Construction of car1 Deletion Mutant fromSaccharomyces cerevisiaeand Evaluation of Its Fermentation Ability

Abstract

In order to reduce ethyl carbamate content in yellow wine (YW), a car1 deletion mutant (S car1) was constructed by SFH-PCR-mediated gene knockout and the YW fermentation process of the S car1 were analyzed. The results indicated that S car1 was successfully constructed. The stationary phase of the S car1 was at 30 h and 6 h later than that of the wild strain (24 h).The arginase activity in cultural supernatant of S car1 was not detected, while the 5.2 U activity was detected in that of the wild strain after being cultured for 18 h in YNBG. The fermentation profile of the S car1 was basically the same with that of the wild strain. The arginine (5.29 g/100 L), lysine (3.16 g/100 L) and cysteine concentrations (1.38 g/100 L) in the YW brewed with S car1 were higher than that in the YW brewed with wild strain (0.44 g/100 L,1.46 g/100 L and 0.63 g/100 L, respectively),but the ornithine concentration (0.58 g/100 L) was lower than that in the YW brewed with wild strain (1.98 g/100 L).The EC concentration in YW brewed with S car1 (5.93 µg/L) was notably lower than that in YW brewed with wild strain (40.65 µg/L).The successful construction of S car1 would provide a strain to produce YW with low concentration EC. However, the safety of the mutant should be assessed before it is used as starter.