Transformation of Indigo carmine by Phanerochaete chrysosporium ligninolytic enzymes

The reaction between P. chrysosporium extracellular ligninolytic peroxidase s and the dye Indigo carmine was studied. This dye can be successfully deco lorized by both manganese (MnP) and lignin (LiP) peroxidases. By using a pr oper culture medium composition, a growth medium exhibiting high MnP or hig h LiP activity was obtained. Additionally, some peroxidase isoenzymes were isolated. Although the dye was successfully decolorised by both groups of e xtracellular peroxidases, the reaction by MnP was faster. Besides a yellow final product, the decolorization of Indigo carmine by MnP resulted in a re d product formation that was not observed at the decolorization by LiP. The final concentration of the red product can be influenced by the pH value o f the reaction mixture as well as by the initial dye concentration. The max imum formation of the red product was achieved at pH 5 with 60 mg/liter of the Indigo carmine in the reaction mixture. The red product was isolated an d partially characterized using W-VIS and H-1 NMR spectroscopy, and TLC. (C ) 2001 Elsevier Science Inc. All rights reserved.