<i>Natronolimnohabitans</i>

Na.tro.no.lim.no.ha’bi.tans. Arabic n. natrun or natron, soda, sodium carbonate; Gr. fem. n. limne, lake; L. masc. n. habitans, an inhabitant; N.L. masc. n. Natronolimnohabitans, an organism living in soda lakes.The genus Natronolimnohabitans represents a currently monospecies alkaliphilic haloarchaeon inhabiting hypersaline soda lakes. Initially, the type species was placed in the genus Natronolimnobius mainly based on the phylogenetic relatedness inferred from the 16S rRNA gene sequence similarities. However, later on, it was reclassified to the current genus, Natronolimnohabitans, based on the results of more advanced phylogenomic analyses. Cells are rod-shaped and nonmotile. Gram-stain-negative, and red-pigmented. Obligate aerobic, and oxidase- and catalase-positive. Extremely halophilic with a growth Na+ range between 2.5 and 4.5M (optimum at 3.5 M). Cells lyse in less than 0.5M NaCl. Obligately alkaliphilic with a growth pH range between 7.5 to 10.0 (optimum at 9.5). Mesophilic or thermotolerant (optimal growth at 45∘C). Chemoorgano-trophic, utilizing mostly organic acids as carbon and energy source. The major polar lipids are diphytanyl (C20:C20) and phytanyl-sesterterpanyl (C20:C25) diether derivatives of phosphatidylglycerol (PG) and phosphatidylglycero-phosphate methyl ester (PGP-Me). The major respiratory quinones are MK-8 and MK-8(H2). Isolates have been obtained from soda lakes. DNA G+C content (mol%): 63.1 (HPLC), 64.3 (genome). Type species: Sorokin et al. 2020VP (basonym: Natronolimnobius innermongolicus Itoh et al. 2005, VL105).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work publicBT/Environmental Biotechnolog

Reclassification of the genus Natronolimnobius: Proposal of two new genera, Natronolimnohabitans gen. nov. to accommodate Natronolimnobius innermongolicus and Natrarchaeobaculum gen. nov. to accommodate Natronolimnobius aegyptiacus and Natronolimnobius sulfurireducens

The genus Natronolimnobius, currently including four species, is a member of the order Natrialbales, class Halobacteria, and consists of obligately alkaliphilic and extremely halophilic members found exclusively in highly alkaline hypersaline soda lakes. The species were classified into this genus mostly based on phylogenetic analysis of the 16S rRNA gene. However, a more advanced phylogenomic reconstruction based on 122 conserved single-copy archaeal protein markers clearly indicates a polyphyletic origin of the species included into this genus, thus warranting its reclassification into three separate genera. We therefore propose to transfer Nlb. innermongolicus (type strain N-1311) to a new genus Natronolimnohabitans as Nlh. innermongolicus comb. nov. and to transfer Nlb. aegyptiacus (type strain JW/NM-HA 15) and Nlb. sulfurireducens (type strain AArc1) to a new genus Natrarchaeobaculum as Nbl. aegyptiacum comb. nov. and Nbl. sulfurireducens comb. nov. The phylogenomic differentiation of these four species is also supported by the ANI/AAI distances and unique phenotypes. The most important physiological differences includes a previously unreported ability for cellulose and xylan utilization in Nlb. baerhuensis, thermophily in Nbl. aegyptiacus and anaerobic sulfur respiration in Nbl. sulfurireducens. We further present an emended description of Natronolimnobius baerhuensis.Accepted Author ManuscriptBT/Environmental Biotechnolog