Method of production of β-carotene by fermentation in mixed culture using (+) and (−) strains of Blakeslea trispora

In a method of production of β-carotene by fermentation with mixed cultures of (+) and (−) strains of B. trispora, the improvement comprising fermenting the cultures in a plurality of vegetative growth stages, including an initial stage wherein spores of each of the (+) and (−) strains that have been seeded in respective inoculum media are incubated to form respective primary cultures of the (+) and (−) strains of B. trispora, a cultivation stage wherein the primary cultures of the (+) and (−) strains are cultivated, and a fermentation stage wherein the cultivated primary cultures are mixed and fermented in a fermentation medium, wherein β-ionone and oxygen are added to the fermentation medium in the fermentation stage, the β-ionone being added in an amount that improves the yield of β-carotene as compared with the yield if the β-ionone were not added, the oxygen being added in an amount that decreases a yield of caratenoids other than β-carotene compared with the yield of the other carotenoids if the oxygen were not added, each of the plurality of vegetative growth stages having a duration that is controlled such that the method yields a minimum of 6 g/l of β-carotene in 5-6 days.