On-line and off-line monitoring of the production of alkaline serine protease by Bacillus licheniformis

Subtilisin Carlsberg alkaline serine protease was produced by Bacillus licheniformis on complex medium in a stirred tank reactor and the turbidity and culture fluorescence were monitored in situ, absorbance on-line and off-line, (dry) sediment, (dry) cell mass and DNA concentrations off-line. These data were correlated with each other. The cultivation medium composition: starch, maltose, glucose, urea, ammonia, phosphate concentrations and protease activity were monitored by a six-channel flow injection analysis system on-line and off-line. Protein concentration, α-amylase activity and intracellularly phosphate concentration were evaluated off-line. The on-line and off-line data agreed well. Differences in the on-line and off-line monitored protease activities are caused by the membrane fouling of the sampling system.