Abstract

Two secretion vectors, pUBA240 and pUB340 were constructed by using the promoter and secretory signal region of the α-amylase gene from an α-amylase hyperproducing strain, Bacillus subtilis NA64. In this secretion vector system, various restriction enzyme sites are located immediately after the proregion of the α-amylase gene for easy replacement of various foreign structural genes. To evaluate this secretion vectors, the β-lactamase gene of pBR322 was used as a reporter gene. The expressed and biologically active β-lactamase was secreted into the culture broth from B. subtilis LKS86 transformants harboring each β-lactamase secreting plasmid, pUBAbla and pUBSble. In both cases, more than 92% of expressed β- lactamases were located idn the culture medium. The amount of the secreted β-lactamase was about 80% of the total secreted proteins in the culture medium.

• Keywords: B. subtilis; secretion vector; β-lactamase secretion