Abstract:

Objective To explore the fermentation conditions of ergosterol yeast engineering strain and illustrate that  the yeast strain (YDH/pGAD-ScERGI) can synthesize ergosterol by using corn hydrolysates as fermentation substrates.Methods The different substrates,nitrogen sources,corn syrup contents,inorganic salts,pH were used to measured the cell biomass of engineered strain and ergosterol content.Results When the fermentation parameters of corn hydrolysates 10o Bx, corn steep 6.5%, magnesium sulfate 0.1%, initial pH of 6.5,inoculum 10%,28℃ shaking cultured 16 h,the yeast（YDH/pGAD -ScERG1）cell biomass reached 14.34 g?L-1,the  ergosterol content was  up to 3.05%,ergosterol yield was 435.93 mg?L-1. Conclusion The ERG1 gene expression of yeast strains（YDH/pGAD -ScERG1）is conducive to the synthesis of ergosterol.

Key words: ergosterol, yeast strain, fermentation, corn hydrolysates, corn steep