Cross-linking of horseradish peroxidase adsorbed on polycationic films: utilization for direct dye degradation

Bioprocess Biosyst Eng. 2012 Oct;35(8):1355-65. doi: 10.1007/s00449-012-0724-2. Epub 2012 Mar 27.


Horseradish peroxidase (HRP) was immobilized on the polyaniline (PANI) grafted polyacrylonitrile (PAN) films. The maximum HRP immobilization capacity of the PAN-g-PANI-3 film was 221 μg/cm(2). The HRP-immobilized PAN-g-PANI-3 film retained 79 % of the activity of the same quantity free enzyme. The HRP-immobilized PAN-g-PANI-3 film was operated for the decolorization of two different benzidine-based dyes in the presence of hydrogen peroxide. The maximum decolorization grade was obtained at pH 6.0 for both dyes. The HRP-immobilized PAN-g-PANI-3 film was very effective for removal of Direct Blue-53 compared to Direct Black-38 from aqueous solutions. The immobilized HRP exhibited high resistance to proteolysis by trypsin compared to the free counterpart. Immobilized HRP preserved 83 % of its original activity even after 8 weeks of storage at 4 °C, while the free enzyme lost its initial activity after 3 weeks of storage period.

MeSH terms

  • Acrylic Resins / chemistry*
  • Azo Compounds / chemistry*
  • Coloring Agents / chemistry*
  • Enzyme Stability
  • Enzymes, Immobilized / chemistry*
  • Horseradish Peroxidase / chemistry
  • Membranes, Artificial*
  • Trypan Blue / chemistry*


  • Acrylic Resins
  • Azo Compounds
  • Coloring Agents
  • Enzymes, Immobilized
  • Membranes, Artificial
  • polyacrylonitrile
  • direct black 3
  • Horseradish Peroxidase
  • Trypan Blue