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 present disclosure relates to a genetically modified microbial cell that includes a first genetic modification resulting in the expression of an exogenous vanillate demethylase, such that the microbial cell is capable of metabolizing an S-lignin decomposition product and producing 2-pyrone-4,6-dicarboxylate (PDC).

The present disclosure relates to a genetically modified microbial cell that includes a first genetic modification resulting in the expression of an exogenous vanillate demethylase, such that the microbial cell is capable of metabolizing an S-lignin decomposition product and producing 2-pyrone-4,6-dicarboxylate (PDC).

The present disclosure relates to a genetically modified microbial cell that includes a genetic modification resulting in the expression of a vanillate demethylase, where the microbial cell is capable of metabolizing at least one S-lignin decomposition molecule including at least one of syringate and/or 3-O-methyl gallate, and the genetically modified microbial cell is capable of producing gallate. In some embodiments of the present disclosure, the vanillate demethylase may include VanAB.

A method for producing an objective substance such as vanillin and vanillic acid is provided. An objective substance is produced from a carbon source or a precursor of the objective substance by using a microorganism having an objective substance-producing ability, which microorganism has been modified so that the activity of enolase is reduced.

The present disclosure relates to a genetically modified microbial cell that includes a genetic modification resulting in the expression of a vanillate demethylase, where the microbial cell is capable of metabolizing at least one S-lignin decomposition molecule including at least one of syringate and/or 3-O-methyl gallate, and the genetically modified microbial cell is capable of producing gallate. In some embodiments of the present disclosure, the vanillate demethylase may include VanAB.

A method for producing an objective substance such as vanillin and vanillic acid is provided. An objective substance is produced from a carbon source or a precursor of the objective substance by using a microorganism having an objective substance-producing ability, which microorganism has been modified so that the activity of an L-cysteine biosynthesis enzyme is increased.

A method for producing an objective substance such as vanillin and vanillic acid is provided. An objective substance is produced from a carbon source or a precursor of the objective substance by using a microorganism having an objective substance-producing ability, which microorganism has been modified so that the activity of enolase is reduced.