A novel bacterium, designated TRM 415^T, belonging to the genus Brevibacterium, was isolated from a sediment sample from a salt lake in Xinjiang province, China. Comparative 16S rRNA gene sequence analysis indicated that strain TRM 415^T was phylogenetically most closely related to Brevibacterium album YIM 90718^T (98.4 % sequence similarity) and had low similarity (<95.5 %) to other species of the genus Brevibacterium; however, DNA–DNA hybridization studies between strain TRM 415^T and B. album YIM 90718^T showed only 41.3 % relatedness. Strain TRM 415^T possessed meso-diaminopimelic acid as the diagnostic cell-wall diamino acid, MK-8(H₂) as the major menaquinone and polar lipids including phosphatidylglycerol and diphosphatidylglycerol. The major fatty acids were anteiso-C_17 : 0 and anteiso-C_15 : 0. The genomic DNA G+C content was 69 mol%. Based on the evidence from this polyphasic study, strain TRM 415^T represents a novel species of the genus Brevibacterium, for which the name Brevibacterium salitolerans sp. nov. is proposed. The type strain is TRM 415^T (=JCM 15900^T =CCTCC AB 208328^T =KCTC 19616^T).

A novel filamentous actinomycete strain, designated TRM 46004^T, was isolated from sediment of Aiding Lake in Tulufan Basin (42° 64′ N 89° 26′ E), north-west China. The isolate was characterized using a polyphasic approach. The isolate formed abundant aerial mycelium with few branches and vegetative mycelium, occasionally twisted and coiled; spherical sporangia containing one to several spherical spores developed at the ends of short sporangiophores on aerial mycelium. The G+C content of the DNA was 65.2 mol%. The isolate containedmeso-diaminopimelic acid as the diagnostic diamino acid and xylose, galactose and ribose as the major whole-cell sugars. The diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine and phosphatidylglycerol. The predominant menaquinones were MK-9(H₄), MK-9(H₆) and MK-9(H₁₀). The major fatty acids were iso-C_16 : 0and anteiso-C_17 : 0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain TRM 46004^Tformed a distinct lineage within the family Pseudonocardiaceae and showed 91.7–96.1 % 16S rRNA gene sequence similarity with members of the family Pseudonocardiaceae . On the basis of the evidence from this polyphasic study, a novel genus and species,Longimycelium tulufanensegen. nov., sp. nov., are proposed. The type strain ofLongimycelium tulufanenseis TRM 46004^T( = CGMCC 4.5737^T = NBRC 107726^T).

A bacterial strain, designated TRM 80801^T, was isolated from the Karelinea in Taklamakan desert, Xinjiang Uygur Autonomous Region, north-west China. Cells were Gram-stain-positive, aerobic, non-motile, short rods. Strain TRM 80801^T grew at 4–50 °C, with optimum growth at 28 °C, and grew at pH 6.0–11.0 and 1–15 % (w/v) NaCl. Phylogenetic analyses of the 16S rRNA gene sequences placed strain TRM 80801^T within the genus Microbacterium with the highest similarities to Microbacterium suaedae YZYP 306^T (98.97 %) and Microbacterium indicum BBH6^T (98.17 %), respectively. The DNA G+C content of TRM 80801^T is 69.38 mol%. The cell-wall peptidoglycan contained the amino acids ornithine, glutamic acid, glycine and alanine, the diagnostic diamino acid was ornithine. The acyl type of the peptidoglycan was glycolyl. Whole-cell sugars were ribose, mannose, glucose, rhamnose and galactose. The major cellular fatty acids were anteiso-C_15 : 0, anteiso-C_17 : 0 and iso-C_16 : 0. The predominant menaquinones were MK-10, MK-11 and MK-12. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol. The whole-genome average nucleotide identity (ANI) value between strain TRM 80801^T and Microbacterium suaedae YZYP 306^T is 70.2 %. On the basis of the evidence presented in this study, strain TRM 80801^T is representative of a novel species in the genus Microbacterium , for which the name Microbacterium karelineae sp. nov. is proposed. The type strain is TRM 80801^T (=CCTCC AB 2019248^T=KCTC 49357^T).

