Mixotrophic Cultivation Optimization of Microalga Euglena pisciformis AEW501 for Paramylon Production

Abstract

Euglena, a flagellated unicellular protist, has recently received widespread attention for various high-value metabolites, especially paramylon, which was only found in Euglenophyta. The limited species and low biomass of Euglena has impeded paramylon exploitation and utilization. This study established an optimal cultivation method of Euglena pisciformis AEW501 for paramylon production under mixotrophic cultivation. The results showed that the optimum mixotrophic conditions were 20 °C, pH 7.0, and 63 μmol photons m−2∙s−1, and the concentrations of sodium acetate and diammonium hydrogen phosphate were 0.98 g L−1 and 0.79 g L−1, respectively. The maximal biomass and paramylon content were 0.72 g L−1 and 71.39% of dry weight. The algal powder contained more than 16 amino acids, 6 vitamins, and 10 unsaturated fatty acids under the optimal cultivation. E. pisciformis paramylon was pure β-1,3-glucan-type polysaccharide (the purity was up to 99.13 ± 0.61%) composed of linear glucose chains linked together by β-1,3-glycosidic bonds. These findings present a valuable basis for the industrial exploitation of paramylon with E. pisciformis AEW501.

Metabolite Compounds of Euglena sp. on Mass Cultivation System under MgCl2 and CaCl2 Salt Stress

“…Paramylon is a glucose polymer that functions as storage, reaching 80% of the dry weight of Euglena sp. [22], [23]. Euglena sp.…”

New insights into raceway cultivation of Euglena gracilis under long-term semi-continuous nitrogen starvation

“…In the case of E. gracilis paramylon is considered a valuable bioproduct. Its accumulation has been observed under various conditions such as nutrient starvation, high salinity, electrical stimulation, co-culturing with bacteria, and heterotrophic cultivation 5 , 11 – 16 . Researchers have also attempted genetic modification to improve productivity and paramylon content in E. gracilis 17 , 18 .…”