Integrated process development for grass biomass utilization through enzymatic saccharification and upgrading hydroxycinnamic acids via microbial funneling

• Published in: Bioresource technology 2022-11, Vol.363, p.127836-127836, Article 127836
• Main Authors: Suzuki, Yuzo, Okamura-Abe, Yuriko, Otsuka, Yuichiro, Araki, Takuma, Nojiri, Masanobu, Kamimura, Naofumi, Masai, Eiji, Nakamura, Masaya
• Format: Article
• Language: English
• Subjects: (4S)-3-Carboxymuconolactone; 2-Pyrone-4,6-dicarboxylic acid; alkali treatment; bamboos; biomass; crosslinking; Grass biomass; grasses; Hydroxycinnamic acids; lignin; lignocellulose; Microbial funneling; Pseudomonas putida; rice straw; saccharification
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127836

[Display omitted] •Hydroxycinnamic acids can be easily extracted from grass biomass.•Hydroxycinnamic acids were converted to single intermediate via microbial funneling.•PDC is a promising building block for bio-based polymers.•4S-3CML is a promising chiral building block for bio-based polymers.•Hydroxycinnamic acids extraction improved enzymatic accessibility of lignocellulose. In grass biomass, hydroxycinnamic acids (HCAs) play crucial roles in the crosslinking of lignin and polysaccharides and can be easily extracted by mild alkaline pretreatment, albeit heterogeneously. Here, HCAs were extracted from bamboo and rice straw as model grass biomass with different HCAs composition, and microbial funneling was then conducted to produce 2-pyrone-4,6-dicarboxylic acid (PDC) and (4S)-3-carboxymuconolactone (4S-3CML), promising building blocks for bio-based polymers, respectively. Pseudomonas putida PpY1100 engineered for efficient microbial funneling completely converted HCAs to PDC and 4S-3CML with high titers of 3.9–9.3 g/L and molar yields of 92–99%, respectively. The enzymatic saccharification efficiencies of lignocellulose after HCAs extraction were 29.5% in bamboo and 73.8% in rice straw, which are 8.9 and 6.8 times higher than in alkaline-untreated media, respectively. These results provide a green-like process for total valorization of grass biomass through enzymatic saccharification integrated with upgrading heterogeneous HCAs to a valuable single chemical via microbial funneling.