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The aim of this work was to investigate the mesophilic methane fermentation of rice straw at different organic loading rates (OLRs) in a 300 m 3 bioreactor. It was found that biogas production increased when the OLR was below 2.00 kg VS substrate /(m 3 ·d). The average volumetric biogas production reached 0.86 m 3 /(m 3 ·d) at an OLR of 2.00 kg VS substrate /(m 3 ·d). Biogas production rate was 323 m 3 /t dry rice straw over the whole process. The pH, chemical oxygen demand, volatile fatty acid, and NH 4 + -N concentrations were all in optimal range at different OLRs. High-throughput sequencing analysis indicated that Firmicutes , Fibrobacteres , and Spirochaetes predominated in straw samples. Chloroflexi , Proteobacteria , and Planctomycetes were more abundant in the slurry. The hydrogenotrophic pathway was the main biochemical pathway of methanogenesis in the reactor. This study provides new information regarding the OLR and the differences in the spatial distribution of specific microbiota in a rice straw biogas plant. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) is a promising device for energy generation and organic waste treatment simultaneously by electrochemically active bacteria (EAB). In this study, an integrated aerobic-anaerobic strategy was developed to improve the performance of P. aeruginosa -inoculated MFC. With an aerobic start-up and following an anaerobic discharge process, the current density of MFC reached a maximum of 99.80 µA/cm 2 , which was 91.6% higher than the MFC with conventional constant-anaerobic operation. Cyclic voltammetry and HPLC analysis showed that aerobic start-up significantly increased electron shuttle (pyocyanin) production (76% higher than the constant-anaerobic MFC). Additionally, enhanced anode biofilm formation was also observed in the integrated aerobic-anaerobic MFC. The increased pyocyanin production and biofilm formation promoted extracellular electron transfer from EAB to the anode and were the underlying mechanism for the MFC performance enhancement. This work demonstrated the integrated aerobic-anaerobic strategy would be a practical strategy to enhance the electricity generation of MFC. [ABSTRACT FROM AUTHOR]

Laboratory-scale reactors, in which the pH could be auto-adjusted, were employed to investigate the mesophilic methane fermentation with pig manure (7.8% total solids) at pH 6.0, 7.0, and 8.0. Results showed that the performance of anaerobic digestion was strongly dependent on pH value. Biogas production and methane content at neutral pH 7.0 were significantly higher (16,607 mL, 51.81%) than those at pH 6.0 (6916 mL, 42.9%) and 8.0 (9739 mL, 35.6%). Denaturing gradient gel electrophoresis fingerprinting and Shannon’s index indicated that the samples contained highly diverse microbial communities. The major genus at pH 7.0 was Methanocorpusculum , compared with that was Methanosarcina at both pH 6.0 and 8.0. Our research revealed that cultures maintained at pH 7.0 could support increased biogas production, which has significant implications for the scale-up biogas engineering. [ABSTRACT FROM AUTHOR]

The evolution of the bacterial population during formation of denitrifying phosphorus removal granular sludge was investigated using high-throughput pyrosequencing. As a result, mature granules with a compact structure were obtained in an anaerobic/aerobic/anoxic (A/O/A) sequencing batch reactor under an organic loading rate as low as 0.3 kg COD/(m 3 ·d). Rod-shaped microbes were observed to cover with the outer surface of granules. Besides, reliable COD and simultaneous nitrogen and phosphorus removal efficiencies were achieved over the whole operation period. MiSeq pyrosequencing analysis illustrated that both the microbial diversity and richness increased sharply during the granulation process, whereas they stayed stable after the presence of granules. Some microorganisms seemed to contribute to the formation of granules, and some were identified as functional bacterial groups responsible for constructing the biological reactor. [ABSTRACT FROM AUTHOR]

The evolution of the bacterial population during formation of denitrifying phosphorus removal granular sludge was investigated using high-throughput pyrosequencing. As a result, mature granules with a compact structure were obtained in an anaerobic/aerobic/anoxic (A/O/A) sequencing batch reactor under an organic loading rate as low as 0.3 kg COD/(m 3 ·d). Rod-shaped microbes were observed to cover with the outer surface of granules. Besides, reliable COD and simultaneous nitrogen and phosphorus removal efficiencies were achieved over the whole operation period. MiSeq pyrosequencing analysis illustrated that both the microbial diversity and richness increased sharply during the granulation process, whereas they stayed stable after the presence of granules. Some microorganisms seemed to contribute to the formation of granules, and some were identified as functional bacterial groups responsible for constructing the biological reactor. [ABSTRACT FROM AUTHOR]

