Salinarchaeum chitinilyticum sp. nov., a chitin-degrading haloarchaeon isolated from commercial salt

Two chitin-degrading halophilic archaeal strains, MC-74T and MC-23, were isolated from commercial salt samples. Cells were motile, rod-shaped and stained Gram-negative. Colonies were vermillion-pigmented. Strains MC-74T and MC-23 were able to grow with 1.5–5.1 M NaCl (optimum, 2.6–3.1 M) at pH 6.0–10.0 (optimum, pH 7.0) and at 20–50 °C (optimum, 40 °C). The orthologous 16S rRNA gene sequence similarity between the two strains was 99.8 %, and the closest phylogenetic relative was Salinarchaeum laminariae JCM 17267T with 99.3–99.5 % similarity. The level of DNA–DNA relatedness between the two strains was 93 and 94 % (reciprocally), and those between the two strains and Salinarchaeum laminariae JCM 17267T were 35–36 % and 38–39 % (reciprocally). The polar lipids of both strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate. Glycolipids were not detected. Based on the phenotypic and phylogenetic analyses, the strains represent a novel species of the genus Salinarchaeum , for which the name Salinarchaeum chitinilyticum sp. nov. is proposed. The type strain is MC-74T (=JCM 19597T=KCTC 4262T), isolated from solar salt produced in France. Strain MC-23, isolated from a commercial solar salt sample produced in China, is an additional strain of the species.