F Soundra Josephine et al J. Microbiol. Biotech. Res., 2012, 2 (1):163-168
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Analytical Methods
Determination of Protease Activity
Protease activity was determined by a modified procedure based on the method of[16]. One
protease unit is defined as the amount of enzyme that releases 1 μg of tyrosine per mL per
minute under the standard conditions.
Protein Assay
Protein was measured by the method of [17] with Bovine Serum Albumin (BSA) as the standard.
The concentration of protein during purification studies was calculated from the absorbance at
280 nm.
Factors affecting activity:
The following factors were studied to obtain the optimal condition for activity of partially
purified proteases. These factors include incubation period, incubation temperature, and pH.
Effect of Temperature and pH on Protease from Bacillus Sp:
Effect of temperature was studied from 10 to 80ºC. effect of pH was studied from pH 2.0 to
11.9(HCl/KCl buffer for pH2.0; Glycine/HCl buffer for pH 2.5 to 3.5; Acetate buffer for pH 4.0
to 5.5; Phosphate buffer for pH 6.0 to 7.5; Tris/HCL buffer for pH 8.0 to 9.0; Glycine/NaOH
buffer for pH 9.5 to 10.5 and NaHPO4 /NaOH buffer for pH 11.0 to 11.9)
RESULTS AND DISCUSSION
Isolation and screening of microorganisms producing Protease
Fig. 1 shows the organism producing protease enzyme a clear zone around the colony as the
protein near the colony is utilized. Depending upon the zone of clearance, the strain of Bacilllus
SNR01 was selected for further experimental studies.
Fig. 1: The zone of hydrolysis of Bacillus SNR 01 on gelatin agar
Production and purification of protease from Bacillus SNR01:
The isolated source of Bacillus SNR01 maximum enzyme production was observed at 24 hours
in showed in Fig. 2. Other investors, reported that both Bacillus anthracis, S-44 and Bacillus
cereus var. mycoides, S-98 exhibited their maximum ability to biosynthesize proteases within 24
F