Adaptation of phenol-degrading Pseudomonas putida KB3 to suboptimal growth condition: A focus on degradative rate, membrane properties and expression of xylE and cfaB genes

Ecotoxicology and Environmental Safety

Joanna Żur-Pińska¹  Agnieszka Nowak²  Gabriela Pacek²  Artur Piński²  Agnieszka Mrozik³ 

[1] Corresponding author.;Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia, Jagiellońska 28, 40-032 Katowice, Poland;Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland;

关键词: Pseudomonas putida;    Phenol degradation;    Suboptimal temperatures, pH, salinity;    Membrane properties;    Gene expression;   

DOI  :  

来源: DOAJ

【 摘 要 】

Detailed characterization of new Pseudomonas strains that degrade toxic pollutants is required and utterly necessary before their potential use in environmental microbiology and biotechnology applications. Therefore, phenol degradation by Pseudomonas putida KB3 under suboptimal temperatures, pH, and salinity was examined in this study. Parallelly, adaptive mechanisms of bacteria to stressful growth conditions concerning changes in cell membrane properties during phenol exposure as well as the expression level of genes encoding catechol 2,3-dioxygenase (xylE) and cyclopropane fatty acid synthase (cfaB) were determined. It was found that high salinity and the low temperature had the most significant effect on the growth of bacteria and the rate of phenol utilization. Degradation of phenol (300 mg L−1) proceeded 12-fold and seven-fold longer at 10 °C and 5% NaCl compared to the optimal conditions. The ability of bacteria to degrade phenol was coupled with a relatively high activity of catechol 2,3-dioxygenase. The only factor that inhibited enzyme activity by approximately 80% compared to the control sample was salinity. Fatty acid methyl ester (FAMEs) profiling, membrane permeability measurements, and hydrophobicity tests indicated severe alterations in bacteria membrane properties during phenol degradation in suboptimal growth conditions. The highest values of pH, salinity, and temperature led to a decrease in membrane permeability. FAME analysis showed fatty acid saturation indices and cyclopropane fatty acid participation at high temperature and salinity. Genetic data showed that suboptimal growth conditions primarily resulted in down-regulation of xylE and cfaB gene expression.

【 授权许可】

Unknown