the early logarithmic growth phase, about 9mg/ml of proteins was produced. Such a protein yield was estimated to be nearly maximum from a given amount of glucose. Alterations in cell wall components were found in cells grown in the presence of bacitracin. Possible relationships between cell wall structure and protein production were discussed.