Yeast Extract, 500 g, ยี่ห้อ Difco

รหัสสินค้า : 212750

Bacto™ Yeast Extract, Cat. No. 212750 Dehydrated – 500 g

Summary and Explanation

Yeast Extract are concentrates of the water-soluble portion of Saccharomyces cerevisiae cells that have been autolyzed. The autolysis is carefully controlled to preserve the naturally occurring B-complex vitamins. Yeast extract is considered a non-animal product and is used extensively for many non-animal formulations for bacterial, fungal, mammalian and insect cell culture.

Bacto Yeast Extract has been considered one of the most complete and versatile of the fermentation bionutrients available. It has been a valuable ingredient for the microbiological

assay of vitamins. Yeast extract is also of value in the assay of antibiotics. B factor, a growth substance necessary for the production of rifampin in a Nocardia sp., can be isolated from

yeast extract.

Principles of the Procedure

Yeast Extract are prepared by growing baker’s yeast, Saccharomyces sp., in a carbohydrate-rich plant medium. The yeast is harvested, washed and resuspended in water, where it undergoes autolysis, or self-digestion. Yeast extract is the total soluble portion of this autolytic action. The autolytic activity is stopped by a heating step. The resulting yeast extract is then filtered to produce a clear product and subsequently made into a powder by a spray-drying process.

Yeast Extract provide vitamins, nitrogen, amino acids and carbon in microbiological culture media.

Dehydrated Appearance: Light to medium beige, to medium tan, freeflowing, homogeneous.

Solution: 1.0% and 2.0% solutions, soluble in purified water. 1.0% solution is light to medium amber, clear, may have a very slight precipitate. 2.0% solution is medium amber, clear, may have a very slight precipitate.

Characteristic

pH, 25°C ................ 6.9

Loss on Drying ...... 0.0 - 5.0 %

Ash ........................ 0.0 - 15.0 %

Sodium Chloride .... 0.0 - 5.0 %

Nitrogen ................. 9.0 - 12.0 %