Table_1_Variation of Metagenome From Feedstock to Digestate in Full-Scale Biogas Plants.xlsx

Anaerobic digestion (AD) has been widely used to resolve the problem of organic wastes worldwide. Previous studies showed that the types of feedstock have a great influence on the AD microbiome, and a huge number of AD populations are migrated from upstream feedstocks. However, the changes of microbial compositions from feedstock to AD digestate are still less understood. We collected feedstock samples from 56 full-scale biogas plants, generated 1,716 Gb feedstock metagenomic data in total, and constructed the first comprehensive microbial gene catalog of feedstock containing 25.2 million genes. Our result indicated that the predominant phyla in feedstock are Firmicutes, Bacteroidetes, and Proteobacteria, which is similar to that in AD digestate, and the microbial diversity of feedstock samples is higher than that of AD digestate samples. In addition, the relative abundance of most genes involved in methanogenesis increase from feedstock to AD digestate. Besides, the amount of antibiotic resistance genes (ARGs) and pathogenic bacteria in AD are effectively reduced compared to feedstocks. This study provides a comprehensive microbial gene catalog of feedstock, and deepens the understanding of variation of microbial communities from feedstock to AD digestate of full-scale AD. The results also suggest the potential of AD to reduce the level of ARGs and pathogens in animal manure.

厌氧消化（Anaerobic Digestion，AD）技术已在全球范围内被广泛用于处理有机废弃物难题。既往研究表明，底物类型对厌氧消化微生物组具有显著调控作用，且大量厌氧消化相关微生物类群源自上游进料底物。然而，从进料底物到厌氧消化消化产物的微生物群落组成变化仍未得到充分解析。本研究从56座规模化沼气工程中采集进料底物样本，总计生成1716 Gb的底物宏基因组数据，并构建了首个涵盖2520万个基因的底物微生物综合基因目录。研究结果显示，底物中的优势菌门为厚壁菌门（Firmicutes）、拟杆菌门（Bacteroidetes）和变形菌门（Proteobacteria），这与厌氧消化消化产物中的优势菌门组成高度相似；且底物样本的微生物多样性显著高于厌氧消化消化产物样本。此外，绝大多数参与产甲烷作用的基因的相对丰度从进料底物到厌氧消化消化产物均呈上升趋势。同时，与进料底物相比，厌氧消化体系内的抗生素抗性基因（ARGs）与病原菌丰度得到有效降低。本研究构建的底物微生物综合基因目录，深化了对规模化厌氧消化体系中从进料底物到厌氧消化消化产物的微生物群落变化的认知。研究结果同时揭示了厌氧消化技术在降低畜禽粪便中抗生素抗性基因与病原菌水平方面的应用潜力。