Effects of Salinity on the Synthesis of 3-Methylthiopropanol, 2-Phenylethanol, and Isoamyl Acetate in Zygosaccharomyces Rouxii and Z. Rouxii 3-2.

Zygosaccharomyces rouxii referred as Yeast S is an important microorganism widely applied in traditional fermented food to accelerate flavor formation. Z. rouxii 3-2 referred as Yeast S 3-2 constructed previously is a new strain having higher salt tolerance than wild type. In this study, salt stress response of synthesis key flavor metabolites 3-methylthiopropanol, 2-phenylethyl alcohol, and isoamyl acetate in Yeast S and S 3-2 were investigated based on SPME–GC–MS and RT-qPCR. Analysis of GC–MS data showed that high salinity led to increase the contents of 3-methylthiopropanol and 2-phenylethyl alcohol both in Yeast S and Yeast S 3-2, while inhibited the synthesis of isoamyl acetate, and the induced effect on Yeast S 3-2 was more pronounced than Yeast S. Furthermore, the RT-qPCR results revealed that the salinity could enhance the genes expression of ARO10 and PDC1 , and stronger effect on Yeast S 3-2 than S. However, the gene expression of AFT1 was reduced in high-salt culture conditions, which was consistent with the results of GC–MS data. The results presented in this study can provide theoretical support of Z. rouxii 3-2 application during food fermentation.