International Journal of Systematic and Evolutionary Microbiology, Vol 50, 315-320, Copyright © 2000 by International Union of Microbiological Societies
Thermobacillus xylanilyticus gen. nov., sp. nov., a new aerobic thermophilic xylan-degrading bacterium isolated from farm soil
JP Touzel, M O'Donohue, P Debeire, E Samain and C Breton
INRA (Institut National de la Recherche Agronomique), Unite de Physicochimie et Biotechnologie des Polymeres, Equipe de Fractionnement Enzymatique, BP 1039, F-51687 Reims cedex 2, France
An aerobic, thermophilic, xylanolytic, spore-forming bacterium, XE(TP)
(T=type strain; P=patent strain), has been isolated from farm soil situated
underneath a manure heap in northern France. Strain XE(TP), which stained
negative in the Gram test, occurs as short rods which sometimes form
chains. Its spores are ellipsoidal, central to subterminal and occur in
swollen sporangia. It grows at temperatures up to 63 degrees C and in the
pH range 6.5--8.5. When grown on glucose in optimal conditions, its
doubling time was found to be 33 min. CO(2) was observed to have a
growth-stimulating effect at the start of the culture. In addition to
glucose, the isolate utilizes xylose, arabinose, mannose, cellobiose,
galactose, maltose, sucrose, xylan and starch. Growth is inhibited by 5%
NaCl. The G+C content of strain XE(TP) is 57.5 mol%. The 16S rDNA sequence
analysis indicated that strain XE(TP) falls into the radiation of the
Bacillus--Lactobacillus--Streptococcus subdivision of the Gram-positive
phylum. Its three closest phylogenetic relatives are 'Bacillus viscosus',
Paenibacillus curdlanolyticus and Bacillus popilliae with identity values
of 91.15, 90.94 and 90.92%, respectively. The major cellular fatty acids
are 14-methyl pentadecanoic acid (16:0 iso), hexadecanoic acid (16:0) and
14-methyl hexadecanoic acid (17:0 anteiso). On the basis of 16S rRNA
sequence and chemotaxonomic characteristics, the isolate is different
enough for it to be considered as a member of a new genus. It is therefore
proposed that this isolate represents a new genus and species:
Thermobacillus xylanilyticus. Strain XE(TP), the type strain of
Thermobacillus xylanilyticus, has been deposited in the Collection
Nationale de Cultures Microbiennes (CNCM I-1017) as a patent strain.
