Microbial flocculant. Part II Culture conditions for production of microbial flocculant by Rhodococcus erythropolis.

Addition of yeast extract and casamino acids stimulated the production of a flocculant by Rhodococcus erythropolis. The favorable substrates for flocculant formation were fructose (or glucose), urea, and yeast extract. Optimum culture temperature and optimum culture pH for the production of the flocculant were 30°C and pH 8.5-9.5, respectively. Excess aeration decreased the production of the flocculant. The production of the flocculant paralled the growth curve. More than 90% of the flocculating activity was in the culture broth and less than 10% in the cells.