Pretreatment of activated sludge with sulfuric acid and bioleaching using Acidithiobacillus ferrooxidans along with addition of Fe 2+ on sludge dewaterability was investigated. The sludge dewatering efficiency in terms of capillary suction time (CST) and specific resistant to filtration (SRF) was increased with a decrease in sludge pH. A pH of 2.67 was found to be optimum for dewatering, at which 81% and 63% reduction of CST and SRF were achieved, respectively. The dewaterability of sludge was enhanced after the addition of Fe 2+ and A. ferrooxidans . Ideal concentration of Fe 2+ was 2 g/L for sludge dewaterability, which showed 96% and 88% reduction in CST and SRF, respectively. In the control sludge, maximum part of the biopolymeric macromolecules was contributing by the tightly bound extracellular polymeric substances (TB-EPS). At optimum Fe 2+ concentration, total EPS was reduced by 73%, enhancing sludge dewaterability. Bioleaching conducted by A. ferrooxidans could solubilized 88% Cu and 99% Zn within 120 h. [ABSTRACT FROM AUTHOR]

Abstract: This study sought to elucidate the effect and mechanism of Galactomyces sp. Z3 in improving the bioleaching of heavy metals from sludge. Results showed that co-inoculation of Galactomyces sp. Z3 and two Acidithiobacillus strains (Acidithiobacillus ferrooxidans LX5 and Acidithiobacillus thiooxidans TS6) reduced the period required for sludge bioleaching by 4.5days compared to Acidithiobacillus alone. Further, removal efficiencies of Cu, Zn and oxidation rate of Fe2+ and S0 were higher in co-inoculation system than the Acidithiobacillus alone. Galactomyces sp. Z3 consumed the acetate, propionate, iso-butyrate, butyrate, and iso-valerate in sludge from the initial concentrations of 109.50, 28.80, 7.70, 34.30, and 18.40mg/L to 10.20, 0.61, 0.63, 19.40 and 1.30mg/L, respectively, after 12h in the co-inoculation system, significantly lower than the concentrations observed in the Acidithiobacillus alone. Meanwhile, the surfactant properties of the extracellular polymeric substances produced by the Galactomyces accelerated the rate of sulfur oxidization by A. thiooxidans. [Copyright &y& Elsevier]

