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

Abstract

<jats:p>The genus <jats:italic> <jats:named-content content-type="genus"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.9665" xlink:type="simple">Natronolimnobius</jats:ext-link> </jats:named-content> </jats:italic>, currently including four species, is a member of the order <jats:italic> <jats:named-content content-type="order"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.26390" xlink:type="simple">Natrialbales</jats:ext-link> </jats:named-content> </jats:italic>, class <jats:italic>Halobacteria,</jats:italic> 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 <jats:italic>Nlb. innermongolicus</jats:italic> (type strain N-1311) to a new genus <jats:italic>Natronolimnohabitans</jats:italic> as <jats:italic>Nlh. innermongolicus</jats:italic> comb. nov. and to transfer <jats:italic>Nlb. aegyptiacus</jats:italic> (type strain JW/NM-HA 15) and <jats:italic>Nlb. sulfurireducens</jats:italic> (type strain AArc1) to a new genus <jats:italic>Natrarchaeobaculum</jats:italic> as <jats:italic>Nbl. aegyptiacum</jats:italic> comb. nov. and <jats:italic>Nbl. sulfurireducens</jats:italic> 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 <jats:italic>Nlb. baerhuensis</jats:italic>, thermophily in <jats:italic>Nbl. aegyptiacus</jats:italic> and anaerobic sulfur respiration in <jats:italic>Nbl. sulfurireducens</jats:italic>. We further present an emended description of <jats:italic> <jats:named-content content-type="species"> <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://doi.org/10.1601/nm.9663" xlink:type="simple">Natronolimnobius baerhuensis</jats:ext-link> </jats:named-content> </jats:italic>.</jats:p>

Salinadaptatus halalkaliphilus gen. nov., sp. nov., a haloalkaliphilic archaeon isolated from salt pond in Inner Mongolia Autonomous Region, China

“…No glycolipid was detected in strain XQ-INN 246 T but two glycolipids were present in Hst. larsenii XH-48 T ( [29,30]. Data for Nar.…”

“…Comparative property of Salinadaptatus with the related genera from the family Natrialbaceae. The comparative data were taken from[29][30][31]. Number of species are showed in parenthesis…”

Cultivation of halophilic archaea (class Halobacteria) from thalassohaline and athalassohaline environments

“…It was recovered using anaerobic enrichment with acetate and elemental sulfur at 4 mol/L NaCl. Enrichment strategies (anaerobic or aerobic) were also applied to the isolation of the following halophilic archaea: Halalkaliarchaeum desulfuricum, which was isolated from anaerobic sediment sampled at the hypersaline alkaline Searles Lake in California (USA) (Sorokin et al 2019b); Halococcoides cellulosivorans, recovered from the surface brines and sediments of hypersaline athalassic lakes in the Kulunda Steppe (Altai region, Russia) using amorphous cellulose as the growth substrate (Sorokin et al 2019c); Halodesulfurarchaeum formicicum, isolated from mixed anaerobic sediments of hypersaline chloride−sulfate lakes in Kulunda Steppe (Altai, Russia) (Sorokin et al 2017); Natrarchaeobaculum sulfurireducens, isolated from various soda lakes in Central Asia, Africa and USA (Sorokin et al 2020); Natrarchaeobius chitinivorans and Natrarchaeobius haloalkaliphilus, both enriched and isolated from hypersaline alkaline lakes with chitin as their growth substrate (Sorokin et al 2019a), and Natronobiforma cellulositropha enriched and isolated in pure culture from surface brines and sediments of hypersaline alkaline lakes in various geographical locations with various forms of insoluble cellulose as growth substrate (Sorokin et al 2018). Halegenticoccus soli was isolated from a shore soil sample of Ebi lake in the Xinjiang region of China.…”

“…The authors used a modified Gause medium containing starch as carbon source (Liu et al 2019). Haloalkaliphiles that can grow by dissimilatory sulfur reduction (Natronolimnobius and Halalkaliarchaeum) have recently been reported (Sorokin et al 2019b), as has the proposed transfer of species within the genus Natronolimnobius to two new genera, Natronolimnohabitans and Natrarchaeobaculum (Sorokin et al 2020). Supplementary Table S2 shows the compound composition of each medium for culturing Halobacteria.…”

Anaerobic carboxydotrophy in sulfur-respiring haloarchaea from hypersaline lakes

“…The third group was found in hypersaline soda lakes. It consists of facultatively anaerobic haloalkaliphilic archaea, belonging to two new genera Halalkaliarchaeum and Natrarchaeobaculum, with a more versatile range of the electron donors for anaerobic sulfur respiration, including formate/H 2 , pyruvate, C 4 -C 9 fatty acids and peptone [33][34][35][36]. The last group includes facultatively aerobic haloarchaea, both neutrophilic and alkaliphilic, utilizing carbohydrates as an e-donor and carbon source for anaerobic sulfur respiration.…”