Production of paramylon,a β‐1,3‐glucan,by heterotrophic cultivation of Euglena gracilis on potato liquor

Euglena gracilis is shown to be able to grow on potato liquor as the main medium component leading to an interesting biotechnological product represented by paramylon – a β‐1,3‐glucan – and, at the same time, revaluating an otherwise annoying waste stream of the potato‐starch industry. Paramylon mass fractions of about 75% are obtained for biomass concentrations of 15 g/L during simple batch cultivation under heterotrophic conditions. Supplementation of the growth medium with glucose and the vitamins B₁ and B₁₂ are shown to improve growth rate as well as paramylon content. E. gracilis grows best at about 27.5°C without requiring pH control.