School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, USA.
Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA.
Nat Commun. 2024 Nov 4;15(1):9534. doi: 10.1038/s41467-024-53784-3.
Few aerobic hyperthermophilic microorganisms degrade polysaccharides. Here, we describe the genome-enabled enrichment and optical tweezer-based isolation of an aerobic polysaccharide-degrading hyperthermophile, Fervidibacter sacchari, previously ascribed to candidate phylum Fervidibacteria. F. sacchari uses polysaccharides and monosaccharides for growth at 65-87.5 °C and expresses 191 carbohydrate-active enzymes (CAZymes) according to RNA-Seq and proteomics, including 31 with unusual glycoside hydrolase domains (GH109, GH177, GH179). Fluorescence in-situ hybridization and nanoscale secondary ion mass spectrometry confirmed rapid assimilation of C-starch in spring sediments. Purified GHs were optimally active at 80-100 °C on ten different polysaccharides. Finally, we propose reassigning Fervidibacteria as a class within phylum Armatimonadota, along with 18 other species, and show that a high number and diversity of CAZymes is a hallmark of the phylum, in both aerobic and anaerobic lineages. Our study establishes Fervidibacteria as hyperthermophilic polysaccharide degraders in terrestrial geothermal springs and suggests a broad role for Armatimonadota in polysaccharide catabolism.
少数好氧嗜热微生物能够降解多糖。在这里，我们描述了一种好氧多糖降解嗜热菌 Fervidibacter sacchari 的基于基因组富集和光镊分离的方法，该菌之前被归为候选门 Fervidibacteria。F. sacchari 可在 65-87.5°C 的温度下利用多糖和单糖进行生长，并根据 RNA-Seq 和蛋白质组学表达 191 种碳水化合物活性酶 (CAZymes)，包括 31 种具有不寻常糖苷水解酶结构域 (GH109、GH177、GH179) 的酶。荧光原位杂交和纳米二次离子质谱证实了其在春季沉积物中对 C-淀粉的快速同化。纯化的 GHs 在十种不同多糖上的最适活性温度为 80-100°C。最后，我们建议将 Fervidibacteria 重新归类为 Armata 门内的一个纲，连同其他 18 个种，并表明大量和多样化的 CAZymes 是该门的一个标志，无论是在好氧和厌氧谱系中。我们的研究确立了 Fervidibacter 在陆地地热泉中的嗜热多糖降解菌地位，并表明 Armata 门在多糖代谢中具有广泛的作用。
