High level production of Escherichia coli outer membrane proteins OmpA and OmpF intracellularly in Bacillus subtilis

A high yield of Escherichia coli outer membrane proteins OmpA (about 200 mg/l) and OmpF (about 100 mg/l) was obtained in Bacillus subtilis when produced intracellularly. The yield was more than 100-fold higher than the yield of these proteins by a similar vector containing the complete signal sequence of alpha-amylase of B. amyloliquefaciens. Both proteins isolated after breakage of the B. subtilis cells by low-speed centrifugation were about 70% pure and could be solubilized by Sarkosyl, SDS and guanidine hydrochloride.