一种苯酚降解菌Pseudoxanthomonas sp. BF-6的分离鉴定及其降解特性及途径研究

Isolation,Identification of Phenol-degrading Pseudoxanthomonas sp.BF-6 and Its Degradation Characteristics and Pathway

苯酚是最常见的有机污染物,为了获得降解苯酚的细菌,并探究其降解苯酚的特性和途径,采用连续富集和稀释平板分离,从农药厂活性污泥中得到一株能以苯酚作为唯一碳源生长的菌株BF-6,通过16S rRNA序列分析和生理生化试验将该菌株鉴定为假黄单胞菌(Pseudoxanthomonas sp.)。单因素试验结果表明,菌株BF-6在温度为20-37℃和pH5.0-10.0范围内均可很好的降解苯酚;在此条件下,5%接种量的菌株BF-6在36 h内可将100 mg/L苯酚降解97.79%,96 h可将200 mg/L苯酚降解97.58%。经苯酚诱导后,菌株BF-6细胞粗酶液表现出苯酚羟化酶和邻苯二酚1,2-双加氧酶活性,表明菌株BF-6降解苯酚的途径为邻位途径。本研究为低浓度苯酚的微生物降解提供了新的菌种资源。

The aim of this work is to isolate phenol-degrading bacteria and to explore the characteristics and pathways of phenol degradation.Continuous enrichment and dilution plate method were applied to isolate the phenol-degrading bacteria,and single factor test was to study the characteristics of phenol degradation.The metabolic pathway of degrading by the strain phenol was deduced by determining the activities of phenol hydroxylase and catechol dioxygenase.A phenol-degrading strain BF-6,growing with phenol as the sole carbon source,was isolated and named as BF-6.Strain BF-6 was identified as Pseudoxanthomonas sp.by using 16S rRNA sequence analysis and physiological and biochemical tests.Strain BF-6 degraded phenol well in the temperature range of 20-37℃and pH range of 5.0-10.0;under this condition,strain BF-6 with 5%inoculum degraded 100 mg/L phenol by 97.79%in 36 h and 200 mg/L phenol by 97.58%in 96 h.Cell extracts of strain BF-6 showed enzymatic activity of phenol hydroxylase and catechol 1,2-dioxygenase after induction by phenol,indicating that the strain degraded phenol via ortho-pathway.In conclusion,phenol-degrading bacterium BF-6 is identified as Pseudoxanthomonas sp.,and it degrades phenol under a wide range of temperature and pH conditions.Phenol is degraded via ortho-pathway by strain BF-6.This study provides a new strain for microbial-degration of low-concentration phenol.