## 4 Conclusions  
In this study, high-throughput sequencing technology was used to analyze the microbial communities and their diversity in the fermentation process of passion fruit wine when using different fermentation methods. The results show that totals of eight fungal phyla, 135 fungal genera, 15 bacterial phyla and 130 bacterial genera were identified in NF, while totals of 11 fungal phyla, 389 fungal genera, 15 bacterial phyla and 128 bacterial genera were identified in CF. The dominant fungal genera were _Debaryomyces_, _Meyerozyma_ and _Wickerhamomyces_; furthermore, the dominant bacterial genera were _Paucibacter_, _Pantoea_, _Escherichia_Shigella_, _Achromobacter_, _Lactobacillus_ and _Bifidobacterium_ in NF. The dominant fungal genera were _Meyerozyma_, _Cladosporium_ and _Saccharomyces_, and the dominant bacterial genera were _Paucibacter_, _Achromobacter_ and _Lactobacillus_ in CF. The colony structures of different fermentation methods are quite different, which reflects the complexity of microbial composition during the fermentation of passion fruit wine.  
In NF, the correlations indicate that the variation tendency of _Wickerhamomyces_ was positively correlated with the variation tendency of alcohol content and total acids, and negatively correlated with soluble solids and total sugars. The variation tendencies of _Paucibacter_ and _Pantoea_ were negatively correlated with the variation tendency of alcohol content and total acids, and positively correlated with soluble solids and total sugars. In CF, the variation tendency of _Saccharomyces_ was positively correlated with the variation tendency of alcohol content and total acids, and negatively correlated with soluble solids and total sugars. The variation tendency of _Paucibacter_ was positively correlated with the variation tendency of total phenols. In NF, _Debaryomyces_ and _Meyerozyma_ were negatively correlated with 12 nonvolatile differential metabolites; furthermore, there was a significant negative correlation between _Pantoea_ and 3,6-anhydro-D-galactose. In CF, there was a significant positive correlation between _Paucibacter_ and three nonvolatile differential metabolites. _Wickerhamomyces_, _Achromobacter_, _Bifidobacterium_ and _Lactobacillus_ were significantly related to a variety of esters in NF; moreover, _Saccharomyces_, _Achromobacter_ and _Lactobacillus_ were significantly associated with a variety of esters and alcohols in CF.  
The quality and flavor of wine are greatly affected by microbial metabolites. This study has analyzed microbial community structure and its correlation with flavor during the fermentation of passion fruit wine, providing a theoretical reference for the quality improvement and development of passion fruit wine.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/fermentation9050439/s1](https://www.mdpi.com/article/10.3390/fermentation9050439/s1)]([https://www.mdpi.com/article/10.3390/fermentation9050439/s1](https://www.mdpi.com/article/10.3390/fermentation9050439/s1)), Supplementary Material A: Analytical methods of wine and fruit wine; Supplementary Material B: Green food--Fruit wine.  
Conceptualization and methodology, X.Y. and X.Z.; validation, L.H. and Q.L.; formal analysis and investigation, X.Y., L.H. and Q.L.; writing--review and editing, X.Y., supervision, Y.B. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Key Research and Development Project of Yunnan Province, Key Technology Project of Fruit and Vegetable Industry Upgrading in Low Latitude Plateau (2019 ZG00907).  
Not applicable.  
**Data Availability Statement:** Datasets are contained within the article.  
We are thankful for the technical support of Biomarker Technology Co., Ltd., (Beijing, China).  
The authors declare no conflict of interest.