To investigate the characteristic and biochemical mechanism about the phenol biodegradation by bacterial strains ZD 4-1 and ZD 4-3. Methods Bacterial strains ZD 4-1 and ZD 4-3 were isolated by using phenol as the so...To investigate the characteristic and biochemical mechanism about the phenol biodegradation by bacterial strains ZD 4-1 and ZD 4-3. Methods Bacterial strains ZD 4-1 and ZD 4-3 were isolated by using phenol as the sole source of carbon and energy, and identified by 16S rDNA sequence analysis. The concentrations of phenol and total organic carbon (TOC) were monitored to explore the degradation mechanism. The biodegradation intermediates were scanned at 375 nm by using a uv-vis spectrophotometer. The enzyme assays were performed to detect the activities of dioxygenases. Results Bacterial strains ZD 4-1 and ZD 4-3 were identified as Comamonas testosteroni and Pseudomonas aeruginosa by 16S rDNA sequence analysis, respectively. The growth of the two strains was observed on a variety of aromatic hydrocarbons. The strains ZD 4-1 and ZD 4-3 metabolized phenol via ortho-pathways and meta-pathways, respectively. In addition, the results of enzyme assays showed that the biodegradation efficiency of phenol by meta-pathways was higher than that by ortho-pathways. Finally, the results of induction experiment indicated that the catechol dioxygenases, both catechol 1,2-dioxygenase (C12O) and catechol 2,3-dioxygenase (C23O), were all inducible. Conclusion The strains ZD 4-1 and ZD 4-3 metabolize phenol through ortho-pathways and meta-pathway, respectively. Furthermore, the biodegradation efficiency of phenol by meta-pathways is higher than that by ortho-pathways.展开更多
利用水热合成法合成了分子组成为(C6H11NH3)5H(P2Mo5O23)4H2O的杂多化合物, 用单晶X-ray衍射方法测定了它的结构,该晶体属于单斜晶系,空间群P21/c, a = 12.830(3), b = 14.848(3), c = 25.258(5) ? b = 92.95(3), Mr = 1483.62, V = 48...利用水热合成法合成了分子组成为(C6H11NH3)5H(P2Mo5O23)4H2O的杂多化合物, 用单晶X-ray衍射方法测定了它的结构,该晶体属于单斜晶系,空间群P21/c, a = 12.830(3), b = 14.848(3), c = 25.258(5) ? b = 92.95(3), Mr = 1483.62, V = 4805.1(17) 3, Z = 4, Dc = 2.051 g/cm3, m = 1.431 mm-1, F(000) = 3000, I >2s(I) 的可观察衍射点4426个, 最终结构偏差因子R = 0.0464, wR = 0.0801, S = 0.731。在[P2Mo5O23]6-杂多阴离子中5个MoO6八面体通过共边和共角相连, 形成1个近似的五角平面骨架, 2个PO4四面体加在五角平面的两侧。热性质研究表明杂多阴离子骨架在547.4 ℃左右分解。展开更多
文摘To investigate the characteristic and biochemical mechanism about the phenol biodegradation by bacterial strains ZD 4-1 and ZD 4-3. Methods Bacterial strains ZD 4-1 and ZD 4-3 were isolated by using phenol as the sole source of carbon and energy, and identified by 16S rDNA sequence analysis. The concentrations of phenol and total organic carbon (TOC) were monitored to explore the degradation mechanism. The biodegradation intermediates were scanned at 375 nm by using a uv-vis spectrophotometer. The enzyme assays were performed to detect the activities of dioxygenases. Results Bacterial strains ZD 4-1 and ZD 4-3 were identified as Comamonas testosteroni and Pseudomonas aeruginosa by 16S rDNA sequence analysis, respectively. The growth of the two strains was observed on a variety of aromatic hydrocarbons. The strains ZD 4-1 and ZD 4-3 metabolized phenol via ortho-pathways and meta-pathways, respectively. In addition, the results of enzyme assays showed that the biodegradation efficiency of phenol by meta-pathways was higher than that by ortho-pathways. Finally, the results of induction experiment indicated that the catechol dioxygenases, both catechol 1,2-dioxygenase (C12O) and catechol 2,3-dioxygenase (C23O), were all inducible. Conclusion The strains ZD 4-1 and ZD 4-3 metabolize phenol through ortho-pathways and meta-pathway, respectively. Furthermore, the biodegradation efficiency of phenol by meta-pathways is higher than that by ortho-pathways.
