Correlation Analysis between Physicochemical Characteristics and Bacterial Taxa of Fen-flavor Daqu in Changzhi Area

In this study, the physicochemical characteristics and bacterial taxa of 11 fen-flavor Daqu samples from Changzhi, Shanxi Province were analyzed using a combination of physicochemical analysis and MiSeq high-throughput sequencing, and the correlation between them was revealed. The physicochemical analysis showed that the variation coefficients of amino acid nitrogen, liquefaction power and alcoholization power of different fen-flavor Daqu samples were greater than 15%, with the largest difference in liquefaction power and the smallest difference in ash. MiSeq high-throughput sequencing analysis found that the bacterial genera presented in all samples with an average relative content >1.0% were Aquabacterium, Pelomonas, Bacillus, Ralstonia, Sphingomonas, Burkholderia, Methylobacterium and Bradyrhizobium, and a large number of bacterial taxa were shared among the different samples. Correlation analysis revealed that Sphingomonas showed a significant positive correlation with protein content (P<0.05) and a significant negative correlation with acidity (P<0.05), Ralstonia showed a significant positive correlation with both water activity and esterification power (P<0.05), and Pelomonas and Aquabacterium both showed a significant positive correlation with water activity (P<0.05). It is evident that there are a large number of shared bacterial taxa among the different fen-flavor Daqu, and there is a correlation between bacterial taxa and some physicochemical properties of Daqu.