Efficient production by Escherichia coli of recombinant protein using salting-out effect protecting against proteolytic degradation

Abstract

To produce glucoamylase efficiently as a recombinant protein, E. coli was grown with 20 g (NH₄)₂SO₄ l⁻¹ which removed proteolytic activity but did not effect cell growth. Growth in M9 medium with 20 g (NH₄)₂SO₄ l⁻¹ produced 11 U glucoamylase ml⁻¹ compared to 7 U ml⁻¹ without addition. Furthermore, the glucoamylase activity was maintained at about 9 U ml⁻¹.