Abstract
The process parameters governing the production of fibrinolytic enzyme
in solid state fermentation employing
Bacillus
cereus
IND5 and using cuttle fish waste and cow dung substrate were
optimized. The pH value of the medium, moisture content, sucrose, casein and
magnesium sulfate were considered for two-level full factorial design and pH, casein
and magnesium sulfate were identified as the important factors for fibrinolytic
enzyme production. Central composite design was applied to investigate the
interactive effect among variables (pH, casein and magnesium sulfate) and response
surface plots were created to find the pinnacle of process response. The optimized
levels of factors were pH 7.8, 1.1% casein and 0.1% magnesium sulfate. Enzyme
production was increased 2.5-fold after statistical approach. The enzyme was
purified up to a specific activity of 364.5 U/g proteins and its molecular weight
was 47 kDa. It was stable at pH 8.0 and was highly active at 50 °C. The mixture of
cuttle fish waste and cow dung could find great application as solid substrate for
the production of fibrinolytic enzyme.