Polymenakou Paraskevi N, Stephanou Euripides G
Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Knossos Avenue PO Box 1470, 714 09 Heraklion, Greece.
Biodegradation. 2005 Oct;16(5):403-13. doi: 10.1007/s10532-004-3333-1.
A new indigenous soil bacterium Pseudomonas sp. growing on phenol and on a mixture of phenol, toluene, o-cresol, naphthalene and 1,2,3-trimethylbenzene (1,2,3-TMB) was isolated and characterized. Phylogenetic analysis suggested its classification to Pseudomonadaceae family and showed 99.8% DNA sequence identity to Pseudomonas pseudoalcaligenes species. The isolate was psychrotroph, with growth temperatures ranging from ca. 0 to 40 degrees C. The GC-MS structural analysis of metabolic products of phenol degradation by this microorganism indicated a possible ortho cleavage pathway for high concentrations (over 200 mg L(-1)) of phenol. Biodegradation rates by this species were found to be three times more effective than those previously reported by other Pseudomonas strains. The effect of temperature on phenol degradation was studied in batch cultures at temperatures ranging from 10 to 40 degrees C and different initial phenol concentrations (up to 500 mg L(-1)). Above 300 mg L(-1) of initial phenol concentration no considerable depletion was recorded at both 10 and 40 degrees C. Maximum degradation rates for phenol were recorded at 30 degrees C. The biodegradation rate of phenol was studied also in the presence of additional carbon sources (o-cresol, toluene, naphthalene, 1,2,3-TMB) at the optimum growth temperature and was found significantly lower by a factor of eight in respect to the strong competitive inhibition between the substrates and the more available sources of carbon and energy. The Haldane equation mu = mum S/(Ks + S + S2/K1) was found to best fit the experimental data at the optimum temperature of 30 degrees C than the Monod equation with kinetic constants mum = 0.27 h(-1), KS = 56.70 mg L(-1), KI = 249.08 mg L(-1).
分离并鉴定了一种新的本土土壤细菌假单胞菌属（Pseudomonas sp.），该菌能在苯酚以及苯酚、甲苯、邻甲酚、萘和1,2,3-三甲基苯（1,2,3-TMB）的混合物上生长。系统发育分析表明它属于假单胞菌科，并显示与假产碱假单胞菌（Pseudomonas pseudoalcaligenes）物种的DNA序列同一性为99.8%。该分离株为嗜冷菌，生长温度范围约为0至40摄氏度。对该微生物降解苯酚的代谢产物进行的气相色谱-质谱（GC-MS）结构分析表明，对于高浓度（超过200 mg L⁻¹）的苯酚，可能存在邻位裂解途径。发现该物种的生物降解率比其他假单胞菌菌株先前报道的效率高两倍。在10至40摄氏度的温度范围和不同初始苯酚浓度（高达500 mg L⁻¹）下，在分批培养中研究了温度对苯酚降解的影响。当初始苯酚浓度高于300 mg L⁻¹时，在10摄氏度和40摄氏度下均未记录到明显的消耗。在30摄氏度时记录到苯酚的最大降解率。还在最佳生长温度下，在存在额外碳源（邻甲酚、甲苯、萘、1,2,3-TMB）的情况下研究了苯酚的生物降解率，发现由于底物与更多可用碳源和能源之间的强烈竞争抑制，其生物降解率显著降低了八倍。发现Haldane方程μ = μmaxS/(Ks + S + S²/Ki)比Monod方程更能拟合30摄氏度最佳温度下的实验数据，动力学常数为μmax = 0.27 h⁻¹，KS = 56.70 mg L⁻¹，KI = 249.08 mg L⁻¹。