[Display omitted] • Diverse biochar adsorbents were produced from Goji branch by co-pyrolysis with KOH. • Appropriate moisture in agro-wastes contributed to develop porosity in biochar. • K 50% W 29% C-700 presented S BET of 1378.05 m2/g and Q m of 769.23 mg MB/g. • K 50% W 29% C-700 showed excellent reusability and wide applicability. The agricultural waste (Goji branch) was pyrolyzed into biochars with one-step potassium hydroxide (KOH) activation under different processing conditions. The biochars were first characterized in structural features and functional groups and then evaluated for adsorptive performance with methylene blue as a model pollutant. Different adsorption models were applied to fit the adsorption process and reveal the possible mechanisms. The adsorption capacity was found to strongly correlate (R2 = 0.9642) with the surface area of the biochars, among which biochar K 50% W 29% C-700 (pyrolysis at 700 °C in the presence of 50 % KOH and 29 % water) possessed the largest surface area (1378 m2/g) and exhibited the highest adsorption capacity (769 mg/g) compared to its homologous products. Biochar K 50% W 29% C-700 also showed excellent recyclability and potent adsorption capacity toward other common organic pollutants. The results suggest that traces of water in agricultural wastes could significantly intensify the KOH-involved activation efficiency of producing porous biochar. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion is considered to be an efficient way to improve the biogas production. The abundance, dynamic and interactional networks of prokaryotic community were investigated between co-digestion and mono-digestions of corn stalk and pig manure in mesophilic batch test. Co-digestion showed higher methane production, and contributed to suitable microenvironment as well as stable prokaryotic community structure. The highest methane production was achieved with the highest relative abundance of Methanosaeta. Prokaryotic community in mono-digestions might inhibited by FA or FVFA. The functional modules in co-digestion and mono-digestion of pig manure clustered together with bigger size and higher degree, and the connections of metabolic functions were better-organized, which means high-efficient utilization of substrate and prevention of the two digestion systems crash. The partial mantel tests showed the functional modules were significantly affected by environmental factors. These results further explained that why co-digestion was more efficient than mono-digestion owing to suitable microenvironment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The feasibility of DLC pretreatment in anaerobic digestion (DLC-AD) was proved. • Lower scum, higher substrate utilization and organic biodegradability promoted CH 4. • DLC pretreatment enriched Ruminofilibacter and Methanobacterium in AD. • More positive interspecies relationships were detected in co-network of DLC-AD. • Comamonas and Methanobacterium , etc. as the hub microbes were constructed in DLC-AD. The recalcitrant characteristics of lignocellulosic waste and difficulties in biomass transportation and storage severely limit bioenergy production through anaerobic digestion (AD). In this study, Densifying Lignocellulosic biomass with Chemicals (DLC) pretreatment was developed to address these issues. The results showed that DLC treated corn stover (CS) reached a cumulative methane yield of as high as 224.30 mL/g VS (Volatile Solids), which was 59.27 % higher than that of un-treated. The reduced scum formation in the reactor, increased components consumption of solid phase, and higher organic biodegradability of liquid phase in AD of DLC treated CS enhanced methane yield. Microbial analysis indicated that DLC pretreatment affected the bacterial and methanogenic community structure, and a co-network with Comamonas and Methanobacterium , etc. as hub microbes was constructed. This study proposed a promising technology that could be potentially applied to industrial AD of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reinforcement of the precursor supply module enhanced the D-pantothenate production. • Enhancing the supply of one carbon unit module increased the yield of D-pantothenate. • Reinforcement of cofactor and energy provision enhanced D-pantothenate biosynthesis. • Omics analysis characterized metabolic variation and offered targets of modification. • 45.35 g/L D-pantothenate with a yield of 0.31 g/g glucose was produced. Biosynthesis of D-pantothenate has been widely studied as D-pantothenate is one kind of important vitamins used in food and pharmaceuticals. However, the engineered strain for D-pantothenate production was focused solely on the main biosynthetic pathway, while other important factors such as one carbon unit were ignored. Here the systematic modular engineering on different factors coupled with omics analysis were studied in Escherichia coli for efficient D-pantothenate production. Through reinforcing the precursor pool, refactoring the one carbon unit generation pathway, optimization of reducing power and energy supply, the D-pantothenate titer reached 34.12 g/L with the yield at 0.28 g/g glucose under fed-batch fermentation in 5-L bioreactor. With a further comparative transcriptome and metabolomics studies, the addition of citrate was implemented and 45.35 g/L D-pantothenate was accumulated with a yield of 0.31 g/g glucose. The systematic modular engineering coupled with omics studies provide useful strategies for the industrial production of D-pantothenate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Material-focused strategy achieves 54% more carbon credit than the energy-focused. • Carbon credit from biogas energy recovery drop by 23% and 38% in 2030 and 2060. • Carbon credit from biogas material recovery boost by 35% and 59% in 2030 and 2060. • Material-focused biogas strategies better align with climate change goals. Two novel biogas upgrading strategies that recover high-value chemicals or CO 2 liquid fertilizer from biogas besides biomethane were evaluated from the view of global warming potential (GWP) through life cycle assessment in comparison with conventional approaches. Results show that the scenarios producing biomethane with nano calcium carbonate or CO 2 liquid fertilizer from biogas present significantly lower GWP (–3.4 kgCO 2 -eq/Nm3-biogas and –4.4 kgCO 2 -eq/Nm3-biogas, respectively), compared to combined heat and power scenario (–2.4 kgCO 2 -eq/Nm3-biogas) and biogas upgrading by high pressure water scrubbing scenario (–1.3 kgCO 2 -eq/Nm3-biogas). The carbon sequestration and utilization from CO 2 -rich water significantly enhanced carbon reduction in overall biogas management. Furthermore, considering cleaner electricity in the future, strategies focusing on managing biogas for materials will align more with climate change goals than energy-focused strategies. This study provides insight for decision-makers in developing roadmaps for carbon reduction pathways in biogas-relating sectors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Leaf and tree pruning are used in aerobic composting treating kitchen waste. • Leaf bulked composting degrades kitchen waste more effectively than tree pruning. • Leaf bulked composting emits less odorous gases than tree pruning composting. • More strains correlate to pollutants degradation for the leaf bulked composting. • Fewer strains correlate to gases emission for the leaf bulked composting. Though aerobic composting has been frequently applied to kitchen waste disposal, appropriate bulking agents are essential to acquire a promising performance. Fallen leaves and tree pruning in urbans face huge disposal demands and have great potentials as bulking agents of aerobic composting while have been seldom examined yet. This study comparably explored the performance of fallen leaves bulked and tree pruning bulked aerobic composting disposing kitchen waste. Results indicated that though both reactors were effective in degrading kitchen waste, leaf bulked composting was superior to tree pruning bulked composting in terms of longer thermophilic period and higher maximum temperature, higher organics degradation efficiency, higher humification and less odorous gas emission. Bacterial community was a driving mechanism for above results. This study shows that fallen leaves bulked aerobic composting has great potentials for kitchen waste disposal. [ABSTRACT FROM AUTHOR]

