Salt-Tolerant Yeasts in Soy Sauce Fermentation: Community Dynamics, Flavor Contribution, and Microbial Interactions

Soy sauce is a time-honored fermented condiment, the quality of which is primarily influenced by the growth and metabolism of microorganisms during fermentation. Among these, salt-tolerant yeasts play a particularly important role in flavor development, garnering increasing attention recently. This review summarizes the reported genera and succession of salt-tolerant yeasts in soy sauce fermentation, covering a total of 23 genera, mainly from the Ascomycota, with 6 genera present in the koji-making stage and 23 during moromi fermentation. In addition, the factors influencing yeast community succession, including raw materials, environmental conditions, fermentation containers, and technological parameters, were summarized. The contributions of key yeasts, such as Zygosaccharomyces rouxii, Candida versatilis, and Pichia guilliermondii, to flavor formation are discussed, as well as the application and current progress of inoculation strategies based on microbial interactions. Finally, on the basis of the limitations of existing research, four key directions for future studies were proposed: investigating low-abundance yet key strains, elucidating the taste contributions of specific strains, understanding environmental factors driving microbial community succession, exploring microbial interaction mechanisms, and designing synthetic microbial communities.