Chinese Baijiu - Finding a channel to design a defined starter culture

Qu (a starter composed of multiple microbes, enzymes, and nutrients) is essential for initiating Chinese baijiu fermentation and is usually prepared in an open system to enrich the starter complex with microorganisms from the local environment. However, with the challenge of increasing manufacturing and labor costs, traditional spontaneous fermentation cannot meet the growing industrial needs for standardization and modernization. Nowadays, the development of a synthetic microbiota built up from selected and cultured microorganisms enables the repeatable, standardized production of fermented foods. The use of such synthetic microbiota to convert raw materials into foods can hopefully reproduce the smells and tastes of traditional products. This review critically summarizes the properties of traditional qu and discusses the potential of a defined synthetic microbiota to revolutionize the production of such fermentation starters for future baijiu production. The prospects and challenges in dealing with the identification, selection, cultivation, and incorporation of microbes into such synthetic microbiota (or new ecological complexes) are specifically related to developing a fully defined and effective mixed-starter culture for use in traditional fermented food production are detailed.