Abstract: The invention relates to a process for biochemical synthesis of 1,4-butanediamine in a microorganism having an increased level of an ornithine decarboxylase activity (increased ODC activity) as compared to the native level of the ornithine decarboxylase activity, wherein the increased ODC activity is obtained by means of overexpression of an ornithine decarboxylase encoding gene with increased translational and/or transcriptional efficiency, and wherein 1,4-butanediamine produced in the microorganism is excreted into a fermentation broth, and is recovered from the fermentation broth. In preferred embodiments also increased enzyme activity is obtained by of overexpression of either (i) an arginine decarboxylase encoding gene speA and an agmatinase encoding genespeB; or (ii) an arginine decarboxylase encoding gene speA and an agmatine iminohydrolase encoding gene aguA, and an N-carbamoylpotrescine amidohydrolase encoding geneaguB, and optionally also an agmatinase encoding gene speB.

Abstract: The invention relates to isolated mutants of enzymes from the group of 2-deoxy-D-ribose 5-phosphate aldolase wild-type enzymes having a productivity factor (as determined by a specific test) which is at least 10% higher than the productivity factor for the corresponding wild-type enzyme from which it is a mutant. The mutants have at least one amino acid substitution at one or more of the positions corresponding to K13, T19, Y49, N80, D84, A93, E127, A128, K146, K160, I166, A174, M185, K196, F200, and S239 in Escherichia coli K12 (EC 4.1.2.4) wild-type enzyme sequence, and/or a deletion of at least one amino acid at the positions corresponding to S258 and Y259 therein, optionally combined with, specific, C-terminal extension and/or N terminal extension.

Abstract: The invention relates to a process for the biosynthetic production of 4-amino-4-deoxychorismate (ADC) performed fermentatively in vivo with a 4-amino-4-deoxychorismate synthase, preferably a PabAB bipartite protein (which may be a fusion protein), at an increased level of activity, thereby obtaining a broth comprising ADC and 4-amino-4-deoxyprephenate (ADP), that are recovered. The invention also relates to a further process of converting the ADP into p-aminophenylalanine. The invention, moreover relates to biosynthetic production of [3R,4R]-4-amino-3-hydroxycyclohexa-1,5-diene-1-carboxylic acid (3,4-CHA), by concerted action of such 4-amino-4-deoxychorismate synthase and of an enzyme capable of converting isochorismate into [5S,6S]-5,6 dihydroxycyclohexa-1,3-diene-1-carboxylic acid (2,3-CHD), preferably a phenazine biosynthesis protein PhzD, including recovery of 3,4-CHA. The invention also relates to expression vectors and host cells for use in any of such processes.