TITLE:
Enzymatic activities and kinetic properties of β-glucosidase from selected white rot fungi
AUTHORS:
Priscilla M. Mfombep, Zachary N. Senwo, Omoanghe S. Isikhuemhen
KEYWORDS:
White Rot Fungi; β-Glucosidase; EC 3.2.1.21; Enzymatic Activities; Kinetic Properties; Plant Biomass
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.3 No.2,
April
30,
2013
ABSTRACT: Beta-glucosidase is among the suite of enzymes produced
by white rot fungi (WRF) to biodegrade plant biomass. This study investigated
the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following
species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus
squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied
showed β-glucosidase activities.
Significant variations in protein and carbohydrate contents were also recorded.
Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic
constant (Km) ranged from
0.47 μM (A. auricular-1120) to 719 μM (L.
edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase
activities also exhibited pH optima between 3.5 and 5.0 while temperature
optima were between 60°C and 70°C
with some media exhibiting a secondary temperature peak at 90°C attributable to
the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose
to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.