| 1. |
- Yan, Jinci, et al.
(författare)
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Identification of FtfL as a novel target of berberine in intestinal bacteria
- 2023
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Ingår i: BMC Biology. - 1741-7007. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Berberine (BBR) is a commonly used anti-intestinal inflammation drug, and its anti-cancer activity has been found recently. BBR can intervene and control malignant colorectal cancer (CRC) through intestinal microbes, but the direct molecular target and related mechanism are unclear. This study aimed to identify the target of BBR and dissectrelated mechanisms against the occurrence and development of CRC from the perspective of intestinal microorganisms. Results: Here, we found that BBR inhibits the growth of several CRC-driving bacteria, especially Peptostreptococcus anaerobius. By using a biotin-conjugated BBR derivative, we identified the protein FtfL (formate tetrahydrofolate ligase), a key enzyme in C1 metabolism, is the molecular target of BBR in P. anaerobius. BBR exhibits strong binding affinity and potent inhibition on FtfL. Based on this, we determined the crystal structure of PaFtfL(P.anaerobius FtfL)-BBR complex and found that BBR can not only interfere with the conformational flexibility of PaFtfL tetramer by wedging the tetramer interface but also compete with its substrate ATP for binding within the active center. In addition, the enzymatic activities of FtfL homologous proteins in human tumor cells can also be inhibited by BBR. Conclusions: In summary, our study has identified FtfL as a direct target of BBR and uncovered molecular mechanisms involved in the anti-CRC of BBR. BBR interferes with intestinal pathogenic bacteria by targeting FtfLs, suggesting a new means for controlling the occurrence and development of CRC.
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| 2. |
- Yang, Pengjie, et al.
(författare)
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A toolbox for genetic manipulation in intestinal Clostridium symbiosum
- 2024
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Ingår i: Synthetic and Systems Biotechnology. - 2405-805X. ; 9:1, s. 43-54
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Tidskriftsartikel (refereegranskat)abstract
- Gut microbes are closely related with human health, but remain much to learn. Clostridium symbiosum is a conditionally pathogenic human gut bacterium and regarded as a potential biomarker for early diagnosis of intestinal tumors. However, the absence of an efficient toolbox that allows diverse genetic manipulations of this bacterium limits its in-depth studies. Here, we obtained the complete genome sequence of C. symbiosum ATCC 14940, a representative strain of C. symbiosum. On this basis, we further developed a series of genetic manipulation methods for this bacterium. Firstly, following the identification of a functional replicon pBP1 in C. symbiosum ATCC 14940, a highly efficient conjugative DNA transfer method was established, enabling the rapid introduction of exogenous plasmids into cells. Next, we constructed a dual-plasmid CRISPR/Cas12a system for genome editing in this bacterium, reaching over 60 % repression for most of the chosen genes as well as efficient deletion (>90 %) of three target genes. Finally, this toolbox was used for the identification of crucial functional genes, involving growth, synthesis of important metabolites, and virulence of C. symbiosum ATCC 14940. Our work has effectively established and optimized genome editing methods in intestinal C. symbiosum, thereby providing strong support for further basic and application research in this bacterium.
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| 3. |
- Bolívar Caballero, José Juan, et al.
(författare)
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Advanced application of a geometry-enhanced 3D-printed catalytic reformer for syngas production
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 287
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Tidskriftsartikel (refereegranskat)abstract
- Catalyst research on reforming processes for syngas production has mainly focused on the active metals and support materials, while the effect of the catalyst's geometry on the reforming reactions has been poorly studied. The application of 3D-printed materials with enhanced geometries has recently started to be studied in heterogeneous catalysis and is of interest to be implemented for reforming biomass and plastic waste to produce H2-rich syngas. In this study, a geometry-enhanced 3D-printed Ni/Al2O3/FeCrAl-based monolithic catalyst with a periodic open cellular structure (POCS) was designed and fabricated. The catalyst was used for batch steam reforming biomass pyrolysis volatiles for syngas production at different parameters (temperature and steam-to-carbon ratio). The results showed complete reforming of pyrolysis volatiles in all experimental cases, a high H2 yield of ≈ 7.6 wt% of biomass was obtained at the optimized steam-to-carbon ratio of 8 and a reforming temperature of 800 °C, which is a higher yield compared to other batch reforming tests reported in the literature. Moreover, CFD simulation results in COMSOL Multiphysics demonstrated that the POCS configuration improves the reforming of pyrolysis volatiles for tar/bio-oil reforming and H2 production thanks to enhanced mass and heat transfer properties compared to the regular monolithic single-channel configuration.
