【摘要】 分离到一株能以苯酚、苯甲酸、对甲酚、萘为唯一碳源和能源生长、具有同时降解单环和双环芳烃能力的细菌菌株,经生理生化、16SrRNA基因序列分析等鉴定为红球菌PNAN5菌株(Rhodococcussp.strainPNAN5).在实验条件下和在温度为20～40℃、pH7 0～9 0范围内菌株PNAN5降解苯酚的效率保持在80%～100%之间,苯酚浓度在2～10mmol·L-1范围内变化对降解效率没有明显的影响.该菌株通过邻苯二酚1,2 双加氧酶催化的开环途径降解芳烃,不同于已知的浑浊红球菌(R.opacus)是通过邻苯二酚2,3 双加氧酶催化芳烃降解.以细胞裂解液测定该酶的酶促反应动力学常数Km值为35 94μmol·L-1,Vmax为0 84μmol·L-1·min-1·mg-1.更多还原

【Abstract】 A bacterial strain using phenol, naphthalene, benzoate and p-cresol as sole carbon and energy sources was isolated from waste sludge and was identified as Rhodococcus sp. strain PNAN5 according to morphological, physiological and its 16S rRNA gene sequence. This strain is able to degrade both polycyclic aromatics such as naphthalene and monocyclic aromatics such as phenol. Under experimental conditions, strain PNAN5 degraded 80～100% of the added phenols at temperatures of 20～40℃ and pH of 7.0～9.0. The concentrations of phenol at 2～10?mmol·L^-1　did not significantly affect its removal efficiency. Its aromatic-degradation pathway is different from catechol 2,3-dioxygenase of the R. opacus, but adopted to that of catechol 1,2-dioxygenase. The kinetic constants of the catechol 1,2-dioxygenase in cellular lysates were determined. The K_m and V_max of catechol 1,2-dioxygenase for catechol were 35.94?μmol·L^-1 and 0.84?mol·L^-1·min^-1·mg^-1（protein）, respectively.更多还原