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YEPG Agar (Yeast Extract Peptone Glycerol Agar) AS-1437 | Ausamics
$95.00 AUD
YEPG Agar — Yeast Extract Peptone Glycerol Agar
Non-Fermentable Carbon Medium for Petite Mutant Screening, Mitochondrial Studies & Respiratory Competence Verification | Cat. No. AS-1437
Cat. No. AS-1437 pH 6.5 ± 0.2 Glycerol 3% v/v Non-Fermentable Carbon ✕ Petite Mutants Cannot Grow ✓ Respiratory-Competent WT Grows ✓ HiMedia M1368 Equivalent 🇦🇺 Made in Melbourne ⚡ Same-Week Dispatch
Cat. No.
AS-1437
pH (25°C)
6.5 ± 0.2
Dissolution
50 g/L + 30 mL glycerol
Glycerol
30 mL/L (3% v/v)
Sterilisation
121°C / 15 min
📄 Full DocumentationCOA, TDS & SDS every batch
🇦🇺 Australian StockNo import delays
⚡ Same-Week DispatchMelbourne warehouse
🔬 Technical SupportDirect from our team
Overview
YEPG Agar (AS-1437) is a specialised non-fermentable carbon medium for yeast genetics, mitochondrial biology, and respiratory competence studies. Based on the standard YPG formulation described in Burke, Dawson & Stearns (2000) Methods in Yeast Genetics (Cold Spring Harbor Laboratory Press), it uses glycerol (3% v/v, 30 mL/L) as the sole carbon source in place of the glucose used in conventional YPD/YEPD media.
Because glycerol is a non-fermentable carbon source, organisms must rely exclusively on aerobic oxidative phosphorylation — mitochondrial respiration — for ATP production. This is the defining property that makes YEPG Agar the standard tool for identifying respiratory-deficient "petite" mutants of Saccharomyces cerevisiae: petite strains (ρ⁻ or ρ⁰) lack functional mitochondrial DNA and cannot grow on YEPG, while wild-type respiratory-competent strains grow normally.
Mode of Action — Why Glycerol Matters
Glycerol — The Non-Fermentable Carbon Source: Unlike glucose, glycerol cannot be metabolised by fermentation (glycolysis → ethanol). It must be converted to dihydroxyacetone phosphate (DHAP) and fed into the TCA cycle via gluconeogenesis, requiring functional mitochondria throughout. This metabolic requirement is absolute — there is no fermentative bypass available.
Petite Mutant Exclusion: Saccharomyces cerevisiae petite mutants carry deletions or point mutations in mitochondrial DNA (mtDNA) that impair or eliminate the function of the mitochondrial electron transport chain. On glucose (YPD), these strains survive by fermentation, forming small (petite) colonies. On YEPG, they cannot generate ATP and fail to grow — providing an unambiguous readout of respiratory competence.
Rich Nutritional Base: The YEP base (Peptone 20 g/L + Yeast Extract 10 g/L) provides abundant amino acids, B-vitamins, and growth cofactors so that respiratory-competent cells are not limited by nutrition — only by their ability to use the glycerol carbon source via mitochondrial respiration.
Petite Mutant Exclusion: Saccharomyces cerevisiae petite mutants carry deletions or point mutations in mitochondrial DNA (mtDNA) that impair or eliminate the function of the mitochondrial electron transport chain. On glucose (YPD), these strains survive by fermentation, forming small (petite) colonies. On YEPG, they cannot generate ATP and fail to grow — providing an unambiguous readout of respiratory competence.
Rich Nutritional Base: The YEP base (Peptone 20 g/L + Yeast Extract 10 g/L) provides abundant amino acids, B-vitamins, and growth cofactors so that respiratory-competent cells are not limited by nutrition — only by their ability to use the glycerol carbon source via mitochondrial respiration.
Growth Behaviour on YEPG Agar
✓ GROWS on YEPG
- Wild-type S. cerevisiae (ρ⁺)
- Respiratory-competent strains
- Functional mtDNA strains
- Aerobic fungi and yeasts
- Non-petite laboratory strains
✕ FAILS TO GROW on YEPG
- Petite mutants (ρ⁻ or ρ⁰)
- mtDNA deletion strains
- Respiratory chain mutants
- Strict fermenters
- Obligate anaerobes
ⓘ Petite frequency in S. cerevisiae: Approximately 1–3% of cells in a wild-type S. cerevisiae population spontaneously lose mitochondrial function and become petite mutants during normal growth. YEPG Agar is used to measure this "petite frequency" — an important quality indicator for yeast strain integrity, particularly in industrial fermentation and brewing applications.
