Trypan Blue, an azo dye, was decolorized
using the self-immobilizing fungal biomass of Pycnoporus
sanguineus. The extent and the rate of dye
decolorization were directly proportional to the initial
dye concentration (20–60 mg L−1) and the reaction
temperature (25–45°C). Mass transfer within and
outside the pellets did not limit dye degradation.
The apparent kinetics of the decolorization reaction
followed a first-order behavior. Activation energy for
the biological decolorization was calculated at 23 kJ
mol−1. The decolorization process was endothermic
with the enthalpy and entropy values calculated at
45.6 kJ mol−1 and 146 J mol−1 K−1, respectively.
Based on the value of Gibbs free energy change, the
decolorization reaction under the conditions studied
was non-spontaneous below 39°C but was spontaneous
at higher temperatures.