Preparation of 1,4-diaminobutane
The present invention relates to a novel method for the preparation of 1,4-diaminobutane [DAB]. The method according to the present invention involves at least one biocatalytic step which comprises the biocatalytic production of at least one N-protected precursor of DAB. The present invention also relates to a method for the preparation of DAB involving at least one biocatalytic step, and comprising the steps of a) biocatalytically preparing an N-protected precursor of DAB yielding a—biocatalytic reaction mixture containing the N-protected precursor of DAB, b) recovering the N-protected precursor from the biocatalytic reaction mixture and c) converting the N-protected precursor into DAB. More in particular, the present invention relates to a method for the preparation of DAB, wherein the at least N-protected precursor of DAB is selected from the group consisting of N5-protected ornithine, N-protected DAB, and N-protected 4-aminobutyraldehyde.
1. An in vitro method for the preparation of 1,4-diaminobutane [DAB] comprising
a) enzymatically preparing N-acetyl DAB which comprises a step of contacting N 5 -acetyl ornithine with a decarboxylase (EC 4.1.1), or a step of contacting N-acetyl-4-aminobutyraldehyde with an aminotransferase (EC 2.6.1) to produce an enzymatic reaction mixture
(b) recovering the N-acetyl-DAB from the enzymatic reaction mixture, and
(c) converting the recovered-N-acetyl-DAB into DAB in an in vitro process comprising at least one further step which is an enzymatic conversion comprising contacting N-acetyl DAB with a hydrolytic enzyme selected from the group consisting of carboxylic ester hydrolases (E.C. 3.1.1), thiolester hydrolases (E.C. 3.1.2) and peptidases (E.C 3.4), or a chemical conversion involving deacylation by (PhO) 3 PCl 2 reagent.
2. The in vitro method according to claim 1 , wherein in the recovery of the N-acetyl-DAB from the enzymatic reaction mixture is carried out by at least one step selected from the group consisting of filtration, sedimentation, crystallization, affinity chromatography, size exclusion chromatography, membrane separation and evaporation.
3. The in vitro method for the preparation of DAB according to claim 1 , wherein the enzymatic conversion comprises contacting said N-acetyl-DAB with a hydrolytic enzyme.
4. The in vitro method according to claim 3 , wherein the hydrolytic enzyme is a peptidase selected from the group of a serine carboxypeptidase, a metallocarboxypeptidase, a cysteine carboxypeptidase, a serine endopeptidase, a cysteine endopeptidase, an aspartic endopeptidase and a metalloendopeptidase.
5. The in vitro method according to claim 4 , wherein the hydrolytic enzyme is a serine endopeptidase.
6. The in vitro method according to claim 5 , wherein the serine endopeptidase is a subtilisin.
7. The in vitro method according to claim 5 , wherein the serine endopeptidase is subtilisin Carlsberg.