Fermentative Firmicutes species are key players in anaerobic digestion; however, their niche differentiation based on carbohydrate utilization in full-scale systems remains unclear. In this study, we investigated niche differentiation among four major Firmicutes classes using a genome-centric approach, reconstructing 39 high-quality metagenome-assembled genomes. Limnochordia and Clostridia exhibited the broadest substrate versatility, utilizing 24% and 18% of the predicted substrates, respectively. Although common substrates were shared, each class demonstrated unique substrate preferences driven by distinct functional and metabolic differences. Limnochordia and Clostridia possess unique carbohydrate-active enzyme families, such as GH177 and CBM91, which enable xylan and arabinan degradation. Bacilli were abundant with the GH1 and GH3 families, which are critical for cellulose degradation. Overall, the Firmicutes classes showed low overlap in substrate use and functional profiles, confirming significant niche differentiation. Our results demonstrate that Firmicutes occupy distinct dietary niches supporting insights into bacterial coexistence in anaerobic digestion systems.

中文翻译：

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基于基因组的分析揭示了全尺寸厌氧消化系统中厚壁菌门之间的生态位分化


发酵厚壁菌门物种是厌氧消化的关键参与者;然而，它们基于全尺寸系统中碳水化合物利用率的生态位分化仍不清楚。在这项研究中，我们使用以基因组为中心的方法研究了四个主要厚壁菌门类别之间的生态位分化，重建了 39 个高质量的宏基因组组装基因组。Limnochordia 和 Clostridia 表现出最广泛的底物多功能性，分别利用了 24% 和 18% 的预测底物。尽管共同的底物是共享的，但每类都表现出由不同的功能和代谢差异驱动的独特底物偏好。Limnochordia 和 Clostridia 具有独特的碳水化合物活性酶家族，例如 GH177 和 CBM91，它们能够降解木聚糖和阿拉伯聚糖。芽孢杆菌富含 GH1 和 GH3 家族，这对纤维素降解至关重要。总体而言，厚壁菌门类别在底物使用和功能谱方面表现出低重叠，证实了显着的生态位分化。我们的结果表明，厚壁菌门占据不同的饮食生态位，支持对厌氧消化系统中细菌共存的见解。