| 1. |
- Hu, Xiao, et al.
(författare)
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Product gas biomethanation with inoculum enrichment and grinding
- 2022
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823.
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Tidskriftsartikel (refereegranskat)abstract
- The use of cheap product gas from biomass air gasification to produce methane via anaerobic digestion is a novel and potential pathway for the large-scale production of biomass-based substitute natural gas (BioSNG). In this experimental work, the product gas biomethanation (PGB) was studied with respect to the biosludge enrichment and inoculum partial grinding as well as the mesophilic and thermophilic conditions. The results show that the biosludge enrichment can effectively stop methanogenesis inhibition from the product gas, particularly CO, thus increase the biomethanation reaction rate and shorten the reaction start-up time. The inoculum partial grinding treatment can clearly change the microorganism composition and effectively reduce the diversity of microorganisms in the mixed bacterium system for the mesophilic biomethanation, thereby improving the product gas biomethanation efficiency, which is limited for the thermophilic biomethanation.
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| 2. |
- Jiang, Bingyi, et al.
(författare)
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A novel approach to enhance CO biomethanation by semi-disaggregation of anaerobic granular sludge
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 276
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Tidskriftsartikel (refereegranskat)abstract
- The syngas produced from biomass gasification is a great potential energy resource, which can well be utilized to produce biomass-based substitute natural gas (BioSNG) via syngas biomethanation. CO biomethanation is one of the key issues in the biomethanation process and was studied experimentally in this work with respect to the effect of anaerobic granular sludge semi-disaggregation. The results show 1.07 times higher averaged CH4 production rate with the semi-disaggregated granular sludge than the whole granular sludge at 35 °C, and 1.69 times higher at 55 °C. The main mechanisms behind the enhanced CH4 production rate, especially under the thermophilic condition, are the improvement of microbial interspecific syntrophic association caused by the higher electron and substrate transfer rate, and more active cell growth and metabolism as reflected in higher abundance of functional genes and enzymes and less useless extracellular polymeric substances. The CO biomethanation enhancement occurs in the conversion of the substrate to the intermediate products. The semi-disaggregation of anaerobic granular sludge or similar way to strengthen interspecific association is an effective approach to improve the ability and tolerance of microbial cultures under the CO atmosphere. This technique can well be applied for the energy conversion from the CO-rich gas substrates into BioSNG via CO biomethanation under the thermophilic condition, or for the production of intermediates as fuels/chemicals under the mesophilic condition.
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| 3. |
- Jiang, Bingyi, et al.
(författare)
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Evaluation of nano-scaled zero valent iron (nZVI) effects on continuous syngas biomethanation under the thermophilic condition
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 470
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Tidskriftsartikel (refereegranskat)abstract
- The nano-scaled zero valent iron (nZVI) particles were applied to strengthen the syngas biomethanation under the thermophilic condition in a continuous bubble column reactor with gas circulation. The CH4 productivity was increased by 6.80% from 71.20 mmol & BULL;Lr 1 & BULL;day 1 to the highest 76.04 mmol & BULL;Lr 1 & BULL;day 1 at the nZVI concen-tration of 2.5 g/L. The measurement of iron concentration and the observation of the iron nanoparticles dis-tribution indicate that nZVI can act as an electron conduit to enhance more efficient direct interspecies electron transfer by physically close contact between microorganisms, instead of biological corrosion. Further analysis of metabolic products shows that the nZVI addition can stimulate the EPS secretion, and the direct electron transfer relying on nZVI particles tends to replace other transfer modes. Microbial community analysis reveals that the Bacteria Bacteroidia and Firmicutes, and Archaea Methanothermobacter are the potential dominating enriched syntrophic partners. The expression of functional genes involved in methane production was also found to in-crease. On the other hand, the nZVI accumulation can lead to the albefaction and inactivation of partial sludge granules due to its toxicity. The negative effects of nZVI at high concentration are also more pronounced. This work shows the feasibility of improving continuous syngas biomethanation by strengthening interspecific as-sociation and accelerating electron transfer.
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| 4. |
- Jiang, Bingyi, et al.
(författare)
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Identification of the biomethanation pathways during biological CO2 fixation with exogenous H2 addition
- 2022
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Power-to-gas allows conversion of surplus electricity to methane when CO2 is available, which becomes an important technology for carbon capture, utilization and sequestration, as well as for increasing the flexibility of electricity production from renewable energy resources such as wind and solar energy. H2/CO2 biomethanation is a potentially promising alternative to the conversion of H2/CO2 to methane without limitation of variable hydrogen production. To identify mixed culture-based metabolic pathways of H2/CO2 under the mesophilic (35 °C) and thermophilic (55 °C) conditions, two specific inhibitors, 2-bromoethane sulfonate (BES) and vancomycin were employed in this experimental study. The combination of hydrogenotrophic and homoacetogenesis-acetoclastic methanogenesis makes up the pathway for the mesophilic cultivated microbial consortia. 16S rRNA gene analysis indicates that abundant Bacteria, Methanobacterium and Methanosaeta play important role in the conversion. Further analysis shows close collaboration between microorganisms by the formation of microbial clustering and the production of humic acids. The detailed metabolic mechanisms further confirm a diverse biomethanation network under the mesophilic condition. While under the thermophilic condition, the H2/CO2 biomethanation is fully dominated by the direct hydrogenotrophic methanogenesis mainly with Methanothermobacter, which is straightforward but more efficient.
