Aim: The present study highlights the research explorations carried out on process
parameter optimization for the formulation of a new growth medium for mixotrophic cultivation
of a novel algal strain, ‘Chlorella sorokiniana TERI-A’.
Method: Acid-treated Sorghum stover biomass hydrolysate (Sorghum stover prehydrolysate)
was used as carbon source that was composed of 22.2 g L-1 total sugar (with 15 g L-1 xylose
& arabinose), 16 g L-1 of acetic acid along with small amount of succinic acid, formic acid
along with furfural, and Hydroxyl Methyl Furfural (HMF). Sorghum stover prehydrolysate
concentration (Substrate) was optimized for the enhancement of biomass productivity of
TERI-A strain in mixotrophic growth mode.
Results: At optimum temperature; 28°C, initial pH; 7.8 and 180 rpm, biomass productivity of
TERI-A strain was 2.35 g L-1. C5 sugar concentration of this Sorghum stover prehydrolysate
based growth medium was; 1.5%. FAME profile analysis of ‘TERI-A’ biomass revealed that
‘TERI-A’ strain could accumulate 68.2% unsaturated fatty acid. This indicates that this algal
strain has potential application in biodiesel production.
Conclusion: Carrying forward these research explorations, scale-up of mixotrophic cultivation
of ‘TERI-A’ strain was standardized in 3.7 L scale photobioreactor to further enhance
the biomass productivity from Sorghum stover prehydrolysate. This is the first report for
mixotrophic cultivation of Chlorella sorokiniana in sorghum stover prehydrolysate.