L-Glutamine(56-85-9)

Production method: L-glutamine widely exists in nature. For example, it is contained in pumpkin and sunflower seedlings in free state, and its N-ethyl compound (theanine) is contained in tea. Although glutamine can be extracted from natural products, fermentation and synthesis methods are used for mass production. 1. The synthesis method is obtained by condensation, addition, salification and hydrolysis of L-glutamic-5-methyl ester ([1499-55-4]). Glutamic acid is esterified with methanol in the presence of concentrated sulfuric acid, and the resulting esterified liquid drops are added to the mixture of methanol and carbon disulfide, and ammonia is added while dripping while cooling. After the esterification liquid drops are added, continue to add ammonia, then add triethylamine, and place it for 40 hours at 30 ℃. After decompression, concentration and ammonia removal γ- Methyl-L-glutamic acid-N-ammonium salt concentrate. Heat it to 40-45 ℃ and add acetic acid. After stirring for 30min, remove carbon disulfide under reduced pressure, and a large number of crystals are formed at this time. Then add the same volume of methanol, place at 0 ℃ for 12h, and filter to obtain the crude glutamine. The finished product is obtained by decolorization and recrystallization of activated carbon. 2. The fermentation method uses glucose or acetic acid and ethanol as the carbon source of the culture medium, and ferments with Brevibacterium flavum. The yield is 39 g/L based on glucose, and the yield is 39%