Studies on a Strain of Bacillus brevis Isolated from Soil : Part I. Isolation of an Antibiotic Producing Strain and its Bacteriological Characteristics

A strain producing two kinds of antibiotics was isolated from soil. This report describes the morphologic and physiologic characteristics of the strain. As a result of the detailed examination, it was determined that this bacillus belonged to the species of Bacillus brevis. The most striking characteristic of this strain was its ability of simultaneous production of two different antibiotics (Gramicidin S and Polymyxin A described in another paper by the author). This kind of phenomenon has not been previously recognized. Another characteristic noted was the shift in the optimal temperature for growth of the strain, i. e., changing of the optimal temperature was found from 35℃ on 5 hours cultivation to 29℃ after 24 hours cultivation.