Abstract:

Using gene recombination method, the alpha amylase gene amyE (without promoter) of Bacillus subtilis was
integrated into Paxo1 plasmid and the galactosidase gene lacZ of B. subtilis strain 168 was introduced into the recombinant
expression plasmid Paxo1-amyE. After transformation and screening analysis, genetically engineered strain PaE containing
the recombinant alpha amylase gene was selected. With the addition of four different carbon sources, the alpha amylase
production by the recombinant strain was promoted under the induction of 2 g/100 mL xylose. In addition, the recombinant
strain could overcome the carbon catabolic repression caused by reducing saccharides such as glucose to a certain extent to
improve the yield of alpha amylase.

Key words: α-amylase, Bacillus subtilis, genetic recombination, xylose