De Novo Synthesis of Benzenoid Compounds by the Yeast Hanseniaspora vineae Increases the Flavor Diversity of Wines

Abstract

Benzyl alcohol and other benzenoid-derived metabolites of particular importance in plants confer floral and fruity flavors to wines. Among the volatile aroma components in Vitis vinifera grape varieties, benzyl alcohol is present in its free and glycosylated forms. These compounds are considered to originate from grapes only and not from fermentative processes. We have found increased levels of benzyl alcohol in red Tannat wine compared to that in grape juice, suggesting de novo formation of this metabolite during vinification. In this work, we show that benzyl alcohol, benzaldehyde, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol are synthesized de novo in the absence of grape-derived precursors by Hanseniaspora vineae. Levels of benzyl alcohol produced by 11 different H. vineae strains were 20-200 times higher than those measured in fermentations with Saccharomyces cerevisiae strains. These results show that H. vineae contributes to flavor diversity by increasing grape variety aroma concentration in a chemically defined medium. Feeding experiments with phenylalanine, tryptophan, tyrosine, p-aminobenzoic acid, and ammonium in an artificial medium were tested to evaluate the effect of these compounds either as precursors or as potential pathway regulators for the formation of benzenoid-derived aromas. Genomic analysis shows that the phenylalanine ammonia-lyase (PAL) and tyrosine ammonia lyase (TAL) pathways, used by plants to generate benzyl alcohols from aromatic amino acids, are absent in the H. vineae genome. Consequently, alternative pathways derived from chorismate with mandelate as an intermediate are discussed.

Genomic and Transcriptomic Basis of Hanseniaspora vineae's Impact on Flavor Diversity and Wine Quality

“…All 14 S. cerevisiae industrial strains only showed one copy of ARO10 (Table S5). Further, ARO10 has been shown to be related to the production of benzyl alcohol in a putative metabolic pathway of mandelate (7). Therefore, this decarboxylase activity might be involved in the enhanced (more than two orders of magnitude) synthesis of benzylic alcohol in H. vineae compared to that in S. cerevisiae (Table 5).…”

Contribution of Non-Saccharomyces Yeasts to Wine Freshness. A Review

“…Among them, the first two esters are released in higher concentrations (2-7) than S. cerevisiae; by comparison, ethyl lactate is usually produced below the sensory threshold. Formation de novo of benzyl acetate and 2-phenylethyl acetate from sugars by the chorismate-prephenate pathway has been reported ( [36], Figure 3). It has been observed that nitrogen nutrition affected the formation of benzyl and 2-phenylethyl acetates.…”

“…High doses of diammonium phosphate (100-250 mg/L) inhibited the production of these phenylpropanoid compounds and negatively affected the global balance of aromatic esters [37]. Benzyl alcohol, precursor of benzyl acetate, can be obtained de novo without using grape precursors by 11 different H. vineae strains at concentrations 20-200 fold higher than with S. cerevisiae strains [36]. Regarding the H. vineae species, the main esters with sensory repercussion from its exometabolome are benzyl acetate, 2-phenylethyl acetate, ethyl lactate and 3-methylbutyl acetate [35].…”

The Influence of Non-Saccharomyces Species on Wine Fermentation Quality Parameters

“…At an industrial scale, Hanseniospora guilliermondii, Hanseniospora uvarum, and Hanseniospora vinae [130] are the most appropriate species to achieve these purposes [125]. The aroma improvements are explained from a chemical point of view due to the production of higher concentrations of 2-phenylethyl acetate [131,132], acetate esters such as isoamyl acetate [124,127,130,132,133], medium-chain fatty acid ethyl esters [134], benzenoids [135,136], and terpenes [125,127] and reductions in the final concentration of higher alcohols [124,130,133]. Martin et al 2018 [125] have explained the main metabolic pathways responsible for the ability of some species of Hanseniaspora/Kloeckera genera to produce benzenoids, diacetyl-acetoin, lactones, higher alcohols, acetate esters, fatty acids, and isoprenoids.…”