Enhancing biomass and oil accumulation of Monoraphidium sp FXY-10 by combined fulvic acid and two-step cultivation

The combination of combined fulvic acid (FA) and two-step cultivation was proposed as a novel strategy to enhance biomass and oil accumulation of Monoraphidium sp. FXY-10 compared with the traditional monoculture of microalgae. In this study, the effect of FA on the growth and lipid accumulation of Monoraphidium sp. FXY-10 was investigated using one- and two-stage cultivation. In the heterotrophic one stage cultivation, 1.5-fold biomass was enhanced with 80 mg L-1 FA (6.41 g L-1) compared with the control biomass (4.21 g L-1). In the heterotrophic-photoautotrophic two-stage cultivation, different FA concentrations were used to stimulate lipid accumulation. The lipid content increased from 30.78% to 54.65% when 25 mg L-1 FA was added to the culture. The main fatty acids in the FA-triggered Monoraphidium sp. FXY-10 were C16/C18 fatty acids (97%), which are appropriate for biodiesel production. Results showed that the proposed strategy is useful for biomass and oil production of Monoraphidium sp. FXY-10. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.