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.

在它们潜在地用于环境微生物学和生物技术应用之前，需要并且完全有必要对降解有毒污染物的新假单胞菌菌株进行详细表征。因此，本研究检查了恶臭假单胞菌KB3 在次优温度、pH 和盐度下的苯酚降解。同时，细菌对压力生长条件的适应性机制涉及苯酚暴露期间细胞膜特性的变化以及编码儿茶酚 2,3-双加氧酶 ( xylE ) 和环丙烷脂肪酸合酶 ( cfaB )的基因的表达水平) 确定。结果表明，高盐度和低温对细菌的生长和苯酚利用率的影响最为显着。苯酚的降解（300 mg L ^-1) 与最佳条件相比，在 10 °C 和 5% NaCl 下进行的时间延长了 12 倍和 7 倍。细菌降解苯酚的能力与相对较高的儿茶酚 2,3-双加氧酶活性相结合。与对照样品相比，抑制酶活性约 80% 的唯一因素是盐度。脂肪酸甲酯 (FAME) 分析、膜渗透性测量和疏水性测试表明，在次优生长条件下苯酚降解过程中，细菌膜特性发生了严重变化。pH、盐度和温度的最高值导致膜渗透性降低。FAME 分析显示脂肪酸饱和指数和环丙烷脂肪酸在高温和盐度下的参与。xylE和cfaB基因表达。