Accumulation of Astaxanthin by Co-fermentation of Spirulina platensis and Recombinant Saccharomyces cerevisiae.

This study aimed to explore an effective, simple, and time-saving method for astaxanthin accumulation. Wild-type Saccharomyces cerevisiae as a bioreactor, the SpcrtR gene was first ligated with the signal peptide S to construct pYES2/NT-A-S-SpcrtR plasmid in Saccharomyces cerevisiae. The detection of SDS-PAGE and Western blotting protein proved that SpCRTR was successfully extracellular expressed in Saccharomyces cerevisiae. The target product astaxanthin was produced by co-fermentation of Spirulina platensis and recombinant Saccharomyces cerevisiae. The test results showed that after 18 h of fermentation, the astaxanthin concentration was highest in the mixed fermentation broth with 4% Spirulina platensis and recombinant Saccharomyces cerevisiae, and the content of astaxanthin was 0.25 ± 0.02 μg/mL. In addition, the source of astaxanthin was explored. During the fermentation process of the Saccharomyces cerevisiae strain, SpCRTR enzyme catalyzed the Spirulina platensis canthaxanthin, which almost completely converted into astaxanthin, providing a simple method for astaxanthin synthesis. Compared with culture of Haematococcus pluvialis, this culture route not only shortens culture time, but also eliminates the limitation of the conditions in the culture process.