Optimization and lipid production enhancement of microalgae culture by efficiently changing the conditions along with the growth-state

Specifically growth-state-based schemes for cultivation optimization of microalgae Chlorella sp. were researched for the lipid enhancement in biodiesel production, compared with common optimization experiments. The optimized conditions of initial cell density, light intensity and aeration flow in common optimization were about 0.45 cm−1 (in OD686, i.e. 0.15 g/L), 6000 lux and 0.2 vvm (mL mL−1 min−1) respectively, taking into account the lipid yield and energy consumption. The maximum dry weight and lipid content were 1.2 g/L and 33.6% respectively. Then three specific schemes for cultivation conditions adjustment were conducted to study the effects of changing conditions along with growth state for the potential enhancement of biomass and lipid production. The results showed that excellent enhancement of both biomass dry weight of 1.9 g/L and lipid yield of 0.6 g/L was achieved. The new and specific cultivation method significantly improved the biomass and lipid production by 52.7% and 64.7% respectively, compared with the aforementioned three common optimization experiments. The GC–MS analysis indicated that C16–C18 components accounted for more than 90% of fatty acid, and the fatty acid had better properties than that in common cultivation.