Breeding of a Low Pyruvate-Producing Sake Yeast by Isolation of a Mutant Resistant to Ethyl α-Transcyanocinnamate, an Inhibitor of Mitochondrial Pyruvate Transport

Horie, Kenta; Oba, Takahiro; Motomura, Saori; Isogai, Atsuko; Yoshimura, Takashi; Tsuge, Keisuke; Koganemaru, Kazuyoshi; Kobayashi, Genta; Kitagaki, Hiroshi

doi:10.1271/bbb.90373

Cited by 31 publications

(22 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The S. cerevisiae sake strains Kyokai no.7 (Tsukahara et al, 1947;Akao et al, 2011), its derivative TCR7 (Horie et al, 2010) 1.0 mg calcium pantothenate, 1.0 mg nicotinic acid, 25 mg inositol, 1.0 mg pyridoxine, 0.2 mg p-aminobenzoic acid and 1.0 mg thiamin. To avoid pH changes due to ammonia uptake and acetate production, the medium was supplemented with 50 mM potassium hydrogen phthalate.…”

Section: Strains and Growth Conditionsmentioning

confidence: 99%

“…Differently from its WT, TCR7 secretes less pyruvate during sake mash fermentation both on laboratory and factory scales and is now utilized in the actual sake industry to prevent secretion of off-flavours (Horie et al, 2010). Differently from its WT, TCR7 secretes less pyruvate during sake mash fermentation both on laboratory and factory scales and is now utilized in the actual sake industry to prevent secretion of off-flavours (Horie et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation

et al. 2013

Self Cite

View full text Add to dashboard Cite

Although the decrease in pyruvate secretion by brewer's yeasts during fermentation has long been desired in the alcohol beverage industry, rather little is known about the regulation of pyruvate accumulation. In former studies, we developed a pyruvate under-secreting sake yeast by isolating a strain (TCR7) tolerant to ethyl α-transcyanocinnamate, an inhibitor of pyruvate transport into mitochondria. To obtain insights into pyruvate metabolism, in this study, we investigated the mitochondrial activity of TCR7 by oxigraphy and (13) C-metabolic flux analysis during aerobic growth. While mitochondrial pyruvate oxidation was higher, glycerol production was decreased in TCR7 compared with the reference. These results indicate that mitochondrial activity is elevated in the TCR7 strain with the consequence of decreased pyruvate accumulation. Surprisingly, mitochondrial activity is much higher in the sake yeast compared with CEN.PK 113-7D, the reference strain in metabolic engineering. When shifted from aerobic to anaerobic conditions, sake yeast retains a branched mitochondrial structure for a longer time than laboratory strains. The regulation of mitochondrial activity can become a completely novel approach to manipulate the metabolic profile during fermentation of brewer's yeasts.

show abstract

Section: Strains and Growth Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although yeasts undergo autophagy during wine fermentation (17-19), selective modes of autophagy, such as mitophagy, have not been reported. Moreover, there are no published studies on the relationship between mitophagy and the fermentation characteristics of yeast.Our laboratory focuses on the effects of mitochondrial activities and the metabolic engineering of sake yeast strains that influence their ability to ferment substrates (1,(20)(21)(22)(23)(24)(25)(26). Mitochondria depolarize during anaerobiosis, which corresponds to the conditions used for industrial alcoholic fermentation (27-29), and mitophagy occurs when mitochondrial electron potential decreases…”

mentioning

confidence: 99%

“…Our laboratory focuses on the effects of mitochondrial activities and the metabolic engineering of sake yeast strains that influence their ability to ferment substrates (1,(20)(21)(22)(23)(24)(25)(26). Mitochondria depolarize during anaerobiosis, which corresponds to the conditions used for industrial alcoholic fermentation (27)(28)(29), and mitophagy occurs when mitochondrial electron potential decreases (30).…”

mentioning

confidence: 99%

Enhancement of Ethanol Fermentation in Saccharomyces cerevisiae Sake Yeast by Disrupting Mitophagy Function

