Clones with New Phenotypes through Transformation of Bacillus brevis 47, a Protein-producing Bacterium

抄録

Bacillus brevis No. 47, a high protein producer, was treated with deoxyribonucleic acid (DNA) from different strains of B. subtilis and B. amyloliquefaciens, the latter being an efficient producer of extracellular enzymes such as α-amylase, protease and ribonuclease (RNase). From the new clones obtained by the transformation procedure, about eighty were purified and used for examining the productivity and nature of trichloroacetic acid precipitable extracellular proteins, and the levels of activities and characteristics of α-amylase, protease and RNase secreted into the extracellular medium. The incorporation of various donor genetic markers into the new clones was also examined.
Despite little homology between the donor and the recipient DNAs, the appearance of the new clones was most probably the result of donor DNA mediated recombination events, because these clones exhibited unpredictably diverse combinations of phenotypes (e.g., extracellular enzyme activities or expression of donor markers). Among the recombinant clones obtained were those which produced greater amounts of extracellular proteins or possessed many-fold higher extracellular enzyme activities than their respective parents. The results presented in this paper show the usefulness of heterologous transformation for obtaining bacteria with new and varied phenotypes.