Wen Feng, Yang Guo, Zhao Xueling, Zhao Tiantian, Bai Linquan, Xia Zhanfeng
Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, College of Life Sciences and Technology, Xinjiang Production & Construction Corps, Tarim University, Alar, China.
State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
Front Microbiol. 2025 Aug 7;16:1580401. doi: 10.3389/fmicb.2025.1580401. eCollection 2025.
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.
塔克拉玛干沙漠是一个天然的碱性生态系统，蕴藏着丰富多样的耐碱微生物。然而，关于它们的分布、多样性和生物技术潜力的系统研究仍然有限。在本研究中，从塔克拉玛干沙漠中部采集了五个代表性土壤样本，那里原始土壤的pH值在8.78至9.8之间。为了研究碱性条件对微生物群落的影响，将样本在pH值调整为9至11的培养基中进行富集培养。使用不依赖培养的16S rRNA基因扩增子测序评估富集部分的细菌群落结构，同时对一个未富集的对照组（CK）——由未经pH值调整的相同土壤组成——进行测序，以确定细菌组成的基线。同时，采用依赖培养的方法，使用pH值为9、10和11的吉本斯培养基从相同样本中分离耐碱细菌菌株。根据不同的菌落形态选择分离株，通过划线法反复纯化，并通过16S rRNA基因测序进行分类鉴定，共获得291株菌株。这些分离株被分类归为4个门、6个纲、17个目、25个科和56个属。其中，114株菌株与已知物种的序列同一性低于98.65%，表明存在许多潜在的新分类单元。分别约有14.07%和61.48%的分离株被归类为耐碱菌和嗜碱菌，有85株能够在极端条件下（pH值为12和/或盐度为25%）生长。功能筛选显示，相当一部分分离株具有酶活性：20.35%产生淀粉酶，19.91%产生蛋白酶，30.30%产生纤维素酶，47.61%表现出至少一种酶功能。总体而言，本研究综合了不依赖培养和依赖培养的方法，揭示了塔克拉玛干沙漠耐碱细菌的分类和功能多样性，突出了它们的生态作用以及在工业生物技术中的潜在应用。
