Fermentation lysine

If a pathway is branched, a decrease in the concentration of one end product often causes the accumulation of another end product. A commercially important example of this principle is the lysine fermentation. Lysine is a member of the aspartic add family in which... 

H2N-CH2 [CH2j3.CH(NH2) COOH. Colourless needles, m.p. 224 C (decomp.), very soluble in water, insoluble in alcohol. L-(-H)-Lysine is one of the basic amino-acids occurring in particularly large quantities in the protamine and histone classes of proteins. It is an essential amino-acid, which cannot be synthesized by the body and must be present in the food for proper growth. It can be manufactured by various fermentation processes or by synthesis. 

After recovery of L-lysine, the residual dl-(49) is epimerized to a mixture of the DL and meso isomers, and the latter is subjected to the same decarboxylation step. This reaction is a part of a microbial process in which glucose is fermented by a lysine auxotroph of E. coli to meso- which accumulates in the medium. Meso-(49) is quantitatively decarboxylated to L-lysine by cell suspensions oi erobacteraerogenes (93). However, L-lysine and some... 

Molasses is also used as an inexpensive source of carbohydrate in various fermentations for the production lactic acid, citric acid, monosodium glutamate, lysine, and yeast (60). Blackstrap molasses is used for the production of mm and other distilled spirits. 

Many products made by fermentation are also based on the conversion of starch. Some examples of the use of enzymatically hydrolyzed starches are the production of alcohol, ascorbic acid, enzymes, lysine, and penicillin. 

The fermentation wastes Corynebacterium glutamicum biomass) were obtained in a dried powder form from a lysine fermentation industry (BASF-Korea, Kunsan, Korea). The protonated biomass was prepared by treating the raw biomass with a 1 N HNO3 solution for 24 h, thereby replacing the natural mix of ionic species with protons. The resulting C glutamicum biomass was dried and stored in a desiccator and used as a biosorbent for the sorption experiments. 

R. D. Kiss and G. N. Stephanopolous, Metabolic activity control of the L-lysine fermentation by restrained growth fed-batch strategies, Biotechnol Prog. 7, 501-509 (1991). 

One interesting paper addresses amino acid production.37 The authors describe a fed-batch process for production of amino acids, such as L-lysine (from Corynebacterium glutamicium) and L-threonine (from Escherichia coli). For the fermentation broth of the L-lysine, the optical density, ammonium, and L-lys were measured. For L-threonine, OD, ammonium, and L-thr were measured. For all materials, the values were deemed acceptable and comparable with the reference methods. 

Condensation products of DHB (which usually is found also in the fermentation broth) with amino acids were reported, viz. with glycine ixom Bacillus subtilis (164) named subsequently itoic acid (282) with serine from Escherichia coli (261) and Klebsiella oxytoca (196) with threonine from Klebsiella oxytoca (196) and Rhizobium spp. (275, 327) with arginine from Pseudomonas stutzeri (62) with glycine and threonine from Rhizobium sp. (240) with threonine and lysine as well as with leucine and lysine from Azospirillum lipoferum (312, 320). In most cases the isolate (sometimes designated as being a siderophore) was hydrolyzed and the constituents were determined by paper chromatography. The relative amounts of the constituents, the chiralities of the amino acids and the molecular mass of the isolate have not been determined. Hence it is not known whether condensation products of the enterobactin type exist. 

The complicated technology used makes this approach economically uncompetitive with fermentation processes for the production of natmally occurring amino acid, such as L-phenylalaitine, L-glutamic acid or L-lysine, for which large markets exist, and for which significant economies of scale in production costs can thus be gained. 

L-Lysine is an essential amino acid and is used in veiy large quantities to supplement human foods and animal feeds so as to improve their nutritional quality. Efficient fermentation for its production have been developed in Japan. An alternative production process method involves first the chemical synthesis of DL-df-amino-... 

The competition is with fermentation processes which rely on the over-prodnction of L-lysine from cheap glucose sources by Corymbacterium glutamicum strains nsed on a 500 m scale and producing ca. 120 g/1 lysine. In some cases the lysine is nsed in the form of a spray-dried fermentation broth containing lysine snlphate. 

Well developed and large scale fermentation processes to produce several amino acids snch as lysine, had already been developed. This know-how was then used as a basis to develop very cost-effective L-phenylalanine fermentation processes. 

Removal of the hulls is important to reduce oxalic acid content, increase protein content (72) and increase digestibility (74). Sesame proteinTas low solubility, and one method of increasing solubility is with partial enzymatic hydrolysis (75,). Hydrolysis with fungal enzymes increased the soluble protein content of sesame meal from 7.21 to 64.14%, values considered comparable to those in soy due to the tempeh fermentation. Increased lysine in the hydrolysis extract was accompanied by decreased methionine. 

The product is hydrolyzed and oxidized to glutaryl-CoA, rejoining the pathways shown in Fig. 24-15. A remarkable and very different approach to lysine breakdown has been developed by clostridia which obtain energy from the fermentation of Eq. 24-31 ... 

L-Lysine. Hd io3 Fermentation (AM) First limiting amino acid for cereals... 

That summary is based on the reports of a well-conceived and carefully executed research program carried out by Rohan. Mohr et al. (7) extended these studies and was able to draw additional conclusions. First, without exception, free amino acids are much more sensitive to destruction in this system than the peptide-bound amino acids. Second, differences in the stability of amino acids under these conditions are not great —from 25% loss for isoleucine to 68.5% for lysine, over a relatively short period of time. In this system the reducing sugars must be the limiting factor, since the glucose and fructose are completely destroyed or removed. Third, neither cystine nor cysteine are reported to be present, and the only other sulfur-containing amino acid, methionine, is present at a much lower concentration than any other amino acid. Clearly, as we shall see later, cocoa would probably have a considerably different flavor if cysteine or cystine were present in the fermented beans. 

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