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Optimizing Anaerobic Digestion: Benefits of Mild Temperature Transition from Thermophilic to Mesophilic Conditions

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Date 2024 Jul 12
PMID 38993655
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Abstract

Anaerobic digestion (AD) plays a significant role in renewable energy recovery. Upgrading AD from thermophilic (50-57 °C) to mesophilic (30-38 °C) 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 35 °C on cell viability, microbial dynamics, and interspecies interactions. A sharp transition (ST) is a one-step transition by 20 °C d, while a mild transition (MT) is a stepwise transition by 1 °C d. 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 A) 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.

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Wu H, Zhang H, Yan R, Li S, Guo X, Qiu L Adv Sci (Weinh). 2024; 11(43):e2406119.

PMID: 39264245 PMC: 11578306. DOI: 10.1002/advs.202406119.

References
1.
Zhang W, Li L, Xing W, Chen B, Zhang L, Li A . Dynamic behaviors of batch anaerobic systems of food waste for methane production under different organic loads, substrate to inoculum ratios and initial pH. J Biosci Bioeng. 2019; 128(6):733-743. DOI: 10.1016/j.jbiosc.2019.05.013. View

2.
Jang H, Ha J, Kim M, Kim J, Kim Y, Park J . Effect of increased load of high-strength food wastewater in thermophilic and mesophilic anaerobic co-digestion of waste activated sludge on bacterial community structure. Water Res. 2016; 99:140-148. DOI: 10.1016/j.watres.2016.04.051. View

3.
Li Y, Li X, Wang P, Su Y, Xie B . Size-dependent effects of polystyrene microplastics on anaerobic digestion performance of food waste: Focusing on oxidative stress, microbial community, key metabolic functions. J Hazard Mater. 2022; 438:129493. DOI: 10.1016/j.jhazmat.2022.129493. View

4.
Kim J, Lee C . Response of a continuous anaerobic digester to temperature transitions: A critical range for restructuring the microbial community structure and function. Water Res. 2015; 89:241-51. DOI: 10.1016/j.watres.2015.11.060. View

5.
Garcia F, Clegg T, ONeill D, Warfield R, Pawar S, Yvon-Durocher G . The temperature dependence of microbial community respiration is amplified by changes in species interactions. Nat Microbiol. 2023; 8(2):272-283. DOI: 10.1038/s41564-022-01283-w. View