Characterization of the microbial community in three types of fermentation starters used for Chinese liquor production

This study examined and compared the microbial community in three typical fermentation starters (called as Daqu, Xiaoqu, and Fuqu in China) used for liquor production by analysing the 16S and 18S rRNA gene clone library. The results show that the microbial diversity in the three types of fermentation starters (JiuQu) differs significantly. The bacterial species in Daqu and Fuqu were mainly thermophilic or thermotolerant. In Daqu, the dominant bacterial species were Thermoactinomyces sanguinis (53.85%) and Pantoea agglomerans (19.23%), followed by uncultured bacteria (15.39%). The lactic acid bacterium Weissella cibaria (50%) and a member of Enterobacteriaceae, Enterobacter ludwigii (10%), were the dominant bacterial species in Xiaoqu. Low abundances of other bacteria, including Deinococcus radiodurans, Corynebacterium variabile and Acinetobacter baumannii, were reported for Xiaoqu. Enterococcus faecium, Clostridium beijerinckii and Bacillus cereus were observed in Fuqu and accounted for 46.67, 23.33 and 16.67% of the total bacteria identified, respectively. Fungal diversity was high in Daqu and consisted exclusively of thermophilic moulds, such as Aspergillus glaucus (62.5%), Thermomyces lanuginosus (12.5%) and Thermoascus crustaceus (12.5%). Only two fungal species were reported for Fuqu and Xiaoqu and both contained the mould Rhizopus oryzae. Saccharomyces cerevisiae and the non-Saccharomyces yeast (Saccharomycopsis fibuligera) were also identified in Fuqu and Xiaoqu, respectively. This finding suggests that microbial community structure in JiuQu starters is the key factor to determine the variety of flavours. Copyright (c) 2015 The Institute of Brewing & Distilling