嗜联苯红球菌B403对酚类污染物的降解特性及动力学分析

Degradation characteristics and kinetic analysis of phenolic pollutants by Rhodococcus biphenylivorans B403

为提高降酚菌株的降酚能力,实验测定了嗜联苯红球菌B403对6种酚的最小抑菌浓度,考察了该菌在不同碳源条件下的生长与降酚特性及其关联,进而研究其降解动力学规律。结果表明,菌株B403对苯酚、间甲酚、邻苯二酚、对硝基苯酚、2,4-二氯苯酚和2,4,6-三氯苯酚的最小抑菌浓度分别为1190、630、700、140、70、48 mg·L-1,菌株B403对苯酚、间甲酚、邻苯二酚表现出较强的耐受性。分别以这3种酚为唯一碳源,该菌株能有效降解苯酚和间甲酚,无机盐培养基中处理30h后,苯酚、间甲酚、邻苯二酚的降解率分别为97.85%、100%、56.54%;当有其他有机碳源存在时,菌株B403的生物量大幅度提高,3种酚的降解效率也显著提高,处理15 h后LB-无机盐混合培养基中苯酚、间甲酚、邻苯二酚的降解率分别为98.92%、99.93%、94.35%。菌株B403的降酚动力学过程符合Haldane模型,菌株B403降解苯酚的动力学参数为qm=0.503 h-1,Ks=270.9 mg·L-1,KI=69 mg·L-1;降解间甲酚时,qm=0.672 h-1,Ks=171.9 mg·L-1,KI=23.74 mg·L-1;降解邻苯二酚时,qm=1.749 h-1,Ks=541.9 mg·L-1,KI=42.61 mg·L-1。根据动力学方程,推论降解苯酚、间甲酚、邻苯二酚的最佳浓度分别为136.4、87.4、116.1 mg·L-1。综合上述结果,其他有机碳源的存在可以显著提高该菌株降酚能力和降解效率,在工业含酚废水治理及有机质丰富的酚类污染土壤修复领域具有一定的应用潜力。

The removal of phenolic pollutants is a key issue in the treatment of industrial wastewater,therefore,characterizing strains with degradation ability of phenolic pollutants is of great significance.In this study,the minimum inhibitory concentrations of Rhodococcus biphenylivorans B403 agaisnt six phenolic pollutants of phenol,such as m-cresol,catechol,p-nitrophenol,2,4-dichlorophenol and 2,4,6-trichlorophenol,were determined.The results showed that the minimum inhibitory concentrations of strain B403 on phenol,m-cresol,catechol,p-nitrophenol,2,4-dichlorophenol and 2,4,6-trichlorophenol were 1 190,630,700,140,70,48 mg·L-1,respectively.And strain B403 had stronger tolerability on phenol,m-cresol and catechol than others.Subsequently,the growth and degradation properties of Rhodococcus biphenylivorans B403 for these three pollutants under different carbon sources were investigated.The strain B403 could effectively degrade phenol and m-cresol when a phenolic compound was used as the sole carbon source.After 30 h treatment in inorganic salt medium,the degradation rates of phenol,m-cresol and catechol were 97.85%,100%,56.54%,respectively.At the present of other organic carbon sources,the biomass of strain B403 greatly increased,and the degradation effieciency of the three types of phenolic pollutants was significantly improved.After 15 h treatment in the mixed medium of LB-inorganic salt,the degradation rates of phenol,m-cresol and catecholwere 98.92%,99.93%,94.35%,respectively.To further characterize the properties of strain B403,the Haldane model was used to fit the phenol degradation kinetics under optimal degradation conditions.For phenol degradation by strain B403 at different concentrations,the qm,Ks and KI were 0.503 h-1,270.9 mg·L-1 and 69 mg·L-1,respectively.As to m-cresol and catechol degradation,the qm,Ks,KI were 0.672 h-1 and 1.749 h-1,171.9 mg·L-1 and 541.9 mg·L-1,23.74 mg·L-1and 42.61 mg·L-1,respectively.Based on the kinetic equations,the optimum concentrations for phenol,m-cresol and catechol degradation by strain B403 were 136.4,87.4,116.1 mg·L-1,respectively.This study indicated that B403 presented stronger degradation ability agaisnt phenolic contaminants at the presence of other organic carbon sources,and strain B403 possesses certain application potential in the field of organic wastewater treatment with phenolic pollutants and organic phenol-contaminated soil remediation.