Main content area

STR3 and CYS3 Contribute to 2-Furfurylthiol Biosynthesis in Chinese Sesame-Flavored Baijiu Yeast

Zha, Musu, Yin, Sheng, Sun, Baoguo, Wang, Xin, Wang, Chengtao
Journal of agricultural and food chemistry 2017 v.65 no.27 pp. 5503-5511
Pichia kudriavzevii, Saccharomyces cerevisiae, Wickerhamomyces anomalus, biosynthesis, cysteine, fermentation, flavor, furfural, gene overexpression, genes, odor compounds, yeasts
2-Furfurylthiol is an important aroma compound with characteristic sesame flavor. It was recently identified as the representative aroma compound of Chinese sesame-flavored Baijiu. But its formation mechanism is unclear. In this study, the dominant yeast species Saccharomyces cerevisiae, Pichia kudriavzevii, and Wickerhamomyces anomalus were isolated from samples of Chinese sesame-flavored fermentation and were screened for the capacity of 2-furfurylthiol biosynthesis. Some isolates were found to be capable of generating 2-furfurylthiol using furfural and l-cysteine as precursors, among which S. cerevisiae G20 exhibited the strongest capacity with a yield of 3.03 mg/L. Furthermore, the genes STR3 and CYS3 from S. cerevisiae were cloned and overexpressed in the reference strain S. cerevisiae S288c and the isolate strain G20, respectively, which resulted in a significant increase in 2-furfurylthiol release in the two strains. Moreover, inactivation of STR3 gene in S288c and G20 led to obvious reduction in 2-furfurylthiol production, demonstrating that STR3 got involved in 2-furfurylthiol biosynthesis in S. cerevisiae. It is the first time that the yeast isolates with high capacity of 2-furfurylthiol biosynthesis were found during Chinese sesame-flavored Baijiu fermentation and confirmed that the genes STR3 and CYS3 were closely relevant to 2-furfurylthiol biosynthesis.