Identification and Characterization of a Highly Efficient and Resistant Aniline-Degrading Strain AD4

Abstract

Environmental friendly and effective bio-augmentation is a very promising technology in the aniline wastewater treatment field. In this study, an aniline degradation bacterial strain was isolated from activated sludge, designated AD4. It was proved to be capable of removing aniline effectively in the concentration range between 200 and 800 mg/L within 72 h and could tolerate 1,400 mg/L of aniline, which was identified as Delftia tsuruhatensis. The influence of environmental factors containing initial aniline concentration, initial pH, temperature, shaker speed, salinity, and inoculum amount on the growth and degradation of strain AD4 were investigated. The results showed that AD4 had a wide range of suitable pH (5–8) and higher efficiency in a weak acidic environment than in weak base. The aniline concentration, pH, and temperature were used as independent parameters to optimize the aniline degradation by strain AD4, and a statistically significant (R2 = 0.9817, p < 0.001) quadratic polynomial mathematical model was built. Meanwhile, a simulated reactor was designed to test the aniline-degradation ability of strain AD4 during the aeration stage. The degradation rate in 600 mg/L of aniline solution reached 51.5% after 8 h.