Assessment of coffee endophytic yeasts for efficient mucilage removal and consistent quality improvement in coffee...

Endophytic yeasts are commonly isolated from coffee plants, yet their capacity for mucilage removal remains underexplored. In this study, 42 pectinolytic yeast strains were isolated from coffee cherries and classified into five species. Among them, Pichia kluyveri YE7 showed superior mucilage removal and cold tolerance, achieving complete mucilage degradation within 4-12 h at 5-30 °C. Genomic analysis identified multiple genes encoding pectinases, cellulases, and hemicellulases, consistent with its enzymatic capacity. Fermentation with P. kluyveri YE7 primarily altered alkane levels in green coffee beans; however, these compounds were substantially reduced during roasting, resulting in minimal alteration of the final volatile profile. Electronic tongue analysis indicated that, under equivalent roasting conditions, the sensory attributes of fermented and unfermented beans were comparable. These findings suggest that P. kluyveri YE7 is a suitable candidate for large-scale wet coffee fermentation, offering high processing efficiency and stable sensory quality under variable environmental conditions.