초록
<P><B>Highlights</B></P><P>► Screening of mixotrophic nutrients for biomass production by <I>C. vulgaris</I> using RSM. ► Glucose, MgSO<SUB>4</SUB>, KNO<SUB>3</SUB> and NaCl are the critical mixotrophic nutrients of <I>C. vulgaris</I>. ► Mixotrophic <I>C. vulgaris</I> biomass can be used as the raw material for biorefinery.</P> <P><B>Abstract</B></P><P>The design of an optimum and mixotrophic medium for biomass production and biochemical composition biosynthesis by <I>Chlorella vulgaris</I> was attempted by using response surface methodology. Based on the Plackett–Burman design, glucose, MgSO<SUB>4</SUB>·7H<SUB>2</SUB>O, KNO<SUB>3</SUB> 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 4.28g/L was predicted when the concentrations of glucose, MgSO<SUB>4</SUB>·7H<SUB>2</SUB>O, KNO<SUB>3</SUB> and NaCl were 25g/L, 1.33g/L, 1.30g/L and 3.02g/L, respectively. Verification of the optimization showed that the biomass content of <I>C. vulgaris</I> could be enhanced from 0.24g/L in photoautotrophic SEM and 1.89g/L in unoptimized mixotrophic medium to 4.24g/L giving 17.67-fold and 2.24-fold increase in biomass production, respectively. The biochemical composition of <I>C. vulgaris</I> cultured in optimized mixotrophic medium indicated that the biomass can be used as the raw material for biorefinery.</P>