Production of Paramylon by Photo-mixotrophic Cultivation of Euglena gracilis Using Sewage Effluent and Organic By-products

摘要

Euglena gracilis, a unicellular flagellated microalga, has been recognized as a feedstock to produce biodiesels and bioproducts. E. gracilis produces a unique metabolite, paramylon (β-1,3-glucan). Recently, paramylon has been found to have medical potentials such as antitumor activity, anti-infection activity, and cholesterol lowering effect. The use of wastewater and organic by-products/wastes as an E. gracilis culture medium would improve the economics and sustainability of paramylon production. Therefore, the objectives of this study were to demonstrate the paramylon production by E. gracilis cultivation using wastewater and organic by-products and to examine the effects of organic by-products on growth and paramylon productivity of E. gracilis. In this study, E. gracilis was cultured in synthetic medium (C medium) or sewage effluent with and without industrial by-products, corn steep liquor and molasses, under photo-mixotrophic conditions. E. gracilis efficiently grew and produced paramylon in sewage effluent. Biomass and paramylon productivities of E. gracilis in sewage effluent was higher than those in C medium. E. gracilis could metabolize corn steep liquor and molasses as nitrogen and growth factor source for biomass and paramylon production. Addition of the both by-products into sewage effluent increase paramylon productivity of E. gracilis.