In the present study, mixed microbial culture isolated from the
sludge of effluent treatment plant of a refinery was tested for its phenol
biodegradation potential under static batch condition. The result showed that,
after acclimatization, the culture could biodegrade upto 750 mg L
$^{-1}$
of phenol.
100% phenol degradation was achieved for the various concentrations studied.
Kinetic study showed that specific growth rate of microorganisms and specific
substrate degradation rate increased up to 300 mg L
$^{-1}$
of initial phenol
concentration and then started decreasing. The biodegradation kinetics was
fitted to different substrate inhibition models by using optimization software
tool (solver) in Microsoft office 2007. Among all models, Aiba model
(μmax = 0.3187 h
$^{-1}$
, K
$_I$
= 400, R
$^2$
= 0.915) and Edward Model
(μmax = 0.0011 h
$^{-1}$
, K
$_I$
= 210 mg L
$^{-1}$
, R
$^2$
= 0.942) were fitted the best. Growth kinetics was also fitted well to the classical Haldane model. The
values of inhibition constant, K
$_I$
from Yano model indicated that this culture
may well degrade phenol beyond 750 mg L
$^{-1}$
.
