Bio-separation of value-added products from Kraft lignin: A promising two-stage lignin biorefinery via microbial electrochemical technology

Abstract

The most ubiquitous aromatic biopolymer in nature, lignin offers a promising foundation for the development of bio-based chemicals with wide-ranging industrial uses attributable to its aromatic structure. Lignin must first be depolymerized into smaller oligomeric and monomeric units at the initial stage of lignin bioconversion, followed by separation to recover valuable products. This study demonstrates an integrative biorefinery idea based on in-situ depolymerization of the lignin via microbial electro-Fenton reaction in a microbial peroxide-producing cell and recovery of the identified products i.e., phenolic or aromatic monomers by one step high throughput chromatography. The yield percentage of acetovanillone, ethylvanillin, and ferulic acid recovered from the depolymerized lignin using the integrative biorefinery strategy were 2.1 %, 9.1 %, and 9.04 %, respectively. These products have diverse industrial usage and can be employed as platform chemicals. The development of a novel system for efficient simultaneous lignin depolymerization and subsequent quality separation are demonstrated in this study.