scholarly journals Wort Substrate Consumption and Metabolite Production During Lambic Beer Fermentation and Maturation Explain the Successive Growth of Specific Bacterial and Yeast Species

2018 ◽  
Vol 9 ◽  
Author(s):  
Jonas De Roos ◽  
Peter Vandamme ◽  
Luc De Vuyst
Keyword(s):  
Yeast Species ◽  
Substrate Consumption ◽  
Metabolite Production ◽  
Beer Fermentation

scholarly journals Kveik brewing yeasts demonstrate wide flexibility in beer fermentation temperature and flavour metabolite production and exhibit enhanced trehalose accumulation

2021 ◽  
Author(s):  
Barret Foster ◽  
Caroline Tyrawa ◽  
Emine Ozsahin ◽  
Mark Lubberts ◽  
Kristoffer Krogerus ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Distinct Group ◽  
The Other ◽  
Fermentation Performance ◽  
Metabolite Production ◽  
Beer Fermentation ◽  
Wide Range ◽  
Insight Into ◽  
Brewing Yeasts ◽  
Trehalose Accumulation

Traditional Norwegian Farmhouse ale yeasts, also known as kveik, have captured the attention of the brewing community in recent years. Kveik were recently reported as fast fermenting thermo- and ethanol tolerant yeasts with the capacity to produce a variety of interesting flavour metabolites. They are a genetically distinct group of domesticated beer yeasts of admixed origin with one parent from the Beer 1 clade and the other unknown. While kveik are known to ferment wort efficiently at warmer temperatures, its range of fermentation temperatures and corresponding flavour metabolites produced, remain uncharacterized. In addition, the characteristics responsible for its increased thermotolerance remain largely unknown. Here we demonstrate variation in kveik strains at a wide range of fermentation temperatures and show not all kveik strains are equal in fermentation performance, flavour metabolite production and stress tolerance. Furthermore, we uncovered an increased capacity of kveik strains to accumulate intracellular trehalose, which likely contributes to its increased thermo- and ethanol tolerances. Taken together our results present a clearer picture of the future opportunities presented by Norwegian kveik yeasts and offer further insight into their applications in brewing.

scholarly journals Dry-Hop Creep Potential of Various Saccharomyces Yeast Species and Strains

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 66
Author(s):  
James Bruner ◽  
Andrew Marcus ◽  
Glen Fox
Keyword(s):  
Yeast Species ◽  
Pilot Scale ◽  
Fermentable Sugars ◽  
Beer Fermentation ◽  
Analytical Measurements ◽  
Apparent Correlation ◽  
Saccharomyces Yeast ◽  
New Perspective ◽  
Live Yeast

Previous research has shown that hops contain enzymes able to hydrolyze unfermentable dextrins into fermentable sugars when added during the dry-hopping process. In the presence of live yeast, these additional fermentable sugars can lead to an over-attenuation of the beer; a phenomenon known as “hop creep”. This study attempts to analyze the effect of different Saccharomyces yeast species and strains on hop creep, with the intent to find an ability to mitigate the effects of dry-hop creep by using a specific yeast. Thirty different yeast species and strains were chosen from commercial and academic collections and propagated for pilot fermentations. Brews were performed at the Anheuser-Busch Research Brewery (1.8 hL, 10 °P, 20 IBU) at UC Davis and split to 40 L cylindroconical fermenters, with one fermenter in each yeast pair receiving 10 g/L Centennial hop pellets towards the end of fermentation. Standard analytical measurements were performed over the course of fermentation, with real degrees of fermentation (RDF) and extract measured on an Anton Paar alcolyzer. In order to preemptively determine the amount of hop creep to be experienced with each unknown fermentation, bench-top fermentations with 20 g/L dry-hops were performed concurrently and compared to the pilot scale fermentations. RDF was significantly higher (p < 0.01) on dry-hopped than non-dry-hopped fermentations beginning two days post dry-hopping to the end of fermentation, with the exceptions of SafAle™ BE-134, a S. cerevisiae var. diastaticus, and UCDFST 11-510, a S. mikatae. No apparent correlation between flocculation and increased RDF was shown in dry-hopped treatments. pH was significantly different between the dry-hopped and non-hopped fermentations (p < 0.05 one day post dry-hop, p < 0.01 for all subsequent days); this may have impacted on additional attenuation. No yeasts in this study indicated their use for mitigation of dry-hop creep, but this is a first look at beer fermentation for some of the chosen yeasts. The results also present a new perspective on how hop creep varies in fermentation.

Hypoxic metabolism in wild rice (Zizania palustris): enzyme induction and metabolite production

1993 ◽  
Vol 89 (1) ◽  
pp. 165-171 ◽  
Author(s):  
Douglas G. Muench ◽  
O. William Archibold ◽  
Allen G. Good
Keyword(s):  
Enzyme Induction ◽  
Wild Rice ◽  
Metabolite Production ◽  
Zizania Palustris

De novo metabolite production through co-cultivation of different fungal species on solid media

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
A Azzollini ◽  
JL Wolfender ◽  
K Gindro
Keyword(s):  
De Novo ◽  
Fungal Species ◽  
Metabolite Production ◽  
Solid Media

Investigation of culture conditions by Response Surface Methodology and kinetic modeling for exopolysaccharide production by Klebsiella oxytoca ICCF 419 strain, using lactose as substrate

2020 ◽  
Vol 25 (6) ◽  
pp. 2033-2044
Author(s):  
CATERINA TOMULESCU ◽  
◽  
MIŞU MOSCOVICI ◽  
ROXANA MĂDĂLINA STOICA ◽  
GABRIEL BUJOR ALBU ◽  
...  
Keyword(s):  
Citric Acid ◽  
Klebsiella Oxytoca ◽  
Fermentation Medium ◽  
Culture Conditions ◽  
Biomass Growth ◽  
Initial Value ◽  
Substrate Consumption ◽  
Polysaccharide Production ◽  
Crude Polysaccharide ◽  
Central Composite

The objective of this work was to optimize the bioprocess parameters, using Klebsiella oxytoca ICCF 419 to obtain an exopolysaccharide based on lactose as substrate. A kinetic study was employed and Logistic and Gompertz models were applied to describe the polysaccharide production, in relation with biomass growth and substrate consumption. The RSM methodology based on Central Composite Rotatable Design was used to evaluate and optimize the effect of lactose, corn extract, KH2PO4 and citric acid concentrations as independent variables on the polysaccharide production, biomass growth and substrate consumption as the response functions. The interaction effects and optimal parameters were obtained using Design Expert Software (version 9.0.6.2). The significance of the variables and their interactions was tested by means of ANOVA analysis with a 99% confidence level. The optimum culture conditions were determined and the model prediction was compared with experimental results. At an initial value of 23.45 for the C/N in the fermentation medium, the strain produces 17.41 g/L of crude polysaccharide and 2.53 g/L dry biomass. The EPS production was significantly influenced by lactose, corn extract and KH2PO4, while the citric acid had no influence. The biomass growth was influenced by the corn extract, KH2PO4 and citric acid.

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