Construction of recombinant fusant yeasts for the production of cider with low alcohol and enhanced aroma

Abstract

Increasing levels of alcohol abuse and changes in consumer interests have motivated the production of ciders with enhanced aroma and flavor, but low alcohol content. The improvement of fermentation has always been an important issue in the brewing industry. In this study, new recombinant fusant yeasts based on Saccharomyces cerevisiae and Candida ethanolica were constructed by protoplast fusant. The combination of ultrasonic and enzymatic hydrolysis could significantly improve protoplast formation and regeneration rates. In the presence of PEG-6000, the 24 fastest-growing regenerated colonies were selected for further fermentation and re-screening identification, and nine stable fusant strains were inoculated in the subsequent fermentation. The alcohol content of the ciders was 2.0–5.2%, which was much lower than that of the parental strain. Fusants R6 and R7 revealed the best fermentation performance. The sensory scores of fusants R5 and R6 exhibited excellent performance than others. GC–MS analysis and fuzzy comprehensive evaluation showed fusant R6 displayed superior performance and desirable properties from both parental strains. This study demonstrated that recombinant fusant yeast of R6 has great potential for the production of high-quality, low-alcohol cider. The present work provides new avenues for the construction of potent recombinant fusant yeasts and a new strategy for the production of low-alcohol cider with enhanced aroma.