Snails as Taxis for a Large Yeast Biodiversity

Abstract

Yeasts are unicellular fungi that harbour a large biodiversity of thousands of species, of which particularly ascomycetous yeasts are instrumental to human food and beverage production. There is already a large body of evidence showing that insects play an important role for yeast ecology, for their dispersal to new habitats and for breeding and overwintering opportunities. Here, we sought to investigate a potential role of the terrestrial snails Cepaea hortensis and C. nemoralis, which in Europe are often found in association with human settlements and gardens, in yeast ecology. Surprisingly, even in a relatively limited culture-dependent sampling size of over 150 isolates, we found a variety of yeast genera, including species frequently isolated from grape must such as Hanseniaspora, Metschnikowia, Meyerozyma and Pichia in snail excrements. We typed the isolates using standard ITS-PCR-sequencing, sequenced the genomes of three non-conventional yeasts H. uvarum, Meyerozyma guilliermondii and P. kudriavzevii and characterized the fermentation performance of these three strains in grape must highlighting their potential to contribute to novel beverage fermentations. Aggravatingly, however, we also retrieved several human fungal pathogen isolates from snail excrements belonging to the Candida clade, namely Ca. glabrata and Ca. lusitaniae. Overall, our results indicate that diverse yeasts can utilise snails as taxis for dispersal. This courier service may be largely non-selective and thus depend on the diet available to the snails.

Yeast Biotechnology 4.0

“…Insects play an important role in the dispersal of yeasts to new habitats as well as in breeding and the provision of overwintering opportunities. Akan et al [6] investigated the potential role of European terrestrial snails Cepaea hortensis and C. nemorales in yeast ecology since these snails are often found in association with human settlements and gardens. They found various yeast genera, including species frequently isolated from grape must, such as Hanseniaspora, Metschnikowia, Meyerozyma, and Pichia.…”

Co-Fermentations of Kveik with Non-Conventional Yeasts for Targeted Aroma Modulation

“…Previously, we isolated and characterized a series of NCYs and identified H. uvarum, M. guilliermondii and P. kudriavzevii as potentially beneficial strains for co-fermentations [ 24 ]. In this study, we examined if beer yeast flavor can be specifically modulated by these NCYs, enriching the fermented beverages with fruity esters.…”

Development of Genetic Modification Tools for Hanseniasporauvarum

“…It was initially thought that the gradual increase in ethanol concentration was primarily responsible for the decline in the Hanseniaspora population, but there is growing scientific evidence suggesting that a variety of metabolites secreted by S. cerevisiae significantly impacts the viability of Hanseniaspora within a grape must fermentation [12]. Moreover, Hanseniaspora strains have been shown to withstand ethanol concentrations of more than 10% and are able to produce a considerable amount of ethanol themselves [12][13][14]. In the past, Hanseniaspora populations have been regarded to be spoilage yeasts when a significant proportion of these apiculate yeasts persists within a fermentation, as some strains are capable of producing significant amounts of acetaldehyde, acetic acid, and ethyl acetate.…”

“…Apart from its predominance and importance in winemaking, H. uvarum strains have also been isolated from many other fermented beverages, such as cider [20] or tequila [21], as well as from various food-related niches such as the processing of coffee beans [22] and cocoa fermentations [23] and from fresh-squeezed orange juice [24]. In addition to its presence in foods and beverages, H. uvarum has also been isolated from soil [25], plants [26], insects [27], birds [28], molluscs [29], shrimps [30] and snails [14]. Due to its antagonistic properties against mould development, H. uvarum's potential as a biocontrol agent has also been investigated [31][32][33].…”

“…In addition to its presence in foods and beverages, H . uvarum has also been isolated from soil [ 25 ], plants [ 26 ], insects [ 27 ], birds [ 28 ], molluscs [ 29 ], shrimps [ 30 ] and snails [ 14 ]. Due to its antagonistic properties against mould development, H .…”