Fed-batch cultivation of Euglena gracilis for the high-yield production and GPC-assisted molecular weight determination of paramylon.

This article focuses on optimizing the heterotrophic fed-batch cultivation of Euglena gracilis to enhance biomass and paramylon production, a starch-like β-1,3-glucan carbohydrate with potential as a raw material for chemical products. The study found that cultivation at 28 °C yielded a maximum dry cell weight of 108.9 g/L with 87.2% paramylon content, surpassing previous reports in both yield and cultivation time. Paramylon molecular weight was determined to range between 220,000 and 320,000 Da, showing a positive correlation with intracellular paramylon content but little variation across culture conditions. The research also compared organic and inorganic nitrogen sources, noting higher glucose-to-paramylon conversion efficiency with inorganic nitrogen, and highlighted the beneficial effects of phosphorus and vitamin supplementation. These findings contribute to understanding paramylon production parameters and molecular characteristics relevant for its industrial application.