Increased Astaxanthin Production by Phaffia rhodozyma Mutants Isolated as Resistant to Diphenylamine

概要

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To improve astaxanthin production by Phaffia rhodozyma, resistance to a carotenoid biosynthesis inhibitor was employed to screen higher astaxanthin producers. The wild type strain generated pinkish salmon-colored colonies due to the intracellular astaxanthin accumulation, but the colonies have turned white when grown in the presence of some of carotenoid biosynthesis inhibitors. Among the compounds tested, diphenylamine (DPA) was selected as the most effective inhibitor that did not significantly affect colony numbers and sizes・Upon mutagenesis and screening, DPA-resistant mutants were isolated as salmon-colored colonies on plates containing DPA, and two of the DPA-resistant mutants exhibited a two-fold increase in astaxanthin production over that of the wild type. In the DPA-treated wild type, 15-cis phytoene was identified as the major carotenoid, indicating that the target enzyme of DPA was likely to be phytoene desaturase (PDS). When trated with DPA and/or nicotine, an inhibitor of a lycopene cyclase, lycopene accumulation was similarly enhanced in the resistant mutant, and the degrees of inhibition by DPA were also found analogous to astaxanthin formation in the wild type and in the DPA-resistant mutant. These results indicated that the enhanced carotenogenesis most probably occured at the PDS stage.
社団法人日本生物工学会の論文
1997-05-25