Biotin enhances salt tolerance of Torulopsis mogii

Abstract

Halophilic aromatic yeasts, such as Torulopsis mogii and Zygosaccharomyces rouxii, are usually used for soy sauce fermentation, in order to enhance the flavor and quality of the high-salt oriental food seasoning sauce. However, in the process of soy sauce brewing, salt stress affects the cell growth of the aromatic yeasts and extends the fermentation process. The tolerance to high NaCl concentrations is important for Torulopsis to produce flavor in soy sauce. In this study, we report that supplementation of biotin improved cell growth of T. mogii at high salt environment. Further studies suggested that biotin enhanced the osmotic tolerance (salt tolerance) of T. mogii through accumulating trehalose in cells, increasing the ratio of K+/Na+; promoting the activity of ATPase, and increasing the synthesis of fatty acids with long chain and high saturation. These results indicated that biotin could be an effective supplement for improvement of soy sauce fermentation.