[Show abstract][Hide abstract] ABSTRACT: Two novel anaerobic, moderately thermophilic and cellulose-/cellobiose-digesting bacteria, EBR45(T) and EBR596(T), were isolated from anaerobic sludge of a cellulose-degrading methanogenic bioreactor. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belonged to cluster III within the low-G+C-content Gram-positive bacteria. The close relatives of EBR45(T) were Clostridium straminisolvens DSM 16021(T) (sequence identity, 94.6 %) and Clostridium thermocellum DSM 1237(T) (93.4 %). The closest relative of EBR596(T) was Clostridium stercorarium DSM 8532(T) (95.9 %). Both isolates were rod-shaped sporulators, growing optimally at 60 degrees C. EBR45(T) was Gram-staining-reaction-variable and non-motile, formed bright-yellow colonies on solid media, and grew on a relatively narrow range of carbohydrates including cellulose and cellobiose. EBR596(T) was Gram-staining-reaction-negative and motile, formed glossy white colonies and grew on cellobiose and various carbohydrates except cellulose. Major fatty acid compositions were 16 : 0 iso, 16 : 0 and 16 : 0 dimethylacetal (strain EBR45(T)) and 15 : 0 iso, 16 : 0 iso, 15 : 0 anteiso and 17 : 0 anteiso (strain EBR596(T)). The DNA G+C contents were 36.9 mol% (EBR45(T)) and 51.1 mol% (EBR596(T)). Based on the phenotypic and phylogenetic data and genomic distinctiveness, strains EBR45(T) and EBR596(T) represent two novel species, for which the names Clostridium clariflavum sp. nov. (type strain EBR45(T) =DSM 19732(T) =NBRC 101661(T)) and Clostridium caenicola sp. nov. (type strain EBR596(T) =DSM 19027(T) =NBRC 102590(T)) are proposed.
Preview · Article · Jul 2009 · International Journal of Systematic and Evolutionary Microbiology
[Show abstract][Hide abstract] ABSTRACT: A novel anaerobic, moderately thermophilic, spore-forming, rod-shaped bacterium (strain EBR46T) was isolated from an enrichment culture derived from an anaerobic thermophilic (55 degrees C) methanogenic bioreactor treating artificial solid wastes. Phylogeny based on 16S rRNA gene sequence analysis placed strain EBR46T within a distinct lineage between Clostridium clusters II and III. The closest recognized relative of strain EBR46T was Gracilibacter thermotolerans DSM 17427T (85.3 % 16S rRNA gene sequence similarity). The DNA G+C content of strain EBR46T was 36.2 mol%. The novel strain grew optimally at 55-58 degrees C and at pH 7.5-8.0 and was able to grow on peptone, tryptone, Casamino acids, casein hydrolysate, methionine, threonine, tryptophan, cysteine, lysine and serine in the presence of 0.2 % yeast extract. Carbohydrates were not utilized. The main products from tryptone utilization were acetate, iso-butyrate, propionate and iso-valerate. Strain EBR46T produced hydrogen sulfide from cysteine. The major fatty acids were iso-C15 : 0, C14 : 0, C16 : 0 DMA (dimethyl acetal) and iso-C15 : 0 DMA. Based on its unique phylogenetic and physiological features, strain EBR46T is considered to represent a novel species of a new genus, for which the name Lutispora thermophila gen. nov., sp. nov. is proposed. The type strain of the type species is EBR46T (=NBRC 102133T=DSM 19022T).
Preview · Article · May 2008 · International Journal of Systematic and Evolutionary Microbiology