• Mucilaginibacter polytrichastri RG4-7 had the cellulose degradation capability. • High CMCase and betaglucosidase activity could be detected in RG4-7. • The cellulase related genes in RG4-7 were predicted based on its genome sequence. • The GH family determines cellulose degradation in RG4-7 might be GH9, GH1 and GH3. In this study, whole genome sequencing and comparative genomic analyses were performed for Mucilaginibacter polytrichastri RG4-7 and its carboxymethyl cellulose degradation potential was assessed. The results showed that the genome of strain RG4-7 was 5.84 Mb and contained 5019 predicted genes, in which a high proportion of strain-specific genes were related to carbohydrate metabolism. The carboxymethyl cellulose (CMC) degradation and cellulase activity tests revealed the strong cellulose degradation ability, CMCase and β-glucosidase activity in strain RG4-7. Real-time RT-PCR testing of most cellulose degradation related glycoside hydrolase (GH) families showed that GH9 (OKS85969), GH1 (OKS85832), GH3 (OKS89331 and OKS85615) were significantly up-regulated when strain RG4-7 was inoculated with CMC-Na, which suggested that GH9, GH1 and GH3 might determine its cellulose degradation ability. Certainly, further research need to be done to elucidate cellulose degradation mechanisms in strain RG4-7 in order to develop its industrial application value in lignocellulosic biomass degradation and waste management. [ABSTRACT FROM AUTHOR]

Highlights • BioAu modification significantly improved the electricity generation of MFCs. • Better performance was achieved with BioAu/MWCNT nanohybrids as the modifier. • BioAu/MWCNT had higher electrocatalytic activity and affinity towards exoelectrogens. • Electroactive bacteria in the modified electrode biofilms shared higher proportions. • The class Negativicutes might be specifically enriched by Au nanoparticles. Abstract In this study, carbon cloth anodes were modified using biogenic gold nanoparticles (BioAu) and nanohybrids of multi-walled carbon nanotubes blended with BioAu (BioAu/MWCNT) to improve the performance of microbial fuel cells (MFCs). The results demonstrated that BioAu modification significantly enhanced the electricity generation of MFCs. In particular, BioAu/MWCNT nanohybrids as the modifier displayed a better performance. The MFC with the BioAu/MWCNT electrode had the shortest start-up time (6.74 d) and highest power density (178.34 ± 4.79 mW/m2), which were 141.69% shorter and 56.11% higher compared with those of the unmodified control, respectively. These improvements were attributed to the excellent electrocatalytic activity and strong affinity towards exoelectrogens of the BioAu/MWCNT nanohybrids on the electrode. High throughput sequencing analysis indicated that the relative abundance of electroactive bacteria in the biofilm community, mostly from the classes of Gammaproteobacteria and Negativicutes , increased after anode modification. [ABSTRACT FROM AUTHOR]

