title: Metabolic production of a novel polymer feedstock, 3-carboxy muconate, from vanillin.
abstract: Vanillin can be produced on a commercial scale by depolymerising renewable lignin. One product of microbial metabolism of vanillin by common soil microbes, such as Acinetobacter baylyi, is a tricarboxylic acid with a butadiene backbone known as 3-carboxy muconate (3CM). Three enzymes, 4-hydroxy benzaldehyde dehydrogenase, vanillate monooxygenase and protocatechuate 3,4-dioxygenase, catalyse the biotransformation of vanillin to 3CM. These three enzymes were metabolically engineered into an Escherichia coli host, giving a biocatalyst that converted vanillin into 3CM. The biocatalyst was found to give 100% yield of 3CM from 1 mM of vanillin after 39 h. The rate-limiting reaction was identified as the conversion of vanillate to 3,4-dihydroxybenzoate catalysed by vanillate monooxygenase. Low expression of the reductase subunit of this enzyme was identified as contributing to the reduced rate of this reaction. Proof of principle of a novel application for 3CM was demonstrated when it was converted into a trimethyl ester derivative and copolymerised with styrene.
authors.affiliation: Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia. agosling@unimelb.edu.au
authors.forename: Aaron
authors.initials: A
authors.lastname: Gosling
authors.forename: S Jane
authors.initials: SJ
authors.lastname: Fowler
authors.forename: Michael S
authors.initials: MS
authors.lastname: O'Shea
authors.forename: Melissa
authors.initials: M
authors.lastname: Straffon
authors.forename: Geoff
authors.initials: G
authors.lastname: Dumsday
authors.forename: Michael
authors.initials: M
authors.lastname: Zachariou
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry / Q000378:metabolism*; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism*; D001711:Biotransformation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005818:Genetic Engineering; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: C558759:3-carboxymuconate; D001547:Benzaldehydes; D001704:Biopolymers; C100058:vanillin; D013011:Sorbic Acid