Applications
🧬
Petite Mutant Screening
Identify ρ⁻/ρ⁰ strains by failure to grow on glycerol
🧒
Mitochondrial Studies
mtDNA function, OXPHOS, electron transport chain research
🍻
Brewery & Fermentation QC
Verify yeast strain respiratory competence before fermentation runs
🔬
Yeast Genetics Research
Genetic screens, mitochondrial inheritance, mtDNA stability
📚
Teaching Labs
Fermentation vs respiration demonstrations; petite mutant isolation
📊
Strain Verification
Confirm respiratory competence of recombinant yeast strains
YEPG vs YPD — Key Comparison
| Feature | YEPG Agar (AS-1437) — This Product | YPD/YEPD Agar (AS-1438) |
|---|---|---|
| Carbon source | Glycerol 3% v/v (non-fermentable) | Dextrose 2% (fermentable) |
| Metabolic requirement | Aerobic respiration (OXPHOS) — mitochondria required | Fermentation or respiration — mitochondria optional |
| Petite mutants | ✕ Cannot grow | ✓ Grow (small colonies) |
| Wild-type growth | ✓ Normal colonies | ✓ Larger colonies (fermentation faster) |
| Primary use | Respiratory competence testing; petite mutant screening | General cultivation, propagation, routine growth |
| pH | 6.5 ± 0.2 | 6.5 ± 0.2 |
| Use together? | ✓ Yes — inoculate same strain on both plates in parallel to identify petite mutants by differential growth | |
FAQs
❓ Why does glycerol require functional mitochondria when glucose does not?
Glucose can be metabolised by fermentation (glycolysis → pyruvate → ethanol + CO₂) in the absence of oxygen or functional mitochondria. This provides enough ATP for S. cerevisiae to grow — slowly, in small colonies. Glycerol has no fermentation pathway. It must enter gluconeogenesis as DHAP, and the resulting metabolites must be oxidised through the TCA cycle and electron transport chain (OXPHOS) to generate ATP. Without functional mitochondrial electron transport, there is no ATP from glycerol — and no growth.
❓ What are petite mutants and why do they matter in fermentation?
Petite mutants (ρ⁻ = deleted mtDNA; ρ⁰ = no mtDNA) arise spontaneously in S. cerevisiae populations at ~1–3% frequency. In brewing and industrial fermentation, high petite frequency in a yeast culture is associated with poor fermentation performance, off-flavour production, and inconsistent results. YEPG Agar provides a rapid, visual method to quantify petite frequency: plate a diluted culture on both YPD and YEPG simultaneously, then compare colony counts. Colonies on YPD but absent on YEPG = petite mutants.
❓ Can I use ethanol instead of glycerol as a non-fermentable carbon source?
Ethanol is also a non-fermentable carbon source used in some yeast respiratory screens (YPEG or YEPEG media). However, YEPG with glycerol is the more widely used standard, referenced in Cold Spring Harbor Laboratory manuals and the majority of published yeast genetics protocols. Glycerol is more stable in autoclaved agar than ethanol, which is added post-sterilisation in ethanol-based media. For standard petite mutant screening, YEPG with glycerol is the recommended approach.
❓ Why is the glycerol added separately and not included in the dehydrated base?
Glycerol is a viscous liquid (density ~1.26 g/mL) that cannot be incorporated into a dry dehydrated powder. It is added to the water before or during dissolution of the dehydrated base — 30 mL of laboratory-grade glycerol per litre. The dehydrated base (50 g/L) contains the Peptone, Yeast Extract, and Agar components. Glycerol is heat-stable and withstands autoclaving without degradation.
❓ Is AS-1437 equivalent to HiMedia M1368?
Yes — AS-1437 follows the same standard YPG formulation: Peptic Digest of Animal Tissue (Peptone) 20 g/L, Yeast Extract 10 g/L, Glycerol 30 mL/L (3% v/v), Agar 20 g/L, pH 6.5 ± 0.2, dissolve 50 g/L base + 30 mL glycerol per litre. Full COA included with every batch.
