Bakery yeasts, a new model for studies in ecology and evolution

Abstract

Yeasts have been involved in bread making since ancient times and have thus played an important role in the history and nutrition of humans. Bakery-associated yeasts have only recently attracted the attention of researchers outside of the bread industry. More than 30 yeast species are involved in bread making, and significant progress has been achieved in describing these species. Here, we present a review of bread-making processes and history, and we describe the diversity of yeast species and the genetic diversity of Saccharomyces cerevisiae isolated from bakeries. We then describe the metabolic functioning and diversity of these yeasts and their relevance to improvements in bread quality. Finally, we examine yeast and bacterial interactions in sourdoughs. The purpose of this review is to show that bakery yeast species are interesting models for studying domestication and other evolutionary and ecological processes. Studying these yeasts can contribute much to our fundamental understanding of speciation, evolutionary dynamics, and community assembly, and this knowledge could ultimately be used to adjust, modify, and improve the production of bread and the conservation of microbial diversity.

Artisanal and farmer bread making practices differently shape fungal species community composition in French sourdoughs

“…All PCR products were sent to be sequenced with Sanger sequencing (Eurofins, Germany). Species were identified using NCBI [22], YeastIP [23] and a personal database, which was constructed after ITS1 , RPB2 , LSU sequencing of all 33-yeast species reportedly found in sourdoughs in the literature [1].…”

“…Since the Neolithic, bread history is intimately combined with the evolution of cereals, bread making associated tools and the advent of Mediterranean civilizations [7]. Leavened bread was traditionally made with flour, water and a fermenting agent, which was either a fermenting beverage or a fermenting dough, termed sourdough [1, 8]. This sourdough was generally initiated from a mixture of flour and water, naturally colonized by lactic acid bacteria (LAB) and yeasts [1, 9].…”

“…Leavened bread was traditionally made with flour, water and a fermenting agent, which was either a fermenting beverage or a fermenting dough, termed sourdough [1, 8]. This sourdough was generally initiated from a mixture of flour and water, naturally colonized by lactic acid bacteria (LAB) and yeasts [1, 9]. Sourdough was then either maintained from one bread making process to the other or initiated again and again, depending on the craftsman [10, 11].…”

The ecology of killer yeasts: Interference competition in natural habitats

“…One of the biggest questions in ecology is how diversity is maintained in ecosystems (Hutchinson, 1959). As with biodiversity in general, yeast diversity is broad across nearly every imaginable ecosystem (Buzzini, Turchetti, & Yurkov, 2018;Carbonetto, Ramsayer, Nidelet, Legrand, & Sicard, 2018;Chappell & Fukami, 2018;Stefanini, 2018;Yurkov, 2018). The current understanding of killer yeasts' impacts on diversity is based mostly on mathematical models, and only a few hypothesis-driven observational studies have addressed killer yeasts' impacts on diversity in nature.…”

Quantifying the efficiency and biases of forest Saccharomyces sampling strategies

“…These studies made inferences based on the phenotypes and genotypes of isolates collected from wild and domesticated substrates. And Saccharomyces substrates are diverse: Wild substrates include tree bark, insect guts, fresh leaves, leaf litter, soil, fruits, and parasitic Cyttaria galls, (Glushakova, Ivannikova, Naumova, Chernov, & Naumov, 2007;Kowallik & Greig, 2016;Libkind et al, 2011;Mortimer & Polsinelli, 1999;Sampaio & Goncalves, 2008;Stefanini et al, 2012), and domesticated substrates include wine, beer, bread, kimchi, kombucha, palm wine, and pulque, among many other substrates (Boynton & Greig, 2016;Carbonetto, Ramsayer, Nidelet, Legrand, & Sicard, 2018;Estrada-Godina et al, 2001;Ezeronye & Okerentugba, 2001;Gallone et al, 2016;Greenwalt, Steinkraus, & Ledford, 2000;Jeong, Jung, Lee, Jin, & Jeon, 2013). Saccharomyces yeasts are also a single clade in the diverse polyphyletic group of yeasts (singlecelled fungi that reproduce by budding or fission; Kurtzman, Fell, & Boekhout, 2011).…”