A process for the production of an aryl acylamidase enzyme involves culturing bacteria of one of the strains Pseudomonas fluorescens ATCC 39005 (or suitable mutants or variants thereof) or Pseudomonas putida ATCC 39004 (or suitable mutants or variants thereof) in a culture medium in which the bacterial strains produce aryl acylamidase and collecting the enzyme containing material, generally the cell material. Preferably the resulting cells are then disrupted, especially by enzymatic treatment, and the aryl acylamidase is separated from the other unwanted substances, generally the other cell constituents.Preferably the culture medium contains N-acylaniline, especially N-acetyl aniline. The N-acylaniline may form part of a complex or defined salts medium.