Caldimonas taiwanensis sp. nov., a amylase producing bacterium isolated from a hot spring

During screening for amylase-producing bacteria, a strain designated On1^T was isolated from a hot spring located in Pingtung area, which is near the very southern part of Taiwan. Cells of this organism were Gram-negative rods motile by means of a single polar flagellum. Optimum conditions for growth were 55°C and pH 7. Strain On1^T grew well in minimal medium containing starch as the sole carbon source, and its extracellular products expressed amylase activity. The 16S rRNA gene sequence analysis indicates that strain On1^T is a member of β-Proteobacteria. On the basis of a phylogenetic analysis of 16S rDNA sequences, DNA-DNA similarity data, physiological and biochemical characteristics, as well as fatty acid compositions, the organism belonged to the genus Caldimonas and represented a novel species within this genus. The predominant cellular fatty acids of strain On1^T were 16:0 (about 30%), 18:1 ω7c (about 20%) and summed feature 3 (16:1ω7c or 15:0 iso 2OH or both [about 31%]). Its DNA base ratio was 65.9 mol% G+C. We propose to classify strain On1^T (=BCRC 17405^T=LMG 22827^T) as Caldimonas taiwanensis sp. nov.