Although higher aeration
(0.2 vvm) than 0.133 vvm resulted in the increased growth, the lipid
content was decreased for the reason that the microalgae might use
more energy and nutrients to multiply cells rather synthesis lipid
[27]. At the aeration of 0.267 and 0.333 vvm, the lipid content
showed a further decline mainly due to the damage to the cells by
intense turbulence. However, due to high dry biomass yield the
maximum lipid production 0.31 g/L was determined at the aeration
flow of 0.2 vvm with lipid content 28%. Chiu et al.[42]reported that
pH decreasing could lead to the decrease of lipid content for the specific microalgae. Consequently, 0.2 and 0.267 vvm were selected as
the optimum aeration flow for the cultivation ofChlorellasp. in different growth states, considering lipid content and lipid production
at the end of 13 days culture cycle