| 摘要 |
2111477 9222648 PCTABS00018 High carotenoid-producing, in particular astaxanthin-producing, microorganisms are generated by treating cells of a carotenoid-producing microorganism strain with a mutagen, culturing the mutagenized cells in the presence of a phytoene dehydrogenase inhibitor to reduce the level of carotenoid production of all the cells, and selecting a mutant cell or colony showing increased carotenoid coloring compared to the background. In particular, the carotenoid-producing microorganism is Phaffia rhodozyma, and the cells are grown to the late stationary phase before they are treated with the mutagen. The obtained microorganisms can be grown to obtain a biomass containing the carotenoid in an amount of at least 1600, preferably at least 1900 .mu.g/g dry weight. When culturing a carotenoid-producing microorganism to produce carotenoid-containing microbial cells or purified carotenoid, particularly high yields of carotenoid can be obtained by growing the cells to the haploid phase before they are harvested or further treated. Still higher yields may be obtained by using a culture medium containing peroxisome-inducing substances.
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