K. Aikat et al., Decolorization and purification of crude protease from Rhizopus oryzae by activated charcoal and its electrophoretic analysis, BIOTECH LET, 23(4), 2001, pp. 295-301
Activated charcoal decolorized and partially purified the protease from a c
rude extract of solid state fermentation of wheat bran by Rhizopus oryzae.
Treatment for 5 min was sufficient. Depending on the initial colour intensi
ty of crude, the charcoal to crude extract ratio could be optimized to achi
eve 90% decolorization, 85% enzyme recovery, and over a 3-fold purification
, even up to 20-fold variation in batch size (from 1 ml to 20 ml crude extr
act). Decolorization followed the Freundlich and the Langmuir models, the F
reundlich constant, n, being 2.74. Partial purification was confirmed by na
tive PAGE and the protease band identified by gelatin-PAGE. SDS-PAGE showed
the protease consisted of two sub-units (about 22 and 24 kDa).
List of symbols: c(o), initial solute concentration in liquid before adsorp
tion; c*, equilibrium solute concentration in liquid after adsorption; k, e
mpirical constant for Freundlich adsorption isotherm; U, unit of protease a
ctivity; v, volume of solution per unit weight of adsorbent.