• Purification and characterization of laccase from Coriolopsis floccosa MTCC-1177 and its use in the selective oxidation of aromatic methyl group to aldehyde without mediators

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      https://www.ias.ac.in/article/fulltext/jcsc/125/06/1395-1403

    • Keywords

       

      Cu enzymes; yellow laccases; lignolytic enzymes; Coriolopsis floccosa; 2,6- dimethoxyphenol; white rot fungus.

    • Abstract

       

      A laccase from the culture filtrate of white rot fungus Coriolopsis floccosa MTCC-1177 has been purified to homogeneity. The method involved concentration of the culture filtrate by ammonium sulphate precipitation and an anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) as well as native polyacrylamide gel electrophoresis (native-PAGE) produced single protein bands indicating that the enzyme preparation was pure. Molecular mass of the enzyme determined from SDS-PAGE analysis was 64 kDa. Using 2,6-dimethoxyphenol (DMP), 2,2'-[Azino-bis-(3-ethylbonzthiazoline-6-sulphonic acid (ABTS) diammonium salt and 4-hydroxy-3,5-dimethoxy benzaldehyde azine (syringaldazine) as the substrates, the $K_m$, $k_{\text{cat}}$ and $k_{\text{cat}}$/$K_m$ values of the laccase were found to be 112.5 𝜇M, 5.16 s-1, $4.60 \times 10^4$M-1 s-1, 58 𝜇M, 5.16 s-1, $8.90 \times 10^4$M-1 s-1 and 100 𝜇M, 5.16 s-1, $5.16 \times 10^4$M-1 s-1, respectively. The pH and temperature optima were 5.0°C and 40°C, respectively. Activation energy for thermal denaturation of the enzyme was 36.6 kJ/mol/K. The enzyme was most stable at pH4.0 when exposed for 1 h. The purified laccase has yellow colour and does not show absorption band around 610 nm found in blue laccases. The enzyme transforms toluene, 3-nitrotoluene and 4-chlorotoluene to benzaldehyde, 3-nitrobenzaldehyde and 4-chlorobenzaldehyde, respectively, in the absence of electron transfer mediators.

    • Author Affiliations

       

      P K Chaurasia1 A Yadav1 R S S Yadav1 S Yadava1

      1. Department of Chemistry, DDU Gorakhpur University, Gorakhpur 273 009, India
    • Dates

       
  • Journal of Chemical Sciences | News

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