Anaerolinea thermophila gen. nov., sp nov and Caldilinea aerophila gen. nov., sp nov., novel filamentous thermophiles that represent a previously uncultured lineage of the domain Bacteria at the subphylum level

Two thermophilic, Gram-negative, non-spore-forming, multicellular filamentous micro-organisms were isolated from thermophilic granular sludge in an upflow anaerobic sludge blanket reactor treating fried soybean-curd manufacturing waste water (strain UNI-1(T)) and from a hot spring sulfur-turf in Japan (strain STL-6-O1(T)). The filaments were longer than 100 mum and of 0(.)2-0(.)3 mum (strain UNI-1(T)) or 0(.)7-0(.)8 pm (strain STL-6-O1(T)) in width. Strain UNI-1(T) was a strictly anaerobic organism. The optimum temperature for growth was around 55 degreesC; growth occurred in the range 50-60 degreesC. The optimum pH for growth was around 7(.)0; growth occurred in the range pH 6(.)0-8(.)0. Strain STL-6-O1(T) was a facultatively aerobic bacterium. The optimum temperature for growth was around 55 degreesC growth occurred in the range 37-65 degreesC. The optimum pH for growth was around 7(.)5-8(.)0; growth occurred in the range pH 7(.)0-9(.)0. The two organisms grew chemo-organotrophically on a number of carbohydrates and amino acids in the presence of yeast extract. The G+C content of the DNA of strains UNI-1(T) and STL-6-O1(T) was 54(.)5 and 59(.)0 mol%, respectively. Major cellular fatty acids for strain UNI-1(T) were C-16 : 0, C-15 : 0, C-14 : 0 and C-18 : 0, whereas those for strain STL-6-O1(T) were C-18 : 0, C-16 : 0, C-17 : 0 and iso-C-17 : 0. MK-10 was the major quinone from aerobically grown STL-6-O1(T) cells. Phylogenetic analyses based on 16S rDNA sequences revealed that both strains belong to an uncultured, previously recognized clone lineage of the phylum Chloroflexi (formerly known as green non-sulfur bacteria). These phenotypic and genetic properties suggested that each strain should be classified into a new independent genus; hence, the names Anaerolinea thermophila and Caldilinea aerophila are proposed for strains UNI-1(T) (= JCM 11387(T) = DSM 14523(T)) and STL-6-O1(T)(= JCM 11388(T) = DSM 14525(T)), respectively. These strains represent the type and sole species of the genera Anaerolinea and Caldilinea, respectively.