Production of paramylon, a β-1,3-glucan, by heterotrophic cultivation of Euglena gracilis on a synthetic medium

Euglena gracilis was cultivated on a synthetic medium of well-defined components. Biomass and paramylon (beta-1,3-glucan) concentrations were the most important variables monitored. Mass production in the bioreactor was carried out following studies of operating conditions in shaken flasks. E. gracilis grew best at about 30 degrees C and at a low pH of 3. A pH control was not necessary, although the pH increased considerably at the end of the cultivation processes. Aeration could be performed at low stirrer frequency. Biomass concentrations of about 13-1.4 g/L were obtained with paramylon mass fractions of 50-60%, by starting with a synthetic medium containing 15 g/L of glucose as the main carbon source.