Overview:
Casein Acid Hydrolysate (also known as Acid Hydrolyzed Casein or Casamino Acids) is a refined, vitamin-free hydrolysate derived from casein, the primary protein in bovine milk, produced through acid hydrolysis using hydrochloric acid at elevated temperature and pressure, followed by neutralization and filtration. This process breaks down the intact protein into a mixture of free amino acids, short peptides, and polypeptides, providing a highly soluble, organic nitrogen source essential for microbial nutrition. Developed for precise microbiological applications, it minimizes interference from vitamins and growth factors, making it indispensable for assays requiring controlled nutritional environments. Its pale yellow to off-white powder form ensures rapid dissolution, supporting the cultivation of fastidious bacteria without promoting overgrowth of contaminants.
Applications:
?? Nitrogen supplementation in vitamin bioassay media (e.g., for thiamine, riboflavin, and tryptophan per USP/EP methods)
?? Preparation of antibiotic susceptibility testing media and fermentation broths for bacteria like Lactobacillus and Streptococcus
?? Component in selective agars and broths for clinical pathogens (e.g., Campylobacter in mCCDA, enteric bacteria in enrichment media)
?? Nutritional enhancement in food microbiology, dairy fermentation studies, and probiotic viability assessments
Key Features:
?? Exceptionally high water solubility (>20% w/v) for seamless integration into dehydrated or liquid media formulations
?? Vitamin- and tryptophan-free to enable accurate microbiological assays without exogenous nutrient interference
?? Balanced amino acid profile rich in essentials (e.g., leucine, lysine) but low in cystine; total nitrogen ?7%, amino nitrogen ?4.6%
?? Neutral pH range (5.0�7.0 in 2% solution) compatible with most culture media; low ash content (?42%) reduces precipitation
?? Validated in pharmacopeial standards (USP, EP, JP) and ATCC protocols for consistent performance in vitamin-free environments
Typical Specifications:
ParameterValue/RangeAppearanceOff-white to pale yellow powderTotal Nitrogen?7.0% (w/w)Amino Nitrogen?4.6% (w/w)Loss on Drying?5.0%Ash Content?42.0%pH (2% aqueous)5.0�7.0Solubility (in water)Freely soluble
Approximate Amino Acid Profile (% of total amino acids):
Alanine: 2.8%
Arginine: 3.6%
Aspartic Acid: 6.3%
Cystine: 0.3%
Glutamic Acid: 21.1%
Glycine: 1.8%
Histidine: 2.5%
Isoleucine: 5.0%
Leucine: 9.0%
Lysine: 7.5%
Methionine: 2.5%
Phenylalanine: 4.5%
Proline: 10.0%
Serine: 5.0%
Threonine: 4.0%
Tryptophan: <0.1% (negligible)
Tyrosine: 5.0%
Valine: 6.5%
(Profiles may vary slightly by manufacturer; sourced from typical commercial analyses for acid-hydrolyzed casein.)
Preparation:
As a dehydrated ingredient, weigh the required amount (typically 3�20 g/L depending on medium) and suspend in the specified volume of purified/distilled water for the culture medium formulation. Mix thoroughly; gentle heating (?50�C) may aid dissolution if clumping occurs, but avoid boiling to preserve amino acids. Adjust pH as needed for the final medium, then sterilize by autoclaving (121�C, 15 min) or filtration per recipe. For direct use in assays, prepare a 2% stock solution in sterile water, filter-sterilize, and store refrigerated. The solution should be clear, pale yellow, and free of particulates.
Storage:
Dehydrated powder: Store in a tightly closed, original container at room temperature (15�30�C), in a cool, dry place protected from moisture, light, and humidity; stable for 3�5 years or until the manufacturer's expiry date. Once opened, reseal immediately and use a desiccant if available to prevent hygroscopic clumping.
Prepared solutions: Refrigerate at 2�8�C and use within 1�2 weeks; discard if turbid, precipitated, or discolored.
?? For laboratory and research use only. Not for diagnostic procedures without proper validation. Not for human or veterinary consumption. May cause eye/skin/respiratory irritation�consult SDS for handling; wear gloves, protective eyewear, and lab coat. Dispose of as chemical waste per local regulations; not combustible but avoid dust inhalation. Profiles may vary; verify with supplier for specific lots.5.2s