Abstract: Owing to its role as an important source for astaxanthin accumulation, Haematococcus pluvialis has gained more and more attention in recent years. In this research, we examined the effects of butyl hydroxyanisole (BHA) at different concentrations on the astaxanthin production under unfavorable conditions during the logarithmic growth phase of H. pluvialis LUGU. The results demonstrated that 2 mg/L BHA was optimal for maximum astaxanthin production, which reached 29.03 mg/g, 2.03 times higher than that of the control (14.30 mg/g). Moreover, under the same condition of BHA induction, initial algal cells with different growth status also had a great influence on astaxanthin synthesis. The accumulation of astaxanthin in the algal cells in the late exponential growth phase (14 d) reached the highest level of 29.3 mg/g, which was 2.93, 1.01 and 1.73 times higher those in the early and middle exponential, and stationary growth phases, respectively. qRT-PCR analysis shows that the transcriptional levels of phytoene synthase (psy) gene induced by 2 mg/L BHA was 9.2 times higher that of control. These findings showed that appropriate concentration of BHA could not only increase the transcription of psy gene, but also could obviously promote intracellular astaxanthin accumulation in microalgae, providing an effective strategy for the industrialization of astaxanthin.

Key words: butyl hydroxyanisole (BHA), Haematococcus pluvialis LUGU, astaxanthin, different growth phases, psy gene