Shiroma

Jayakody

Horie

et al. 2014

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

c Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 has one of the highest fermentation rates among brewery yeasts used worldwide; therefore, it is assumed that it is not possible to enhance its fermentation rate. However, in this study, we found that fermentation by sake yeast can be enhanced by inhibiting mitophagy. We observed mitophagy in wild-type sake yeast during the brewing of Ginjo sake, but not when the mitophagy gene (ATG32) was disrupted. During sake brewing, the maximum rate of CO 2 production and final ethanol concentration generated by the atg32⌬ laboratory yeast mutant were 7.50% and 2.12% higher than those of the parent strain, respectively. This mutant exhibited an improved fermentation profile when cultured under limiting nutrient concentrations such as those used during Ginjo sake brewing as well as in minimal synthetic medium. The mutant produced ethanol at a concentration that was 2.76% higher than the parent strain, which has significant implications for industrial bioethanol production. The ethanol yield of the atg32⌬ mutant was increased, and its biomass yield was decreased relative to the parent sake yeast strain, indicating that the atg32⌬ mutant has acquired a high fermentation capability at the cost of decreasing biomass. Because natural biomass resources often lack sufficient nutrient levels for optimal fermentation, mitophagy may serve as an important target for improving the fermentative capacity of brewery yeasts. Sake is a traditional Japanese alcoholic beverage produced from steamed rice and koji. During the manufacturing process, glucose is produced (saccharification) from the starch present in rice by the actions of enzymes produced by the koji fungus Aspergillus oryzae. Glucose is fermented to ethanol by Saccharomyces cerevisiae sake yeast strains (1). Sake contains the highest ethanol concentration of all the brewed alcoholic beverages worldwide. This high ethanol concentration is generated by technologies that include successive addition of enzymes and nutrients derived from koji during sake brewing (2, 3), a 3-step pitching process, brewing in winter, and the historical selection of high-ethanol-producing sake yeast strains (1). Sake yeast strains have been selected through a long history of cultivation, ranging from 100 to 400 years. The most frequently used sake yeast at present is Kyokai no. 7 (K7), which was isolated from sake mash in 1946 (4, 5). This strain produces a high concentration of ethanol, because it lacks functions of proteins encoded by MSN4, PPT1, and RIM15, which are required to mount a stress response (6-8). For this reason, researchers in this field believe that it is difficult to further augment the fermentation rate of this sake yeast.Although rice is used as a raw material to brew sake, the surface of rice contains many constituents such as amino acids that impart a heavy and complex taste to sake. Because Japanese consumers tend to prefer a light and clear taste, rice with a polished surface is used for sake brewing. Sake is categorized into...

show abstract

“…Mpc2p is a subunit of the mitochondrial pyruvate transporter, highly conserved in eukaryotes (Bricker et al ., ). Selecting strains having increased mitochondrial pyruvate transport has been found to reduce off‐flavours in alcoholic beverages (Horie et al ., ). RNA sequence data (http://onlinelibrary.wiley.com/doi/10.1111/1462-2920.12327/suppinfo) indicate that SFA1 had a more than 10‐fold higher expression in oenological strains compared with S288c, at 45 g l −1 .…”

Section: Discussionmentioning

confidence: 99%

The impact of genomic variability on gene expression in environmental Saccharomyces cerevisiae strains

Treu

Toniolo

Nadai

et al. 2013

Environmental Microbiology

View full text Add to dashboard Cite

Environmental Saccharomyces cerevisiae strains are crucially important, as they represent the large pool from which domesticated industrial yeasts have been selected, and vineyard strains can be considered the genetic reservoir from which industrial wine strains with strong fermentative behaviour are selected. Four vineyard strains with different fermentation performances were chosen from a large collection of strains isolated from Italian vineyards. Their genomes were sequenced to identify how genetic variations influence gene expression during fermentation and to clarify the evolutionary relationship between vineyard isolates and industrial wine strains. RNA sequencing was performed on the four vineyard strains, as well as on the industrial wine yeast strain EC1118 and on the laboratory strain S288c, at two stages of fermentation. We showed that there was a large gene cluster with variable promoter regions modifying gene expression in the strains. Our results indicate that it is the evolvability of the yeast promoter regions, rather than structural variations or strain-specific genes, that is the main cause of the differences in gene expression. This promoter variability, determined by variable tandem repeats and a high number of single-nucleotide polymorphisms together with 49 differentially expressed transcription factors, explained the strong phenotypic differences in the strains.

show abstract

Breeding of a Low Pyruvate-Producing Sake Yeast by Isolation of a Mutant Resistant to Ethyl α-Transcyanocinnamate, an Inhibitor of Mitochondrial Pyruvate Transport

Cited by 31 publications

References 17 publications

Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation

Improved sake metabolic profile during fermentation due to increased mitochondrial pyruvate dissimilation

Enhancement of Ethanol Fermentation in Saccharomyces cerevisiae Sake Yeast by Disrupting Mitophagy Function

The impact of genomic variability on gene expression in environmental Saccharomyces cerevisiae strains

Contact Info

Product

Resources

About