Production Process of L-Arginine Hydrochloride

1. Modern Main Process: Microbial Fermentation Method

Flow Chart

Detailed Steps

1. Strain & Fermentation

• Strains: Corynebacterium glutamicum, Brevibacterium flavum (mutant strains)
• Raw materials: Glucose, corn steep liquor, urea, inorganic salts
• Fermentation conditions: 30–32 °C, aeration culture, 48–72 h

2. Pretreatment of Fermentation Broth

• Heating to inactivate enzymes
• Filtration (plate-and-frame or membrane filtration) to remove thalli
• Obtain clear supernatant containing L-arginine

3. Ion Exchange Resin Separation

• Adsorb L-arginine using strong-acid cation exchange resin
• Elute with ammonia water or sodium hydroxide solution
• Collect high-purity L-arginine eluate

4. Neutralization and Salt Formation

• Add high-purity hydrochloric acid to adjust pH to 4.0–4.5
• Reaction:
  L‑Arginine + HCl → L‑Arginine Hydrochloride

5. Decolorization & Concentration

• Decolorize with activated carbon, filter
• Concentrate under reduced pressure at 60–70 °C

6. Crystallization & Drying

• Cool to crystallize, centrifuge to get wet crystals
• Wash with ethanol
• Vacuum dry at ≤80 °C
• Mill and sieve to obtain final product

2. Traditional Process: Protein Hydrolysis Method

1. Acid Hydrolysis

• Raw materials: gelatin, hair, blood powder
• Hydrolyze with concentrated HCl at 116–122 °C for 12–16 h

2. Isolation using Benzaldehyde

• Adjust to alkaline pH, add benzaldehyde to form benzylidene arginine precipitate

3. Decomposition & Salt Formation

• Hydrolyze the precipitate with HCl to release L‑arginine
• Neutralize, concentrate, crystallize to get L‑arginine hydrochloride

3. Key Quality Control Points

• pH value: 4.0–4.5
• Assay (HPLC): ≥99.0%
• Heavy metals: ≤10 ppm
• Loss on drying: ≤0.5%
• Residue on ignition: ≤0.1%