1990 Volume 31 Issue 1 Pages 22-29_1
Identification of 14 strains of genus Bacillus isolated from corn soup was attempted by a gas chromatographic (GC) method. The identification was based on the differences in the GC pattern of volatile compounds extracted from culture broth of bacteria. After cultivation of bacteria in YBG medium (0.25% yeast extract, 0.5% bacto tryptone, 0.25% glucose, pH 7.5) at 30°C for 24hr, the culture supernatant (200ml) was charged on a Porapak Q column (2ml). The adsorbed compounds were eluted with ethyl ether (3ml) and the eluate was concentrated to 30μl under vacuum. The concentrate was analyzed by GC. Twelve different species of Bacillus, which are causative bacteria of food spoilage, were used as standards for identification of isolates. To identify the isolates, the GC data of each of the isolates and those of 20 strains of genus Bacillus were subjected to cluster analysis. For 13 strains of the isolates, the results of the GC method were consistent with those of the conventional method based on biological properties. One strain which was classified as B. circulans according to its biological properties could not be identified by the GC method, because the properties of the strain were rather different from those of B. circulans JCM 2504T used as the standard. The present method could distinguish between strains such as B. cereus and B. thuringiensis which are difficult to distinguish on the basis of their biological properties. The present GC method is expected to be useful for chemotaxonomical studies, though further research on the identification of various Bacillus species isolated from food samples by the GC method seems to be necessary.
