Lignin is one of the most important carbon resources, existing in woody plants at 15-30% by dry weight. The effective utilization of lignin waste from pulp production and bio-ethanol fermentation has been main concern of the society. PDC, 2-pyrone-4,6-dicarboxylic acid is the terminal chemical substance of lignin bio-degradation before streaming into the TCA cycle in Sphingobium sp. SYK-6 and has never appeared in chemical synthesis. The metabolic conversion of lignin into stable and functional intermediates has been extensively investigated, and we recently reported the massive production of 2-pyrone-4,6-dicarboxylic acid (PDC) from lignin via protocatechuic acid by the action of transformed bacterium [1]. PDC consists of the polar pseudo-aromatic ring system and two carboxylic acids. By using it character as bi-functional monomer for stepwise polymerization, our group has synthesized the biomass-based polymer consisted of PDC [2]. In the presented study, the production of PDC from vanillic acid, one of the major component of monomeric lignin, by the combination of genes encoding demethylase, protocatechuate 4,5-dioxygenase, 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase in transgenic bacterium Pseudomonas putida PpY1100 and PDC polyester which has the tenacious adhesive property to metals and glasses was described.
We achieved enhanced production of PDC from vanillic acid with a yield of 50 g/L or more by hybrid metabolic function of Sphingobium sp. SYK-6 and P. putida PpY101.
Polyester consisted of PDC was synthesized [2]. Tenacious adhesion properties of bio-based polyesters as high as about 30 ~ 60 MPa against several metals were reported. Generally, the biomass-based materials are poor in terms of usefulness. The biomass-based material presented here is prospect for not only an alternative to petroleum one but also the useful material with higher quality compared to the ordinary one.