Cloning and expression of the gene encoding industrial α-amylase from Bacillus subtilis ORBA97 in Escherichia coli and Bacillus subtilis YB886

The alpha-amylase encoding gene from Bacillus subtillis ORBA97 strain was cloned and expressed in Escherichia coli with the plasmid vector called pUC18 as well as in the alpha-amylase negative Bacillus subtilis YB886 strain by using the pUB110 vector. The specific activity of the enzyme was determined to be 5.052 mumol (mg protein min)(-1). Zymogram analysis revealed no sign of protease degradation in the YB886 strain. The optimum temperature and pH of the enzyme were found to be 50degreesC and 5 respectively. Relative enzyme activity decreased to 3696 of the original activity when it was subjected to a temperature of 90degreesC for 15 minutes. Calcium chloride stimulated the enzyme activity and resulted in an approximately 23% increase in the activity. The pH tolerance of the enzyme seems to be suitable for the poultry digestive system. However, the thermostability of the enzyme may restrict its application in pelleted feeds.