Scale-up of S-Layer Protein Secretion by Bacillus brevis 47

Bacillus brevis 47 is a soil bacterium which produces two S-layer wall proteins which are 115 and 104 kDa in size. This strain can, under appropriate cell cultivation conditions, be induced to secrete up to about 14 g/L of these S-layer proteins into the culture medium. This situation has prompted researchers to evaluate this organism as a host for the production and secretion of large quantities of heterologous proteins of commercial value. Proteins which are secreted into the medium are potentially easier to recover and purify than are intracellular proteins. Indeed, the production of recombinant proteins by this organism has been reported (Takao et al., 1989; Yamagata et al., 1989; Konishi et al., 1990), although at substantially lower levels than the native S-layer proteins.