Studies on Haematococcus pluvialis for improved production of astaxanthin by mutagenesis

Cultures of Haematococcus pluvialis were exposed to mutagens like u.v. and EMS (ethyl methanesulphonate). The results showed that the survival rate decreased with the increase in u.v. exposure time and increase in EMS concentration. These mutants were further screened using inhibitors of the carotenoid biosynthetic pathway viz. diphenylamine (15-90 muM), nicotine (160-320 muM) and compactin (1.5-3.0 muM). The mutants thus obtained showed early enhanced (2.2-3.2-fold) astaxanthin accumulation and also exhibited higher lycopene cyclase activity.