Characterization of non-native promoters in Saccharomyces cerevisiae

Abstract

Yeast has been a valuable model organism for both industry and research. However, until recently, the use of native promoters in scale-up production has led to strain instability and subsequently, loss of productivity. Previous studies have found TEF promoters to give stable expression levels across culture conditions in addition to being a gene very conserved among yeast strains. Therefore, we investigated the strength of TEF promoters from different organisms by analyzing their expression of GFP on different carbon sources and developed a synthetic biology toolkit containing different strength non-native promoters for Saccharomyces cerevisiae to avoid several copies of the same promoter in the genome. Kluyveromyces marxianus promoter sequence showed promising results, surpassing our positive control. Cyberlindnera jardinii and Candida parapsilosis TEF2 exhibited medium strength, and Candida parapsilosis TEF1, Scheffersomyces stipites, and Yarrowla lipolytica promoters demonstrated weaker strength but were still functional in the yeast, performing better than the negative control. These results show that the investigated promoters could be used to engineer cell factories in research and industry.