Uniform design for optimizing biomass and intracellular polysaccharide production from self-flocculating Scenedesmus sp.-BH

Abstract

Four microalgae species were isolated from freshwaters in Xinjiang, one of which was identified as Scenedesmus sp.-BH. Analysis of the specimens showed not only the characterization of self-flocculation with a flocculating rate of 92.29 % in 12 h, but relatively high biomass and intracellular polysaccharide (IPS) production (250.5 and 5.55 mg/L) under original BG11 medium. Uniform design was applied to optimize the nutritional conditions of Scenedesmus sp.-BH. The maximum biomass yield of 556.7 ± 16.97 mg/L appeared at NaNO3 0.77 g/L, K2HPO4·3H2O 0.24 g/L, MgSO4·7H2O 0.24 g/L, ferric ammonium citrate 0.021 g/L, and NaHCO3 3.85 g/L, while a maximum IPS yield of 14.3 ± 0.46 mg/L appeared at NaNO3 0.004 g/L, K2HPO4·3H2O 0.24 g/L, MgSO4·7H2O 0.21 g/L, ferric ammonium citrate 0.024 g/L, and NaHCO3 1.42 g/L. Both biomass and IPS production were over two-fold of those cultured under the original condition, which demonstrated that uniform design could successfully improve the production of biomass and IPS.