The main aim of the book to explain rDNA technology experimentally is explained to understand the graduate students of biotechnology to know isolation of the amylase gene in Bacillus subtilis from soil and transforming into E. coli to express amylase enzyme that catalyses the breakdown of starch into sugars. This amylase enzyme has a commercial value in industry so to increase the yield of amylase by rDNA technology by developing strain which yield better. The main aim of the book is to identify the amylase gene in Bacillus subtilis from soil and transforming into E. coli. Amylase is an enzyme that catalyses the breakdown of starch into sugars. These amylase enzyme has a commercial value in industry so to increase the yield of amylase by rDNA technology by developing strain which yield better.