Optimum Conditions of Production and Purification of Gastroenteritis E. coli Protease Isolated from Iraqi Patients

  • Ataa R. Khayoon Ali J. AL-Sa’ady


This study was performing on isolates of Escherichia coli bacteria, which isolated from stool of people with gastroenteritis and diarrhea. These isolates were examined on skim milk agar medium in order to screening if isolates produce protease enzyme, as well as determination some optimal conditions for protease production like carbon source, nitrogen source pH, temperature, and duration of incubation. The protease was purified by ion exchange chromatography and gel filtration after its precipitated by 0-80% ammonium sulphate. The results showed that the highest production of protease from local E. coli 29 isolate in the medium containing of brain heart infusion broth supported with fructose, sodium nitrate, pH 6.0, and incubated at 37 °C, for 24 hours. The results of protease purification by ion exchange and gel filtration chromatography, showed that the specific activity was 19250 U/mg, yield 49 and purification fold 4.94.