On-line determination of intracellular beta-galactosidase activity in recombinant Escherichia coli using flow injection analysis (FIA)

A flow injection analysis (FIA) system was developed for the determination of cytoplasmic beta-galactosidase activity in recombinant Escherichia coli. The FIA system and its application for on-line monitoring of beta-galactosidase production during cultivation of recombinant E. coli in a 60-l airlift tower loop reactor is described. The results demonstrate that an FIA assay in conjunction with a cell disintegration step can be applied successfully for on-line monitoring of intracellular protein formation.