Threonine manufacture

Because of the simplicity of swiae and poultry feeds, most feed manufacturers add vitamins (qv) and trace minerals to ensure an adequate supply of essential nutrients. Amino acids (qv) such as methionine [7005-18-7] lysiae [56-87-17, threonine [36676-50-3] and tryptophan [6912-86-3], produced by chemical synthesis or by fermentation (qv), are used to fortify swiae and poultry diets. The use of these supplements to provide the essential amino acids permits diets with lower total cmde proteia coateat. 

Crystallization Method. Such methods as mechanical separation, preferential crystallisation, and substitution crystallisation procedures are included in this category. The preferential crystallisation method is the most popular. The general procedure is to inoculate a saturated solution of the racemic mixture with a seed of the desired enantiomer. Resolutions by this method have been reported for histidine (43), glutamic acid (44), DOPA (45), threonine (46), A/-acetyl phenylalanine (47), and others. In the case of glutamic acid, the method had been used for industrial manufacture (48). 

An estimation of the amount of amino acid production and the production methods are shown ia Table 11. About 340,000 t/yr of L-glutamic acid, principally as its monosodium salt, are manufactured ia the world, about 85% ia the Asian area. The demand for DL-methionine and L-lysiae as feed supplements varies considerably depending on such factors as the soybean harvest ia the United States and the anchovy catch ia Pern. Because of the actions of D-amiao acid oxidase and i.-amino acid transamiaase ia the animal body (156), the D-form of methionine is as equally nutritive as the L-form, so that DL-methionine which is iaexpensively produced by chemical synthesis is primarily used as a feed supplement. In the United States the methionine hydroxy analogue is partially used ia place of methionine. The consumption of L-lysiae has iacreased ia recent years. The world consumption tripled from 35,000 t ia 1982 to 100,000 t ia 1987 (214). Current world consumption of L-tryptophan and i.-threonine are several tens to hundreds of tons. The demand for L-phenylalanine as the raw material for the synthesis of aspartame has been increasing markedly. 

There are 22 different AAs in the body of the bird, 10 of which are essential AA (EAA arginine, methionine, histidine, phenylalanine, isoleucine, leucine, lysine, threonine, tryptophan and valine), i.e. cannot be manufactured by the body and must be derived from the diet. Cystine and tyrosine are semi-essential in that they can be synthesized from methionine and phenyla-... 

Near infra red reflectance spectroscopy (NIRS) is becoming increasingly used for the analysis of nutrients in feedstuffs. It is very rapid and cost-effective and may eventually replace the slower chemical methods of analysis used currently in the feed-manufacturing industry. NIRS may also be used for amino acid analysis. Another method now being adopted widely in feed manufacture is to use predichon equations based on chemical or NIRS analysis to predict amino acid contents of some feedstuffs. The NRC (1994) published equations for the predichon of lysine, tryptophan, threonine,... 

Amino Acids. Amino acids are produced by both fermentation and biocatalysis for use in animal feed, fertilizer, as flavor enhancers, dietary supplements, and in pharmaceutical manufacture. By volume, the most important products are L-lysine, L-methionine, L-threonine, and L-tryptophan, most of which are produced by fermentation. Biocatalysis still plays an important role in amino acid supply and has been used to synthesize both L- and D-amino acids, including a variety of nonnatural analogues. The major producers are Degussa, Tanabe Seiyaku, and Kyowa Hakko. 

Although all of the amino acids listed in Table SO-1 are present in the proteins of the human body, not all of them need to be in the food. Experiments have been carried out which show that nine of the amino acids are essential to man. 1 hese nine essential amino acids are histidine, lysine, tryptophan, phenylalanine, leucine, isoleucine, threonine, methionine, and valine. The human body seems to be able to manufacture the others, which are called the non-essential amino acids. Some organisms that we usually consider to be simpler than man have greater powers than the human organism, in that they are able to manufacture all of the amino acids from inorganic constituents. The red bread mold, Neurospora, has this power. 

Degussa/Rexim, partly in collaboration with Chinese manufacturers, produce (L)-threonine, (L)-valine and (L)-isoleucine by fermentation. [62] With genetically modified strains from Echerichia coli and Serratia marcescens, they are able to achieve end concentrations of 100 grams per litre. 

The enzymatic synthesis of peptides (Scheme 6.24) from which proteins can be constructed is not so limited, and chemical synthesis has an even wider application, but these are not yet suitable techniques for manufacture. Moreover, there are no general methods for building the peptides into full protein structures. Nevertheless, enzymes do have a role in the manufacture of peptides themselves. In a mixture of butan-l,4-diol and water, trypsin will catalyse the exchange of the carboxy-terminal alanine of porcine insulin with threonine t-butyl ester (Scheme 6.25). The reaction is essentially a transpeptidation in which the acyl group of lysine is transferred from one amino group on alanine to another on the threonine. This converts porcine insulin into the ester of the human hormone, and a simple deprotection yields one of the commercial products. 

In addition to the amino acid derived amino alcohols mentioned above, two other amino alcohols have been widely used ( R, 25)-ephedrine (8) which is a naturally occurring plant alkaloid, and the (5, 5)-amino diol (9) which is produced microbiologically as a byproduct from the manufacture of the antibiotic chloramphenicol. Note the presence of two adjacent [or contiguous] stereogenic centres in both these molecules, a useful feature also present in two of the amino acids, (5,5)-isoleucine (10) and (25,3/ )-threonine (11). The (/ )-amino alcohol (12) is also readily available in enantiomerically pure form. 

D-hydroxyphenylglycine, L-hydroxyproKne, L-isoleucine, L-lysine, L-ornithine, L-phenylalanine, o-phenylglycine, L-polylysine, L-proline, L-serine, L-threonine, L-tryptophan, and L-tyrosine) was investigated and successfully manufactured on an industrial scale. Glycine is produced by chemical methods because the molecule has no chiral center, and methionine is also produced by chemical methods in its racemic form because the main use of the amino acid is as feedstuff. o-Methionine is metabolized in animals by the action of D-amino acid oxidase. These amino acids were useful as sources of medicines, food additives, feed-stuffs, and starting materials for chemical synthesis. 

It is essential to feed poultry according to amino acids requirements to avoid excess and environmental pollution. Never before has the economic success of feed manufacturers been so heavily dependent on optimal and accurate amino acid composition as today (D Mello, 2003). The threonine (Thr) is important not only for protein deposition, but also for mucin production and digestive system (Ball et al., 1999). This study aimed to estimate the digestible Thr requirement for maintenance using adult roosters of different body weights and composition. 

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