HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by De Bartolomeo, A. Articles by Mastrandrea, V. Search for Related Content PubMed Articles by De Bartolomeo, A. Articles by Mastrandrea, V. Agricola Articles by De Bartolomeo, A. Articles by Mastrandrea, V.

Numerical Analysis and DNA Base Compositions of Some Thermophilic Bacillus Species

Dipartimento di Igiene, Università di Perugia, 06100 Perugia, Italy

^* Corresponding author.

ABSTRACT

Morphological, physiological, and biochemical characteristics and the DNA base compositions of 133 thermophilic Bacillus strains were determined. A total of 54 of these strains were received as identified species (mainly Bacillus stearothermophilus, Bacillus coagulans, Bacillus brevis, and Bacillus licheniformis) from international culture collections, and 79 newly isolated strains, which were isolated mainly from sugar diffusion juices of Italian plants, were also examined. Numerical taxonomy techniques (simple matching coefficient and unweight pair grouping using the mathematical average) and DNA G+C values showed that the strains aggregated into nine clusters. Both B. licheniformis and B. brevis were well separated from the other organisms. B. stearothermophilus and B. coagulans were confirmed as separate clusters and exhibited greater heterogeneity than previously shown. The B. stearothermophilus strains clustered into four groups, three of which have been recognized previously by other authors; the members of the fourth group had distinctive characteristics, including considerable biochemical inertness, an inability to grow at temperatures greater than 60°C, and a high G+C content. Within the B. coagulans cluster the strains with characteristics very similar to those of the new species Bacillus smithii clustered together. However, the remaining strains were still clearly separated into two groups; one of these groups was considered B. coagulans sensu stricto, and the other was distinguished by morphological and biochemical criteria, such as spores which do not swell the sporangia, utilization of citrate, a higher proteolytic activity, and acidification of some carbohydrates. Our results were confirmed by comparing them with distinctive characteristics of recently described thermophilic Bacillus species.