Decolorization of Maxilon-Red by Kissiris Immobilized Phanerochaete Chrysosporium in a Trickle-Bed Bioreactor-Involvement of Ligninolytic Enzymes

Abstract

<em>The decolorization of Maxilon-red dye by Kissiris immobilized Phanerochaete chrysosporium in the trickle-bed reactor (TBR) using the basal nitrogen-limited growth medium was studied. The influence of the superficial liquid velocity (SLV) on the decolorizing ability of the fungus was examined at four SLVs (cm sec^-1): 0.05, 0.075, 0.1, and 0.15. Maximum level of the decolorizing activity was about 94 % by day 4-5 of the process when the TBR operated at SLV=0.075 to 0.1 cm sec^-1. At these SLVs, the maximum activities of the lignin peroxidase (LiP) and the manganese peroxidase (MnP) were (UL^-1): 87 and 207, respectively. In a successive decolorization of the tested dye in a continuous dye addition in the TBR when glucose level decreased to 2 gL^-1, significant reduction in the characteristics of the interest were observed. While by controlling the glucose concentration, these properties were improved considerably: The decolorizing ability of the Kissiris immobilized mycelia was more than 85 % after nearly 20 days of the process while the maximum activities of the LiP and the MnP were (UL^-1): 320 and 151, respectively. Considerable levels of the enzyme activities were detected by day 19 and after 11 times of the dye additions.</em>