The biotreatment of industrial effluents that
contain heavy metals, detergents and metal chelating
agents represents a great concern to industries as these
compounds are either toxic to microbes or they act as noncompetitive
inhibitors/denaturing agents for several
enzymes. So, it is essential to know the effect of various
agents usually present in the treatment plant on activity of
the enzyme, for extending its applications in in situ treatment
processes. This study describes the immobilization
conditions of laccase and analysis of the sensitivity of
immobilized laccase from
Trichoderma viride
Pers
NFCCI-2745 to heavy metals, detergent and copper chelating
agents. The concentrations and combinations of
cations influenced the activity of immobilized enzyme and
its yield. The immobilized Cu–Ba alginate enzyme showed
comparatively higher activity compared to the Cu-alginate
enzyme. Most of the metal ions tested enhanced laccase
activity at lower concentration. Immobilized laccase
retained more than 70 % of its activity even in the presence
of 20 mM copper chelating agents like EDTA and sodium
thioglycolic acid. Sodium azide, on the other hand, inhibited
80 % of the activity of all the beads even at a very low
concentration of 0.5 mM. Cu–Ba and Cu–Ni alginate
enzyme exhibited comparatively higher tolerance than Cualginate
beads to EDTA and sodium thioglycolate. Tween
20 and cetyl trimethyl ammonium bromide significantly
increased the activity of all the beads. These properties of
the immobilized laccase may be aptly considered and
suitably utilized in treating phenolic effluents that may
contain heavy metals, detergents and certain copper chelating
agents which may otherwise pose a threat to enzymatic
activity.
