Mycelium transformation of Streptomyces toxytricini into pellet: Role of culture conditions and kinetics

The present study envisages the role of different carbon sources, nitrogen sources, metals, pH, inoculum volume and agitation rate in pellet formation of S. toxytricini at shake-flask level. It was found that galactose, ammonium sulphate, sodium nitrate, Cu2+, Zn2+, higher inoculum volume (5% v/v) and agitation rate at 300 rpm caused significant reduction in pellet size (up to the range of 30 μm-0.5 mm) but biomass formations was also reduced subsequently. Interestingly diffused type of morphology was obtained in Fe2+ supplemented medium with reduced biomass (1.5 g L−1). Rheological study revealed that non-Newtonian behaviour of culture broth. Besides this, kinetics study was also made to understand the growth kinetics (0.39 g L−1 h−1), oxygen uptake rate (0.1146 mg L−1 h−1), and production of lipstatin (0.0072 g h−1).