Isolation of mutants and construction of intersexual heterokaryons of Blakeslea trispora.

The Mucoral fungus Blakeslea trispora is used for the industrial production of β-carotene and lycopene. Two genetic techniques have been used to increase carotene accumulation: the isolation of mutants and the formation and segregation of heterokaryons. Because all life stages are multinucleated, recessive mutants are isolated after exposure to N-methyl-N'-nitro-N-nitrosoguanidine, a strong mutagen and inactivator of nuclei.

Stimulation of bikaverin production by sucrose and by salt starvation in Fusarium fujikuroi.

The fungus Fusarium fujikuroi (Gibberella fujikuroi mating group C) exhibits a rich secondary metabolism that includes the synthesis of compounds of biotechnological interest, such as gibberellins, bikaverin, and carotenoids. The effect of the carbon source on their production was checked using a two-phase incubation protocol, in which nine different sugars were added upon transfer of the fungus from repressed to appropriate inducing conditions, i.e.

Mutants and intersexual heterokaryons of Blakeslea trispora for production of beta-carotene and lycopene.

The industrial production of beta-carotene with the zygomycete Blakeslea trispora involves the joint cultivation of mycelia of opposite sex in the presence of beta-ionone and other chemical activators. We have obtained improved strains by mutation and heterokaryosis. We chose wild strains on the basis of their growth and carotene content in single and mated cultures.