Influence of a Cell-Wall-Associated Protease on Production of α-Amylase by Bacillus subtilis

Abstract

ABSTRACT AmyL, an extracellular α-amylase from Bacillus licheniformis , is resistant to extracellular proteases secreted by Bacillus subtilis during growth. Nevertheless, when AmyL is produced and secreted by B. subtilis , it is subject to considerable cell-associated proteolysis. Cell-wall-bound proteins CWBP52 and CWBP23 are the processed products of the B. subtilis wprA gene. Although no activity has been ascribed to CWBP23, CWBP52 exhibits serine protease activity. Using a strain encoding an inducible wprA gene, we show that a product of wprA , most likely CWBP52, is involved in the posttranslocational stability of AmyL. A construct in which wprA is not expressed exhibits an increased yield of α-amylase. The potential role of wprA in protein secretion is discussed, together with implications for the use of B. subtilis and related bacteria as hosts for the secretion of heterologous proteins.