Optimizing anaerobic digestion: Benefits of mild temperature transition from thermophilic to mesophilic conditions  

作　　者：Xingxing Zhang Pengbo Jiao Yiwei Wang Yinying Dai Ming Zhang Peng Wu Liping Ma 

机构地区：[1]Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration,Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste,School of Ecological and Environmental Sciences,East China Normal University,Shanghai,200241,China [2]School of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou,215009,China [3]Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area,Ministry of Natural Resources,Shanghai,200062,China

出　　处：《Environmental Science and Ecotechnology》2024年第5期381-395,共15页环境科学与生态技术（英文）

基　　金：supported by the National Key Research and Development Program of China(2019YFC1905001);the National Natural Science Foundation of China(41907356);the Program for Professor of Special Appointment(Eastern Scholar)(TP2019020).

摘　　要：Anaerobic digestion(AD)plays a significant role in renewable energy recovery.Upgrading AD from thermophilic(50e57C)to mesophilic(30e38C)conditions to enhance process stability and reduce energy input remains challenging due to the high sensitivity of thermophilic microbiomes to temperature fluctuations.Here we compare the effects of two decreasing-temperature modes from 55 to 35C on cell viability,microbial dynamics,and interspecies interactions.A sharp transition(ST)is a one-step transition by 20C d1,while a mild transition(MT)is a stepwise transition by 1C d1.We find a greater decrease in methane production with ST(88.8%)compared to MT(38.9%)during the transition period.ST mode overproduced reactive oxygen species by 1.6-fold,increased membrane permeability by 2.2-fold,and downregulated microbial energy metabolism by 25.1%,leading to increased apoptosis of anaerobes by 1.9-fold and release of intracellular substances by 2.9-fold,further constraining methanogenesis.The higher(1.6 vs.1.1 copies per gyrA)metabolic activity of acetate-dependent methanogenesis implied more efficient methane production in a steady mesophilic,MT-mediated system.Metagenomic binning and network analyses indicated that ST induced dysbiosis in keystone species and greatly enhanced microbial functional redundancy,causing loss of microbial syntrophic interactions and redundant metabolic pathways.In contrast,the greater microbial interconnections(average degrees 44.9 vs.22.1)in MT at a steady mesophilic state suggested that MT could better maintain necessary system functionality and stability through microbial syntrophy or specialized pathways.Adopting MT to transform thermophilic digesters into mesophilic digesters is feasible and could potentially enhance the further optimization and broader application of practical anaerobic engineering.

关 键 词：Temperature transition Methane production Cellular viability Microbial community Metagenomic binning 

分 类 号：X51[环境科学与工程—环境工程]