Response of heterotrophic nitrifying/aerobic denitrifying strain Pseudomonas stutzeri YXH-102 to hypersaline stress

Abstract

Background

Hypersaline wastewater poses significant environmental challenges, necessitating efficient bioremediation strategies. This study investigates the hypersaline tolerance mechanisms of Pseudomonas stutzeri YXH-102, a heterotrophic nitrifying/aerobic denitrifying bacterium isolated from Yuncheng Salt Lake sediments, under high-salinity stress.

Results

Comparative transcriptomic analysis revealed 268 differentially expressed genes (DEGs) in response to a 10 % NaCl shock, with 86 upregulated and 182 downregulated. Key findings highlight the critical roles of oxidative stress mitigation, energy metabolism adaptation, and ion homeostasis. Salt stress triggered reactive oxygen species (ROS) accumulation, countered by upregulated cytochrome c oxidase (reducing ROS generation) and glutathione S-transferase (enhancing ROS scavenging). Concurrently, energy metabolism pathways, including fatty acid β-oxidation and acetyl-CoA production, were activated to sustain cellular energy demand. Notably, the electron transport chain (ETC) generated a robust proton motive force (PMF), which directly fueled potassium uptake via H⁺/K⁺ symporters to counteract osmotic imbalance. TonB-dependent transporters for nutrient uptake were also significantly upregulated, suggesting enhanced nutrient acquisition under salinity.

Conclusions

These findings elucidate how P. stutzeri YXH-102 combats salt stress through integrated ROS detoxification, energy optimization, and PMF-driven ion transport, providing molecular insights for its application in hypersaline wastewater bioremediation.

How to cite: Wang Y, Wang Z, Hu Y, et al. Response of heterotrophic nitrifying/aerobic denitrifying strain Pseudomonas stutzeri YXH-102 to hypersaline stress. Electron J Biotechnol 2025;76. https://doi.org/10.1016/j.ejbt.2025.05.001.