Biochemical production of bio-based terephthalic acid from lignocellulosic biomass for CO2 emission reduction

Terephthalic acid, a key precursor for polyester production, is traditionally derived from fossil resources, contributing to global warming. Although numerous studies have explored the production of terephthalic acid from biomass polysaccharides, energy-intensive chemical processes are predominantly employed. In this study, we have developed a biochemical process to produce bio-based terephthalic acid from lignocellulosic biomass for reducing CO2 emissions. Among the tested six underutilized lignocellulosic biomasses, hardwood, with high cellulose contents of 52.8%, was subjected to alkaline pretreatment (165 °C for 2.5 hr) to eliminate lignin, and the resulting water-insoluble fraction was hydrolyzed by cellulases to yield monosaccharides. These monosaccharides were then biochemically transformed into terephthalic acid via p-tolualdehyde using two microorganisms, Phlebia sp. (a p-tolualdehyde-producing strain) and Comamonas testosteroni DSM6577. Comamonas testosteroni DSM6577 was used to oxidize the side chains of p-tolualdehyde into carboxylic acid to obtain terephthalic acid. This report describes the successful production of small amounts of bio-based terephthalic acid from lignocellulosic biomass. One-Sentence Summary: This paper shows that terephthalic acid, a key precursor for polyester production, can be produced from lignocellulosic biomass by microbial fermentation, which would contribute to reduce CO2 emission compared with other previous processes.