AUTHOR=Jia Yun , Liu Yuanfa , Hu Wanrong , Cai Wen , Zheng Zhaojun , Luo Cheng , Li Dongliang 

TITLE=Development of Candida autochthonous starter for cigar fermentation via dissecting the microbiome

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1138877

DOI=10.3389/fmicb.2023.1138877

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>The main goal of tobacco fermentation technology is to minimize the alkaloid content while improving flavor substance content.</p></sec><sec><title>Methods</title><p>This study revealed the microbial community structure and their metabolic functions during cigar leaf fermentation by high-throughput sequencing and correlation analysis, and evaluated the fermentation performance of functional microbes based on in vitro isolation and bioaugmentation fermentation.</p></sec><sec><title>Results</title><p>The relative abundance of <italic>Staphylococcus</italic> and <italic>Aspergillus</italic> increased first but then decreased during the fermentation, and would occupy the dominant position of bacterial and fungal communities, respectively, on the 21st day. Correlation analysis predicted that <italic>Aspergillus</italic>, <italic>Staphylococcus</italic> and <italic>Filobasidium</italic> could contribute to the formation of saccharide compounds, <italic>Bacillus</italic> might have degradation effects on nitrogenous substances. In particular, <italic>Candida</italic>, as a co-occurring taxa and biomarker in the later stage of fermentation, could not only degrade nitrogenous substrates and synthesize flavor substances, but also contribute to maintaining the stability of microbial community. Moreover, based on <italic>in vitro</italic> isolation and bioaugmentation inoculation, it was found that <italic>Candida parapsilosis</italic> and <italic>Candida metapsilosis</italic> could significantly reduce the alkaloids content and increase the content of flavor components in tobacco leaves.</p></sec><sec><title>Discussion</title><p>This study found and validated the critical role of <italic>Candida</italic> in the fermentation of cigar tobacco leaves through high-throughput sequencing and bioaugmentation inoculation, which would help guide the development of microbial starters and directional regulation of cigar tobacco quality.</p></sec>