Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/11/2008
Publication Date: 7/15/2009
Citation: Nelson, D.M., Glawe, A.J., Labeda, D.P., Cann, I.K., Mackie, R.I. 2009. Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov., Psychrotolerant, Xylan-Degrading, Bacteria from Alaskan Tundra. International Journal of Systematic and Evolutionary Microbiology. 59(pt. 7):1708-1714. Interpretive Summary: Xylan hydrolysis is important in the decomposition of plant material in soils and the low temperatures and high moisture content in arctic soils result in the accumulation of organic matter in soils. The effects of global warming in raising the temperatures of arctic soils and causing them to dry may stimulate the microbial communities present and cause degradation of the organic matter in these soils, but little is known about the types of microorganisms present. Microorganisms were isolated from a variety of Alaskan tundra soils collected from between the Arctic Coastal Plain and the northern foot slopes of the Brooks Range and these were taxonomically characterized. Two new species of the genus Paenibacillus were identified that are capable of growing at low temperatures and hydrolyzing xylan, for which the names Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov. are proposed.
Technical Abstract: Psychrotolerant, xylan-degrading, strains of bacteria were isolated from soil beneath moist non-acidic and acidic tundra in northern Alaska. Phylogenetic analysis based on 16S rRNA gene sequences revealed that each strain belonged to the genus Paenibacillus. The highest levels of 16S rRNA gene similarity were found between the strains and Paenibacillus amylolyticus NRRL NRS-290 (98.9-99.1%)T and Paenibacillus pabuli NCIMB 12781T (97.7-97.9%). However, DNA G+C content, repetitive elements genotyping, and phenotypic properties revealed that the strains differed from these species. The DNA G+C contents of the strains ranged from 46.4-50.3 mol%. Significant phenotypic features of the novel strains that differentiate them from P. amylolyticus include their inability to utilize L-arabinose, and ability to utilize glycogen, as sole carbon sources. Unlike strains 1B4a and B22aT, strains A6a and A10bT produced ethanol as an end product of glucose fermentation, utilized acetic acid and 2,3-butanediol, and did not utilize D-gluconic acid. On the basis of phenotypic characteristics and genomic contents, strains A10bT and B22aT are considered to represent novel species of the genus Paenibacillus, for which the names Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov. are proposed. The type strains of Paenibacillus tundrae sp. nov. and Paenibacillus xylanexedens sp. nov. are A10bT (=NRRL B-51094T = DSM 21291T) and B22aT (=NRRL B-51090T = DSM 21292T), respectively.