, Volume 24, Issue 2, pp 106-112

Effect of different limitations in chemostat cultures on growth and production of exocellular protease byBacillus licheniformis

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Summary

Maximal molar growth yields (Y sub max ) and protease production ofBacillus licheniformis S 1684 during NH 4 + -, O2-, and NH 4 + +O2-limitation with either glucose or citrate as carbon and energy source and during glucose-, and citratelimitation in chemostat cultures were determined. Protease production was repressed by excess ammonia when glucose served as C/E-source. Glucose and citrate repressed protease production during NH 4 + -limitation. A low oxygen tension enbanced protease production at low μ-values. It was concluded that, besides ammonia repression, catabolite flux and oxygen tension influence protease production, indicating that the energy status of the cell is important for the level of protease production.Y sub max -values were high during glucose-limitation and indicate a high efficiency of growth caused by a highY ATP max . During NH 4 + -, O2-, and NH 4 + +O2-limitation with glucose as C/E-values were lower than during glucose limitation. The lowerY sub max -values were due to a lower efficiency of energy conservation.Y sub max -values during limitations with citrate as C/E-source were lower than during limitations with glucose as C/E-source.