Construction of a Bacillus subtilis strain deficient in three proteases.

Bacillus subtHis secretes a variety of proteins directly into the culture medium at high levels.1} It is therefore possible to cause efficient secretion of useful foreign proteins using the expression and secretion systems of B. subtHis. A large number of both procaryotic and eucaryotic genes have successfully been fused t'o several secretion vectors.2~8) In most cases, however, the systems yielded the secreted products at a low level, mainly due to 1307