Microbial community structure and dynamics during the traditional brewing of Fuzhou Hong Qu glutinous rice wine as determined by culture-dependent and culture-independent techniques

Xu-Cong Lv, Zhi-Chao Chen, Rui-Bo Jia, Zhi-Bin Liu, Wen Zhang, Shao-Jun Chen, Ping-Fan Rao, Li Ni

Institute of Food Science and Technology, College of Biological Science and Technology, Fuzhou University, Fuzhou, Fujian 350108, China.

Abstract

The aim of this study was to investigate the bacterial and fungal community structure and dynamics during the traditional brewing of Fuzhou Hong Qu glutinous rice wine through culture-dependent and culture-independent methods. The culture-independent DGGE profiles revealed the presence of eleven bacterial species (Janthinobacterium lividum, Lactobacillus plantarum, Weissella soli, Leuconostoc mesenteroides, Lactobacillus brevis, Pediococcus pentosaceus, Lactococcus lactis subsp. lactis, Pediococcus acidilactici, Bacillus subtilis, Bacillus aryabhattai and Bacillus megaterium) and seven fungal species (Saccharomycopsis fibuligera, Pichia guilliermondii, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Rhizopus oryzae, Candida glabrata and Monascus purpureus) during the traditional brewing process. Furthermore, the microbial compositions of fermented samples were investigated using culture-dependent approach (conventional plate count technique combined with molecular identification). Results showed that the relative proportions of some fungal species (C. glabrata, W. anomalus, P. guilliermondii and S. fibuligera) and bacterial species (Lc. lactis subsp. lactis, Staphylococcus pasteuri, Bacillus sp., P. pentosaceus) detected at the early brewing stage decreased as the fermentation progressed, while S. cerevisiae, L. brevis, L. plantarum and Lactobacillus paracasei became the predominant species during the late brewing period. Some differences were also found between the profiles obtained by PCR–DGGE and culture-dependent technique. Comparative analysis revealed that some species (J. lividum, W. soli, B. aryabhattai and P. guilliermondii) could only be detected using PCR–DGGE technique. Conversely, some species (L. paracasei, S. pasteuri, Bacillus methylotrophicus, Mucor indicus and Aspergillus flavus) could only be detected by culture-dependent method. Therefore, the combination of culture-dependent and -independent approaches is quite necessary because they provided complementary information about the composition of the microbial community during the traditional brewing of Fuzhou Hong Qu glutinous rice wine. This study provides the first detailed evaluation of fungal community and dynamics in Fuzhou Hong Qu glutinous rice wine traditional brewing process using culture-dependent and -independent methods, which would facilitate scientific understanding of the traditional brewing mechanism and be useful for the selection of the suitable and beneficial strains to improve the wine quality.

Keywords: Microbial community dynamics; Fuzhou Hong Qu glutinous rice wine; PCR–denaturing gradient gel electrophoresis (PCR–DGGE); Conventional plate count method; Amplified ribosomal DNA restriction analysis (ARDRA); Species-specific PCR.