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bioRxiv · 10.1101/2025.11.24.690113

Lignin degradation and valorization by Pseudomonas putida KT2440: a new role for glutathione peroxidase

Zhou, Q.·Fransen, A.·Innocenti, P.·Ram, A. F. J.·de Winde, J.
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Abstract

Lignin, a complex natural aromatic polymer, poses significant challenges to its efficient degradation, hindering the utilization of biomass for many industrial applications. Bacterial degradation of lignin may offer a promising solution to this challenge. This project aimed at elucidating the function of secreted oxidative enzymes from Pseudomonas putida involved in lignin degradation and utilization. Using CRISPR-Cas9 and CRISPR-Cas3 systems, the putative lignin-degrading versatile peroxidase gene (VP; PP_1686, originally annotated as glutathione peroxidase GPx) and dye-decolorizing peroxidase gene (PP_3248) were individually knocked out from P. putida KT2440. The {Delta}PP_1686 mutant exhibited impaired growth and utilization of lignin-derived compounds. This correlated with reduced expression of p-hydroxybenzoate hydroxylase pobA and of DNA repair modules, alongside compensatory upregulation of energy and redox supply pathways. This work expands our knowledge on bacterial glutathione peroxidase by presenting a role beyond ROS scavenging. This work revealed the importance of P. putida VP/GPx in maintaining redox balance while supporting lignin-derived aromatic metabolism, offering new targets for future investigation into stress-metabolism crosstalk and lignin valorization strategies.

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Zhou, Q., Fransen, A., Innocenti, P., Ram, A. F. J., de Winde, J.. 2025-11-24. Lignin degradation and valorization by Pseudomonas putida KT2440: a new role for glutathione peroxidase. https://doi.org/10.1101/2025.11.24.690113

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