Chitinivorax tropicus gen. nov., sp. nov., a chitinolytic bacterium isolated from a freshwater lake
A facultatively anaerobic, chitinolytic bacterium, strain KL-9T, was isolated from a freshwater lake in Taiwan and characterized by using a polyphasic taxonomic approach. Cells of strain KL-9T were Gram-negative, rod-shaped, motile by means of a single polar flagellum and non-spore-forming. Growth occurred at 15–40 °C (optimum, 30–37 °C), at pH 7.0–9.0 (optimum, pH 8.0) and with 0–1.0 % NaCl (optimum, 0 %). The predominant fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The major isoprenoid quinone was Q-8. The DNA G+C content of strain KL-9T was 64.6 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidyldimethylethanolamine and several uncharacterized phospholipids and aminolipids. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain KL-9T formed a distinct lineage with respect to closely related genera within the class Betaproteobacteria , being most closely related to members of the genera Leeia , Chitinimonas , Silvimonas and Andreprevotia . Levels of 16S rRNA gene sequence similarity with respect to the type strains of type species of these genera were below 91 %. On the basis of genotypic and phenotypic data, strain KL-9T is thus considered to represent a novel species of a new genus within the class Betaproteobacteria , for which the name Chitinivorax tropicus gen. nov., sp. nov. is proposed. The type strain of Chitinivorax tropicus is KL-9T ( = BCRC 80168T = LMG 25530T).