Dataset Information

MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast.

ABSTRACT: For maltose fermentation, budding yeast Saccharomyces cerevisiae operates a mechanism that involves transporters (MALT), maltases (MALS) and regulators (MALR) collectively known as MAL genes. However, functional relevance of MAL genes during sake brewing process remains largely elusive, since sake yeast is cultured under glucose-rich condition achieved by the co-culture partner Aspergillus spp.. Here we isolated an ethyl methane sulfonate (EMS)-mutagenized sake yeast strain exhibiting enhanced maltose fermentation compared to the parental strain. The mutant carried a single nucleotide insertion that leads to the extension of the C-terminal region of a previously uncharacterized MALR gene YPR196W-2, which was renamed as MAL73. Introduction of the mutant allele MAL73L with extended C-terminal region into the parental or other sake yeast strains enhanced the growth rate when fed with maltose as the sole carbon source. In contrast, disruption of endogenous MAL73 in the sake yeasts decreased the maltose fermentation ability of sake yeast, confirming that the original MAL73 functions as a MALR. Importantly, the MAL73L-expressing strain fermented more maltose in practical condition compared to the parental strain during sake brewing process. Our data show that MAL73(L) is a novel MALR gene that regulates maltose fermentation, and has been functionally attenuated in sake yeast by single nucleotide deletion during breeding history. Since the MAL73L-expressing strain showed enhanced ability of maltose fermentation, MAL73L might also be a valuable tool for enhancing maltose fermentation in yeast in general.

SUBMITTER: Ohdate T

PROVIDER: S-EPMC5997316 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast.

Ohdate Takumi T Omura Fumihiko F Hatanaka Haruyo H Zhou Yan Y Takagi Masami M Goshima Tetsuya T Akao Takeshi T Ono Eiichiro E

PloS one 20180612 6

For maltose fermentation, budding yeast Saccharomyces cerevisiae operates a mechanism that involves transporters (MALT), maltases (MALS) and regulators (MALR) collectively known as MAL genes. However, functional relevance of MAL genes during sake brewing process remains largely elusive, since sake yeast is cultured under glucose-rich condition achieved by the co-culture partner Aspergillus spp.. Here we isolated an ethyl methane sulfonate (EMS)-mutagenized sake yeast strain exhibiting enhanced m ...[more]

PMID: 29894505

Similar Datasets

Project description:The effect of chromosomal aneuploidy on the brewing characteristics of brewery yeasts has not been studied. Here we report that chromosomal aneuploidy in sake brewery yeast (Saccharomyces cerevisiae) leads to the development of favorable brewing characteristics. We found that pyruvate-underproducing sake yeast, which produces less off-flavor diacetyl, is aneuploid and trisomic for chromosomes XI and XIV. To confirm that this phenotype is due to aneuploidy, we obtained 45 haploids with various chromosomal additions and investigated their brewing profiles. A greater number of chromosomes correlated with a decrease in pyruvate production. Especially, sake yeast haploids with extra chromosomes in addition to chromosome XI produced less pyruvate than euploids. Mitochondrion-related metabolites and intracellular oxygen species in chromosome XI aneuploids were higher than those in euploids, and this effect was canceled in their "petite" strains, suggesting that an increase in chromosomes upregulated mitochondrial activity and decreased pyruvate levels. These findings suggested that an increase in chromosome number, including chromosome XI, in sake yeast haploids leads to pyruvate underproduction through the augmentation of mitochondrial activity. This is the first report proposing that aneuploidy in brewery yeasts improves their brewing profile.IMPORTANCE Chromosomal aneuploidy has not been evaluated in development of sake brewing yeast strains. This study shows the relationship between chromosomal aneuploidy and brewing characteristics of brewery yeast strains. High concentrations of pyruvate during sake storage give rise to ?-acetolactate and, in turn, to high concentrations of diacetyl, which is considered an off-flavor. It was demonstrated that pyruvate-underproducing sake yeast is trisomic for chromosome XI and XIV. Furthermore, sake yeast haploids with extra chromosomes produced reduced levels of pyruvate and showed metabolic processes characteristic of increased mitochondrial activity. This novel discovery will enable the selection of favorable brewery yeasts by monitoring the copy numbers of specific chromosomes through a process that does not involve generation/use of genetically modified organisms.

Project description:Kimoto-style seed mash is a traditional preparation method for sake that takes advantage of spontaneous lactic acid fermentation before the growth of yeast. Lactic acid helps decrease the pH in seed mash and control the growth of unfavorable microorganisms. In this study, we carried out a comprehensive analysis of the change in the bacterial community and chemical composition during the lactic acid fermentation stage in kimoto-style seed mash preparation. The bacterial transitions were diverse at five sake breweries, but they exhibited three patterns. Lactobacillus sakei was the dominant species in the later stage of lactic acid fermentation in all sake breweries. This species was found to be the most important bacterium for the accumulation of lactic acid, because its average production rate of lactic acid in seed mash reached 4.44 × 10-11 mg cell-1 h-1, which is 10 times higher than those of other species. As a result of specific growth rate analysis, it was revealed that the growth rate of L. sakei was influenced by the strain, pH, and temperature. The effects of pH and temperature were explained by the square root model, and the result indicates that the strains isolated in this study were incapable of growth below pH 3.9. The growth curve predicted using the growth model fit the actual cell density in two out of five sake breweries; however, our model did not work well for the remaining three sake breweries, and we presume that the error was caused by the strain or an unknown factor.IMPORTANCE It is important to produce lactic acid in kimoto-style seed mash; however, the bacterial transition is different depending on the sake brewery. The reason why there are diverse bacterial transitions during kimoto-style seed mash preparation for each sake brewery is unclear so far, and it causes difficulty in starting kimoto-style seed mash. Our findings indicate that the changes in pH caused by lactic acid bacteria grown prior to L. sakei in seed mash influence the growth of L. sakei and are related to the diversity of the bacterial transition. This study uses comprehensive analytical methods to reveal that there is a diversity of bacterial transition and chemical compositions in kimoto-style seed mash depending on the sake brewery and to explain the differences in bacterial transition depending on the characteristics of L. sakei.

Dataset Information

MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast.

Publications

MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure