Sulfur Dioxide Treatment Alters Wine Microbial Diversity and Fermentation Progression in a Dose-Dependent Fashion

摘要

The use of sulfur dioxide (SO_2) as an antimicrobial in winemaking is a well-established, common practice. Although much is known about the antimicrobial effects of SO_2 at single concentrations, little is known about its effects on microbial growth dynamics across a range of concentrations or when used in conjunction with yeast inoculation. Using high-throughput marker-gene sequencing, we investigated the cumulative impacts of yeast inoculation and SO_2 treatments across a broad concentration range (0 to 150 mg/L SO_2) on the bacterial and fungal communities in wine fermentations. Our results indicated a dose-dependent effect of SO_2, with lactic acid bacteria and Gluconobacter proliferating in fermentations with ＜25 mg/L SO_2, but other bacteria and fungi were unaffected by the SO_2 addition. Microbial profiles stabilized at concentrations ＞25 mg/L SO_2, and fermentation performance decreased at higher concentrations (100 to 150 mg/L SO_2). Yeast inoculation alone conferred a stabilizing effect, reducing the bacterial growth observed in unsulfited fermentations, but this effect was not additive with an increase in SO_2 concentrations.