Abstract:

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.