Streptomyces leeuwenhoekii sp. nov., the producer of chaxalactins and chaxamycins, forms a distinct branch in Streptomyces gene trees.

A polyphasic study was carried out to establish the taxonomic status of an Atacama Desert isolate, Streptomyces strain C34T, which synthesises novel antibiotics, the chaxalactins and chaxamycins. The organism was shown to have chemotaxonomic, cultural and morphological properties consistent with its classification in the genus Streptomyces. Analysis of 16S rRNA gene sequences showed that strain C34T formed a distinct phyletic line in the Streptomyces gene tree that was very loosely associated with the type strains of several Streptomyces species. Multilocus sequence analysis based on five house-keeping gene alleles underpinned the separation of strain C34T from all of its nearest phylogenetic neighbours, apart from Streptomyces chiangmaiensis TA-1T and Streptomyces hyderabadensis OU-40T which are not currently in the MLSA database. Strain C34T was distinguished readily from the S. chiangmaiensis and S. hyderabadensis strains by using a combination of cultural and phenotypic data. Consequently, strain C34T is considered to represent a new species of the genus Streptomyces for which the name Streptomyces leeuwenhoekii sp. nov. is proposed. The type strain is C34T (= DSM 42122T = NRRL B-24963T). Analysis of the whole-genome sequence of S. leeuwenhoekii, with 6,780 predicted open reading frames and a total genome size of around 7.86 Mb, revealed a high potential for natural product biosynthesis.