Genomic sequencing in Colombian coffee fermentation reveals new records of yeast species

Abstract

The post-harvest processing of coffee plays a crucial role in developing high-quality beverages with differential sensory attributes. The present study aims to determine the yeast diversity associated with spontaneous wet fermentation of Colombian coffee and to analyze the composition of green coffee and the sensory quality of the beverage. It was found that the yeast community is made up of 46 species, many of which are reported for the first time in coffee fermentation, as is the case of Kazachstania humilis, which leads the entire fermentation process. The contents of sugars and total soluble proteins in green coffee beans showed a dependence on fermentation time, where glucose and fructose decrease and sucrose and TSP increase. Amino acids generally did not show significant differences with respect to time; however, alanine was the most abundant, followed by glutamic acid and aspartic acid. Finally, the beverages obtained were classified as specialty coffees with distinctive fruity, floral, chocolatey, and sweet attributes, whose quality scores were positively correlated with gamma-aminobutyric acid, TSP, Picha mandshurica, and sucrose. These findings provide new insights into the microbial diversity in coffee fermentation, the content of sugars, proteins, and amino acids in green coffee, and their contribution to the generation of differential sensory profiles. The new yeasts reported in this study may be explored as starter cultures in further studies.