Perspectives and advances in consolidated bioprocessing strategies for lignin valorization

Abstract

Complex and heterogeneous aromatic structures present limitless opportunities for the valorization of abundant residual lignin resources in nature and industry. The consolidated bioprocessing (CBP) of lignin valorization, which integrates bio-depolymerization and aromatic catabolism modules in a microbial cell, is an advanced and promising strategy that can significantly reduce the processing steps and cost. Given the efficiency and yield limitations of native strains, rational development and design strategies represent fundamental and necessary approaches to constructing appropriate bacterial hosts for lignin CBP. This manuscript provides a summary of the history and latest progress in lignin CBP, with a primary focus on the developments of native microbial hosts, metabolic engineering, and synthetic biology strategies. The key technological bottleneck was analyzed, leading to the expectation that direct and efficient bioconversion of lignin, which is a significant component of abundant lignocellulosic biomass, will be possible in the future.