In this study, the effect of reduced hydrogen partial pressure ( P H2 ) on the generation of carboxylic acids from acidogenic fermentation of glucose was investigated. Three strategies were applied to reduce P H2 : headspace removal (T1), CO 2 sparging (T2) and H 2 :CO 2 (80:20) sparging (T3). Results showed that the production of carboxylic acids in T1-T3 were 10.21, 11.64 and 12.71 g/L, respectively, which were 1.04, 1.19 and 1.30-fold of that in the control (T4). The composition of carboxylic acids changed significantly in T3 with enhancement of homoacetogenesis, as more acetate and butyrate were produced comparing to the control. In addition, decreasing P H2 led to more carbon flow to carboxylic acids. Species of Clostridium became dominant in treatment T3, resulting in the shift of metabolic pathways. This study demonstrated that decreasing P H2 could increase the production of carboxylic acids, especially under the strategy of enhancing homoacetogenesis. [ABSTRACT FROM AUTHOR]

This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F 420 , and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers. The polypropylene fiber system maintained the highest biogas and methane production in the reactor, which was 44.80% and 49.84% higher than that noted in the control, respectively, during the entire anaerobic fermentation cycle. Meanwhile, the polypropylene fiber system exhibited the highest TS, VS, and COD removal efficiency. The results of high-throughput sequencing indicated that the dominant species in the polypropylene fiber system were Methanoregula and Methanobacterium . [ABSTRACT FROM AUTHOR]

An aerobic granules simultaneous nitrification, denitrification and phosphorus removal (SNDPR) system was evaluated in terms of the reactor performance and microbial population dynamics with decreasing C/P ratios from 50 to 16. The effects of C/P ratios on organic carbon and nutrients removal were investigated, as well as the alpha diversity of the bacterial community and bacterial compositions by using Illumina MiSeq pyrosequencing technology. Finally, the relative abundances and distribution patterns were identified and assessed given the key functional groups involved in biological nutrients removals to reveal the effects of C/P ratios to aerobic granules in the SNDPR from the molecular level. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of specific inoculation and acetate supplement in LBR-UASB was studied. • Exogenous additives improved FW hydrolysis and lactate–butyrate conversion in LBR. • The increase in methane yield relied on the enhancement of butyrate fermentation. • Carbon conversion efficiency in this two-phase AD increased by 33% with additives. In this study, exogenous Megasphaera elsdenii inoculum and acetate supplementation were introduced at the acidogenic phase to regulate the acidogenic fermentation pathway and assess their effects on food waste (FW) carbon conversion in two-phase anaerobic digestion (AD) system. These two additives significantly accelerated organic removal efficiency and subsequently increased FW hydrolysis and acidogenesis by 16% and 35%, respectively. As expected, two exogenous additives promoted butyrate fermentation during FW acidogenesis. With regard to the role of exogenous additives, both hydrogen and butyrate yields increased by over 60%. This desired increment resulted in a 25% increase in methane production. The overall carbon conversion from FW in the integrated two-phase AD system was enhanced by biochemical additives, which was 1.3-fold higher than that in control without any additives. Collectively, findings demonstrate the feasibility of regulating acidogenic fermentation via exogenous biochemical additives and its benefits on FW carbon conversion during AD process. [ABSTRACT FROM AUTHOR]

Highlights: [•] The phzM overexpression strain showed higher electrochemical activity. [•] Overexpressing phzM decreased the charge transfer resistance of MFC. [•] The electron shuttle (pyocyanin) concentration increased upon phzM overexpression. [•] Genetic modification is efficient to improve the electricity power output of MFC. [ABSTRACT FROM AUTHOR]

