Effects of phosphate limitation on agarase production byStreptomyces lividansTK21

Abstract

The dagA gene from Streptomyces coelicolor, encoding an extracellular agarase, has been expressed in Streptomyces lividans on a multicopy plasmid. Chemostat cultures were used to investigate the influence of phosphate limitation on the synthesis and secretion of this enzyme. The strain was cultivated with glucose as the carbon source and magnesium or phosphate as growth‐limiting substrates and samples used to determine dagA transcription, agarase secretion and alkaline phosphatase activity under the various limitations. The data show that, compared to growth under magnesium limitation, phosphate‐limited cells show increases in dagA transcription, the rate of agarase production and secretion, and alkaline phosphatase activity.