Aliphatic amidase of rhodococcus rhodochrous PA-34: Purification,characterization and application in synthesis of acrylic acid

An intracellular aliphatic amide degrading inducible amidase produced by rhodococcus rhodochrous pa-34 was characterized and acrylic acid synthesis from acrylamide was carried out using whole cell amidase. a bioprocess was developed at 50 ml fed batch reaction using 400 mm acrylamide feeding at an interval of 30 min resulted in the production of 4 g acrylic acid with volumetric and catalytic productivity of 80 g/l and 19 g/g/h respectively. the amidase of this organism had molecular weight of 40 kda and was purified to 8.5 fold with 8% yield. this enzyme was active within the temperature range of 30 to 60 °c,with optimum temperature 45 °c and ph 7.5. the vmax,km,and kcat of purified amidase were calculated as 250 u/mg protein,4.5 mm,and 166 sec-1 for acrylamide. the enzyme showed tolerance to metal chelating agent (edta) and was strongly inhibited by heavy metal ions hg2+,ag2+,cu2+ and co2+. r. rhodochrous pa-34 amidase preferentially hydrolyzed small aliphatic toxic amide such as acrylamide. thus,the amidase of r. rhodochrous pa-34 is promising biocatalyst for the synthesis of industrially important acids and biodegradation of toxic amides. © 2016 bentham science publishers.