High-throughput screening of mutant strain to reduce the accumulation of ethyl carbamate precursor in rice wine fermentation

Abstract:

[Objective] Ethyl carbamate is a common potential hazard in different fermented foods. Urea and ethanol are the major precursors of ethyl carbamate in rice wine. In this study, the accumulation of urea was reduced based on a high-throughput screening strategy, therefore decrease the accumulation of ethyl carbamate in rice wine.[Methods] An industrial strain Saccharomyces cerevisiae XZ-11 was used for the study. Lower urea accumulating strains were achieved by using Atmospheric and Room Temperature Plasma (ARTP) mutagenesis and high-throughput screening strategy. RT-qPCR analysis was used to detect the change of DUR1,2 and DUR3, two important urea metabolism and transport genes.[Results] A mutant strain 5-11C was obtained with the capacity of both efficiently urea using and genetic stability. The accumulation of urea was 50.6% lower than that of S. cerevisiae XZ-11. RT-qPCR results showed that the expression levels of DUR1,2 and DUR3 increased 3.3 and 2.2 folds, respectively.[Conclusion] High-throughput screening strategy can be applied to obtain mutants with reduced accumulation of ethyl carbamate precursor in rice wine.