Enhanced astaxanthin production from Haematococcus pluvialis using butylated hydroxyanisole

Haematococcus pluvialis is a promising natural source of high-value antioxidant astaxanthin under stress conditions. Biotic or abiotic elicitors are effective strategies for improving astaxanthin production in H. pluvialis. Butylated hydroxyanisole (BHA) was identified as an effective inducer for H. pluvialis LUGU. Under a treatment of 2 mg L-1 BHA (BHA(2)), astaxanthin content reached a maximum of 29.03 mgg(-1) dry weight (DW) (2.03-fold of that in the control) after 12 day of the mid-exponential growth phase. Subsequently, H. pluvialis LUGU was subjected to BHA(2) at different growth phases because an appropriate time node for adding elicitors is vital for the entire production to succeed. As a result, the highest astaxanthin content (293 mgg(-1) DW) was obtained in cells on day 14 (BHA(2) 14) of the late-exponential growth phase. Furthermore, the samples treated with BHA(2) 14 and the control group were compared in terms of the transcriptional expression of seven carotenogenesis genes, fatty acid composition, and total accumulated astaxanthin. All selected genes exhibited up-regulated expression profiles, with chy, crtO, and bkt exhibiting higher maximum transcriptional levels than the rest. Oleic acid content increased 33.15-fold, with acp, fad, and kas expression being enhanced on the day when astaxanthin was produced rapidly. (C) 2016 Elsevier B.V. All rights reserved.