First Report of Pichia bruneiensis in a Spontaneous Sugarcane Juice Fermentation: A Case Study from an Artisanal Distillery in the Ecuadorian Amazon

Abstract Native microbiota drives spontaneous fermentation in artisanal aguardiente in the Ecuadorian Amazon, an occurrence that has received little attention from a microbiological perspective. Juice samples were collected at three stages (0, 48, and 96 h), and three yeast morphotypes (Y01, Y02, and Y03) were isolated. A reduction in diversity occurred towards the final phase, where Y01 prevailed. Cell viability, evaluated by gentian violet staining, was higher in Y01, suggesting better adaptation to fermentative stress. Selective culture techniques, biochemical assays, and DNA sequencing were applied, resulting in a ≥99% match with Pichia bruneiensis. This is the first evidence of the species’ participation in these fermentations, providing information on microbial biodiversity in Amazonian aguardiente and Amazonian distillates’ biotechnological potential. The species is ethanol-tolerant and metabolically versatile and can generate differential aromatic compounds, making it a promising native starter culture that could improve the product, reinforce local microbial identity, and support valorization strategies.