Abstract:
Thermophilic processes appear more stable, rapid and less expensive and facilitate reactant activity and product recovery.
Amylases have a quarter of the world enzyme market and thermostable amylases possess extensive commercial applications.
Since little work has been done on strain isolation, growth and enzyme yield optimization, the level of thermophilic enzyme
production remains relatively low. Therefore, large scale exploitation of thermophiles requires further intensive and
integrated work. The present study describes isolation of four amylase producing bacilli from Sudanese soil. The isolates were
identified and named as Bacillus licheniformis (SUDK1, SUDK2, SUDK4 and SUDO) . These isolates were tested for the
production of amylase enzymes as they recorded the largest zone of activity. Amylase activity was determined using DNS
method. The strain was cultured in liquid media to produce amylases. The enzyme production conditions of the newly isolated
bacillii revealed that the maximum enzyme production after 24 h of cultivation at alkalophile pH and 50°C. 5m M Mg++ ions,
1% soluble starch in production medium enhanced the enzyme productivity for all isolates . 1% Peptone was the best nitrogen
source for all isolates except SUDK2 which needed malt extract. The results showed that B. licheniformis (SUDK1, SUDK2,
SUDK4 and SUDO) is a good producer of extracellular amylase at high temperatures which could be an indication that amylase
produced would be thermostable and suitable for application in starch processing and food industries.
