PhD defence
Towards microbial platforms for lignin valorization: Pseudomonas putida cell factories and Bacillus synthetic communities
- Q Zhou
- Date
- Friday 12 June 2026
- Time
- Address
-
Academy Building
Rapenburg 73
2311 GJ Leiden
Supervisor(s)
Summary
Lignin is one of the most abundant natural polymers on Earth and is an important part of plant biomass. However, it is very difficult to break down and is still largely underused. In my PhD research, I studied how microorganisms and enzymes can help degrade lignin and convert lignin-derived compounds, with the long-term aim of supporting more sustainable biobased production.
I focused on the bacterium Pseudomonas putida, which is naturally good at using aromatic compounds. By deleting and analysing specific genes, I found that a glutathione peroxidase helps this bacterium grow on lignin-related compounds and deal with oxidative stress during their conversion. I also studied synthetic microbial communities made of lignin-degrading bacteria and showed that combining different bacteria can be a promising strategy for lignin degradation. In addition, I explored whether P. putida can be used as a platform to produce lignin-degrading enzymes.
These results were obtained through genetic engineering, microbial cultivation, enzyme activity tests, chemical analysis, microscopy, and transcriptome analysis. Together, they show that engineered bacteria and designed microbial communities can both contribute to lignin conversion.
This research is special because it combines microbiology, biotechnology, and synthetic biology to address a major challenge in using plant biomass and helps turn lignin from an underused waste stream into a renewable resource.
PhD dissertations
Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.
Press enquiries (journalists only)
+31 (0)71 527 1521
nieuws@leidenuniv.nl
General information
Beadle's Office
pedel@bb.leidenuniv.nl
+31 71 527 7211