Significance evaluation of the effects of environmental factors on the lipid accumulation of Chlorella minutissima UTEX 2341 under low-nutrition heterotrophic condition

The effects of a variety of environmental factors on lipid accumulation of Chlorella minutissima UTEX 2341 under low-nutrition conditions were investigated. The growth of UTEX 2341 reached the exponential phase on the 1st day in low-nutrition medium. And the highest biomass productivity of 3.07 g L−1 d−1 was achieved on the 2nd day. The optimum pH and temperature for lipid accumulation were 6 and 20 °C respectively. 43.69 g L−1 of NaCl and 0.11 mmol L−1 of Fe(III) resulted in higher lipid content, analyzed by Design-Expert. And then under nitrogen starvation stress, the lipid content reached 22.84%. Meanwhile, the lipid yield was 2.5 g L−1. The yield coefficient against carbon was 0.36 g g−1, which was 4.68 times as much as that in OM medium. With the high proportion of C16 and C18 in the lipids, C. minutissima UTEX 2341 was proved to be a potential option for renewable biodiesel production.