Studies of astaxanthin biosynthesis in Xanthophyllomyces dendrorhous (Phaffia rhodozyma). Effect of inhibitors and low temperature.

The effect of nicotine and diphenylamine on astaxanthin biosynthesis in Xanthophyllomyces dendrorhous was studied. The effects were analysed under standard and low temperature conditions. It was found that 10 mM-nicotine inhibits the cyclization of lycopene and de novo protein synthesis was not needed to reverse the inhibition. The oxidation of beta-carotene was irreversibly inhibited by 10 microM-diphenylamine while the dehydrogenation of phytoene was reversibly inhibited by 60 microM-diphenylamine. The simultaneous exposure to low temperature (4 degrees C) overcomes the inhibition of beta-carotene oxidation at low diphenylamine concentration.