Characterization of tolerance and multi‐enzyme activities in non‐ Saccharomyces yeasts isolated from Vidal blanc icewine fermentation

Abstract This work aim to study the tolerance and aroma‐related enzymes activities of the non‐ Saccharomyces yeasts in Vidal blanc icewine from the Huanren region of China. The strains were identified by sequencing internal transcribed spacer (ITS) region and the 26S rDNA D1/D2 domain genes and all representative non‐ Saccharomyces yeasts were belonged to genera Metschnikowia , Hanseniaspora , Torulaspora, Candida , and Debaryomyces . A total of 28 strains were carried out for tolerance experiments and results suggested that most of them could tolerate 500 g/L glucose, 4% ethanol, 20 g/L tartaric acid, and 350 mg/L SO 2 . Finally, a total of 17 strains with better tolerance were carried out for the β‐glucosidase, β‐xylosidase, and pectinase activities experiments. The results showed that Candida railenensis HC08 and the strains of Hanseniaspora genus have satisfactory multi‐enzyme activities, which can be used to design mixed fermentation to produce characteristic icewine. Practical applications Non‐ Saccharomyces yeasts produces a series of hydrolytic enzymes that are thought to have a significant contribution to the aroma complexity of wines, however, are poorly explored in icewine. In this work, most of the non‐ Saccharomyces yeasts screened from Chinese icewine can adapt well to the high‐sugar and high‐acid environment of icewine, and can secrete hydrolase. The application of these strains in mixed fermentation could provide a prospect for the production of characteristic icewine.