Evaluation of a Brazilian Fuel Alcohol Yeast Strain for Scotch Whisky Fermentations

Abstract Omnipotent suppressors decrease translational fidelity and cause misreading of nonsense codons. In the presence of the non-Mendelian factor [eta+], some alleles of previously isolated omnipotent suppressors are lethal. Thus the current search was conducted in an [eta+] strain in an effort to identify new suppressor loci. A new omnipotent suppressor, SUP39, and alleles of sup35, sup45, SUP44 and SUP46 were identified. Efficiencies of the dominant suppressors were dramatically reduced in strains that were cured of non-Mendelian factors by growth on guanidine hydrochloride. Wild-type alleles of SUP44 and SUP46 were cloned and these clones were used to facilitate the genetic analyses. SUP44 was shown to be on chromosome VII linked to cyh2, and SUP46 was clearly identified as distinct from the linked sup45.

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Influence of L. thermotolerans and S. cerevisiae Commercial Yeast Sequential Inoculation on Aroma Composition of Red Wines (Cv Trnjak, Babic, Blatina and Frankovka)

Fermentation ◽

10.3390/fermentation7010004 ◽

2020 ◽

Vol 7 (1) ◽

pp. 4

Author(s):

Ana-Marija Jagatić Korenika ◽

Ivana Tomaz ◽

Darko Preiner ◽

Marina Lavrić ◽

Branimir Šimić ◽

...

Keyword(s):

Yeast Strain ◽

Isoamyl Alcohol ◽

Starter Cultures ◽

Geranyl Acetate ◽

Red Wines ◽

Wine Quality ◽

Volatile Phenol ◽

Sequential Inoculation ◽

Commercial Yeast ◽

The Impact

Even though Saccharomyces cerevisiae starter cultures are still largely used nowadays, the non-Saccharomyces contribution is re-evaluated, showing positive enological characteristics. Among them, Lachancea thermotolerans is one of the key yeast species that are desired for their contribution to wine sensory characteristics. The main goal of this work was to explore the impact of L. thermotolerans commercial yeast strain used in sequential inoculation with S. cerevisiae commercial yeast on the main enological parameters and volatile aroma profile of Trnjak, Babić, Blatina, and Frankovka red wines and compare it with wines produced by the use of S. cerevisiae commercial yeast strain. In all sequential fermented wines, lactic acid concentrations were significantly higher, ranging from 0.20 mg/L in Trnjak up to 0.92 mg/L in Frankovka wines, while reducing alcohol levels from 0.1% v/v in Trnjak up to 0.9% v/v in Frankovka wines. Among volatile compounds, a significant increase of ethyl lactate and isobutyl acetate, geraniol, and geranyl acetate was detected in all wines made by use of L. thermotolerans. In Babić wines, the strongest influence of sequential fermentation was connected with higher total terpenes and total ester concentrations, while Trnjak sequentially fermented wines stood up with higher total aldehyde, volatile phenol, and total lactone concentrations. Control wines, regardless of variety, stood up with higher concentrations of total higher alcohols, especially isoamyl alcohol. The present work contributed to a better understanding of the fermentation possibilities of selected non-Saccharomyces strains in the overall red wine quality modeling.

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Comparison of Three Approaches to Assess the Flavour Characteristics of Scotch Whisky Spirit

Applied Sciences ◽

10.3390/app11041410 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1410

Author(s):

Martina Daute ◽

Frances Jack ◽

Irene Baxter ◽

Barry Harrison ◽

John Grigor ◽

...

Keyword(s):

