Extracellular protease produced by Bacillus subtilis isolated from contaminated paracetamol oral preparation

Abstract

In a study to evaluate the microbiological safety of some paracetamol oral solutions sold in some Nigerian drug stores, 40.0% of the samples examined was contaminated with protease-producing Bacillus subtilis. The production of extracellular protease was induced by casein in the minimal medium and was found to be the major enzyme in the growth medium. The enzyme was partially purified by ammonium sulphate precipitation technique and the specific activity determined. The quantitative assay revealed that the produced enzyme exhibited proteolytic activity at different assay conditions. The level of enzyme production increased with increase in cell density. The enzyme was stable at the pH and temperature ranges 7.5-10 and 45-60°C, respectively, indicating proteolysis over a wide range of environmental conditions.

Keywords: microbiological safety, paracetamol oral solutions, Bacillus subtilis, extracellular protease, proteolysis

Global Journal of Pure and Applied Sciences Vol. 12(1) 2006: 55-60