Paenibacillus xylanilyticus sp nov., an airborne xylanolytic bacterium

During a search for xylan-clegrading micro-organisms, a sporulating bacterium was recovered from xylan-containing agar plates exposed to air in a research laboratory (Salamanca University, Spain). The airborne isolate (designated strain XIL14(T)) was identified by 16S rRNA gene sequencing as representing a Paenibacillus species most closely related to Paenibacillus illinoisensis JCM 9907(T) (99.3 % sequence similarity) and Paenibacillus pabuli DSM 3036 T (98% sequence similarity). Phenotypic, chemotaxonomic and DNA-DNA hybridization data indicated that the isolate belongs to a novel species of the genus Paenibacillus. Cells of strain XIL14(T) were motile, sporulating, rod-shaped, Gram-positive and facultatively anaerobic. The predominant cellular fatty acids were anteiso-C-15 : 0 and C-16 : 0. The DNA G + C content of strain XIL14(T) was 50.5 mol%. Growth was observed with many carbohydrates, including xylan, as the only carbon source and gas production was not observed from glucose. Catalase was positive and oxidase was negative. The airborne isolate produced a variety of hydrolytic enzymes, including xylanases, amylases, gelatinase and beta-galactosidase. DNA-DNA hybridization levels between strain XIL14(T) and P. illinoisensis DSM 11733(T) and P. pabuli DSM 3036(T) were 43(-)3 and 36.3 %, respectively. According to the data obtained, strain XIL14(T) is considered to represent a novel species for which the name Paenibacillus xylanilyticus sp. nov. is proposed (= LMG 21957(T) = CECT 5839(T)).