Development of engineered yeast for biosorption of beer haze-active polyphenols

Abstract

Compared to most other alcoholic beverages, the shelf life of beer is much more limited due to its instability in the bottle. That instability is most likely to appear as turbidity (haze), even sedimentation, during storage. The haze in beer is mostly caused by colloidal particles formed by interactions between proteins and polyphenols within the beer. Therefore, beers are usually stabilized by removing at least one of these components. We developed and constructed a Saccharomyces cerevisiae strain with a proline-rich QPF peptide attached to the cell wall, using the C-terminal anchoring domain of α-agglutinin. The QPF peptide served to bind polyphenols during fermentation and, thus, to decrease their concentration. Strains displaying QPF were able to bind about twice as much catechin and epicatechin as a control strain displaying only the anchoring domain. All these experiments were done with model solutions. Depending on the concentration of yeast, uptake of polyphenols was 1.7-2.5 times higher. Similarly, the uptake of proanthocyanidins was increased by about 20 %. Since the modification of yeasts with QPF did not affect their fermentation performance under laboratory conditions, the display of QPF appears to be an approach to increase the stability of beer.

The Potential of Traditional Norwegian KVEIK Yeast for Brewing Novel Beer on the Example of Foreign Extra Stout

“…Turbidity (haze) often appears during beer aging, usually due to the interactions between proteins and polyphenols (e.g., catechin and epicatechin) within the beer [ 18 , 19 , 20 ]. The formation of protein–polyphenolic sediments could be one of the reasons behind the decreased content of phenolic compounds in beer observed after the aging stage.…”

Yeast Surface Display System: Strategies for Improvement and Biotechnological Applications

“…In the food industry YSD can be used to immobilize enzymes that synthesize relevant compounds to produce sweeteners such as isomaltulose and fructooligosaccharides ( Zhang et al, 2016 ; Zheng et al, 2019 ) and beneficial fats, e.g., omega 3-fatty acids ( Singh et al, 2020 ). Additionally, whole-cell biocatalysts have been used to improve the sensory properties of beverages which include beer and wine ( Cejnar et al, 2017 ; Zhang et al, 2019 ). In agri-food applications YSD can be used to develop biocontrol agents, e.g., expressing flagellin to increase the resistance of tomatoes towards Botrytis cinerea infection ( Zhao et al, 2020a ).…”

Impact of the genetic improvement of fermenting yeasts on the organoleptic properties of beer

“…-Improve beer quality, either by trying to obtain strains that modify the metabolism of active sensory compounds (mainly oriented to the elimination, as far as possible, of diacetyl) [35,36]; strains oriented to improve foam stability and quality [37]; or the brightness of beer [38].…”