Metaproteomic Characterization of Daqu, a Fermentation Starter Culture of Chinese Liquor

Daqu is an essential fermentation starter for the prodcution of Chinese liquor, and it is closely related to the quality and yield of liquor. The aim of this study was to investigate the microbial community of Daqu by using the metaproteomic approach. A total of 45 protein spots in the two-dimensional electophoresis gel were excised and identified. Seventeen protein spots represent 16 proteins that originate from the secretion of bacteria, yeast, and filamentous fungi. Moreover, Nitrobacter winogradskyi, Agrobacterium tumefaciens and Neurospora crassa were first identified in Daqu. To the best of our knowledge, this is the first report on the community structure of Chinese liquor Daqu through metaproteomic analysis. Results presented in this study may further elucidate the microbial community structure in Daqu and may facilitate the development of Daqu for the manufacture of Chinese liquor.