Vanderlaan Olivia J M, Simmons Emily M, Damman Kelli M, Waddell Makenna D, Ross Savannah F, Armstrong Amanda D, Walker Mackenzie L, Sattley S Josiah, Sattley W Matthew
Department of Biology, Indiana Wesleyan University, Marion, IN, United States.
The King's Academy, Jonesboro, IN, United States.
Front Microbiol. 2025 Aug 6;16:1620605. doi: 10.3389/fmicb.2025.1620605. eCollection 2025.
Despite their potential for harboring novel microorganisms exhibiting beneficial metabolisms or that produce useful products for biotechnology and industry, alkaline lakes and soils are among the least studied extreme environments. With its high productivity and meromictic water column, haloalkaline Soap Lake (Washington, USA) is among the most intriguing soda lakes in the world. We sampled the water column of Soap Lake and used both culture-based and culture-independent (16S rRNA amplicon-based) methods to analyze the microbial diversity of both its oxic and anoxic waters. Cultivable aerobic heterotrophs were specifically targeted in enrichment cultures, and over 100 isolates were obtained. Small-subunit rRNA gene sequences were obtained for isolates that exhibited diverse colony morphologies and grew well on alkaline media containing varying concentrations of NaCl, and two of these isolates were chosen for in-depth characterization: strain 12SL-E129, which aligned within the genus ; and strain SL14, of the genus . Both strains grew optimally at or above pH 9 and were halophilic-no growth was evident in the absence of NaCl for either isolate. In addition, strain SL14 exhibited impressive cold adaptation, showing a faster growth rate at 0°C than at 37°C. Community (16S rRNA) analyses conducted on Soap Lake water samples from both the mixolimnion (3 m) and the monimolimnion (23 m) revealed an extensive diversity of , with the shallower depth dominated by species of (especially ), , and ; Deep anoxic waters were dominated by , including many taxa containing endospore formers, as well as a marked increase in sulfate-reducing . Only low numbers of were identified in both the upper and lower waters of Soap Lake. Our data suggest that despite its extreme conditions (high alkalinity, steep salinity gradient, and reportedly extraordinarily high sulfide concentrations in the monimolimnion), Soap Lake is a highly productive aquatic system supporting thriving and diverse bacterial communities.
尽管碱性湖泊和土壤有可能蕴藏着具有有益代谢的新型微生物，或者能产生对生物技术和工业有用的产品，但它们却是研究最少的极端环境之一。美国华盛顿州的盐碱化肥皂湖拥有高产率和半混合水柱，是世界上最引人入胜的苏打湖之一。我们对肥皂湖的水柱进行了采样，并使用基于培养和不依赖培养（基于16S rRNA扩增子）的方法来分析其有氧和无氧水域的微生物多样性。在富集培养中专门针对可培养的需氧异养菌，获得了100多个分离株。对具有不同菌落形态且在含有不同浓度NaCl的碱性培养基上生长良好的分离株，获得了小亚基rRNA基因序列，并选择其中两个分离株进行深入表征：菌株12SL-E129，其在属内排列；以及属的菌株SL14。两种菌株在pH 9或更高时生长最佳，并且都是嗜盐菌——在没有NaCl的情况下，两种分离株均未明显生长。此外，菌株SL14表现出令人印象深刻的冷适应性，在0°C时的生长速度比在37°C时更快。对来自混合湖上层（3米）和静水层（23米）的肥皂湖水样进行的群落（16S rRNA）分析显示，存在广泛的多样性，较浅深度以物种（尤其是）、和为主；深层缺氧水域以为主，包括许多含有芽孢形成菌的分类群，以及硫酸盐还原菌的显著增加。在肥皂湖的上层和下层水域中仅鉴定出少量。我们的数据表明，尽管肥皂湖处于极端条件下（高碱度、陡峭的盐度梯度以及据报道在静水层中异常高的硫化物浓度），但它是一个高产的水生系统，支持着繁荣多样的细菌群落。
