The effects of exogenous butylated hydroxytoluene on astaxanthin accumulation in Haematococcus pluvialis under abiotic stress

Abstract:

[Background] The Haematococcus pluvialis is the best source of natural astaxanthin and is widely used in industrial production of astaxanthin. [Objective] The current study is to explore influences of different concentrations butylated hydroxytoluene (BHT) on accumulation of astaxanthin in H. pluvialis, with a view to build the BHT technology system for enhancing astaxanthin content of H. pluvialis. [Methods] Without nitrate bold’s basal medium was selected as the induction medium for the culture of Haematococcus pluvialis strain LUGU. Meanwhile, high light treatment medium maintained induction conditions. the effects of different concentrations of butylated hydroxytoluene (BHT) on the growth, astaxanthin accumulation, reactive oxygen species, antioxidant system and the expression of related gene were studied in Haematococcus pluvialis under high light and nitrogen deficiency. [Results] The results showed that the astaxanthin content was enhanced efficiently in alga cells treated with 2mg/L BHT, within the range of 0–3 mg/L BHT, reaching 31.66 mg/g. In addition, 2 mg/L BHT treatment group effectively reduces the level of reactive oxygen species, increases intracellular nitric oxide levels, improves the algal cells catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) activity and glutathione (GSH) content, inducing efficient expression of lcy and chy. [Conclusion] Under abiotic stress conditions, exogenous BHT could promote astaxanthin accumulation, which was associated with BHT mediating the levels of ROS and NO, and astaxanthin biosynthetic related genes expressions in H. pluvialis.