A bacterial strain named R4 was isolated from a wastewater treatment pool containing triethylamine (TEA) as the sole source of carbon and nitrogen. Strain R4 was identified as Arthrobacter protophormiae based on 16S rRNA gene sequence analysis and morphological and physiological properties. The optimal pH, temperature and concentration of NaCl for TEA degradation by strain R4 were 7.0, 30 degrees C and 0.5%, respectively. Strain R4 could completely degrade 100 mg l(-1) TEA to ammonia in 32 h, and could also effectively degrade diethylamine (DEA) and ethylamine (EA) to ammonia. The degradation of TEA was strongly inhibited by some metal ions (Cu2+, Mn2+, Zn2+, Co2+, Ni2+ and Ag+) (1.0 mM). Addition of either SO42- or NH4+ reduced the degradation efficiency of TEA by strain R4 to a certain extent. The inhibition became significant when the concentration of SO42- and NH4+ reached toll mM and 30 mM, respectively. Cell-free extracts prepared from cells grown in TEA exhibited TEA monooxygenase, DEA monooxygenase and EA monooxygenase activity. Here, we propose the metabolic pathway of TEA degradation in strain R4. The efficiency of TEA removal by immobilized cells of strain R4 was found to be equivalent to that of free cells. In addition, the immobilized cells could be reused without reduction in their ability to degrade TEA. (C) 2010 Elsevier B.V. All rights reserved.