Profiling of Fungal Diversity and Fermentative Yeasts in Traditional Chinese Xiaoqu

Abstract

To increase the safety and quality of baijiu and rice wine in China, controlling the use of traditional Xiaoqu by studying the beneficial yeasts present has recently been considered. The fungal diversity of six Chinese Xiaoqu including five traditional and one commercial samples was investigated to screen fermentative yeasts with low yields of higher alcohols. A high throughput sequencing approach detected fifteen fungal species with relative abundance higher than 1%, and displayed dissimilarities of fungal diversity among Xiaoqu samples. The 15 fungal species were composed of 11 filamentous fungi with Rhizopus arrhizus as the most common specie and four yeast species, containing Hyphopichia burtonii , Saccharomyces cerevisiae , Saccharomycopsis fibuligera , and Saccharomycopsis malanga . Classic culture-dependent approaches, including 5.8S-ITS-RFLP analysis and D1/D2 sequencing of the 26S rRNA gene, identified nine yeast species in the five traditional Chinese Xiaoqu . In addition to the four yeast species also detected by high throughput sequencing approach, the other five yeast species isolated were Clavispora lusitaniae , Cryptococcus neoformans , Komagataella pastoris , Trichosporon asahii , and Wickerhamomyces anomalus . Further micro-fermentations of rice wine were performed using 19 single yeast isolates, and after the fermentation of rice wine, higher alcohols and ethanol were analyzed by gas chromatography. Two yeast strains, Saccharomyces cerevisiae FBKL2.8022 and Wickerhamomyces anomalus FBKL2.8023, were found to have low yields of higher alcohols and could produce 11.70%vol and 7.10%vol ethanol separately. This study for the first time, to the best of our knowledge, explored the fungal resources in traditional Xiaoqu from different regions of Guizhou, China. The screened S. cerevisiae and W. anomalus strains could be used to establish specific starters to promote the standardization of the production of baijiu and rice wine.

Effects of ultra-long fermentation time on the microbial community and flavor components of light-flavor Xiaoqu Baijiu based on fermentation tanks

“…Higher alcohols, mainly including n-propanol, isobutyl alcohol, and isoamyl alcohol, are produced as the secondary metabolites of yeast during alcoholic fermentation (Wang et al 2020c ). At moderate level, these flavor components contribute to the flavor of many alcoholic beverages, whereas the excess level may be a health hazard (Hu et al 2021c ).…”

Characteristics of the Microbial Community in the Production of Chinese Rice-Flavor Baijiu and Comparisons With the Microflora of Other Flavors of Baijiu

“…Saccharomyces can ferment sugars to produce alcohol, and most of them can survive under high-sugar and relatively acidic conditions and enable alcoholization and esterification during the fermentation of baijiu ( Liu and Miao, 2020 ). Among them, Saccharomyces cerevisiae mainly plays an alcohol-producing role and has a strong alcohol-producing capacity ( Wang et al, 2020 ). Most of the other yeasts are ester-producing yeasts, and although their alcohol production volume is relatively small, they can convert production materials into aldehydes, esters, higher alcohols, etc., during baijiu fermentation.…”

Microbial diversity analysis of vineyard son the eastern foothills of the Helan Mountain region using high-throughput sequencing

“…Soil sampling method: Plant residues were removed from the soil surface, the soil was dug vertically with a soil shovel, and about 0.5 kg of soil was obtained for each sampling point at a depth of 20 cm (Wang et al, 2020a).…”