Dissertation

Towards microbial platforms for lignin valorization: Pseudomonas putida cell factories and Bacillus synthetic communities

Lignin is a major component of plant biomass and the largest renewable source of aromatic carbon, but it is difficult to break down and is still mostly underused. My PhD research focused on how bacteria can contribute to lignin degradation and valorization.

Author: Q. Zhou
Date: 12 June 2026
Links: Thesis in Leiden Repository

First, I reviewed known lignin-degrading microorganisms and enzymes, and evaluated Pseudomonas putida as a promising bacterial host for lignin conversion. I then investigated how P. putida KT2440 uses lignin-derived aromatic compounds and discovered that a glutathione peroxidase-like enzyme plays an important role in supporting growth, redox balance, and aromatic metabolism. Inspired by natural microbial cooperation, I also constructed a defined Bacillus-based synthetic community for lignin degradation, showing that biofilm formation and functional division of labour can contribute to lignin breakdown. Finally, I explored engineering P. putida as a cell factory by expressing lignin-active DyP peroxidases.Together, this work provides mechanistic insights and microbial platform strategies that may help develop more controllable and sustainable approaches for converting lignin into valuable products.