• Linking microbial community with fluorescence regional integration parameters. • Adjusting pH to 8.5 at 60% MC could meet product standards and save costs. • Microbial community was mainly affected by total carbon, pH, and moisture content. • Thermobifida, Mycothermus and Thermomyces may be related to the compost maturity. Composting is an effective way to treat agricultural waste, whereas inappropriate initial conditions could cause lower maturity and system instability. In this study, the dissolved organic matter dynamics and microbial community succession of cattle-manure composting were investigated under different initial moisture content (MC) and pH of raw material. The results indicated that the extended duration of thermophilic phase and the highest GI (germination index) value of final product were observed at matrix 60% MC and pH 8.5 (AT2 treatment). Microbial analysis showed that the succession of bacterial and fungal community was significantly influenced by total carbon (TN), pH and MC (P < 0.05). The relationship between microbial community and fluorescence regional integration (FRI) parameters demonstrated that Thermobifida (bacterial genus), Mycothermus and Thermomyces (fungal genera) were positively correlated with P V, n (the integral aera of Region V). This study could provide a potential strategy for large-scale industrial application of compost. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 3 , H 2 S, and TVOCs emission decreased by 20.04%, 16.18%, and 17.55% in the EG group. • The TN, NH 4 +-N, and NO 3 –-N contents were higher in the EG group. • Pusillimonas and Pseudomonas (N-cycling) became more active in the EG group. • Hydrogenispora (sulfur-cycling) decreased in the EG group. • NH 3 , H 2 S, and TVOCs removal rates reached 95%, 97%, and 53% in the BTF system. The high-nitrogen content and dense structure of poultry manure compost cause volatilization of N to ammonia (NH 3). This study evaluated the combined application of biochar and biotrickling filtration (BTF) to remove of odor in chicken manure mixed straw compost (w/w, 2.5:1). Adding of 10% biochar reduced NH 3 , hydrogen sulfide (H 2 S), and total volatile organic compounds (TVOCs) contents by 20.04%, 16.18%, and 17.55% respectively, and decreased the N loss rate by 8.27%, compared with those observed in control. The organic matter content decreased by 28.11% and germination index reached 97.36% in the experimental group. Meanwhile, the N-cycling microorganisms such as Pusillimonas and Pseudomonas became more active, and the relative abundance of sulfur-cycling microorganisms Hydrogenispora decreased in the experimental group. Following BTF application, the NH 3 , H 2 S, and TVOCs removal rates reached 95%, 97%, and 53%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Food waste digestate can be effectively co-composted with sawdust and mature compost. • Biochar additive strategy is effective in reducing nitrogen loss. • Biochar amendment enhanced the carbon degradation and humification rate. • 10% biochar could reduce 58% of NH 3 emission and 50% of nitrogen loss. • Compost maturity could be achieved in 15 days with 10% biochar amendment. High concentration of NH 4 +-N in food waste digestate (FWD) produced from biological treatment of food waste is considered as a major threat on the composting process resulting in production of immature compost. Hence, a laboratory batch composting study was conducted to examine the feasibility of using biochar as a physical additive to ameliorate the inhibitory effect of NH 4 +-N and to mitigate the nitrogen loss during FWD composting. FWD was co-composted with tobacco biochar at a dosage of 0%, 2.5%, 5% or 10% (dw) in bench-scale composters with a controlled aeration system. The addition of 10% biochar enhanced the degradation rate resulting in 44% higher carbon decomposition than the control. Besides, 10% biochar amendment reduced NH 3 and N loss by 58% and 5%, respectively and significantly reduced NH 4 +-N content to HKORC limit of < 700 mg/kg dw within 5 days showing the beneficiary impact of biochar addition. [ABSTRACT FROM AUTHOR]

Abstract: Detailed compositional analysis of a bio-oil (BO) from pyrolysis of rice husk was carried out. The BO was extracted sequentially with n-hexane, CCl4, CS2, benzene and CH2Cl2. In total, 167 organic species were identified with GC/MS in the extracts and classified into alkanes, alcohols, hydroxybenzenes, alkoxybenzenes, dioxolanes, aldehydes, ketones, carboxylic acids, esters, nitrogen-containing organic compounds and other species. The benzene ring-containing species (BRCCs) were attributed to the degradation of lignin while most of the rests were derived from the degradation of cellulose and hemicellulose. Along with guaiacyl and p-hydroxyphenyl units as the main components, a new type of linkage was suggested, i.e., Car–CH2–Car in 4,4′-methylenebis(2,6-dimethoxyphenol). Based on the species identified, a possible macromolecular structure of the lignin and the mechanism for its pyrolysis are proposed. The BO was also extracted with petroleum ether in ca. 17.8% of the extract yield and about 82.1% of the extracted components are BRCCs. [Copyright &y& Elsevier]

