The Biosynthesis Of β-Carotene In Saccharomyces Cerevisiae

As a model organism for food safety, Saccharomyces cerevisiae has become a natural product biosynthesis preferred host cells. β-carotene has drawn a lot of attention because of its high-efficiency oxidation resistance and high value-added features.With the synthetic biology, we used different sources of synthetic β-carotene gene to improve the titer of production. Specific work is as follows:After strain InvScl-GAB begins to ferment 12 h,18 h,24 h, we added ergosterol inhibitors ketoconazole to give a final concentration of 30 mg·L-1. Adding after 18 hours of fermentation, the yield of P-carotene from experimental group was 20% higher than that from control group. The highest yield was 20 mg·L-1.Connected all the genes from the MVA pathway by FMDV 2A sequence to express in the same reading frame. Constructed strain InvScl-2A-YBIE, InvScl-2A-BYIE, InvScl-2A-YBIG and InvScl-2A-BYIG in order to express the genes from Erwinia and the replacement of geranyl pyrophosphate synthase from different source.Constructed strain InvScl-YBIE(2A), InvScl-YBIE(2A)/pR-t-2A-i, InvScl-IE-YB(2A), InvScl-ABG(2A), InvScl-AEB(2A) with optimized FMDV 2A sequence. The expression ability was improved by optimization of connection order and the involvement of genes from upstream. Besides, the expression ability of crtE was confirmed better by comparison of crtE from Erwinia and ggps from B lakes lea trispora.In this study, the best medium and the optimal indution time were also explored during the fermentation process of strain InvSc 1-ABG(2A). After comparing the cell growth and yield, the SD medium was performed better than YPD medium. Strain InvScl-GAB and InvScl-AEB(2A) were grew under the optimized condition. Their yield were 2.9 mg·g-1 and 2.8 mg·g-1, respectively.