Mass Spectrometry ◽

Descriptive Analysis ◽

Analytical Techniques ◽

Gas Chromatography Mass Spectrometry ◽

Multiple Factor Analysis ◽

Quantitative Descriptive Analysis ◽

Yeast Strains ◽

Quantitative Descriptive ◽

Scotch Whisky ◽

Multiple Factor

This study compared the use of three sensory and analytical techniques: Quantitative Descriptive Analysis (QDA), Napping, and Gas Chromatography-Mass Spectrometry (GC-MS) for the assessment of flavour in nine unmatured whisky spirits produced using different yeasts. Hierarchical Multiple Factor Analysis (HMFA) showed a similar pattern of sample discrimination (RV scores: 0.895–0.927) across the techniques: spirits were mostly separated by their Alcohol by Volume (ABV). Low ABV spirits tended to have heavier flavour characteristics (feinty, cereal, sour, oily, sulphury) than high ABV spirits, which were lighter in character (fruity, sweet, floral, solventy, soapy). QDA differentiated best between low ABV spirits and GC-MS between high ABV spirits, with Napping having the lowest resolution. QDA was time-consuming but provided quantitative flavour profiles of each spirit that could be readily compared. Napping, although quicker, gave an overview of the flavour differences of the spirits, while GC-MS provided semi-quantitative ratios of 96 flavour compounds for differentiating between spirits. Ester, arenes and certain alcohols were found in higher concentrations in high ABV spirits and other alcohols and aldehydes in low ABV spirits. The most comprehensive insights on spirit flavour differences produced by different yeast strains are obtained through the application of a combination of approaches.

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Optimization of medium and cultivation conditions for pullulan production by a new pullulan-producing yeast strain

Enzyme and Microbial Technology ◽

10.1016/s0141-0229(03)00119-4 ◽

2003 ◽

Vol 33 (2-3) ◽

pp. 206-211 ◽

Cited By ~ 98

Author(s):

Zhenming Chi ◽

Shuangzhi Zhao

Keyword(s):

Yeast Strain ◽

Cultivation Conditions

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Conditional lethality of a yeast strain expressing human RHOA in place of RHO1.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.91.20.9317 ◽

1994 ◽

Vol 91 (20) ◽

pp. 9317-9321 ◽

Cited By ~ 28

Author(s):

H. Qadota ◽

Y. Anraku ◽

D. Botstein ◽

Y. Ohya

Keyword(s):

Yeast Strain

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The influence of yeast strain on the oxidative stability of beer

Journal of the Institute of Brewing ◽

10.1002/jib.650 ◽

2021 ◽

Author(s):

David Jenkins ◽

Sue James ◽

Frieda Dehrmann ◽

Katherine Smart ◽

David Cook

Keyword(s):

Oxidative Stability ◽

Yeast Strain

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High Foam Phenotypic Diversity and Variability in Flocculant Gene Observed for Various Yeast Cell Surfaces Present as Industrial Contaminants

Fermentation ◽

10.3390/fermentation7030127 ◽

2021 ◽

Vol 7 (3) ◽

pp. 127

Author(s):

Catarina M. de Figueiredo ◽

Daniella H. Hock ◽

Débora Trichez ◽

Maria de Lourdes B. Magalhães ◽

Mario L. Lopes ◽

...

Keyword(s):

Biofilm Formation ◽

Yeast Strain ◽

Phenotypic Diversity ◽

Strain Engineering ◽

Fuel Ethanol ◽

Invasive Growth ◽

Foam Formation ◽

Yeast Strains ◽

Length Polymorphisms ◽

Contaminant Yeast

Many contaminant yeast strains that survive inside fuel ethanol industrial vats show detrimental cell surface phenotypes. These harmful effects may include filamentation, invasive growth, flocculation, biofilm formation, and excessive foam production. Previous studies have linked some of these phenotypes to the expression of FLO genes, and the presence of gene length polymorphisms causing the expansion of FLO gene size appears to result in stronger flocculation and biofilm formation phenotypes. We performed here a molecular analysis of FLO1 and FLO11 gene polymorphisms present in contaminant strains of Saccharomyces cerevisiae from Brazilian fuel ethanol distilleries showing vigorous foaming phenotypes during fermentation. The size variability of these genes was correlated with cellular hydrophobicity, flocculation, and highly foaming phenotypes in these yeast strains. Our results also showed that deleting the primary activator of FLO genes (the FLO8 gene) from the genome of a contaminant and highly foaming industrial strain avoids complex foam formation, flocculation, invasive growth, and biofilm production by the engineered (flo8∆::BleR/flo8Δ::kanMX) yeast strain. Thus, the characterization of highly foaming yeasts and the influence of FLO8 in this phenotype open new perspectives for yeast strain engineering and optimization in the sugarcane fuel-ethanol industry.

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