eukaryotic microorganism
unicellular
ubiquitious
500 gr = 3,200 billion cells
ubiquitious
Kingdom Fungi
Mitosis, budding, spore
Able to convert carbohydrates to carbon dioxide and alcohols
Old English
gist
,
gyst
Indo-European
yes : b
oil, foam, or bubble
Food products
Science
Pathogen
Product spoilage
Benefits
Negative sides
Biofuel
Bioremediation
Hobby
Pharmaceutical
Late 1800s
Late 1900s
End of 20th century-present
Isolation of single to- and bottom-fermenting yeast and employment as
starter for beer and wine Yeast in malt:
Improvement of industrial strains Yeast taxonomy study
Genomic sequence of S.cerevisiae
Genetic improvements of industrial yeasts
2000-6000BC
Late 1600s
Early 1800s
Wine making (Caucasia)
Beer brewing (Sumeria, Babylonia) Dough leavening (Egypt)
Microscopic observation (Anton van Leeuwenhoek, 1685) ‘globular structures’
Verstrepen et al. (2006) starter for beer and wine
Yeast in malt:
Saccaromyces cerevisiae
Louis Pasteur, 1857 : Pasteur effect
1755 Dictionary of the English language
Molecular biology
Systems biology
Synthetic biology
Exploitation of biological complexity of improved yeast (strains, processes)
Prospect of genome synthesis to create
‘ideal’ strain
Microbiology
Biochemistry
Genetics
Genetics breeding
Mutagenesis and selection Clonal selection
Isolation and identification
Genetics engineering by gene cloning and transformation of desirable traits
Metabolic engineering by directed genetic modification and
reconstruction
Alcoholic drinks
beer, wine, cider, brem
Non alcoholic drinks
carbonated drinks (root beer, kombucha)
Baking
leavening agent
Nutritional supplements
deactivated yeast, S.cerevisiae, single cell proteins
Probiotics
S. boulardiiFood additives/flavor
yeast extract/autolysateDairy fermentation
kefirSoy fermentation
soy sauce, tauco
Colorants
Rhodotorula, Cryptococcus, Sporobolomyces, etc.
Yeast polysaccharides
S.cerevisiae, Rhodotorula, Pichia holstii, etc.
Traditional food
i 2 2
Glucose 2 ADP 2 P
i= 2 ethanol 2 CO
22 ATP 2 H
2O
Zymology/zymurgy
Where ?
How ?
What metabolic pathway ?
Enzymatic reaction?
Monoterpenes Thiols
Norisoprenoids Ethyl acetate Ester
Ester
Fatty acids
Hydrogen sulfide Glycerol
Embden–Meyerhof–Parnas (EMP pathway)
Preparatory phase Pay-off phase
Harvest
Crushing (destemming)
Mixture of juice, skin, and seeds Yeast addition
Wine Yeast
Oenology
The science of wine and winemaking
Fermentation
Time on skins Extraction method Temperature Fermentation vessel Type of yeast
Pressing
Storage and aging Bottling
The science of wine and winemaking
‘Cultured’ yeast
Saccharomyces cerevisiae
Skin of fruits Equipments
Surrounding environment Surrounding environment Leek of previous fermentation
Brettanomyces Candida
Kloeckera (common wild yeast) Saccharomycodes
Schizosaccharomyces (fission yeast)
Non toxic
Quickly begin fermentation, out-competing other "wild yeasts”
Completely utilize all fermentable sugars
High alcohol-tolerance (≥15%)
Have a high SO tolerance but low production of sulfur compounds
Requirements of wine yeasts
Have a high SO
2tolerance but low production of sulfur compounds
Produce
minimum
amount
of
residual
pyruvate,
acetic
acid and acetaldehyde
Produce minimum foaming
Organoleptik
Conversion rate of substrate to ethanol
Ethanol concentration
Residual sugar
Sedimentation rate of yeast and lees
Product
Quantity
Quality
Sedimentation rate of yeast and lees
Titratable acidity
pH
Sulfur concentration
Volatile compounds production
Growth rate of yeast
Contamination
Quality
Distiller’s Yeast
Baker’s Yeast
Purpose?
Active Dry Yeast
Baker’s Yeast
Bread Machine / instant/rapid rise yeast Fresh Yeast
Warm liquid
S.cerevisiae
Highly active, one rise only
Extremely perishable, tested prior use
Fresh Yeast Liquid Yeast
Extremely perishable, tested prior use
Raw materials
FERMENTATION STAGES
Flask fermentation Pure culture fermentation
Filtration
Blending Pure culture fermentation
Intermediate fermentation Stock fermentation
Pitch fermentation Trade fermentation
Extrusion and cutting
Compressed yeast
Drying
Packaging
Dried yeast
Fixed-state yeast
Two-step fermentation
Usage of previous leek
Ambient yeast
Harvesting time
Addition of fruit juice
Addition of sulphur / chilling
Exploration of new yeast strains sources:
marine, endemic species/location/situation
Creation of new strains
GMO / natural process exploitation
