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Abstract

Daqu is a traditional Chinese baijiu starter. To investigate the composition of the microbial community of daqu starters, high-throughput sequencing (HTS) combined with culture-dependent method was used to analyze the fungal diversity of thirty starters made at three temperatures (low-, medium- and high-temperature). In the study, we isolated 420 isolates of fungal strains through the plate culture method. Saccharomyces cerevisiae , Wickerhamomyces anomalus and Saccharomycopsis fibuligera were the most common yeasts encountered in these daqu starters, accounting for 79% of the relative abundance. HTS showed that the dominant genera in low-temperature daqu were distinct from those of medium- and high-temperature. The genera, Thermomyces and Thermoascus , exhibited a higher relative abundance and were considered to be the dominant flora in high-(75%) and medium-(47%) temperature starters, respectively. These two genera were thermotolerant fungi. Saccharomycetaceae was the predominant microflora in low-temperature daqu with a relative abundance of 68%. The present study suggests that the effect of the daqu processing temperature on the fungal community was important and that a knowledge of microbial composition should help to screen fermentation strains thus improving the quality of baijiu liquor.