Selection and characterization of Euglena anabaena var. minor as a new candidate Euglena species for industrial application.

Euglena gracilis is a microalgae used as a model organism. Recently, mass cultivation of this species has been achieved for industrial applications. The genus Euglena includes more than 200 species that share common useful features, but the potential industrial applications of other Euglena species have not been evaluated. Thus, we conducted a pilot screening study to identify other species that proliferate at a sufficiently rapid rate to be used for mass cultivation; we found that Euglena anabaena var. minor had a rapid growth rate. In addition, its cells accumulated more than 40% weight of carbohydrate, most of which is considered to be a euglenoid specific type of beta-1-3-glucan, paramylon. Carbohydrate is stored in E. anabaena var. minor cells during normal culture, whereas E. gracilis requires nitrogen limitation to facilitate paramylon accumulation. These results suggest the potential industrial application of E. anabaena var. minor.