Demequina aestuarii gen. nov., sp. nov., a novel actinomycete of the suborder Micrococcineae, and reclassification of Cellulomonas fermentans Bagnara et al. 1985 as Actinotalea fermentans gen. nov., comb. nov.

An actinobacterial strain containing demethylmenaquinone DMK-9(H(4)) as the diagnostic isoprenoid quinone was isolated from a tidal flat sediment sample, from South Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain JC2054(T) represents a distinct phyletic line within the suborder Micrococcineae of the order Actinomycetales. The closest phylogenetic neighbour was Cellulomonas fermentans, with 94.7 % 16S rRNA gene sequence similarity. The novel isolate was strictly aerobic and slightly halophilic, with optimum growth occurring in 2-4 % (w/v) NaCl. Cells were non-motile, non-sporulating and rod-shaped. The peptidoglycan type was of the A-type of cross-linkage. l-ornithine was the diamino acid and d-glutamate represented the N-terminus of the interpeptide bridge. The predominant fatty acids were anteiso-branched and straight-chain fatty acids. The major polar lipids were phosphatidylinositol, diphosphatidylglycerol and an unknown phospholipid. The menaquinone composition of C. fermentans was determined to be MK-10(H(4)), MK-9(H(4)) and MK-8(H(4)) in the ratio 56 : 2 : 1. On the basis of the polyphasic evidence presented in this study, it is proposed that strain JC2054(T) should be classified as representing a novel genus and species of the suborder Micrococcineae, with the name Demequina aestuarii gen. nov., sp. nov. The type strain is JC2054(T) (=IMSNU 14027(T)=KCTC 9919(T)=JCM 12123(T)). In addition, it was clear from the phylogenetic analysis and chemotaxonomic data that C. fermentans does not belong to the genus Cellulomonas or any other recognized genera. Therefore, C. fermentans should be reclassified as representing a novel genus, for which the name Actinotalea fermentans gen. nov., comb. nov. is proposed, with strain DSM 3133(T) (=ATCC 43279(T)=CFBP 4259(T)=CIP 103003(T)=NBRC 15517(T)=JCM 9966(T)=LMG 16154(T)) as the type strain.