EXOPOLYSACCHARIDE PRODUCTION BY THE CYANOBACTERIUM ANABAENA SP. ATCC-33047 IN BATCH AND CONTINUOUS-CULTURE

The halotolerant, filamentous, heterocystous cyanobacterium Anabaena s p. ATCC 33047 released, during the stationary growth phase in batch cu lture and, at low dilution rate, in continuous culture, large amounts of an exopolysaccharide (EPS) to the culture medium. Different environ mental, nutritional and physical parameters affected production and ac cumulation of the EPS. The presence of either a combined nitrogen sour ce or NaCl at high concentration led to decreased EPS production, with out affecting cell growth. In contrast, generation of the EPS was mark edly enhanced in response to an increase in either air flow rate, temp erature or irradiance. In continuous culture, accumulation of EPS in t he medium increased in response to a decrease in the dilution rate, wi th maximal EPS productivity being reached at a dilution rate of 0.03 h (-1). (C) 1998 Elsevier Science B.V. All rights reserved.