Production of Proteases by Alkalophilic Bacteria from a Hot Sprinq at Wondo Genet
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Date
1993-06
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Addis Ababa,University
Abstract
Two organisms with high proteolytic activity on casein,
gelatin or haemoglobin were selected out of the bacterial isolates
obtained from a hot spring at Wondo Genet. The test
organisms were Gram posi ti ve, rod-shaped, spore-forming with
chains of two or more cells, motile bacteria. Based on the
biochemical and morphological tests, it has been confirmed that
they belong to the genus Bacillus. Growth of the two isolates was
observed in the pH and temperature ranges of between 5-10, and
30-55 °C , respectively. Their optimum pH and temperature for
growth were 10 and 55°C. Glucose 0.5% and peptone at 0.5%, 0.4%,
respectively resulted better yield of biomass and protease
production. 0.5mM Ca +2 , O.lmM Mg+2 , and 1mM P044 increased biomass
and enzyme production of both isolates. High enzyme production
was observed in the presence of 1mM Cu+2 and 5mM Mn+2 for Bacillus
sp-A, and O.lmM Zn+2 and 5mM Mn+2 for Bacillus sp-B. The highest
enzyme activity of both isolates was observed when assayed at
55°C and pH 9.5. The protease of Baccilus sp-A showed higher
hydrolytic activity on casein than on gelatin or haemoglobin.
The protease of Bacillus sp-B have been found to hydrolyse only
gelatin. However, both isolates failed to hydrolyse egg
albumin. The two organisms were more efficient in degrading skin
when supplied in the growth medium than feather, horn or hair.
T high degrading activity on feather than Bacillus sp-B. On the
other hand Bacillus sp-B showed high degrading activity on horn
than Bacillus sp-A. The protease of Bacillus sp-A was thermally
stable between 60-70 o C, with a half life of 50 min at 60°C and
65°C, and 40 min at 70°C. The protease of Bacillus sp-B was
thermally stable at 60 and 65°C, and the half life was 50 min at
these temperatures. However, the enzyme activity of both isolates
ceased after 60 min of incubation at the temperatures examined.
viihe least weight lose was recorded on hair. Bacillus sp-A showed
high degrading activity on feather than Bacillus sp-B. On the
other hand Bacillus sp-B showed high degrading activity on horn
than Bacillus sp-A. The protease of Bacillus sp-A was thermally
stable between 60-70 o C, with a half life of 50 min at 60°C and
65°C, and 40 min at 70°C. The protease of Bacillus sp-B was
thermally stable at 60 and 65°C, and the half life was 50 min at
these temperatures. However, the enzyme activity of both isolates
ceased after 60 min of incubation at the temperatures examined.
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Keywords
Production of Proteases by Alkalophilic Bacteria