Fluctuations in the anaerobic digestion (AD) organic loading rate (OLR) cause shocks to the AD microbiome, which lead to unstable methane productivity. Managing these fluctuations requires a larger digester, which is impractical for community-scale applications, limiting the potential of AD in advancing a circular economy. To allow operation of small-scale AD while managing OLR fluctuations, we need to tackle the issue through elucidation of the microbial community dynamics via 16S rRNA gene sequencing. This study elucidated the interrelation of the AD performance and the dynamics of the microbial interactions within its microbiome in response to repeated high OLR shocks at different frequencies. The OLR shocks were equivalent to 4 times the baseline OLR of 2 g VS/L/d. We found that less frequent organic load shocks result to deterioration of methane productivity. Co-occurrence network analysis shows that this coincides with the breakdown of the microbiome network structure. This suggests loss of microbial interactions necessary in maintaining stable AD. Identification of species influencing the network structure revealed that a species under the genus Anaerovorax has the greatest influence, while orders Spirochaetales and Synergistales represent the greatest number of the influential species. We inferred that the impact imposed by the OLR shocks shifted the microbiome activity towards biochemical pathways that are not contributing to methane production. Establishing a small-scale AD system that permits OLR fluctuations would require developing an AD microbiome resilient to infrequent organic loading shocks.

厌氧消化 (AD) 有机负荷率 (OLR) 的波动会对 AD 微生物组造成冲击，从而导致甲烷产量不稳定。管理这些波动需要更大的消化器，这对于社区规模的应用来说是不切实际的，从而限制了 AD 在推进循环经济方面的潜力。为了在管理 OLR 波动的同时允许小规模 AD 的操作，我们需要通过 16S rRNA 基因测序阐明微生物群落动态来解决这个问题。本研究阐明了 AD 性能与其微生物组内微生物相互作用的动态之间的相互关系，以响应不同频率下重复的高 OLR 冲击。OLR 冲击相当于基线 OLR 2 g VS/L/d 的 4 倍。我们发现有机负荷冲击频率较低会导致甲烷生产力下降。共现网络分析表明，这与微生物组网络结构的破坏相吻合。这表明失去了维持稳定 AD 所必需的微生物相互作用。对影响网络结构的物种的鉴定表明，该属下的物种Anaerovorax的影响最大，而Spirochaetales和Synergistales是影响最大的物种。我们推断，OLR 冲击施加的影响将微生物组活动转变为对甲烷产生没有贡献的生化途径。建立一个允许 OLR 波动的小规模 AD 系统将需要开发一个能够抵御不常见的有机负荷冲击的 AD 微生物组。