Enhancing Anaerobic Digestion: Innovative Strategies for Improved Efficiency and Sustainability

BackgroundAnaerobic digestion (AD) is a cornerstone technology for integrated waste management and renewable energy production, converting organic wastes into biogas and value-added digestate while reducing environmental burdens. Despite decades of progress, AD performance and stability remain constrained by persistent bottlenecks. Key challenges include microbial inhibition driven by elevated ammonia levels, the accumulation of inhibitory or recalcitrant organic compounds such as Maillard reaction products (MRPs), and suboptimal regulation of carbon flux across hydrolysis, acidogenesis, acetogenesis, and methanogenesis. These constraints can lead to process instability, reduced methane yields, and limited feedstock flexibility, particularly for nitrogen-rich substrates and thermally or mechanically treated or protein-rich wastes.Recent advances point to promising, mechanistically informed strategies to overcome these limitations. Conductive materials and tailored biochar amendments may stimulate syntrophic metabolism and promote direct interspecies electron transfer while buffering inhibitory conditions. Pretreatment technologies, including thermal hydrolysis and oxidant-assisted routes such as potassium ferrate-based treatments, can improve substrate biodegradability and reshape inhibitor profiles. Biochar-iron and related composites are also gaining attention for enhancing methane production and reactor robustness. In parallel, growing interest in arrested or non-methanogenic anaerobic digestion is expanding the role of AD beyond methane production, particularly through the selective recovery of volatile fatty acids (VFAs) and other intermediate metabolites as valuable platform chemicals. However, key questions remain regarding long-term sustainability, life-cycle impacts, techno-economic feasibility, operational boundaries, and transferability from lab-scale demonstrations to full-scale systems. Interest in sub-thermophilic operation adds further potential, but systematic evidence and optimization frameworks are still emerging.GoalThis Research Topic aims to accelerate the optimization of AD efficiency, stability, and sustainability by bringing together cutting-edge research on innovative materials, pretreatment strategies, and operational concepts that address inhibition control and carbon flux regulation. We seek contributions that deepen mechanistic understanding of how these interventions influence microbial networks and process performance, while also evaluating practical implementation through sustainability and economic lenses. By linking fundamental insights with applied engineering and environmental assessment, this collection will support next-generation AD systems that are more robust across variable waste streams and better aligned with circular bioeconomy goals.ScopeSubmissions should address one or more of the following themes. However, editors will also consider articles related to anaerobic digestion, biogas, or VFAs that make a significant contribution to advancing the field, even if they fall outside the specific scope listed above. o Inhibition mechanisms and mitigation: Ammonia inhibition, including thresholds, adaptation strategies, and mitigation pathways; formation, fate, and impacts of MRPs in AD; and interactions among ammonia, MRPs, VFAs, trace metals, and redox conditions. o Biochar and carbon-based functional materials in AD: Links between biochar properties and AD outcomes; roles in humification and digestate quality; conductive materials and electron transfer or syntrophy effects; and performance risks such as aging, saturation, toxicity, and micro-contaminants. o Metal-modified and composite additives: Biochar-iron composites and related materials for methane enhancement and stability; roles of iron species in sulfur control and redox buffering or electron shuttling; and additive recovery, regeneration, and long-term operational performance. o Pretreatment strategies to enhance biodegradability and reduce inhibitors: Thermal hydrolysis and hybrid pretreatments; oxidant-assisted pretreatments, including potassium ferrate, and their influence on biodegradability and inhibitor formation; and comparative evaluations across diverse feedstocks. o Operational optimization and emerging regimes: Sub-thermophilic operation, including stability, kinetics, microbial shifts, and energy balance; carbon flux regulation across AD stages; and monitoring, control, and modeling approaches, both mechanistic and data-driven. o Arrested and non-methanogenic anaerobic digestion for VFA recovery: Strategies to suppress or control methanogenesis; steering of carbon flux toward VFA production; microbial and metabolic regulation in acidogenic systems; optimization of VFA yield and selectivity; downstream recovery and purification; and comparative performance across different feedstocks and reactor configurations. o Scale-up, sustainability, and techno-economics: TEA, LCA, and integrated sustainability assessments; real-world implementation barriers such as supply chains, safety, regulation, digestate implications, and nutrients recovery and reuse; and pilot-scale or full-scale validation, including long-term studies under realistic operating conditions. o Socioeconomics, circular bioeconomy, and biorefineries: Barriers to biogas adoption, rural development and waste management, and the role of AD in regional nutrient and carbon cycling; and integration of AD into circular bioeconomy frameworks and biorefinery systems for holistic waste valorization. Topic editors: Liangcheng Yang, Emmanuel Kweinor Tetteh, Jean Agustin Velasquez-Pinas, Bhagawan Dheravath, Yutaka Tamaru Source: https://www.frontiersin.org/research-topics/77982/enhancing-anaerobic-digestion-innovative-strategies-for-improved-efficiency-and-sustainability