decolorization of maxilon-red by kissiris immobilized phanerochaete chrysosporium in a trickle-bed bioreactor-involvement of ligninolytic enzymes

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.