Utilization efficiency of Ehrlich pathway-related amino acid affected higher alcohol acetate production of non-Saccharomyces yeasts during alcoholic fermentation

Abstract

Non-Saccharomyces yeasts have attracted great oenological interest due to their contribution to wine aroma, while the underlying mechanisms remain complex and insufficiently understood. To elucidate the potential mechanisms responsible for the high fruity esters production by P. kluyveri PK-19, a non-Saccharomyces yeast strain known for its aroma production, the nitrogen assimilation profile, fermentation capacity, and volatile production were compared with those of three other yeast strains, namely Saccharomyces cerevisiae SC-19, Pichia fermentans Z9Y-3, and Hanseniaspora uvarum Yun268. Despite the intermediate fermentation capacity, P. kluyveri PK-19 showed strong nitrogen consumption and rapid uptake of Ehrlich pathway-related amino acids during the early stages of alcoholic fermentation. Moreover, P. kluyveri demonstrated a high efficiency in converting Ehrlich pathway-related amino acids into their corresponding higher alcohol acetates (HAAs), indicating an enhanced ability to synthesize HAAs from Ehrlich pathway precursors. The rapid assimilation of Ehrlich pathway-related amino acids and efficient transformation to HAAs potentially contributed to the high production of HAAs in P. kluyveri PK-19. These results suggest that supplementing P. kluyveri-involved fermentation with Ehrlich pathway-related amino acids can increase HAA production and modify wine aroma profiles.