The present invention provides a nitrilase mutant protein with increased thermal stability and its application in the synthesis of an anti-epileptic drug intermediate, wherein the mutant is obtained by mutating one or two of the amino acids at position 151, 223 and 205 of the amino acid sequence shown in SEQ ID No. 2. the thermal stability of the nitrilase mutant AcN-T151V/C223A/C250G was increased by up to 1.73 folds. The yield of the final product was up to 95% using the recombinant Escherichia coli containing the nitrilase mutant to hydrolyze 1M 1-cyanocyclohexylacetonitrile to produce 1-cyanocyclohexyl acetic acid at 35° C. And the yield of the final product was up to 97% when hydrolyzing 1.2M 1-cyanocyclohexylacetonitrile at 35° C. The final yield was up to 80% when using the nitrilase mutants obtained by the present invention to synthesize gabapentin.

The present invention provides a polypeptide tag and its application in the synthesis of pharmaceutical chemicals, the recombinant nitrilase was obtained by connecting a polypeptide tag to the N-terminus of the amino acid sequence of the nitrilase; wherein amino acids at both ends of the polypeptide tag are uncharged glycine G, and the rest are a random combination of any one or more of glycine G, histidine H, glutamic acid E, aspartic acid D, lysine K and arginine R; The activity of the recombinant nitrilase in the preparation of 1-cyanocyclohexyl acetic acid is up to 3034.7 U/g dcw, the polypeptide tag significantly improves the soluble expression of nitrilase, and the whole cell catalyst hydrolyzes 1M substrate with the same concentration 30 minutes faster than the mother enzyme. The method provided by the present invention can also be used for the biocatalytic reaction of other pharmaceutical intermediates as the substrate catalyzed by the nitrilase, improving the activity of the whole cell catalyst in reaction, and also improving the solubility of other types of nitrilases and the activity of the corresponding whole cell catalysts.

Described herein are methods for the production of 4-cyano benzoic acid or salts thereof from terephthalonitrile using nitrilase as catalyst. Also described herein are compositions including 4-cyano benzoic acid.

The present invention relates to a process for preparing ammonium (meth-) acrylate, aqueous ammonium (meth-) acrylate solutions obtainable by such process, and (meth-) acrylic acid homopolymers or copolymers obtainable by polymerizing such ammonium (meth-) acrylate. The invention furthermore relates to a modular, relocatable bioconversion unit for manufacturing aqueous ammonium (meth-) acrylate solutions.

A strain of Rhodococcus rhodochrous in which a gene coding at least part of a nitrile hydratase enzyme or any gene coding a protein involved in the transcription, translation or formation of at least part of the nitrile hydratase enzyme has been deactivated or rendered ineffective or a strain of Rhodococcus rhodochrous cultured under condition wherein the nitrile hydratase enzyme is been inhibited.

Described herein are methods for the production of ammonium acrylate or salts thereof from acrylonitrile using nitrilase as a catalyst.

The present invention discloses encoding genes of nitrilase mutants and application thereof. The nucleotide sequence of the gene is shown in SEQ ID No.5, and the amino acid sequence of the mutant is shown in SEQ ID No.6. In the present invention, by the protein molecular modification, thermostability of the purified nitrilase LNIT5 is increased by up to 4.5 folds; and by utilizing recombinant E. coli containing the nitrilase mutant to hydrolyze 1-cyanocyclohexylacetonitrile at a high temperature, product tolerance is increased, activity of NIT5-L201F is increased by 20%, and the mutant NITLNIT5-AcN can completely hydrolyze 750 mM 1-cyanocyclohexylacetonitrile within 8 hours and achieve an doubled conversion rate. Therefore, the mutants obtained by the present invention have a good application prospect in efficiently catalyzing 1-cyanocyclohexylacetonitrile to synthesize gabapentin intermediate, 1-cyanocyclohexyl acetic acid.

The present invention provides a polypeptide tag and its application in the synthesis of pharmaceutical chemicals, the recombinant nitrilase was obtained by connecting a polypeptide tag to the N-terminus of the amino acid sequence of the nitrilase; wherein amino acids at both ends of the polypeptide tag are uncharged glycine G, and the rest are a random combination of any one or more of glycine G, histidine H, glutamic acid E, aspartic acid D, lysine K and arginine R; The activity of the recombinant nitrilase in the preparation of 1-cyanocyclohexyl acetic acid is up to 3034.7 U/g dcw, the polypeptide tag significantly improves the soluble expression of nitrilase, and the whole cell catalyst hydrolyzes 1M substrate with the same concentration 30 minutes faster than the mother enzyme. The method provided by the present invention can also be used for the biocatalytic reaction of other pharmaceutical intermediates as the substrate catalyzed by the nitrilase, improving the activity of the whole cell catalyst in reaction, and also improving the solubility of other types of nitrilases and the activity of the corresponding whole cell catalysts.

The present invention discloses encoding genes of nitrilase mutants and application thereof. The nucleotide sequence of the gene is shown in SEQ ID No. 5, and the amino acid sequence of the mutant is shown in SEQ ID No. 6. In the present invention, by the protein molecular modification, thermostability of the purified nitrilase LNIT5 is increased by up to 4.5 folds; and by utilizing recombinant E. coli containing the nitrilase mutant to hydrolyze 1-cyanocyclohexylacetonitrile at a high temperature, product tolerance is increased, activity of NITS-L201F is increased by 20%, and the mutant NITLNIT5-AcN can completely hydrolyze 750 mM 1-cyanocyclohexylacetonitrile within 8 hours and achieve an doubled conversion rate. Therefore, the mutants obtained by the present invention have a good application prospect in efficiently catalyzing 1-cyanocyclohexylacetonitrile to synthesize gabapentin intermediate, 1-cyanocyclohexyl acetic acid.

The present invention discloses a recombinant vector constructed from an encoding gene of a nitrilase mutant, a recombinant genetic engineered strain and application thereof. the nucleotide sequence of the gene is shown in SEQ ID No.5, and the amino acid sequence of the mutant is shown in SEQ ID No.6. In the present invention, by the protein molecular modification, thermostability of the purified nitrilase LNIT5 is increased by up to 4.5 folds; and by utilizing recombinant E. coli containing the nitrilase mutant to hydrolyze 1-cyanocyclohexylacetonitrile at a high temperature (45° C.), product tolerance is increased, activity of NIT5-L201F is increased by 20%, and the mutant NITLNIT5-AcN can completely hydrolyze 750 mM 1-cyanocyclohexylacetonitrile within 8 hours and achieve an doubled conversion rate. Therefore, the mutants obtained by the present invention have a good application prospect in efficiently catalyzing 1-cyanocyclohexylacetonitrile to synthesize gabapentin intermediate, 1-cyanocyclohexyl acetic acid.