Statistical Approach of Nutrient Optimization for Microalgae Cultivation

The Plackett-Burman Design (PBD) was applied to study fresh water microalgae cultivation using Chlorella sp. TISTR 8411 to select the influential nutrient factors for biomass and lipid production. The PBD for 13 trials from 11 nutrient factors with 3 levels was studied in the mixotrophic cultivation at 28 0C under 16:8 light and dark photoperiods over 7 days of cultivation time. Two influential factors were chosen as glucose and cobalt chloride hexahydrate to further design via Box-Behnken Design (BBD) in order to optimize the cultivation of this microalgae for biodiesel production. The 17 trials of 3 factors and 3 levels of BBD experimental design technique were applied with varying factors of glucose (20-40 g/L), cobalt chloride hexahydrate (0.01-0.04 mg/L) and light intensity (4,500-7,500 Lux) under 16:8 light and dark photoperiods over 7 days of cultivation time at 28 0C. Result showed that Chlorella sp. TISTR 8411 cultivation yield 0.52 g/L biomass and 0.31 g/L lipid production resulting in approximately 60% of lipid production when cultivated in 20.05 g/L glucose, 0.04 mg/L CoCl26H2O under light intensity of 4,614 Lux with the supplementation of 4.38 g/L NaHCO3 coupled with 1 g/L of both NaNO3 and KH2PO4. Under statically mixotrophic cultivation, result indicated that Chlorella sp. TISTR 8411 had potential to produce high lipid content for biodiesel application and biomass production for nutraceutical application. Further experiment with the longer cultivation period up to 2 weeks would implement not only for monitoring the growth kinetics but also evaluating the suitable type of fatty acid production