JOURNAL OF PURE & APPLIED MICROBIOLOGY, Nov. 2014. Vol. 8(Spl. Edn. 2), p. 727-731 * To whom all correspondence should be addressed. Tel.: +91 44 24503245; Mob.: +91 9962599534 Production and Partial Purification of Laccase from Pseudomonas aeruginosa ADN04 T. Arunkumar 1 *, D. Alex Anand 2 and G. Narendrakumar 3 1 Department of Bioinformatics, Sathyabama University, Chennai - 600119, India. 2 Department of Biomedical Engineering, Sathyabama University, Chennai - 600119, India. 3 Department of Biotechnology, Sathyabama University, Chennai - 600119, India. (Received: 06 September 2014; accepted: 13 October 2014) The efficient extracellular production of laccase in the liquid culture medium of Pseudomonas aeruginosa ADN04 and the enzyme extraction, characterization and purification were studied. Purified laccase from the culture filtrate of the bacterium has been attained maximum activity after employing ammonium sulphate precipitation, Gel filtration chromatography (Sephadex) and Affinity chromatography DEAE-Sephadex. The molecular mass of the laccase was determined by SDS-PAGE that showed a relative molecular weight of 43 kDa. The enzymatic stability characteristics at different pH and temperature of the purified laccase have been determined. 2,2’-azino-bis (3- ethylbenzothiazoline-6-sulphonic acid) was used as the substrate and have been found to be Vmax is 12.06 and Km is 56.9at 37°C respectively. Key words: Laccase, Pseudomonas aeruginosa ADN04, Optimization, Purification. Laccase (benzenediol: oxygen oxidoreductase; EC 1.10.3.2) is a multicopper oxidase with four copper atoms per monomer distributed in three redox sites. It is one of the extracellular glycoprotein enzymes expressed by microorganisms that play a vital role in the terrestrial carbon cycle by helping to decompose lignocellulosic substances. (Gianfreda et al., 1999) Laccases are multinuclear enzymes (Piontek et al., 2002) and the active site of laccase contains four copper atoms which are distributed in three sites, referred to as T1, T2 and T3 (Solomon, 1996). The laccase enzyme accepts electrons from substrates and converts them to free radicals. After receiving four electrons, the enzyme donates them to molecular oxygen to form two water molecules (Bourbonnais and Paice, 1990). Laccases plays very important role in the lignification and delignification. The main application of laccases is in many industrial processes like pulp and paper industry, biobleaching, biosensing and beverage refining (Cuoto and Herrera, 2006). Other than that in the environmental bioremediations it plays very important role in removal of a large number of environmental pollutants, such as alkenes, chlorophenols, dyes, herbicides, polycyclic aromatic hydrocarbons and benzopyrene (Sathishkumar et al., 2013). Fungi plays very important role in the production of laccase, but now days other than fungi, bacteria are also the main producers of laccase. The aim of this work was to develop a procedure for the purification of extracellular laccases from Pseudomonas aeruginosa ADN04, to determine the individual physicochemical and catalytic properties of these enzymes and to study the kinetics property of the enzyme.