[Display omitted] • The effect of water replacement with/without gas diversion in LBR-UASB was studied. • Water replacement improved solubilization and hydrolysis of solid waste. • Leach bed reactor with 15% TS presented the highest carbon conversion efficiency. • The novel integrated AD system at TS 15% had a 36% increase in energy recovery. • Acidogenic off-gas diversion alone increased 11.2% of energy recovery. An integrated two-phase AD with acidogenic off-gas diversion from a leach bed reactor to an upflow anaerobic sludge blanket was developed for improving methane production. However, this system had its own technical limitation such as mass transfer efficiency for solid-state treatment. In order to optimize the mass transfer in this two phase AD system, leachate recirculation with various water replacement rates regulating the total solids contents (TS) at 12.5%, 15%, and 17.5% was aim to investigate its effect on methane generation. The solubilization of food waste was increased with decreasing TS content, while the enzymatic hydrolysis showed the opposite trend. A TS contents of 15% presented the best acidogenic performance with the highest hydrogen yield of 30.3 L H 2 /kg VS added , which subsequently resulted in the highest methane production. The present study provides an easy approach to enhance food waste degradation in acidogenic phase and energy conversion in methanogenic phase simultaneously. [ABSTRACT FROM AUTHOR]

[Display omitted] • GAC-mediation and temperature rise decreased viscosity of fermentation broth. • Methane yield in the GAC-H system was 214.42 m3/t dry corn straw. • The λ was shorten and R m was increased by GAC-mediation and temperature rise. • Euryarchaeota and Thermotogae were dominant microorganism in GAC-H system. Anaerobic digestion (AD) systems with high substrate concentrations are characterized by high viscosity, which affects material and energy transfer efficiencies, thereby influencing methane production efficiency. In this study, adding granular activated carbon (GAC) and increasing the temperature decreased the viscosity by 4.56–10.19% and 27.13–28.85%, respectively, and improved AD efficiency. Adding GAC and increasing the temperature enhanced the methane yields by 34.37–38.15% and 25.60–28.31%, respectively. Distance-based redundancy analysis showed that the viscosity, temperature, and GAC had the greatest effects on the composition of the microbial community. The dominant bacteria in the medium-temperature AD system at the phylum level belonged to Firmicutes , Bacteroidetes , and Euryarchaeota. In addition to the dominant bacteria in the medium-temperature AD system, the thermophilic phylum Thermotogae was abundant in the high-temperature AD system. Moreover, the relative abundance of Euryarchaeota , which contained most of the methanogens, was higher in the high-temperature AD system than in the medium-temperature AD system. [ABSTRACT FROM AUTHOR]

• The bioanode of mixed culture in-situ synthesized iron sulfide nanoparticles in MFC. • The amorphous nanoparticles, comprising of FeS and FeS 2 , promoted electron transfer. • The nanoparticles coated on bacteria and self-organized a 3D conductive cell network. • The thick "shell" on bacteria formed by nanoparticles inhibited cell viability. • Some electroactive and sulfur reducing bacteria were specifically enriched on anode. The bioanode of mixed consortia was for the first time used to in-situ synthesize iron sulfide nanoparticles in a microbial fuel cell (MFC) over a long-term period (46 days). These poorly crystalline nanoparticles with an average size of 29.97 ± 7.1 nm, comprising of FeS and FeS 2 , significantly promoted extracellular electron transfer and thus the electricity generation of the MFC. A maximum power density of 519.00 mW/m2 was obtained from the MFC, which was 1.92 times as high as that of the control. The cell viability was promoted by a small amount of iron sulfide nanoparticles but inhibited by the thick nanoparticle "shell" covered on the bacterial cells. Some electroactive and sulfur reducing bacteria (eg. Enterobacteriaceae , Desulfovibrio , and Geobacter) were specifically enriched on the anode. This study provides a novel insight for improving the performance of bioelectrochemical systems through in-situ sustainable nanomaterials biofabrication by mixed consortia. [ABSTRACT FROM AUTHOR]

• Effect of aeration rates on cattle manure composting was studied. • AR20 treatment was unfavorable to the uniformity of bacteria in mature phase. • Cellulase, alkaline phosphatase and catalase were main enzymes affecting composting. • Regulating temperature, moisture content and EC could improve maturity. In order to explore changes in microbial enzyme activity and bacterial community, a 60-day composting experiment was conducted using cattle manure and straw under aeration rates of 0.45, 0.68, and 0.90 L min−1 kg−1 fresh weight. High aeration rate increased the cellulase, urease, alkaline and acid phosphatase activities, but decreased that of invertase and catalase. Cellulase, alkaline phosphatase and catalase were the main enzymes that affected the composting process. Microbial analysis showed that high aeration rate increased the uniformity of bacterial community in thermophilic phase, but decreased that in mature phase. Different aeration rate affected the bacterial community structure and further influenced the relationship between enzyme and functional bacteria. Regulating the temperature, moisture content and EC in specific phases to affect bacterial community succession could provide guidance for improving maturity of composting. [ABSTRACT FROM AUTHOR]

