Isolation,Identification of Phenol-Degrading Strain F5-2 and its Degradation Characteristics

A strain named F5-2 capable of utilizing phenol as the sole carbon source and with high efficiency of phenol degradation was isolated from the waste water of a paper mill plant by means of gradually increasing the concentration of phenol in the culture medium.According to its morphology,biochemical characteristics,and the 16S rDNA sequence,this strain was identified as Arthrobacter sp.The phenol degradation activity of this bacterial strain is proportional to its cell growth and the degradation occurs mainly during the logarithmic growth period.The highest phenol concentration that the strain could tolerate to grow is 1500 mg?L?1.In the temperature range of 20~40℃,pH 5.0~9.0,shaking rate of 200 r?min?1,and salinity of 0~40 g?L-1,strain F5-2 remains high phenol degradation activity,and 96.13% of the phenol can be degraded within 57 hours when the initial phenol concentration is 800 mg?L?1 and with a bacterial inoculum size of 2% of the culture medium.The functional enzyme responsible for the phenol degradation in strain F5-2 is the intracellularly localized catechol 2,3-dioxygenase,which is phenol inducible and can cleave the ortho-aromatic ring to degrade the phenol.