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| 5. |
- Jiang, Bingyi, et al.
(författare)
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Low-Grade Syngas Biomethanation in Continuous Reactors with Respect to Gas–Liquid Mass Transfer and Reactor Start-Up Strategy
- 2023
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Ingår i: Fermentation. - : MDPI AG. - 2311-5637. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- In order to utilize a wider range of low-grade syngas, the syngas biomethanation was studied in this work with respect to the gas–liquid mass transfer and the reactor start-up strategy. Two reactors, a continuous stirred tank (CSTR) and a bubble column with gas recirculation (BCR-C), were used in the experiment by feeding an artificial syngas of 20% H2, 50% CO, and 30% CO2 into the reactors at 55 °C. The results showed that the CH4 productivity was slightly increased by reducing the gas retention time (GRT), but was significantly improved by increasing the stirring speed in the CSTR and the gas circulation rate in the BCR-C. The best syngas biomethanation performance of the CSTR with a CH4 productivity of 22.20 mmol·Lr−1·day−1 and a yield of 49.01% was achieved at a GRT of 0.833 h and a stirring speed of 300 rpm, while for the BCR-C, the best performance with a CH4 productivity of 61.96 mmol·Lr−1·day−1 and a yield of 87.57% was achieved at a GRT of 0.625 h and a gas circulation rate of 40 L·Lr−1·h−1. The gas–liquid mass transfer capability provided by gas circulation is far superior to mechanical stirring, leading to a much better performance of low-grade syngas biomethanation in the BCR-C. Feeding H2/CO2 during the startup stage of the reactor can effectively stimulate the growth and metabolism of microorganisms, and create a better metabolic environment for subsequent low-grade syngas biomethanation. In addition, during the thermophilic biomethanation of syngas, Methanothermobacter is the dominant genus.
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| 6. |
- Oris, Chansa, et al.
(författare)
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Forms of potassium and chlorine from oxy-fuel co-combustion of lignite coal and corn stover
- 2019
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Ingår i: Carbon Resources Conversion. - : Elsevier BV. - 2588-9133. ; 2:2, s. 103-110
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the forms of potassium and chlorine from oxy-fuel co-combustion of lignite coal and corn stover under atmospheric pressure were investigated. In order to check transitional stage, the feedstocks were combusted stepwise, first by pyrolysis to form coke under N2 environment and later by coke combustion into the ash at 850 °C in O2/CO2 atmosphere. The results show that an increase in blend ratio from 15% to 40% results in an increase in water-soluble potassium in the feedstock and the ashes from 0.15% to 0.4% and 0.015% to 0.038 % in weight respectively. The water-soluble potassium is present mainly as KCl and K2SO4. For ammonium acetate soluble potassium, a similar trend to water-soluble potassium is presented but with a much lower content of potassium. The bound potassium in the fuel matrix exists, likely in the form of AlKSi2O6. Chlorides are present mainly in the form of KCl which is the dominant water-soluble compound.
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| 7. |
- Vromman, Marieke, et al.
(författare)
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Large-scale benchmarking of circRNA detection tools reveals large differences in sensitivity but not in precision
- 2023
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Ingår i: Nature Methods. - 1548-7091 .- 1548-7105. ; 20:8, s. 1159-1169
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Tidskriftsartikel (refereegranskat)abstract
- The detection of circular RNA molecules (circRNAs) is typically based on short-read RNA sequencing data processed using computational tools. Numerous such tools have been developed, but a systematic comparison with orthogonal validation is missing. Here, we set up a circRNA detection tool benchmarking study, in which 16 tools detected more than 315,000 unique circRNAs in three deeply sequenced human cell types. Next, 1,516 predicted circRNAs were validated using three orthogonal methods. Generally, tool-specific precision is high and similar (median of 98.8%, 96.3% and 95.5% for qPCR, RNase R and amplicon sequencing, respectively) whereas the sensitivity and number of predicted circRNAs (ranging from 1,372 to 58,032) are the most significant differentiators. Of note, precision values are lower when evaluating low-abundance circRNAs. We also show that the tools can be used complementarily to increase detection sensitivity. Finally, we offer recommendations for future circRNA detection and validation. This study describes benchmarking and validation of computational tools for detecting circRNAs, finding most to be highly precise with variations in sensitivity and total detection. The study also finds over 315,000 putative human circRNAs.
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| 8. |
- Zhang, Zhenwen, et al.
(författare)
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CO Biomethanation with Different Anaerobic Granular Sludges
- 2021
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Ingår i: Waste and Biomass Valorization. - : Springer Science and Business Media LLC. - 1877-2641 .- 1877-265X. ; 12:7, s. 3913-3925
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Biomethanation of the syngas from biomass gasification provides an alternative method for production of biofuel and chemicals. CO in syngas plays a key role in biomethanation of syngas, as it is both a substrate and an inhibitor of certain methanogenesis processes. In this study, CO biomethanation by using a mixture of N2 and CO as the gas substrate, was investigated with the help of 5 adapted anaerobic granular sludges under thermophilic and mesophilic conditions. The results show that CO biomethanation by the adapted inocula is omnipresent. The sludge from the juice plant has a methane yield more than 80% of the theoretical value both at 37 °C and 55 °C. Increasing the temperature from 37 °C to 55 °C has a slight effect on the final methane production, but can significantly increase the CO consumption rate and shorten the time for CO biomethanation. Graphic Abstract: [Figure not available: see fulltext.].
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