浙江玫瑰醋发酵过程中细菌菌群结构变化与有机酸形成相关性分析

基于Illumina MiSeq高通量测序对浙江玫瑰醋"冲缸放水"后的醋样中细菌V4区进行测序,并用高效液相色谱对醋样有机酸含量进行测定,得出玫瑰醋发酵过程中细菌相对丰度以及有机酸含量的变化,并用双向正交偏最小二乘(bidirectional orthogonal partial least squares,O2PLS)法模型对两者相关性进行分析,结果表明:玫瑰醋在"冲缸放水"后的发酵过程中,醋酸杆菌属和乳酸杆菌属在细菌菌群中占绝对优势(相对丰度之和大于80%);玫瑰醋中有机酸含量一直呈现上升趋势,乙酸和乳酸含量最高,对玫瑰醋有机酸含量进行系统聚类分析和主成分分析分析,可以将醋样分为发酵前期、发酵中期、发酵后期三大类,各类醋样有机酸组成差异显著;利用O2PLS模型对细菌与有机酸相关性分析,得到23个与有机酸相关重要性指标(VIP(pred))大于1的细菌属,包括Acetobacter、Lactobacillus、Methylobacterium等;对VIP(pred)大于1的细菌与有机酸进行相关性分析,作出细菌与有机酸相关性系数Heatmap,并得出与各种有机酸相关性系数|ρ|0.6的高度相关细菌属。为找寻玫瑰醋发酵过程中的功能微生物,提升玫瑰醋品质提供数据支持。

Correlation between Structural Shifts of Bacterial Community and Organic Acid Formation during the Fermentation of Zhejiang Rosy Vinegar

During the natural fermentation process of Zhejiang rosy vinegar, alcoholic and acetic acid fermentation of saccharified cooked rice starch with microorganisms in the air took place after water addition. This study revealed the composition and diversity of the bacterial community and changes in organic acid contents during the fermentation process of rosy vinegar. The V4 region of the bacterial 16S rRNA gene from rosy vinegar was subjected to Illumina MiSeq high-throughput sequencing and organic acid contents of rosy vinegar were determined by high performance liquid chromatography (HPLC). Furthermore, the correlation between organic acid contents and relative bacterial abundance was investigated by using bidirectional orthogonal partial least squares (O2PLS) analysis. The results showed that Acetobacter and Lactobacillus dominated the bacterial community after water addition and the total relative abundance was higher than 80%. Organic acid contents gradually increased as the fermentation proceeded, with the most abundant being acetic acid and lactic acid. Using hierarchical cluster analysis (HCA) and principal component analysis (PCA), vinegar samples at the early, middle and late stages of fermentation were clearly distinguished based on organic acid contents, and organic acid composition was significantly different among vinegar samples. Through the correlation analysis a total of 23 bacterial genera with VIP(pred) greater than 1 were obtained, including Acetobacter, Lactobacillus, and Methylobacterium. In addition, a heatmap for the correlation between bacteria with VIP(pred) > 1 and organic acids was established, and the bacteria with correlation coefficients |ρ| > 0.6, indicating high correlation, were obtained. This study provides supporting data for finding functional microorganisms involved in the fermentation process of rosy vinegar and improving the quality of rose vinegar.