Object: The phylogenetic relationship of 90 species of the genus Bacillus was analyzed using fatty acid biomarkers.
Methods: Fatty acid biomarkers were detected by Microorganism Identification System (Sherlock MIS) with gas chromatography (Agilent 7890 N, MIDI Inc. , Newark, DE). Based on the distribution characteristics of fatty acid, 10 parameters e. g. 16:0 iso, 16:0, 17:0 iso, 17:0 anteiso, 15:0 iso, 15:0 anteiso, 15:0 iso/15:0 anteiso, 17:0 iso/ 17:0 anteiso, diversity index (H) and evenness index (J) were constructed to perform fatty acid phylogeny of the genus Bacillus.
Results: In the 90 Bacillus species 29 fatty acid biomarkers were found with the carbon lengths ranging from 10 to 20. From statistical analysis, sum of relative percentage content of the 6 largest fatty acid biomarkers were 15:0 anteiso, 15:0 iso, 17:0 anteiso, 16:0, 17:0 iso and 16:0 iso. Among them, 15:0 anteiso and 15:0 iso possessed high content with fully distribution in all species tested. Of the biomarkers, 17:0 anteiso, 16:0, 17:0 iso and 16:0 iso had middle content, being not fully distributed, and the rest belonged to low content and not fully distributed. Ninety Bacillus species were divided into five fatty acid groups, e. g. stenothermic group, eurithermophile group, alkaliphilic group, acidophilus group and mesophilic group. The cluster analyses of phenetic classification and fatty acid classification were further compared to find that both classification systems yielded an identical result.
Conclusion: Phylogenetic classification system of the genus Bacillus using fatty acid biomarkers embraces Bacillus phylogeny with physiological and biochemical charateristics. This fatty acid-based phylogenetic system may become a new system for classification.