Distribution and molecular investigation of highly thermophilic bacteria associated with cool soil environments.

In this study, both molecular and culture-based methods were used to characterize thermophilic bacteria associated with the subsurface soil environment in Northern Ireland. A total of 53 thermophilic, aerobic, sporulating and non-sporulating bacteria were isolated from subsurface soil samples obtained from two sites. They were screened by amplified ribosomal DNA restriction analysis prior to 16 S rRNA gene sequencing. The majority of the sequences were associated with Geobacillus thermoleovorans (50%) and Geobacillus caldoxylosilyticus (34.6%). Isolates F10, F20 and Tf exhibited only 93% similarity with Geobacillus toebii strain F70. Hence they may represent a new species of the genus Geobacillus.

Habitat, applications and genomics of the aerobic, thermophilic genus Geobacillus.

Thermophilic bacteria belonging to Bacillus genetic group 5 have been reclassified as being members of Geobacillus gen. nov., with G. stearothermophilus as the type strain. Geobacillus species, literally meaning earth or soil Bacillus, are widely distributed and readily isolated from natural and man-made thermophilic biotopes. Work within our group has however shown that an abundance of genetically distinct Geobacillus isolates can be obtained from temperate Irish soils. As with many thermophiles there is considerable interest in potential industrial application of these bacteria and their gene products. This review describes two novel applications for Geobacillus isolates, firstly in the metabolism of the herbicide glyphosate and secondly in the metabolism of quorum-sensing signal molecules from Gram-negative bacteria. Finally the current state of the art is described for Bacillus genomics, with details given of three independent genome-sequencing projects of Geobacillus isolates.