A novel Enterococcus faecalis strain designated NJ402 was found with high activity of arginine deiminase (ADI). The optimum condition for catalytic activity was determined in terms of temperature (about 40 degrees C), thermostability (available 37 degrees C) and pH (6-7). The effects of substrate and product concentration were studied. The effects of various metal ions added in reaction mixtures on the biocatalyst were investigated and ADI of NJ402 was found to exhibit Co2+ dependence, different from previous reports. Surfactant, cetyl trimethyl ammonium bromide, was one of the most important keys for producing L-citrulline. The enzyme in resting cells possessed the quality of high stability for reuse.