Metaproteomic characterisation of a Shaoxing rice wine “wheat Qu” extract

The starter culture “wheat Qu” has been used in the fermentation of Chinese rice wine for hundreds of years. In this study, a Shaoxing rice wine, “wheat Qu” (machine-made type), extract was analysed by using the metaproteomic approach. All visible 145 separate protein spots in the two-dimensional electrophoresis gel were excised and identified by Matrix-Assisted Laser Desorption Ionisation-Time of Flight/Time of Flight Mass Spectrometry (MALDI-TOF/TOF MS) analysis. Eleven spots represent 10 proteins that originate from the secretion of fungi or bacteria, 112 spots represent 43 proteins from plants, and one spot represents protein from fauna. These proteins possess diverse functions and participate in the fermentation process of Shaoxing rice wine. This is the first reported study on the ecosystem of a traditional wine starter culture, using a novel method that is termed “metaproteomics”.