苯酚降解菌DF51的分离鉴定，降解特性及其固定化的研究

从太原市郊苯酚污染的土样中分离到一株能以苯酚、苯甲酸、萘、联苯和苯并噻吩为唯一碳源和能源生长，并且具有同时分解单环和双环芳香类物质能力的菌株，经生理生化和16S rDNA基因序列分析鉴定为红球菌DF51(Rhodococcus sp. DF51). 在本实验条件下，菌株DF51能够有效降解浓度范围为100-800mg L-1的苯酚，该菌代谢苯酚主要是通过邻苯二酚1, 2-双加氧酶催化开环途径进行，同时辅以邻苯二酚2, 3-双加氧酶催化开环，表明菌株DF51兼有混浊红球菌(Rhodoccocus opacus R7)和红球菌PNAN5(Rhodoccocus sp. strain DF51)降解苯酚的途径. 菌株DF51固定化实验表明，该菌的固定化细胞具有降解苯酚的潜在应用价值.

Isolation, Identification and Immobilization of Rhodococcus sp. DF51 and its Characterization of Phenol Degradation

A bacterial strain using phenol, benzoate, naphthalene, biphenyl and benzothiophene as sole carbon and energy sources was isolated from waste sludge and was identified as Rhodococcus sp. strain DF51 according to morphological, physiological and its 16S rRNA gene sequence. This strain is able to degrade polycyclic aromatics such as naphthalene and biphenyl as well as monocyclic aromatics such as phenol. Under experimental conditions, strain DF51 is capable of degrading at concentrations of phenol ranging from 100 mg to 800 mg, which is catabolized mainly through the catechol 1, 2-dioxygenase pathway with a minor catechol 2, 3-dioxygenase pathway. It is suggested the degradation way of phenol in the strain DF51 is differed from that of the reported phenol degrader. The results of immobilization of the strain DF51 revealed the optimum operation immobilization temperature is 4 ℃ with 3wt% sodium alginate (SA) , the ratio of 1∶10 cells (g) to SA (mL) ] and 3wt% CaCl2, showing that the immobilized strain DF51 has a certain potential of degrading phenol.