Optimization study for beta-mannanase production from locust bean gum by a local Aspergillus tamarii NRC 3 isolate

A survey of forty locally isolated fungal isolates from Egyptian soil was carried out for the extracellular beta-mannanase production by using both static and shaking cultures. Aspergillus tamarii NRC 3 recorded the highest beta-mannanase activity (30.89 Um l(-1)) when grown statically on a medium contains locust bean gum. No aflatoxins were detected in the culture filtrate of Aspergillus tamarii NRC 3. Molecular identification of the isolate was carried out 5S rRNA using fungal ITS primer. Factors affecting beta-mannanase Production were studied. From the obtained results, sodium nitrate at a concentration of 0.2%, inoculum age (6 days), inoculum size (one disk, 4 mm diameter, equal 2x10(7) spores), aeration ratio (4: 1), 7 days of static incubation, pH 5.0 and 25 -degrees C were the favorable parameters for beta-mannanase production (31.00 Uml(-1), 31.60 Uml(-1), 31.67Uml(-1), 31.70Uml(-1), 31.75Uml(-1), 31.75 Uml(-1), 31.88 Uml(-1), respectively). Surfactants used were, tween 20, 80 and SDS had no effect on beta-mannanase production.