• Mixed inorganic/organic Cu had positive effects on AD performance and ARGs removal. • These positive effects might be due to the low bioavailability of mixed Cu salts. • The highest Clostridia _MBA03 and Methanobacterium abundances were in mixed Cu group. • Microbial community induced by environmental factors mainly determined ARGs profiles. • Mixed Cu could be an alternative to replace inorganic Cu in animal feed additives. This study investigated methane production and ARGs reduction during thermophilic AD of swine manure with the addition of different Cu salts (cupric sulfate, cupric glycinate, and the 1:1 mixture of these two salts). Results showed methane production was increased by 28.78% through adding mixed Cu salts. The mixed Cu group effectively reduced total ARGs abundance by 26.94%, suggesting mixed Cu salts did not promote the potential ARGs risk. The positive effects of mixed Cu salts on AD performance and ARGs removal might be ascribed to the low bioavailability. Microbial community analysis indicated the highest abundances of Clostridia _MBA03 and Methanobacterium in the mixed Cu group might cause the increased methane production. Spearman's rank correlation analysis elucidated the succession in microbial community induced by environmental factors was the main driver for shaping ARGs profiles. Thus, mixed Cu salts could be an alternative to replace the inorganic Cu salt in animal feed additives. [ABSTRACT FROM AUTHOR]

• NH 3 and H 2 S emission decreased by 58.64% and 38.13% in the CT group. • TN, NH 4 +-N, and NO 3 −-N contents were higher in the CT group. • Pseudomonas and Bacillus in the CT group were lower than those in the CK group. • The dominated SRB- Desulfovibrio in the CT group was higher than that in the CK group. A membrane-covered composting system was used to investigate the odor emission and microbial community succession during biogas residue composting. Results showed that in comparison with the control (CK) group, the NH 3 and H 2 S emissions outside the membrane of the membrane-covered (CT) group decreased by 58.64% and 38.13%, respectively. The nitrogen preservation rate of the CT group was increased by 17.27% in comparison with the CK group. Moreover, the ammonium nitrogen and nitrate nitrogen contents of the CT group were 37.68% and 11.77% higher than those of the CK group, respectively. Microbial analysis showed that the average abundance and co-occurrence rate of ammonification bacteria dominated by Pseudomonas and Bacillus in the CT group were lower than those in the CK group, and the abundance of anaerobic sulfate-reducing bacteria (SRB) dominated by Desulfovibrio in the CT group was higher than that in the CK group. [ABSTRACT FROM AUTHOR]

• Phenolic compounds can be completely degraded and mineralized via ring-cleavage pathway. • Voltage generation was inhibited but degradation rate was enhanced under 3.0 g/L phenolic compounds. • AMC collaboration enhanced the degradation rate of parent compounds and their intermediates. • The fermentative bacteria were prevailed, but electrogenic bacteria were inhibited after the operation. This study evaluated the feasibility of microbial fuel cells (MFCs) for simultaneous electricity generation and degradation of phenolic compounds. The voltage generation was inhibited by 36.18–63.90%, but the degradation rate increased by 146.15–392.31% when the initial concentration of syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) increased from 0.3 to 3.0 g/L. The collaboration among the functional microbes significantly enhanced the degradation rate of parent compounds and their intermediates in MFCs systems, while the accumulated intermediates severely inhibited their complete mineralization in fermentative systems. High-throughput sequencing showed that the growth of fermentative bacteria prevailed, but electrogenic bacteria were inhibited in the anode microbial community (AMC) under high concentrations of phenolic compounds (3.0 g/L). These findings provide a better understanding of the dynamic shift and synergy effects of the AMC to evaluate its potential for the treatment of phenolic-containing wastewater. [ABSTRACT FROM AUTHOR]