Considerable interest has been expressed in the development of anaerobic digestion (AD) of straw to solve the environmental problems caused by the dumping and burning of straw and to generate clean energy. However, the poor biodegradability of straw and the low efficiency of energy generation achieved during its AD are problematic. Studying the parameter changes involved in the process of AD is helpful for clarifying its micro-mechanisms and providing a theoretical basis for improving its efficiency. Currently, most research into process parameters has focused on gas production, methane content, pH, and volatile fatty acid (VFA) content; limited research has focused on carbon migration and functional gene changes during the AD of straw. Carbon migration and changes in metagenomic characteristics during the AD of rice straw (RS) were investigated. Accumulated biogas production was 388.43 mL/g VS. Carbon in RS was consumed, and the amount of carbon decreased from 76.28 to 36.83 g (conversion rate 51.72%). The degree of hydrolysis rapidly increased during the first 5 days, and a large amount of carbon accumulated in the liquid phase before migrating into the gas phase. By the end of AD, the amount of carbon in the liquid and gas phases was 2.67 and 36.78 g, respectively. According to our metagenomic analysis, at the module level, the abundance of M00357, M00567, M00356, and M00563 (the modules related to the generation of methane) during AD were 51.23–65.43%, 13.96–26.88%, 16.44–22.98%, and 0.83–2.40%, respectively. Methyl-CoM, 5-methyl-5,6,7,8-tetrahydromethanopterin, and Acetyl-CoA were important intermediates. Carbon was enriched in the liquid phase for the first 5 days and then gradually consumed, and most of the carbon was transferred to the gas phase by the end of AD. In this study, AD proceeded mainly via aceticlastic methanogenesis, which was indicated to be a dominant pathway in methane metabolism. Batch AD could be divided into three stages, including initiation (days 1–5), adaptation (days 6–20), and stabilization (days 21–50), according to biogas production performance, carbon migration, and metagenomic characteristics during AD.

中文翻译：

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稻草厌氧消化过程中的碳迁移和宏基因组特征[J].

发展秸秆厌氧消化（AD）以解决秸秆倾倒和焚烧造成的环境问题并产生清洁能源已引起了人们的极大兴趣。然而，秸秆的可生物降解性差以及在其AD期间实现的能量产生效率低是有问题的。研究AD过程中涉及的参数变化，有助于阐明其微观机理，为提高其效率提供理论依据。目前，对工艺参数的研究大多集中在产气量、甲烷含量、pH值和挥发性脂肪酸（VFA）含量上；有限的研究集中在秸秆AD期间的碳迁移和功能基因变化。研究了稻草 (RS) AD 期间碳迁移和宏基因组特征的变化。累积沼气产量为 388.43 mL/g VS。RS中的碳被消耗掉，碳的量从76.28减少到36.83 g（转化率51.72%）。前5天水解程度迅速增加，大量碳在液相中积累，然后迁移到气相中。到公元结束时，液相和气相中的碳量分别为 2.67 和 36.78 g。根据我们的宏基因组分析，在模块水平上，AD期间M00357、M00567、M00356和M00563（与甲烷产生相关的模块）的丰度分别为51.23-65.43%、13.96-26.88%、16.44-22.98%，和 0.83–2.40%，分别。甲基-CoM、5-甲基-5,6,7,8-四氢甲蝶呤和乙酰-CoA是重要的中间体。碳在前 5 天在液相中富集，然后逐渐消耗，大部分碳在 AD 结束时转移到气相。在这项研究中，AD 主要通过乙酸弹性产甲烷过程进行，这被证明是甲烷代谢的主要途径。根据 AD 期间的沼气生产性能、碳迁移和宏基因组特征，批次 AD 可分为启动（第 1-5 天）、适应（第 6-20 天）和稳定（第 21-50 天）三个阶段。