Abstract:
In the present study, bacteria strains capable of producing protease were isolated and
protease activity and stability were assessed under different pH and temperature
conditions. Four bacterial isolates (B1-B4) were found to have proteolytic activity on
skim milk agar plates. Time course studies indicated that strains Bl, B2 and B3 had the
highest protease activity (36, 50 and 57 U/ml respectively for Bl, B2 and B3) after 24 h
of incubation and strain B4 had the highest protease activity (35 U/ml) after 18 h of the
incubation. The highest protease activity (100%) was found at pH 6 in strains Bl, B2
and B4 and at pH 8 in strain B3. However, the strains Bl and B3 showed optimum pH
stability at pH 8, whereas strains B2 and B4 showed optimum pH stability at pH 7 and 6
respectively. The protease was active between 30 - 80°C with an optimal activity at 50°C
except the strain B4 which recorded optimal protease activity at 40°C. The protease
produced by all the isolated strains showed temperature stability at room temperature
(30°C).
