Optimization of Alkaline Protease Production in Submerged Fermentation Using Bacillus cereus Isolated from an Abattoir Wastewater in Ile-Ife, Nigeria

Abstract

This study isolated and screened protease-producing bacteria from abattoir wastewater, it determined the effect of physical and nutritional components on the production of the crude protease produced by a selected bacterium in order to obtain a bacterium capable of producing protease with properties for industrial applications. Abattoir wastewater samples were collected from different locations in Ile-Ife, Nigeria and using pour plate method, one milliliter each of the aliquot was inoculated into skimmed milk agar medium (SKMA) to obtain colonies of protease-producing bacteria after proper dilution. All the protease-producing bacterial isolates were further screened for protease activity by submerged fermentation technique. The growth curve and protease activity of the best isolate was determined. The effect of different components of the growth medium on protease production was also determined. Forty-three isolates were obtained, five of the isolates gave appreciable diameter of clear zones of hydrolysis by rapid plate assay technique, out of which Bacillus cereus gave the highest enzyme activity of 75.79 Units/ml/min by submerged fermentation process. The optimal production of the enzyme was obtained after 44 hours of incubation with an inoculum volume of 2.0 ml. The optimal pH and temperature of production were 10.0 and 50°C respectively, while the best carbon and nitrogen source was sucrose and NH4Cl respectively. The study concluded that abattoir wastewater served as a good media for the growth of proteolytic bacteria while the strain of Bacillus cereus isolated could be applied in the industries for protease production.