Alkaline Protease of Alkaliphiles Isolated from Ethiopian Rift Valley Soda- Lakes
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Date
2000-05
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Addis Ababa University
Abstract
A prntcolytic alkali phi lie bacteria was selected out of the bacterial isolates obtained from
Riftvallcy soda lakes. The isolate was obtained from lake Chitu water sample. The
organism was Gram variable aerobic, rod shaped spore forming, motile bacterium. It has
been identified to belongs to the genus Bacillus.
The growth of the isolate coded as CH-W 1 was observed in the pH and temperature
ranges between 7-l l and 25-40°C respectively. Protease production was observed
shortly afler inoculation reaching to maximum after 48 h. The crude enzyme had a
temperature optimum of 55 °C and a pH optimum of 9. The enzyme was stable in a
broad pH range of 8.5- l 0.5 after l hr incubation at 50 ° C . It has a half-life of 30 min.
at 60°C . The enzyme was slightly activated by CuSO4 . Where as Ba++ ,Zn ++, Co++ ,
Hg++ , Mn ++, Fc+r ,.Na', K'and Ca" had very little.or no effect cin the activity of the
enzyme. The enzyme was strongly inhibited by I mM PMSF sh o\,,ing that it belongs
to the class of serine protease. EDTA at a concentration of IO mM partially inhibits
the activity. This shows the requirement of Ca'' for stability.
The organism was efficient in degrading Nug meal (GuizotaAbyssinia) and feather
when used as a sole carbon source.
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Biology