Isolation, identification and biodegradation characteristics of a bacterial strain able to degrade nonylphenol

A bacteria strain F-10 was isolated from activated carbon, which was processed with sand filtered water from Songhua River for a long time, pre-oxidized with ozone, PPC and ferrate. The bacterial strain was capable of utilizing nonylphenol (NP) as sole carbon source and identified as Rhodococcus erythropolis with the Sherlock Microbial Identification System (MIS) from the MIDI Corporation. The optimal conditions for NP biodegradation in the shaking flasks were at 30°C and pH 6.0. Under those conditions, NP at concentration of 1 mg/L was biodegraded by 62% with 2% of inoculum amount. The biodegradation reaction fitted well with first-order kinetic model, with a degradation rate constants (k) of 0.0865 d^-1and half-lives (t_1/2) of 8.0 d. Aerobic degradation rate for NP was enhanced by increased level of NH₄⁺, Mn²⁺, Mg²⁺, and NaCl, and by addition of glucose, NaAc, and yeast extract as well as by reduced level of Ca²⁺, Cu²⁺, Fe²⁺, and phosphate, while no apparent effect of original NP concentration was observed. The combination of F-10 with other 27 bacterial strains which were also isolated from activated carbon expressed better biodegradation effectiveness.