Abstract

 

Accepted 7th May, 2014

 

Microorganisms can produce protease that shares nearly 40% of the total worldwide enzyme market. Proteases have many applications in different industries and environmental bioremediations. However, there is no scientific report on protease producing microorganisms in Gondar. The objective the study was to isolate, optimize and characterize protease producing bacteria. One gram soil or 1ml water from each collected sample was added in test tube containing 9 ml saline water and mixed well using vortex mixer. Each test tube containing the suspensions was used as stock culture. Serial dilution was made up to 10-6 for each sample. Hundred micro-liter suspensions were taken from each test tube containing 10-6, spread over milk agar plates and incubated at 370C for 24 hrs. Morphologically distinct colonies were subcultured in to nutrient agar slant for incubation at 370C for 24 hrs and maintained at 40C for further analysis. Isolated colonies were screened on tryptone yeast extract dexterous agar plate for proteolytic activity. The promising isolates were selected for optimization and characterization. From a total of 32 isolates, 9.5 % (ATCSs, DSs and DWs) isolates were shown proteolytic activity. The optimum pH and temperature for growth and protease productions by the isolates were found to be 8-10 and 370C-450C, respectively. Based on morphological and biochemical characterization isolate ATCSs was identified as genus Staphylococcus. Proteolytic activity is influenced by the type of microorganism used chemical and physical parameters.  Therefore, a significant task should be done to get good proteolytic activity on identification and selection of potential microorganisms and optimization of physical and chemical conditions for protease producing isolates.

 

Keywords: Proteolytic activity, protease producing microorganisms, optimization,    characterization