Production and Characterisation of Thermostable Protease from Bacillus Stearothermophilus Strain F1
Screening and isolation of thermophilic proteolytic bacteria were carried out from composting areas, high temperature ponding systems and areas surrounding palm oil mills. Twelve isolates were positive on Skim Milk A gar (10%) of which 11 produced protease in culture broth. A thermophilic and hi...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1994
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/8589/1/FSAS_1994_7_A.pdf |
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| Summary: | Screening and isolation of thermophilic proteolytic bacteria
were carried out from composting areas, high temperature ponding
systems and areas surrounding palm oil mills. Twelve isolates were
positive on Skim Milk A gar (10%) of which 11 produced protease in
culture broth. A thermophilic and highly proteolytic isolate
identifi edas Bacillus stearothermophilus strain F1 isolated from
decomposed oil palm branch, was selected for further study. B. stearothermophilus strain F1 could grow up to 80°C within a broad pH
ranges (pH 5 to 11) with an optimal growth temperature and pH at 70°C
and 9.5, respectively. The doubling time of this bacteria at 60°C was 70
min.
Maximum protease production was achieved after 24 h cultivation
when grown in 50 ml medium (pH 10.0) under shaking condition at
60°C. Static condition inhibited protease production but not growth.
Cultures grown on peptone (iv) generated the highest amount of
protease and lower production was observed when glucose or other
rapidly metabolized carbon sources were added. Ammonium salt (0.5%) and amino acids (0.5%) interfered with protease formation whenever they
were added to the medium. Although the protease production was
calcium independ ent, the presence of the ion at 4.5 mM enhanced the
yield by two-fold. Protease production occurred during the midexponential
growth phase of the bacterial growth and its onset coincided
with sporulation. |
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