A kind of phenylalanine lyase and its application in the preparation of d-tryptophan

Abstract

The invention relates to phenylalanine lyase and an application thereof to a D-tryptophan preparation, and belongs to the field of bioengineering. By an oriented evolving method, a high-vitality phenylalanine lyase mutant is obtained, genetic engineering escherichia coli is constructed, (E)-3-indole acrylic acid ammonification reaction is catalyzed, and D-tryptophan is generated. The enzyme activity of the mutant enzyme disclosed by the invention is notably improved compared with the enzyme activity of a wild enzyme; and through optimization of a reaction technology, the highest conversion rate in 24 hours can reach 95% or above, and the phenylalanine lyase has good industrial application prospects.

Description

technical field [0001] The invention belongs to the field of bioengineering and relates to the preparation of D-tryptophan, in particular to a phenylalanine lyase and its application in the preparation of D-tryptophan. Background technique [0002] D-tryptophan can be used as a feed additive and non-nutritive sweetener. It is also a non-protein active amino acid with the advantages of hypoallergenicity and drug resistance, so it has a large market in the feed industry and the pharmaceutical industry and application value. [0003] There are reports on the synthesis of D-tryptophan in China by enzymatic resolution, chemical resolution, enzymatic synthesis and asymmetric synthesis, and a small number of manufacturers have produced industrialized D-tryptophan. In the current synthetic methods of D-tryptophan, most of the resolving agents used in the chemical resolution method are more expensive, and have problems such as difficult separation, many steps, toxicity and environme...

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Problems solved by technology

In the current synthetic methods of D-tryptophan, most of the resolving agents used in the chemical resolution method are more expensive, and have problems such as difficult separation, many steps, toxicity and environmental pollution; most of the enzymatic resolution methods have the advantages of high cost, low Stability and other disadvantages; the chemical synthesis method has many steps, low yield, and organic reagents are easy to pollute the environment; while the enzymatic synthesis process is simple, specific, mild and does not pollute the environment, which meets the requirements of large-scale industrial production at home and abroad, but Most of the strains used are wild strains with low enzyme activity, long production cycle and small yield

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