Improvement of astaxanthin production from Phaffia rhodozyma by protoplast fusion

Protoplast fusion between intrastrain of P. rhodozyma has been generated in order to increase astaxanthin production. The best protoplast was obtained under osmotic stabilizer using buffer phosphate with the addition of 0.1 M CaC12. Higher frequency of fusion and regeneration were obtained under 8 mg /ml lysozyme and 35 °/0 PEG 4000 treatment. Frequency of regeneration was 36 - 97%, frequency of fusion was 86.5 %. Several hybrids showed two-fold increase levels of ploidy, while yields of carotenoid pigments increased up to 2.03 times than the levels of wild type. Carotenoids accumulated to a level as high as 2. 529 lig /g dcw with the estimation of astaxanthin production reached the value of 488.75 lig/g dcw. Keywords: astaxanthin â Phaffia rhodozyma âprotoplast fusio