The present invention relates to the metabolic engineering of a microbial host for the synthesis of value-added products from oil palm empty fruit brunches (OPEFBs). In one embodiment, the genetically engineered microorganism is Escherichia coli comprising a metabolic pathway consisting of 9 enzymes (11 genes) to utilize depolymerized lignin, namely vanillin, p-coumaric acid, p-hydroxybenzaldehyde, vanillic acid, p-hydroxybenzoic acid and ferulic acid, to produce β-ketoadipic acid, which can be subsequently converted into commercially important derivatives such as adipic acid and levulinic acid. The enzymes are feruloyl-CoA synthetase (fcs), enoyl-CoA hydratase (ech), vanillin dehydrogenase (vdh), vanillate O-demethylase (vanA; vanA and vanB), p-hydroxy benzoate hydroxylase (pobA), protocatechuate 3,4-dioxygenase {pcaGH; pcaG and pcaH), 3-carboxy-cis, cis-muconate cycloisomerase (pcaB), 4-carboxymuconolactone decarboxylase (pcaC), and β-ketoadipate enol-lactone hydrolase (pcaD).

The invention relates to an Amycolatopsis strain derived from the Amycolatopsis Zyl 926 strain having at least one additional copy of the FCS and ECH genes encoding feruloyl-CoA-synthetase and enoyl-CoA-hydratase/aldolase integrated at the integration site of the C31 phage.

The invention also relates to the method for producing such strains, the integration cassette of the FCS and ECH genes, the use of said strains in a method for producing vanillin, and a method for producing vanillin.