节杆菌PJ3降解咔唑和联苯

Biodegradation of carbazole and biphenyl by Arthrobacter sp. PJ3

菌株PJ3经16SrDNA鉴定为节杆菌(Arthrobacter sp.),同源树表明,该菌株与已报道咔唑降解菌株IC177同源关系最近,其次是联苯降解菌株K37和R04。为了明确PJ3菌株对咔唑和联苯的降解能力,在PJ3生长的最适pH值进行优化的基础上,利用分光光度法测定了该菌株在不同浓度咔唑和联苯的矿物培养基中的生长速率以及对咔唑和联苯的降解性能。结果表明,在pH为7、8、9时,PJ3菌株的生长速率一致,而且高于其他pH值的生长速率。在pH为7、咔唑浓度为0.1mg.ml-1的CNFMM培养基中,PJ3菌株生长速度较快,而且15d咔唑的降解率可达到73%。在pH为7、联苯浓度为0.5mg.ml-1的MSB培养基中PJ3菌株生长最好。在0.1和0.5mg.ml-1联苯浓度下,15d对联苯的降解率可达80%～85%。综合评价,PJ3菌株降解咔唑比较适宜的浓度范围应该为0.1～0.2mg.ml-1,降解联苯较适宜的浓度范围为0.1～0.5mg.ml-1。

A strain PJ3 was isolated from soil,and identified as Arthrobacter sp.by 16S rDNA.Homology tree showed that the Arthrobacter sp.PJ3 had the highest homology value with carbazole-degrading bacterium IC177,followed by with biphenyl-degrading bacteria K37 and R04.In order to evaluate the degradation capability of Arthrobacter sp.PJ3 to carbazole and biphenyl,the medium pH for Arthrobacter sp.PJ3 growth was optimized,and spectrophotometry was applied to measure the growth rate of the strain on the mineral medium with different concentration carbazole or biphenyl,and the degradation rate of the two aromatic compounds.The growth rate of the strain was the same at medium pH 7,8,and 9,and higher than that at other medium pH values.At pH 7 and 0.1 mg·ml-1 of carbazole,the growth rate of the strain on CNFMM medium was the highest.After cultured for 15 days,the degradation rate of carbazole was up to 73%.At pH 7 and 0.5 mg·ml-1 of biphenyl,the growth state of PJ3 on MSB medium was the best.When the PJ3 was cultured on MSB medium with 0.1 and 0.5 mg·ml-1 of biphenyl for 15 days,the degradation rate of biphenyl was 80%-85%.Therefore,0.1-0.2 mg·ml-1 of carbazole and 0.1-0.5 mg·ml-1 of biphenyl could be the optimal concentrations for the degradation of the two aromatic compounds by Arthrobacter sp.PJ3.