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

During screening for amylase-producing bacteria, a strain designated On1T 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 On1T 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 On1T 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 On1T 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 On1T (=BCRC 17405T=LMG 22827T) as Caldimonas taiwanensis sp. nov.