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| 4. |
- Cuvilas, Carlos Alberto
(författare)
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Mild Wet Torrefaction and Characterization of Woody Biomass from Mozambique for Thermal Applications
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mozambique has vast forestry resources and also considerable biomass waste material such as bagasse, rice husks, sawdust, coconut husks and shells, cashew nut shell and lump charcoal waste. The potential of the total residues from the agricultural sector and the forest industry is estimated to be approximately 13 PJ. This amount of energy covers totally the production of charcoal which amounted to approximately 12.7 PJ in 2006. Although biomass is an attractive renewable source of energy, it is generally difficult to handle, transport, storage and use due to its lower homogeneity, its lower energy density and the presence of non-combustible inorganic constituents, which leads to different problems in energy conversion units such as deposition, sintering, agglomeration, fouling and corrosion. Therefore, a pretreatment of the biomass to solve these problems could lead to a change of current biomass utilization situation. The aim of this study is to convert Mozambican woody biomass residue into a solid biochar that resembles low-grade coal.In this work the current energy situation in Mozambique has been reviewed, and the available and potential renewable sources including residues from agricultural crops and forest industry as energy have been assessed. It was found that the country is endowed with great potential for biofuel, solar, hydro and wind energy production. However, the production today is still far from fulfilling the energy needs of the country, and the majority of people are still not benefiting from these resources. Charcoal and firewood are still the main sources of energy and will continue to play a very important role in the near future. Additionally, enormous amounts of energy resources are wasted, especially in the agricultural sector. These residues are not visible on national energy statistics. The chemical composition and the fuelwood value index (FVI) showed that by failing to efficiently utilise residues from Afzelia quanzensis, Millettia stuhlmannii and Pterocarpus angolensis, an opportunity to reduce some of the energy related problems is missed. An evaluation of effect of a mild wet torrefaction pretreatment showed that the chemical composition of the biochar is substantially different than the feedstock. The use of diluted acid as catalysts improves the biochar quality, namely in terms of the energy density and ash characteristics; however, the increment of the S content in the final product should be considered for market acceptance (because the fuels have a maximum allowance for S concentration). The thermal behaviour of the untreated and treated biomass was also investigated. The pyrolytic products of umbila and spruce were affected by the treatment and catalyst in terms of yield and composition of the vapours.
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| 5. |
- Gulshan, Samina, et al.
(författare)
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Performance analysis and production of aromatics for ex situ catalytic pyrolysis of engineered WEEE
- 2024
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 0165-2370 .- 1873-250X. ; 179
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Tidskriftsartikel (refereegranskat)abstract
- Ex situ catalytic pyrolysis of engineered waste electrical and electronic equipment (WEEE) was conducted in a two-stage reactor using HZSM-5 catalyst. The effect of the catalysis temperature and the catalyst-to-feedstock (C/F) ratio on products yield, gas and oil composition, and products characterization were investigated in this study. Results indicated that lower reforming temperature and C/F ratio favored organic fractions production. The highest yield of organic fraction was obtained at a catalysis temperature of 450 °C and at a C/F ratio of 0.15, corresponding to 28.5 and 27.4 wt %, respectively. The highest selectivity toward aromatic hydrocarbons and the lowest TAN value of the organic fraction were obtained at a catalysis temperature of 450 °C and a C/F ratio of 0.2, respectively. Most of the alkali and transition metals and 23 % of Br remained in the solid residue after the catalytic pyrolysis of low-grade electronic waste (LGEW).
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| 6. |
- Jin, Yanghao, et al.
(författare)
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Carbon and H-2 recoveries from plastic waste by using a metal-free porous biocarbon catalyst
- 2023
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 404
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Tidskriftsartikel (refereegranskat)abstract
- Carbon and H2 recoveries from plastic waste enable high value-added utilizations of plastic waste while mini-mizing its GHG emissions. The objective of this study is to explore the use of a metal-free biocarbon catalyst for waste plastic pyrolysis and in-line catalytic cracking to produce H2-rich gases and carbon. The results show that the biocarbon catalyst exhibits a good catalytic effect and stability for various plastic wastes. Increasing the C/P ratio from 0 to 2, induce an increase in the conversion rate of C and H in plastics to carbon and H2 from 57.1% to 68.7%, and from 22.7% to 53.5%, respectively. Furthermore, a carbon yield as high as 580.6 mg/gplastic and an H2 yield as high as 68.6 mg/gplastic can be obtained. The hierarchical porous structure with tortuous channels of biocarbon extends the residence time of pyrolysis volatiles in the high-temperature catalytic region and thereby significantly promotes cracking reactions.
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| 7. |
- Jin, Yanghao, et al.
