Product Overview
Lysine, chemically known as 2,6-Diaminohexanoic Acid, is an essential basic amino acid. Lysine is considered the first limiting amino acid because its content in grain foods is very low and it is easily destroyed during processing. Lysine is essential for humans and mammals; it cannot be synthesized by the body and must be obtained from food. Lysine is mainly found in animal products and legumes, with very low levels in grains. It plays a significant nutritional role in promoting growth, enhancing immunity, fighting viruses, aiding fat oxidation, and alleviating anxiety. Additionally, lysine improves the absorption of certain nutrients and works synergistically with other nutrients to enhance their physiological functions.
Lysine Production Process
The biosynthesis pathway of lysine was gradually clarified after the 1950s. Lysine biosynthesis differs among microorganisms. In bacteria, lysine is synthesized from diaminopimelic acid (DAP). In yeasts and molds, lysine is synthesized from α-aminoadipic acid. Different bacteria have different regulatory mechanisms for lysine biosynthesis.
Aspartic Acid Pathway
Aspartic acid reacts to form diaminopimelic acid (DAP), which then synthesizes lysine. In yeast, lysine synthesis requires aspartic acid to react to form α-aminoadipic acid. α-aminoadipic acid is then catalyzed by genes such as lysX, lysZ, lysY, lysJ, argD, lysK, and argE to produce acetylated intermediates like N-acetyl-L-α-aminoadipic acid and ultimately lysine.
α-Aminoadipic Acid Pathway
Synthesized from 2-ketoglutaric acid and acetyl-CoA through the α-aminoadipic acid pathway. This involves five steps catalyzed by isocitrate synthase, aconitase, and α-ketoglutarate dehydrogenase, producing α-aminoadipic acid from 2-ketoglutaric acid and acetyl-CoA. In the second reaction, α-aminoadipic acid is converted to lysine by α-aminoadipate reductase, yeast lysine reductase, and yeast lysine dehydrogenase.
Fermentation Process
Lysine fermentation methods include the two-step fermentation method (also known as precursor addition) and direct fermentation.
Two-Step Fermentation
Developed in the early 1950s, this method uses the lysine precursor, diaminopimelic acid, which is decarboxylated by microbial enzymes (diaminopimelic acid decarboxylase) to produce lysine. Since diaminopimelic acid is also produced via fermentation, it's known as the two-step fermentation method. In the 1970s, Japan improved this process by using immobilized diaminopimelic acid decarboxylase or microbial cells containing this enzyme for continuous lysine production. Despite these improvements, the process is still complex and has been largely replaced by direct fermentation methods.
Direct Fermentation
A widely used method for lysine production, utilizing inexpensive sugar sources like molasses from sugarcane or beets, starch hydrolysates, and other materials such as acetic acid and ethanol. The main microorganisms used are mutants of Corynebacterium glutamicum, Brevibacterium lactofermentum, and Lactobacillus casei. Developed in the late 1950s and matured in the 1970s with advancements in breeding technology, this method has significantly increased lysine yields. The highest acid production rate in industrial production has reached 100-120g per liter of fermentation, with extraction rates of about 80%-90%.
Lysine Benefits and Uses
Lysine helps regulate metabolic balance and provides structural components for carnitine synthesis, which aids in fatty acid synthesis in cells. Adding small amounts of lysine to food stimulates pepsin and gastric acid secretion, enhancing gastric fluid secretion, and promoting appetite and growth in children. Lysine also improves calcium absorption and accumulation, accelerating bone growth. A deficiency in lysine can lead to poor appetite, nutritional anemia, and developmental issues due to inadequate gastric fluid secretion. In medicine, lysine is used as an adjunct to diuretics for treating lead poisoning caused by reduced chloride levels in the blood, and can mitigate adverse reactions with acidic drugs (e.g., salicylic acid). It also helps reduce severe hypertension when combined with methionine and may accelerate recovery from herpes infections and suppress recurrence.
Lysine Applications
Food, feed additives, etc.
Lysine Packaging and Storage
Storage Conditions: Store sealed, protected from light, and away from high temperatures in a dry, cool, and well-ventilated place.
Packaging: Bulk: 25kg/board drum; Samples: 1kg/aluminum foil bag, custom packaging available.
Shipping: Express or logistics; domestic express delivery within three days, logistics within five days. Prices generally include domestic shipping costs.
Shelf Life: Two years
Food Sources
Lysine is one of the components of proteins and is present in protein-rich foods. Foods high in lysine include animal products (such as lean meats, fish, shrimp, crab, shellfish, eggs, and dairy products) and legumes (including soybeans and various beans and their products). Nuts like almonds, hazelnuts, peanuts, and pumpkin seeds also have high lysine content. Lysine content in grains is very low and can be destroyed during processing, making it the first limiting amino acid in grains.
