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 de creased with the increase in u.v. exposure time and increase in EMS concent ration. These mutants were further screened using inhibitors of the caroten oid biosynthetic pathway viz. diphenylamine (15-90 muM), nicotine (160-320 muM) and compactin (1.5-3.0 muM). The mutants thus obtained showed early en hanced (2.2-3.2-fold) astaxanthin accumulation and also exhibited higher ly copene cyclase activity.