(författare)
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From Waste Biomass to Hard Carbon Anodes : Predicting the Relationship between Biomass Processing Parameters and Performance of Hard Carbons in Sodium-Ion Batteries
- 2023
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Ingår i: Processes. - : MDPI AG. - 2227-9717. ; 11:3
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Forskningsöversikt (refereegranskat)abstract
- Sodium-ion batteries (SIBs) serve as the most promising next-generation commercial batteries besides lithium-ion batteries (LIBs). Hard carbon (HC) from renewable biomass resources is the most commonly used anode material in SIBs. In this contribution, we present a review of the latest progress in the conversion of waste biomass to HC materials, and highlight their application in SIBs. Specifically, the following topics are discussed in the review: (1) the mechanism of sodium-ion storage in HC, (2) the HC precursor's sources, (3) the processing methods and conditions of the HCs production, (4) the impact of the biomass types and carbonization temperature on the carbon structure, and (5) the effect of various carbon structures on electrochemical performance. Data from various publications have been analyzed to uncover the relationship between the processing conditions of biomass and the resulting structure of the final HC product, as well as its electrochemical performance. Our results indicate the existence of an ideal temperature range (around 1200 to 1400 degrees C) that enhances the formation of graphitic domains in the final HC anode and reduces the formation of open pores from the biomass precursor. This results in HC anodes with high storage capacity (>300 mAh/g) and high initial coulombic efficiency (ICE) (>80%).
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| 8. |
- Lucas, Carlos, et al.
(författare)
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Mathematical model of biomass gasification using high temperature air in fixed beds
- 2007
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Ingår i: Progress in Computational Fluid Dynamics, An International Journal. - 1468-4349 .- 1741-5233. ; 7:1, s. 58-67
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model has been formulated for predicting the main chemical and physical processes taking place during the fixed-bed gasification of biomass fuels using high temperature air (up to 1000 degrees C). Predicted gas species concentrations profiles and their maximum values are in good agreement with measurements. The results also show that when the temperature of feed gas (air) is increased a higher gasification rate, higher molar fractions of fuel gases (CO, H-2 and CmHn) are obtained, thus resulting in a higher LHV. At a high flow rate of the feed gases, the peaks of the fuel gas concentrations are slightly increased, and the gasification rate is strongly increased. A smaller particle size of the biomass fuels leads to higher peak values of the fuel gas species molar fractions, and a more stable gasification zone for a relatively long period of time.
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| 9. |
- Shi, Ziyi, et al.
(författare)
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Bio-based anode material production for lithium–ion batteries through catalytic graphitization of biochar : the deployment of hybrid catalysts
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Producing sustainable anode materials for lithium-ion batteries (LIBs) through catalytic graphitization of renewable biomass has gained significant attention. However, the technology is in its early stages due to the bio-graphite's comparatively low electrochemical performance in LIBs. This study aims to develop a process for producing LIB anode materials using a hybrid catalyst to enhance battery performance, along with readily available market biochar as the raw material. Results indicate that a trimetallic hybrid catalyst (Ni, Fe, and Mn in a 1:1:1 ratio) is superior to single or bimetallic catalysts in converting biochar to bio-graphite. The bio-graphite produced under this catalyst exhibits an 89.28% degree of graphitization and a 73.95% conversion rate. High-resolution transmission electron microscopy (HRTEM) reveals the dissolution–precipitation mechanism involved in catalytic graphitization. Electrochemical performance evaluation showed that the trimetallic hybrid catalyst yielded bio-graphite with better electrochemical performances than those obtained through single or bimetallic hybrid catalysts, including a good reversible capacity of about 293 mAh g−1 at a current density of 20 mA/g and a stable cycle performance with a capacity retention of over 98% after 100 cycles. This study proves the synergistic efficacy of different metals in catalytic graphitization, impacting both graphite crystalline structure and electrochemical performance.
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| 10. |
- Wang, Shule, 1994-, et al.
(författare)
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Renewable hydrogen production from the organic fraction of municipal solid waste through a novel carbon-negative process concept
- 2022
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 252
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Tidskriftsartikel (refereegranskat)abstract
- Bioenergy with carbon capture and storage (BECCS) is one of the prevailing negative carbon emission technologies. Ensuring a hydrogen economy is essential to achieving the carbon-neutral goal. In this regard, the present study contributed by proposing a carbon negative process for producing high purity hydrogen from the organic fraction of municipal solid waste (OFMSW). This integrated process comprises anaerobic digestion, pyrolysis, catalytic reforming, water-gas shift, and pressure swing adsorption technologies. By focusing on Sweden, the proposed process was developed and evaluated through sensitivity analysis, mass and energy balance calculations, techno-economic assessment, and practical feasibility analysis. By employing the optimum operating conditions from the sensitivity analysis, 72.2 kg H2 and 701.47 kg negative CO2 equivalent emissions were obtained by treating 1 ton of dry OFMSW. To achieve these results, 6621.4 MJ electricity and 325 kg of steam were utilized during this process. Based on this techno-economic assessment of implementing the proposed process in Stockholm, when the negative CO2 equivalent emissions are recognized as income, the internal rate of return and the discounted payback period can be obtained as 26% and 4.3 years, respectively. Otherwise, these values will be 13% and 7.2 years.
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