Mutation of Haematococcus pluvialis using colchicine

초록

To enhance astaxanthin (3,3'-dihydroxy-?z?carotene-4,4'-dione)？n？nproduction by Haematococcus pluvialis mutants, two types of mutation methods were used: UV irradiation and colchicines treatment. Cell suspension was subjected to U.V. irradiation for different period of time (0 min, 5 min, 15 min, 25 min) in sterile open petri dishes using UV lamp (254 nm) at a distance of 12 cm and selected cultures after storing the dishes at 4oC overnight in the dark condition. In separate experiments, cell suspension were treated with various colchicine concentration (25-100 mg/L) in several different solution (modified bold…s basal medium(MBBM), distilled water, and K-phosphate buffer) and the treated algal cells were cultured for 1 to 8 days on MBBM agar plates under continuous light intensity of 40 ?/m2/s at 25oC in the dark condition. The results showed that survival rate decreased with the increase of the duration of U.V. exposure and with the increase of colchicine concentration and treated time. Selected mutants were further screened using inhibitors of the carotenoid biosynthetic pathway. Inhibitors used were nicotine (200 ?) and diphenylamine (15?) and both had decreased the survival rate by 40-50%. The selected mutant strains from U.V. treatment showed 1.6-fold higher total carotenoid contents per cell than that of the wild type strain. On the other hand, the selected mutant strains from colchicine treatment showed faster cell growth than the wild type strain. More detailed study is required to select the final strain of Haematococcus pluvialis for better and efficient producer of astaxanthin.