Department of Biotechnology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague 6, Dejvice, Czech Republic.
Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague 6, Dejvice, Czech Republic.
Appl Microbiol Biotechnol. 2017 Feb;101(4):1477-1485. doi: 10.1007/s00253-016-7923-8. Epub 2016 Oct 21.
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.
与大多数其他酒精饮料相比，啤酒的保质期要短得多，因为它在瓶中不稳定。这种不稳定性在储存过程中很可能表现为浑浊（雾浊），甚至沉淀。啤酒中的浑浊主要是由啤酒中蛋白质和多酚之间相互作用形成的胶体颗粒引起的。因此，啤酒通常通过去除至少一种这些成分来稳定。我们使用α-凝集素的 C 末端锚定结构域，开发并构建了一种带有富含脯氨酸的 QPF 肽的酿酒酵母菌株。QPF 肽在发酵过程中用于结合多酚，从而降低其浓度。与仅显示锚定结构域的对照菌株相比，显示 QPF 的菌株能够结合约两倍的儿茶素和表儿茶素。所有这些实验都是在模型溶液中进行的。根据酵母的浓度，多酚的摄取量增加了 1.7-2.5 倍。同样，原花青素的摄取量也增加了约 20%。由于 QPF 修饰的酵母在实验室条件下的发酵性能不受影响，因此 QPF 的表达似乎是提高啤酒稳定性的一种方法。
