Screening, identification and fermentation performance of wild yeasts from Rubus pectinellus Maxim

Abstract

In order to screen superior yeast strains for the brewing of Rubus pectinellus Maxim. fruit wine, the yeast strains were isolated from R. pectinellus Maxim. fermentation liquid by traditional culture separation method combined with morphological observation. Furthermore, the yeast strains were screened based on gas production, ethanol production, ester production, killing ability, and identified by molecular biological technigue. The tolerance of these screened strains was analyzed using commercial yeast ADT as control. The results showed that 18 yeast strains were isolated and purified, out of which two exceptional strains named WQ-3 and WQ-8 were identified as Pichia cuddleensis and Pichia manshurica, respectively. These two yeasts exhibited remarkable tolerance towards various conditions including ethanol volume fraction 12%, pH 2.5, low temperature 4 ℃, high temperature 40 ℃, SO2 mass concentration 400 mg/L, and glucose mass concentration 400 g/L. This study provided valuable yeast resources for the brewing of R. pectinellus Maxim. fruit wine.

Keywords

• rubus pectinellus maxim. fruit wine|yeast|screening|identification|fermentation performance