Biodegradation of cyanide with Saccharomyces cerevisiae in Baijiu fermentation

Cyanide is a toxic substance which can be released from plants. It can be accumulated in the plant-based food fermentation. Therefore, it is necessary to control the concentration of cyanide in food fermentation with cereals as materials. In this study, Saccharomyces cerevisiae was identified as the cyanide-degrading microbe in Baijiu fermentation using metatranscriptomic analysis, and an indigenous strain S. cerevisiae MT-1 was isolated from Baijiu fermentation. This strain could produce nitrilase and degraded 58.42% cyanide in in vitro experiment. The optimum temperature and pH for cyanide degradation activity of S. cerevisiae MT-1 were 30 degrees C and pH 8.0. Moreover, the cyanide degradation ability of S. cerevisiae MT-1 increased with increase of cyanide concentration. After inoculation of this strain in simulative Baijiu fermentation with additional cyanide, the final cyanide content decreased by 46.45%. In conclusion, this study developed an effective strategy to degrade the content of cyanide in food fermentation.