Cross-Reference / Equivalents
| Manufacturer | Product Name | Cat. No. | Notes |
|---|---|---|---|
| HiMedia | YPG Agar | M1368 | Same formula; 50g + 30mL glycerol/L |
| Cold Spring Harbor / Standard | YPG Agar | — | Reference formula: Burke et al. 2000 |
Related Products
Product Specifications
| Product Name | YEPG Agar (Yeast Extract Peptone Glycerol Agar) |
| Catalogue Number | AS-1437 |
| Synonyms | YPG Agar; YEP-Glycerol Agar; YP-Glycerol Agar; Non-fermentable Carbon Yeast Medium; Petite Mutant Screening Agar |
| Reference Formula | Burke D, Dawson D, Stearns T. Methods in Yeast Genetics: A Cold Spring Harbor Laboratory Course Manual. 2000. [Standard YPG formulation] |
| Commercial Equivalent | HiMedia M1368 |
| Medium Type | Rich non-fermentable carbon agar for yeast genetics and respiratory studies |
| Dissolution | 50.0 g/L dehydrated base + 30 mL glycerol per litre of distilled water |
| Final pH at 25°C | 6.5 ± 0.2 |
| Sterilisation | Autoclave 121°C for 15 minutes |
| Appearance (powder) | Cream to light tan, free-flowing homogeneous powder |
| Appearance (prepared agar) | Clear to slightly opalescent light amber; firm gel |
| Incubation | 25–30°C for 48–72 hours (respiratory-competent strains) |
| Storage (powder) | Below 30°C, dry, tightly sealed, protected from moisture and light |
| Storage (prepared plates) | 2–8°C; use within 2 weeks |
| HS Tariff Code | 3821.00.00 |
Formula — Per Litre (Cold Spring Harbor / HiMedia M1368 Reference)
| Ingredient | Amount | Function |
|---|---|---|
| Peptic Digest of Animal Tissue (Peptone) | 20.0 g | Primary nitrogen, amino acids, and growth factors for yeast |
| Yeast Extract | 10.0 g | B-vitamins, nucleotide precursors, co-factors for rapid growth |
| Glycerol (laboratory grade, 99%) | 30.0 mL (3% v/v) | Sole carbon source — non-fermentable; requires functional mitochondria; forces aerobic OXPHOS; petite mutants cannot grow |
| Agar | 20.0 g | Solidifying agent — 2% (standard for yeast genetics media) |
| Dehydrated base | 50.0 g/L | Add 30 mL glycerol per litre separately before autoclaving | pH 6.5 ± 0.2 |
⚠️ Formula correction vs. some commercial sources: The standard YPG formulation (Cold Spring Harbor Manual; OpenWetWare; HiMedia M1368) specifies Glycerol 30 mL/L (3% v/v) and Agar 20 g/L (2%). Some historical references cite glycerol at 20 mL/L or agar at 15 g/L — these are non-standard and may reduce performance. AuSaMicS AS-1437 uses the correct standard formula.
Preparation Protocol
1
Measure 30 mL of laboratory-grade glycerol (99%) and add to approximately 900 mL of purified or distilled water. Mix well — glycerol is viscous and requires thorough mixing.
2
Add 50.0 g of dehydrated YEPG base (AS-1437). Bring volume to 1 litre with additional distilled water. Mix thoroughly.
3
Heat with frequent agitation and bring to a gentle boil for 1 minute until completely dissolved.
4
Sterilise by autoclaving at 121°C for 15 minutes. Glycerol is heat-stable and withstands autoclaving without degradation.
5
Cool to 45–50°C. Pour approximately 20–25 mL per 90 mm Petri dish on a level surface. Allow to solidify.
6
Inoculate with yeast culture. Incubate at 25–30°C for 48–72 hours. Dry plates at room temperature for 2–3 days before storage at 2–8°C for improved performance.
Quality Control Organisms
| Organism (ATCC) | Expected Result | Incubation | Interpretation |
|---|---|---|---|
| Saccharomyces cerevisiae (9763) — WT | Good to luxuriant growth ✓ | 25–30°C / 48–72h | Respiratory-competent — OXPHOS functional |
| Aspergillus brasiliensis (16404) | Good growth ✓ | 25°C / 5 days | Aerobic fungal growth on glycerol confirmed |
| Candida albicans (10231) | Good growth ✓ | 25–30°C / 48–72h | Respiratory-competent Candida grows on glycerol |
| Petite mutant S. cerevisiae (ρ⁻ or ρ⁰) | No growth or severely impaired ✕ | 25–30°C / 72h | Respiratory-deficient — OXPHOS non-functional |
Literature & References
| # | Reference |
|---|---|
| 1 | Burke D, Dawson D, Stearns T. Methods in Yeast Genetics: A Cold Spring Harbor Laboratory Course Manual. Cold Spring Harbor Laboratory Press; 2000. [Primary reference for YPG medium formulation — Peptone 2%, Yeast Extract 1%, Glycerol 3% v/v, Agar 2%] |
| 2 | Guthrie C, Fink GR (eds). Methods in Enzymology Vol. 194: Guide to Yeast Genetics and Molecular Biology. Academic Press; 1991. [Standard yeast genetics methods including non-fermentable carbon media] |
