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Alkaline protease
production on date waste by an alkalophilic Bacillus
sp. 2-5 isolated from soil
K. Khosravi-Darani1*, H.R. Falahatpishe1
and M. Jalali2
1Department
of Food Technology Research, National Nutrition and Food
Technology Research Institute, Shaheed Beheshti University,
M.C.;
P.O. Box 19395-4147,
Tehran, I. R. Iran.
2Department
of Nutrition and Biochemistry, School of Public Health,
Tehran University of Medical Sciences, Tehran, I. R. Iran.
*Corresponding author. E-mail: kiankh@yahoo.com.
Tel: +98 21 22376426. Fax:
+98 21 22360660.
Accepted 7 March, 2008 |
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This research focused on
isolation and characterization of a new strain of
Bacillus sp. from alkaline soil, which was able
to producing extracellular alkaline protease and amylase
from date waste at pH ranging from 8 to 11 and
temperatures of 20 to 50°C.
Purification was conducted by fractionation, concentration,
and cation exchange chromatography.
The yield and fold of enzyme purification was 24% and 50
times, respectively. Molecular weight of purified enzyme was
measured by SDS-PAGE as 24.7 kDa.
Produced alkaline protease by Bacillus sp. 2 - 5
showed the most caseinolytic activity (without any
gelatinolytic activity) at pH > 10. The highest protease
activity was achieved in the following conditions: starch
concentration (as carbon source) 0.5 g/L, yeast extract and
casamino acid
(as mixed nitrogen source) 0.5 and 0.3% (w/w), temperature
of 45°C
at pH 10.7 after 36 h. Based on the optimization studies of
production and purification stages, specific
and protease activity 143550 APU/mg and 57420 APU/mL
were achieved.
Key words:
Alkalophilic bacillus, alkaline protease, process variables,
purification, Date waste. |
