Enhanced Volatile Fatty Acid Production from Food Waste Fermentation via Enzymatic Pretreatment: New Insights into the Depolymerization and Microbial Traits

Wu, Yang; Hu, Wenjing; Zhu, Zizeng; Zheng, Xiong; Chen, Yuexi; Chen, Yinguang

doi:10.1021/acsestengg.2c00219

Cited by 46 publications

(9 citation statements)

References 55 publications

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“…Then, raw FASTQ files were demultiplexed and quality-filtered via QIIME, and chimeric sequences were recognized and eliminated using UCHIME. In addition, functional genes were predicted by PICRUSt2 analysis, which proved to be a valuable method for characterizing the functional capabilities of microbial populations . In comparison with other similar gene prediction strategies, such as Piphillin2, PanFP3, and Tax4Fun2, the PICRUSt2 prediction method was deemed superior …”

Section: Materials and Methodsmentioning

confidence: 99%

“…The structure of the microbial community was determined by high-throughput sequencing of the 16S rDNA, according to previous research. 24 The samples were obtained from the reactors with CG, bio-M/CG, and abio-M/CG as the catalyst. The total DNA from samples was extracted using a FastDNA kit (BIO 101, Vista, CA) and then amplified by the specific primers (Bacteria: 341F-806R).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Biogenic Melanin-Modified Graphene as a Cathode Catalyst Yields Greater Bioelectrochemical Performances by Stimulating Oxygen–Reduction and Microbial Electron Transfer

Wu,

Liang,

Zhou

et al. 2023

ACS EST Water

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Bioelectrochemical systems (BES) can recover energy from organic-bearing waste streams, but their use has been stymied by poor electron transfer from the cathode. Redoxactive electron shuttles could stimulate electron transfer provided that they are compatible with the exoelectrogenic bacteria. This work evaluated melanin-modified carboxylated graphene (M/CG) as a novel cathode catalyst in a microbial fuel cell. Biogenic melanin catalysts (i.e., bio-M/CG) significantly increased bioelectricity production due to its abundant pyrrole N, which lowered chargetransfer resistance and, thus, promoted the cathodic oxygen− reduction reaction (ORR). The high content of pyrrole N in the bio-M/CG catalyst also enriched exoelectrogens, such as Azospirillum, Chryseobacterium, and Azoarcus, which accounted for over 50% of the total abundance of bacteria in biofilms on the anode. Moreover, the functional genes of key enzymes involved in microbial electron transfer (MET) were increased by the bio-M/CG catalyst. These data confirm that the bio-M/CG catalyst improved the bioelectrochemical performance via synergetic promotion of cathodic ORR and microbial electron transfer, thus providing a new alternative for advancing BES technology. This work highlights the potential application of melanin in enhancing cathodic oxygen−reduction reaction kinetics and improving microbial electron transfer in BES. This study emphasizes the promising application of melanin in enhancing the ORR kinetics and improving MET in BES, offering exciting prospects for future sustainable and environmentally friendly applications.

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Section: Materials and Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Biogenic Melanin-Modified Graphene as a Cathode Catalyst Yields Greater Bioelectrochemical Performances by Stimulating Oxygen–Reduction and Microbial Electron Transfer

Wu,

Liang,

Zhou

et al. 2023

ACS EST Water

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“…Previous studies have shown that Actinobacteria could effectively convert complex organic substrates into VFAs. 61 Also, Qin et al 62 reported that Actinobacteria are involved in the VFA formation process. Similar correlations of digestion substrates with microbial species and metabolic pathways were also found at the genus level and KEGG L3 (Figures S1 and S2).…”

Section: Variable Importance Analysis For Predicting Methane Productionmentioning

confidence: 99%

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Cheng,

Xu,

et al. 2023

ACS EST Eng.

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Accurate prediction of methane production in anaerobic digestion with various pretreatment strategies is of the utmost importance for efficient sludge treatment and resource recovery. Traditional machine learning (ML) algorithms have shown limited prediction accuracy due to challenges in optimizing complex parameters and the scarcity of data. This work proposed a novel integrated system that employed an ensemble semisupervised learning (SSL)-automated ML (AutoML) model with limited variable inputs to reveal the effects of different pretreatments on methane production during sludge digestion with explainable analysis. Considering the direct correlations of the pretreatment type and digestion substrates, the pretreatment type is considered as a hidden variable. Results demonstrated that the AutoML model outperformed the conventional ML models (i.e., support vector regression (SVR), extreme gradient boosting (XGB), etc.), as evidenced by its higher R 2 value. Moreover, the integration of SSL further enhanced the prediction accuracy by effectively leveraging unlabeled data, leading to a reduction in the mean squared error from 11.3 to 9.7. Explainable analysis results revealed the significance of different variables and the utmost importance of operating time, followed by proteins, carbohydrates, chemical oxygen demand, and volatile fatty acids. Furthermore, principal component and correlation analysis unveiled the interconnected relationships among substrate concentration, microbial communities, and metabolic functions for methane production and found that the increasing substrate concentration promoted the enrichment of functional microbial and metabolic functions. These insights shed light on the advantages of SSL-AutoML in predicting methane production in anaerobic digestion systems and elucidate the dependence relationships with key variables, offering valuable guidance for effective sludge pretreatment with enhanced resource recovery capabilities.

