Yeast extract powder is an essential component in microbiology. It produced by drying yeast cell extract. It is a rich source of vital nutrients which support the growth of bacteria. Powdered yeast extract is a complicated combination made up of:
Carbon and Nitrogen Sources: It supplies carbon and nitrogen, which are crucial building components for bacterial cells and are frequently scarce in culture conditions.
Vitamins: B vitamins, which are essential for a number of bacterial metabolic functions, are especially high in it.
Free Amino Acids: Bacteria can directly incorporate these readily available amino acids to produce proteins.
Growth Factors: In addition to providing nucleotides and trace elements, yeast extract powder also provides other growth factors that promote the best possible growth of bacteria.
Shelf life and storage
Store yeast extract powder between 10-30 °C in a ventilated and low humidity place and protected from light. Close the container tightly after use. Use before expiry date.
Typical analysis
| Powder appearance | Light yellow to brownish yellow, homogenous, free flowing |
| Solubility | Completely soluble in water, insoluble in alcohol |
| 2% solution appearance | Clear, light yellow |
| pH (2% in water) | 6.5 – 7.5 |
Chemical analysis
| Total nitrogen | ≥10.5 |
| Sodium chloride | ≤5 |
| Amino nitrogen | ≥4.5 |
| Moisture | ≤6 |
Amino acid composition (mg/g)
| Aspartic acid | 65 |
| Threonine | 26 |
| Serine | 24 |
| Glutamic acid | 115 |
| Proline | 23 |
| Glycine | 30 |
| Alanine | 48 |
| Cysteine | – |
| Methionine | 9 |
| Isoleucine | 31 |
| Leucine | 42 |
| Tyrosine | 11 |
| Phenylalanine | 26 |
| Histidine | 14 |
| Lysine | 46 |
| Arginine | 32 |
| Tryptophan | – |
Microbial Quality ControlCultural response after 18-48 hours incubation at 35-37 °C on Plate Count Agar (AS-1328) prepared by Yeast Extract as a component.
| Strain | ATCC | Growth |
| Escherichia coli | 25922 | Luxuriant |
| Streptococcus pyogenes | 19615 | Luxuriant |
| Staphylococcus aureus | 25923 | Luxuriant |
| Enterococcus faecalis | 29212 | Luxuriant |
| Bacillus subtilis | 6633 | Luxuriant |
| Lactobacillus casei | 9595 | Luxuriant |