Stepwise introduction of regulatory genes stimulating production of .ALPHA.-amylase into Bacillus subtilis: Construction of an .ALPHA.-amylase extrahyper producing strain.

The production of extracellular u-amylase in Bacillus subtilis is probably regulated by many genetic elements, such as amyR, tmrA7, pap, amyB and sacU. Additional genetic elements, C-108 and A-2 for production of the α-amylase were found in D-cycloserine and ampicillin resistant mutants (C108 and A2) of B. subtilis 6160, respectively. Strain C108 in-creased the production of α-amylase about 5 times and protease about 80 times compared to parental 6160 strain. Strain A2 showed a nearly 6-fold increased α-amylase production. These genetic elements displayed a synergistic effect with other genetic factors in production of extracellular α-amylase when these elements were transferred by DNA mediated trans-formation. By stepwise introduction of these and other genetic elements into B. subtilis 6160 by transformation and mutation, strains with higher a-amylase producing activity were ob-tained. The finally obtained strain, T2N26, produced about 1, 500_??_2, 000 times more α-amylase than parental 6160 strain.