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“…2 Apart from the pollution attribute, WAS also exhibited resource features due to the high organic proportion, which could be a promising feedstock for resource recovery. 3 Currently, anaerobic digestion is a widely accepted route for WAS treatment with methane (as a carbon-neutral sustainable fuel) production, which could be used for electricity or heat to reduce greenhouse gas emissions and fossil fuel consumption. The calorific value of pure methane per cubic meter is about 35,807 kJ, and the average power generation price using methane as a storage molecule is 0.18€/kW h. 4 As the microbial-dominated biological process, functional microorganisms exhibited vital roles in the anaerobic digestion process, and their microbial viabilities and activities were easily influenced by those undesirable ECs in WAS.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Because of the limited removal efficiency of conventional treatment processes, most ECs are eventually transferred and highly concentrated (even up to tens of mg/g dry matter) in the waste activated sludge (WAS), which exhibited great ecological risks . Apart from the pollution attribute, WAS also exhibited resource features due to the high organic proportion, which could be a promising feedstock for resource recovery . Currently, anaerobic digestion is a widely accepted route for WAS treatment with methane (as a carbon-neutral sustainable fuel) production, which could be used for electricity or heat to reduce greenhouse gas emissions and fossil fuel consumption.…”

Section: Introductionmentioning

confidence: 99%

Unveiling Polyhexamethylene Guanidine Regulating Behaviors on Methane Generation in a Sludge Anaerobic Digester: Interactive Process, Microbial Metabolic Trait Interference, and Adaptive Mechanisms

Wang,

Luo,

Huang

et al. 2023

ACS EST Eng.

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Extracellular polymeric substances (EPSs) in waste activated sludge (WAS) are important guardians of active microorganisms against toxic emerging contaminants (ECs). However, how ECs interact with EPSs and microorganisms and further interfere with microbial functions during WAS anaerobic digestion has not been systemically disclosed. This work reported the dose-dependent effects of polyhexamethylene guanidine (PHMG, as a potential EC) on methane production during WAS digestion and comprehensively revealed the underlying mechanisms. PHMG at low dose showed an evident lag period for methane production (from 0.09 d in control to 8.23 d) but produced dramatic inhibition at high dose. Although PHMG promoted solubilization, hydrolysis, and acidification via enriching hydrolytic and acidogenic bacteria (i.e., Acidaminobacter and Acidibacter), methanogenesis was inhibited due to the reduction of methanogens (i.e., Methanosaeta and Syntrophomonas) and methanogenic activities related to acetoclastic and hydrogenotrophic methanogenesis (i.e., yhdR, pdhB, f wdB, and f rhD). Meanwhile, PHMG inhibited interspecies electron transfer between acidogens and methanogens via decreasing the biosynthesis of electron shuttles and e-pili (i.e., ribA, yigB, ribBA, and MtrD) and reducing mutualistic microorganisms (i.e., Desulfobulbus and Methanospirillum), which resulted in a decrease of methane formation. Further analysis found that PHMG disrupted EPSs (mainly proteins) and improved cell permeability. Then, it might enter the microbial cells to induce the formation of septal invaginations to disturb microbial replication as well as metabolic functions involved in methane biosynthesis. However, functional microorganisms could adapt to the low PHMG stress and significantly recover metabolic activities for methane production via upregulating functional genes related to microbial growth (e.g., FEN1 and f tsQ) and activating the quorum sensing system (LuxR/I system).

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Enhanced Volatile Fatty Acid Production from Food Waste Fermentation via Enzymatic Pretreatment: New Insights into the Depolymerization and Microbial Traits

Cited by 46 publications

References 55 publications

Biogenic Melanin-Modified Graphene as a Cathode Catalyst Yields Greater Bioelectrochemical Performances by Stimulating Oxygen–Reduction and Microbial Electron Transfer

Biogenic Melanin-Modified Graphene as a Cathode Catalyst Yields Greater Bioelectrochemical Performances by Stimulating Oxygen–Reduction and Microbial Electron Transfer

Predicting and Evaluating Different Pretreatment Methods on Methane Production from Sludge Anaerobic Digestion via Automated Machine Learning with Ensembled Semisupervised Learning

Unveiling Polyhexamethylene Guanidine Regulating Behaviors on Methane Generation in a Sludge Anaerobic Digester: Interactive Process, Microbial Metabolic Trait Interference, and Adaptive Mechanisms

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