title: Aliphatic amidase of Rhodococcus rhodochrous PA-34: Purification, characterization and application in synthesis of acrylic acid.
abstract: 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.
authors.forename: Neerja
authors.initials: N
authors.lastname: Thakur
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.forename: Nirmal Kant
authors.initials: NK
authors.lastname: Sharma
authors.forename: Shikha
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Department of Biotechnology, Himachal Pradesh University, Shimla-171005, India. bhallatc@rediffmail.com.
authors.forename: Tek Chand
authors.initials: TC
authors.lastname: Bhalla
mesh_terms: D000179:Acrylates / Q000138:chemical synthesis*; D000577:Amides / Q000737:chemistry; D000581:Amidohydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D000595:Amino Acid Sequence / Q000235:genetics; D002384:Catalysis; D012240:Rhodococcus / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000179:Acrylates; D000577:Amides; D000581:Amidohydrolases; C019665:amidase; C036658:acrylic acid