Separation of β-Factor Synthesis from Stimulated β-Carotene Synthesis in Mated Cultures ofBlakeslea trispora

Abstract

Mated cultures of Blakeslea trispora, grown in a potato extract-glucose-thiamine medium, produced 10 to 15 times more β-carotene than either unmated culture. Mated, but not unmated, cultures produced a family of compounds (β factor) which stimulated carotenogenesis in unmated cultures. In fact, carotenogenesis was stimulated sixfold more in minus cultures than in plus cultures. By altering the relative amounts of plus and minus inocula used in fermentations of mated cultures, it was possible to separate the synthesis of β factor from the synthesis of extra β-carotene. The plus strain appeared to produce the β factor; the minus strain appeared to produce most of the extra β-carotene. Kinetic studies of β-factor formation suggested that physical contact between the two strains may be required to initiate β-factor synthesis.