Naofumi Kamimura, Mina Endo, Banri Nakamura, Takuya Akiyama, Ryo Kato, Mitsuru Kawazoe, Masaya Fujita, Takuma Araki, Yuzo Suzuki, Tsuyoshi Michinobu, Yuichiro Otsuka, Masaya Nakamura, Eiji Masai
High Resolution Image Download MS PowerPoint Slide Microbial lignin valorization is promising, yet the heterogeneity of aromatic compounds generated from lignin depolymerization remains a significant challenge. Here, we engineered Sphingobium lignivorans SYK-6 to funnel aromatic mixtures in black liquor from oxygen-soda-anthraquinone pulping into the polymer building block 2-pyrone-4,6-dicarboxylic acid (PDC). In softwood (Japanese cedar) black liquor, rich in guaiacyl-type aromatics, a PDC hydrolase gene-deficient strain (Δ ligI ) achieved a 135% (mol/mol) PDC yield based on identified compounds, suggesting conversion of unidentified aromatics, potentially including oligomers. Hardwood (birch) black liquor contains abundant syringyl-type aromatics metabolized via branched pathways in SYK-6. By identifying a previously unidentified catabolism gene ( desY ) and disrupting ligI, ligM, and desY, we redirected metabolic flux toward PDC, obtaining a 91% (mol/mol) PDC yield from syringic acid and 62% from birch black liquor. These results demonstrate the strong potential of engineered SYK-6 for efficient PDC production from diverse lignin streams through biological funneling.