Co-upgrading of ethanol-assisted depolymerized lignin: A new biological lignin valorization approach for the production of protocatechuic acid and polyhydroxyalkanoic acid. (October 2021)

• Record Type: Journal Article
• Authors: Nguyen, Linh Thanh; Tran, My Ha; Lee, Eun Yeol
• Is Part Of: Bioresource technology. Volume 338(2021)
• Publication Date: 2021-10
• Subjects: Co-upgrading -- Lignin valorization -- Polyhydroxyalkanoic acid -- Protocatechuic acid -- Ethanol utilization; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2021.125563
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Ethanol-assisted depolymerized lignin (EDL) was obtained using ethanol as the solvent. Effective co-utilization of ethanol and EDL was conducted using P. putida KT2440. A biological co-upgrading strategy using EDL as the feedstock was demonstrated. Utilization of formaldehyde, a bypass product, promoted cell growth in EDL. Biological production of PCA and biodegradable PHA from EDL has been demonstrated. Abstract: This study presents a promising biological co-upgrading of ethanol-assisted depolymerized lignin (EDL) into protocatechuic acid (PCA) and polyhydroxyalkanoic acid (PHA) without any separation process. A depolymerized alkali lignin containing various G-lignin-type monomers at a concentration of 77 mg/mL was used for co-upgrading. An engineered Pseudomonas putida KT2440 strain was constructed by knocking out the protocatechuate 3, 4-dioxygenase, expression of the formaldehyde utilization pathway, and the expression of aldehyde dehydrogenase to enhance the efficiency of the ethanol utilization pathway. The growth and production of value-added bioproducts have been promoted by the utilization of formaldehyde, resulted in 6.73 ± 0.26 mg/L of PCA with a 17.5% (w/w) yield of total lignin monomers, and 303.66 ± 26.75 mg/L of PHA with 21.26% (w/w) of dry cell weight from 0.5 mL EDL. Moreover, the ethanol solvent used for lignin depolymerization was also utilized along with depolymerized lignin for co-upgrading to value-added products.