Optimization of synthetic pathway and fermentation process of yeast cell factories for production of oleanoic acid / 中国中药杂志

<p><b>OBJECTIVE</b>To optimize the synthetic pathway and fermentation process of yeast cell factories for production of oleanoic acid.</p><p><b>METHOD</b>Using the DNA assembler method, one copy of Glycyrrhiza glabra beta-amyrin synthase (GgbAS), Medicago truncatula oleanolic acid synthase (MtOAS) and Arabidopsis thaliana cytochrome P450 reductase 1 (AtCPR1) genes were introduced into Saccharomyces cerevisiae strain BY-OA, resulting in strain BY-20A. YPD medium with different glucose concentration were then used to cultivate strain BY-2OA.</p><p><b>RESULT</b>Increasing gene copies of GgbAS, MtOAS and AtCPR1 resulted in increased beta-amyrin and oleanolic acid production. The strain BY-2OA produced 136.5 mg x L(-1) beta-amyrin and 92.5 mg x L(-1) oleanolic acid, which were 54% and 30% higher than the parent strain BY-OA. Finally, the titer of oleanolic acid increased to 165.7 mg x L(-1) when cultivated in YPD medium with 40 mg x L(-1) glucose.</p><p><b>CONCLUSION</b>Production of oleanoic acid increased significantly in the yeast strain BY-2OA, which can provide the basis for creating an alternative way for production of oleanoic acid in place of extraction from plant sources.</p>

Construction of Baker’s Yeast Strains with High Fermentative Abilities in both Lean and Sweet Doughs / 微生物学通报

Two parental strains BY-14 and BY-6,with high leavening ability in lean and sweet dough respectively,were selected.Through spore production and separation,two haploids with opposition types were selected for cross-breeding.At last one hybridization strain was obtained,with good fermentation ability as BY-14 in lean dough and better than BY-6 by 25%in sweet dough.