| 3 | Contamine V, Picard M. Maintenance and Integrity of the Mitochondrial Genome: a Plethora of Nuclear Genes in the Budding Yeast. Microbiol Mol Biol Rev. 2000;64(2):281–315. [Petite mutation, mitochondrial DNA, and respiratory competence in S. cerevisiae] |
| 4 | HiMedia Laboratories. YPG Agar, Cat. M1368. Technical specifications. [Commercial reference formula confirmation] |
| 5 | ISO 11133:2014. Performance testing of culture media. Geneva: ISO; 2014. |
📄 Full 16-section GHS SDS available (Australian WHS Regulations 2023 / GHS 7th Edition) — support@ausamics.com.au
Section 1 — Identification
| Product Name | YEPG Agar (Yeast Extract Peptone Glycerol Agar) |
| Catalogue No. | AS-1437 |
| Supplier | AuSaMicS Pty Ltd | ABN 56 676 640 467 |
| Address | 31 Longview CT, Thomastown VIC 3074, Australia |
| Emergency | Poisons Information Centre: 13 11 26 (24 hr) |
| Phone | +61 412 520 598 | support@ausamics.com.au |
Section 2 — Hazard Identification (GHS 7th Ed / WHS 2023)
| GHS Classification | NOT classified as a hazardous substance under Australian WHS Regulations 2023 at intended use concentrations. |
| Signal Word | None required |
| Other Hazards | Combustible dry powder. Dust may cause mild respiratory irritation. Glycerol component (added separately): not classified as hazardous. No significant chemical hazard at laboratory handling levels. |
Composition (Dehydrated Base)
| Component | g/L | CAS | Hazard |
|---|---|---|---|
| Peptic Digest of Animal Tissue (Peptone) | 20.0 | 73049-73-7 | Not hazardous |
| Yeast Extract | 10.0 | 8013-01-2 | Not hazardous |
| Agar | 20.0 | 9002-18-0 | Not hazardous |
| Glycerol (added separately) | 30.0 mL | 56-81-5 | Not hazardous |
| Respiratory PPE | P1 filter when weighing bulk powder |
| Eye Protection | Safety glasses when handling dry powder |
| Skin / Gloves | Nitrile gloves when handling inoculated cultures |
| Waste | Autoclave inoculated plates (121°C / 15 min) before disposal as microbiological waste |
| Transport | Not dangerous goods — ADG, IMDG, IATA |
| Regulatory | Australian WHS Regulations 2023 | GHS 7th Edition | AICIS compliant |
⚠️ Biosafety: Saccharomyces cerevisiae wild-type strains are BSL-1 and present minimal risk. If YEPG Agar is used with recombinant or genetically modified yeast strains, apply the biosafety classification of the modified organism and consult your institutional biosafety officer and relevant OGTR requirements under the Gene Technology Act 2000 (Australia).
Quality Specifications
| Parameter | Specification | Method |
|---|---|---|
| Appearance (powder) | Cream to light tan, free-flowing, homogeneous powder | Visual |
| Appearance (prepared agar) | Clear to slightly opalescent light amber; firm gel | Visual after dissolution |
| pH (prepared, 25°C) | 6.5 ± 0.2 | pH meter (calibrated) |
| Dissolution | Complete at 50 g/L base + 30 mL glycerol with boiling | Visual |
| Moisture Content | ≤5.0% (w/w) | Loss on drying |
| Growth — S. cerevisiae ATCC 9763 (WT) | Good to luxuriant growth; 25–30°C / 48–72h; ≤100 CFU inoculum | ISO 11133:2014 |
| Growth — C. albicans ATCC 10231 | Good growth; 25–30°C / 48–72h; ≤100 CFU | ISO 11133:2014 |
| Non-fermentable carbon function | Confirmed growth of respiratory-competent strains; confirmed no/impaired growth of petite (ρ⁻) mutants on same lot | Differential growth test |
| Batch COA | Available every production lot | Included with every order |
Manufacturing & Documentation
Manufactured by AuSaMicS Pty Ltd
31 Longview CT, Thomastown VIC 3074, Australia | ABN 56 676 640 467
✓ Formulated per Cold Spring Harbor Laboratory standard / HiMedia M1368 reference
✓ Glycerol: 30 mL/L (3% v/v) — standard formula
✓ Agar: 20 g/L (2%) — standard for yeast genetics media
✓ Batch QC per ISO 11133:2014 — pH, growth promotion, non-fermentable carbon function
✓ COA, TDS, SDS included with every order
✓ Australian stock — same-week dispatch, no import delays
31 Longview CT, Thomastown VIC 3074, Australia | ABN 56 676 640 467
✓ Formulated per Cold Spring Harbor Laboratory standard / HiMedia M1368 reference
✓ Glycerol: 30 mL/L (3% v/v) — standard formula
✓ Agar: 20 g/L (2%) — standard for yeast genetics media
✓ Batch QC per ISO 11133:2014 — pH, growth promotion, non-fermentable carbon function
✓ COA, TDS, SDS included with every order
✓ Australian stock — same-week dispatch, no import delays
⚠️ For laboratory, industrial, educational, and research use only. Not for food, drug, cosmetic, or therapeutic applications.