Optimization of mixotrophic medium components for biomass production and biochemical composition biosynthesis by Chlorella vulgaris using response surface methodology

The design of an optimum and mixotrophic medium for biomass production and biochemical composition biosynthesis by Chlorella vulgaris was attempted by using response surface methodology. Based on the Plackett-Burman design, glucose, MgSO4 center dot 7H(2)O, KNO3 and NaCl were selected from the eleven factors as the most critical mixotrophic nutrients. Subsequently, the selected four factors were investigated by the Box-Behnken design. Results showed that the maximum biomass yield of 4.28 g/L was predicted when the concentrations of glucose, MgSO4 center dot 7H(2)O, KNO3 and NaCl were 25 g/L, 1.33 g/L, 1.30 g/L and 3.02 g/L, respectively. Verification of the optimization showed that the biomass content of C. vulgaris could be enhanced from 0.24 g/L in photoautotrophic SEM and 1.89 g/L in unoptimized mixotrophic medium to 4.24 g/L giving 17.67-fold and 2.24-fold increase in biomass production, respectively. The biochemical composition of C. vulgaris cultured in optimized mixotrophic medium indicated that the biomass can be used as the raw material for biorefinery. (C) 2011 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.