Spoilage of bottled lager beer contaminated with Saccharomyces cerevisiae var. diastaticus

ABSTRACT The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach. IMPORTANCE Recent work has suggested the utilization of hybridization techniques for the generation of novel non-genetically modified brewing yeast strains with combined properties not commonly found in a unique yeast strain. We have observed remarkable traits, especially low temperature tolerance, maltotriose utilization, flocculation ability, and production of volatile aroma compounds, among a collection of Saccharomyces cerevisiae strains isolated from cachaça distilleries, which allow their utilization in the production of beer. The significance of our research is in the use of breeding/hybridization techniques to generate yeast strains that would be appropriate for producing new lager beers by exploring the capacity of cachaça yeast strains to flocculate and to ferment maltose at low temperature, with the concomitant production of flavoring compounds.

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Effect of different physiological stress on flocculation and fermentative capacity of Saccharomyces cerevisiae in lager beer

Current Research Topics in Applied Microbiology and Microbial Biotechnology ◽

10.1142/9789812837554_0090 ◽

2009 ◽

Author(s):

C. S. Leal-Guerra ◽

A. Sierra ◽

L. C. Damas-Buenrostro ◽

B. Pereyra-Alférez

Keyword(s):

Saccharomyces Cerevisiae ◽

Physiological Stress ◽

Fermentative Capacity ◽

Lager Beer

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Potential for Lager Beer Production from Saccharomyces cerevisiae Strains Isolated from the Vineyard Environment

Processes ◽

10.3390/pr9091628 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1628

Author(s):

Massimo Iorizzo ◽

Francesco Letizia ◽

Gianluca Albanese ◽

Francesca Coppola ◽

Angelita Gambuti ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Pilot Scale ◽

Brewing Industry ◽

Saccharomyces Pastorianus ◽

Lager Beer ◽

Efficient Fermentation ◽

Saccharomyces Eubayanus ◽

Beer Production ◽

New Strategies

Saccharomyces pastorianus, genetic hybrids of Saccharomyces cerevisiae and the Saccharomyces eubayanus, is one of the most widely used lager yeasts in the brewing industry. In recent years, new strategies have been adopted and new lines of research have been outlined to create and expand the pool of lager brewing starters. The vineyard microbiome has received significant attention in the past few years due to many opportunities in terms of biotechnological applications in the winemaking processes. However, the characterization of S. cerevisiae strains isolated from winery environments as an approach to selecting starters for beer production has not been fully investigated, and little is currently available. Four wild cryotolerant S. cerevisiae strains isolated from vineyard environments were evaluated as potential starters for lager beer production at laboratory scale using a model beer wort (MBW). In all tests, the industrial lager brewing S. pastorianus Weihenstephan 34/70 was used as a reference strain. The results obtained, although preliminary, showed some good properties of these strains, such as antioxidant activity, flocculation capacity, efficient fermentation at 15 °C and low diacetyl production. Further studies will be carried out using these S. cerevisiae strains as starters for lager beer production on a pilot scale in order to verify the chemical and sensory characteristics of the beers produced.

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Hybridization of Saccharomyces cerevisiae Sourdough Strains with Cryotolerant Saccharomyces bayanus NBRC1948 as a Strategy to Increase Diversity of Strains Available for Lager Beer Fermentation

10.20944/preprints202012.0098.v1 ◽

2020 ◽

Author(s):

Martina Catallo ◽

Fabrizio Iattici ◽

Cinzia Randazzo ◽

Cinzia Caggia ◽

Kristoffer Krogerus ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

De Novo ◽

Yeast Culture ◽

Culture Collections ◽

Lager Yeast ◽

Ethyl Hexanoate ◽

Brewing Yeast ◽

Saccharomyces Bayanus ◽

Lager Beer ◽

Saccharomyces Eubayanus

The search for novel brewing strains from non-brewing environments represents an emerging trend to increase genetic and phenotypic diversities in brewing yeast culture collections. Another valuable tool is hybridization, where beneficial traits of individual strains are combined in a single organism. This has been used successfully to create de novo hybrids from parental brewing strains by mimicking natural Saccharomyces cerevisiae ale x Saccharomyces eubayanus lager yeast hybrids. Here, we integrated both these approaches to create synthetic hybrids for lager fermentation using parental strains from niches other than beer. Using a phenotype-centered strategy, S. cerevisiae sourdough strains and the S. eubayanus x Saccharomyces uvarum strain NBRC1948 (also referred to as Saccharomyces bayanus) were chosen for their brewing aptitudes. We demonstrated that, in contrast to S. cerevisiae x S. uvarum crosses, hybridization yield was positively affected by time of exposure to starvation, but not by staggered mating. In laboratory-scale fermentation trials at 20°C, one triple S. cerevisiae x S. eubayanus x S. uvarum hybrid showed a heterotic phenotype compared with the parents. In 2L wort fermentation trials at 12°C, this hybrid inherited the ability to consume efficiently maltotriose from NBRC1948 and, like the sourdough S. cerevisiae parent, produced appreciable levels of the positive aroma compounds 3-methylbutyl acetate (banana/pear), ethyl acetate (general fruit aroma) and ethyl hexanoate (green apple, aniseed, and cherry aroma). Based on these evidences, the phenotype-centered approach appears promising for design of de novo lager beer hybrids and may help to diversify aroma profiles in lager beers.

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Yeast Hybrids in Brewing

10.20944/preprints202201.0084.v1 ◽

2022 ◽

Author(s):

Matthew J. Winans

Keyword(s):

Saccharomyces Cerevisiae ◽

Genomic Diversity ◽

Yeast Saccharomyces Cerevisiae ◽

Sequencing Studies ◽

Molecular Biotechnology ◽

History Of ◽

Species Dynamics ◽

Yeast Biology ◽

Lager Beer ◽

Beer Production

: Microbiology has long been a keystone in fermentation and the utilization of yeast biology rein-forces molecular biotechnology as the pioneering frontier in brewing science. Consequently, modern understanding of the brewer’s yeast has faced significant refinement over the last few decades. This publication presents a condensed summation of Saccharomyces species dynamics with an emphasis on the relationship between traditional ale yeast, Saccharomyces cerevisiae, and the interspecific hybrids used in lager beer production, S. pastorianus. Introgression from other Sac-charomyces species is also touched on. The unique history of Saccharomyces cerevisiae and Saccharo-myces hybrids are exemplified by recent genomic sequencing studies aimed at categorizing brewing strains through phylogeny and redefining Saccharomyces species boundaries. Phylogenetic investigations highlight the genomic diversity of Saccharomyces cerevisiae ale strains long known to brewers by their fermentation characteristics and phenotypes. Discoveries of genomic contribu-tions from interspecific Saccharomyces species into the genome of S. cerevisiae strains is ever more apparent with increased investigations on the hybrid nature of modern industrial and historical fermentation yeast.

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