The utilization of biomass resources in valuable fuels and industrial products is becoming important aspect for conversion from nonrenewable resources to renewable bioresources. Lignin is one of the most important renewable carbon resources, existing in woody plants at 15-30% by dry weight. Aromatics from agricultural wastes are also important resources. Microbial conversion known as “biological funneling” is attracting great attention as a practical way to produce platform chemicals such as 2-pyrone-4,6-dicarboxylic acid (PDC), 3-carboxymuconolactone (3-CML), Muconolactone (KEL) and β-ketoadipic acid (β-KA) from lignin.
In this study, we developed a gene-modified bacterial fermentation system for production of PDC, 3-CML, KEL and β-KA.from various low-molecular-weight aromatic compounds generating by chemical treatment of lignin, alkaline extract from agricultural wastes.
First of all, We focused on PDC as a raw material for novel bio-based polymers. PDC 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. Gene coding for the metabolic enzymes that act on aromatic compounds from SYK-6, were inserted into a broad host-range plasmid vector pKT230MC. The resulting plasmid pKTVPVABC was introduced into Pseudomonas putida strain PpY1100. Gene-modified PpY1100 reliably produced and accumulated PDC from various lignin-derived monoaryls including vanillin, vanillic acid, syringaldehyde, and syringic acid.
Polyester consisted of PDC was synthesized. Tenacious adhesion properties of bio-based polyesters as high as about 30 ~ 60 MPa against several metals were reported.