Purification and characterization of amidase from acrylamide-degrading bacterium Burkholderia sp. strain DR.Y27

An amidase from a newly isolated acrylamide-degrading bacterium Burkholderia sp. strain DR.Y27 was purified to homogeneity by a combination of anion exchange and gel filtration chromatography. The purification strategy achieved 11.15 of purification fold and a yield of 1.55%. The purified amidase consisted of four identical subunits with a molecular weight 47 kDa and was active within the temperature range of 35 to 60°C, with optimum activity at 40°C and within the pH range of 7.5 to 8.0 with an optimum pH of 8.0. Aliphatic amides (acetamide and propionamide) were the best substrates for the amidase from Rhodococcus rhodochrous M8, whereas bulky aromatic amides were poor substrates of this enzyme. The amidase from Burkholderia sp. strain DR.Y27 was not sensitive to sulfhydryl agents such as �-mercaptoethanol and dithiothreitol (DTT).