Although the Taklimakan Desert lacks the necessary nutrients and conditions to support an extensive ecosystem, it is a treasure trove of extremophile resources with special structures and functions. We analyzed the bacterial communities using oligotrophic medium and velvet cloth replicate combined with an extended culture duration. We isolated numerous uncultured microorganisms and rare microorganisms belonging to genera not often isolated or recently described, such as Aliihoeflea, Halodurantibacterium, and Indioceanicola. A total of 669 strains were isolated from the soil of the Taklimakan Desert, which were classified into 5 phyla, 7 classes, 25 orders, 42 families, 83 genera, and 379 species. Among them, 148 strains were potential new species. Our data show that even when working with samples from extreme environments, simple approaches are still useful for cultivating stubborn microbes. Through comparing the isolation effects of different nutrient levels on microbial diversity and abundance, the results show that reducing the nutrient level of the medium was more conducive to improving the culturability of microorganisms in low-nutrient environments, while the high-nutrient medium was more suitable for the isolation of dominant fast-growing strains. This study helps to better reflect the diversity of microbial resources and lays a foundation for the further research and utilization of soil microbial resources in the Taklimakan Desert.

A novel actinomycete strain, designated TRM 46012^T, was isolated from sediment of Aiding Lake in Tulufan Basin (42° 64′ N 89° 26′ E), north-west China. The strain was aerobic and Gram-staining-positive with an optimum NaCl concentration for growth of 0–5 % (w/v). The isolate had sparse aerial mycelium and produced bud-shaped spores at the end of the aerial mycelium on ISP medium 4. The isolate contained ll-diaminopimelic acid as the diagnostic diamino acid and ribose as the major whole-cell sugar. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol mannoside, one unidentified phospholipid and three unidentified glycolipids. The predominant menaquinones were MK-9(H₆), MK-9(H₈) and MK-9(H₄). The major fatty acids were iso-C_16 : 0, anteiso-C_17 : 0 and anteiso-C_15 : 0. The G+C content of the DNA was 74.4 mol%. Phylogenetic analysis showed that strain TRM 46012^T had 16S rRNA gene sequence similarity of 95.7 % with the most closely related species with a validly published name, Streptomyces cheonanensis , and it could be distinguished from all species in the genus Streptomyces by using the data from this polyphasic taxonomic study. On the basis of these data, strain TRM 46012^T should be designated as a representative of a novel species of the genus Streptomyces , for which the name Streptomyces aidingensis sp. nov. is proposed. The type strain is TRM 46012^T ( = CGMCC 4.5739^T = NBRC 108211^T).

The Taklimakan Desert is a naturally alkaline ecosystem harboring a rich diversity of alkali-resistant microorganisms. However, systematic studies on their distribution, diversity, and biotechnological potential remain limited. In this study, five representative soil samples were collected from the central region of the Taklimakan Desert, where the original soil pH ranged from 8.78 to 9.8. To investigate the effect of alkaline conditions on microbial communities, the samples were subjected to enrichment in culture media adjusted to pH 9–11. The bacterial community structure of the enriched fraction was assessed using culture-independent 16S rRNA gene amplicon sequencing, while a non-enriched control (CK) group—consisting of the same soils without pH adjustment—was simultaneously sequenced to determine the baseline bacterial composition. In parallel, a culture-dependent approach was employed to isolate alkali-tolerant bacterial strains from the same samples using Gibbons medium at pH 9, 10, and 11. Based on distinct colony morphologies, isolates were selected, repeatedly purified by streaking, and taxonomically identified via 16S rRNA gene sequencing, resulting in a total of 291 strains. These isolates were taxonomically assigned to four phyla, six classes, 17 orders, 25 families, and 56 genera. Among them, 114 strains shared less than 98.65% sequence identity with known species, suggesting the presence of numerous potential novel taxa. Approximately 14.07 and 61.48% of the isolates were categorized as alkali-tolerant and alkalophilic, respectively, with 85 strains capable of growing under extreme conditions (pH 12 and/or 25% salinity). Functional screening revealed enzymatic activity in a substantial portion of the isolates: 20.35% produced amylase, 19.91% protease, 30.30% cellulase, and 47.61% exhibited at least one enzymatic function. Overall, this study integrates both culture-independent and culture-dependent approaches to reveal the taxonomic and functional diversity of alkali-tolerant bacteria in the Taklimakan Desert, highlighting their ecological roles and potential applications in industrial biotechnology.