2023, Vol. 8, No. 1
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2023, 8(1): 1-14.
doi: 10.1016/j.jobab.2022.11.003
Abstract:
As the second most abundant component of lignocellulosic biomass and the largest source of renewable aromatic compounds, lignin shows great potential to replace finite, non-renewable fossil oils and becomes a renewable feedstock for the production of fuel and aromatic chemicals. Therefore, it is highly important to develop efficient methods to convert lignin into biofuels and valuable chemicals. Electrochemical approaches are considered to be scalable, oxidant/reductant free, easy to control, and can be conducted under mild conditions. This review firstly overviews the structure and deconstruction methods of lignin. And then, different electrochemical lignin conversion approaches, including mediated electrooxidation, electroenzymatic oxidation, photoelectrochemical oxidation, and direct electrooxidation, are discussed in detail. The application of lignin-derived monomeric compounds is also briefly introduced. Finally, the advantages and challenges of different electrochemical lignin upgrading approaches are summarized; meanwhile, suggestions are made for future research on lignin biomass valorization.
As the second most abundant component of lignocellulosic biomass and the largest source of renewable aromatic compounds, lignin shows great potential to replace finite, non-renewable fossil oils and becomes a renewable feedstock for the production of fuel and aromatic chemicals. Therefore, it is highly important to develop efficient methods to convert lignin into biofuels and valuable chemicals. Electrochemical approaches are considered to be scalable, oxidant/reductant free, easy to control, and can be conducted under mild conditions. This review firstly overviews the structure and deconstruction methods of lignin. And then, different electrochemical lignin conversion approaches, including mediated electrooxidation, electroenzymatic oxidation, photoelectrochemical oxidation, and direct electrooxidation, are discussed in detail. The application of lignin-derived monomeric compounds is also briefly introduced. Finally, the advantages and challenges of different electrochemical lignin upgrading approaches are summarized; meanwhile, suggestions are made for future research on lignin biomass valorization.
2023, 8(1): 15-32.
doi: 10.1016/j.jobab.2022.11.001
Abstract:
As the most abundant natural polymer material on the earth, cellulose is a promising sustainable sensing material due to its high mechanical strength, excellent biocompatibility, good degradation, and regeneration ability. Considering the inherent advantages of cellulose and the success of modern sensors, applying cellulose to sensors has always been the subject of considerable investigation, and significant progress has been made in recent decades. Herein, we reviewed the research progress of cellulose functional materials (CFMs) in recent years. According to the different sources of cellulose, the classification and preparation methods for the design and functionalization of cellulose were summarized with the emphasis on the relationship between their structure and properties. Besides, the applications of advanced sensors based on CFMs in recent years were also discussed. Finally, the potential challenges and prospects of the development of sensor based on CFMs were outlined.
As the most abundant natural polymer material on the earth, cellulose is a promising sustainable sensing material due to its high mechanical strength, excellent biocompatibility, good degradation, and regeneration ability. Considering the inherent advantages of cellulose and the success of modern sensors, applying cellulose to sensors has always been the subject of considerable investigation, and significant progress has been made in recent decades. Herein, we reviewed the research progress of cellulose functional materials (CFMs) in recent years. According to the different sources of cellulose, the classification and preparation methods for the design and functionalization of cellulose were summarized with the emphasis on the relationship between their structure and properties. Besides, the applications of advanced sensors based on CFMs in recent years were also discussed. Finally, the potential challenges and prospects of the development of sensor based on CFMs were outlined.
2023, 8(1): 33-44.
doi: 10.1016/j.jobab.2022.11.004
Abstract:
Lignocellulose is the main component of plants and has a wide range of sources. The high-value production of lignocellulose lies in the biorefinery of lignin, cellulose and hemicellulose. The advantages and disadvantages of traditional lignocellulose pretreatment methods were summarized, and the effective pretreatment parameters were listed. As a green solvent system with excellent performance, deep eutectic solvents (DES) are considered to be the most potential biomass pretreatment system. Based on this, the new trend and progress of DES in lignocellulose pretreatment were reviewed, focusing on the effects of distinct kinds of lignocellulose raw materials, distinct components of DES, distinct reaction conditions and assisted by microwave ultrasound on the pretreatment of lignocellulose, and the recyclability of DES solution system was discussed. Finally, the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.
Lignocellulose is the main component of plants and has a wide range of sources. The high-value production of lignocellulose lies in the biorefinery of lignin, cellulose and hemicellulose. The advantages and disadvantages of traditional lignocellulose pretreatment methods were summarized, and the effective pretreatment parameters were listed. As a green solvent system with excellent performance, deep eutectic solvents (DES) are considered to be the most potential biomass pretreatment system. Based on this, the new trend and progress of DES in lignocellulose pretreatment were reviewed, focusing on the effects of distinct kinds of lignocellulose raw materials, distinct components of DES, distinct reaction conditions and assisted by microwave ultrasound on the pretreatment of lignocellulose, and the recyclability of DES solution system was discussed. Finally, the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.
2023, 8(1): 45-58.
doi: 10.1016/j.jobab.2022.10.001
Abstract:
An investigation was conducted to examine the impact of additive mixing with wheat straw (WS) for pellet making. This study manufactured seven types of pellets with different additive combinations to evaluate pellet quality characteristics and their relationships. A laboratory-type hammer mill and a pellet mill were used for feedstock preparation and pellet production. Experimental investigations showed that the lignin content increased from 7.0% to 13.1%, which was a primary need for pelletization. Also, the heating value rose from 17.02 to 20.36 MJ/kg. However, the ash content also increased from 7.09% to 16.2%. Results showed that dimension (length and diameter), durability, and tensile strength increased significantly with additives while the fines content decreased. The fines content had an inverse relationship with durability and strength. Wheat straw (60%), together with 10% sawdust (SD), 10% corn starch (CS), 10% bentonite clay (BC), and 10% biochar (BiC), was optimal with good pellet performance (T7). In addition, both the T5 pellets (70% WS, 10% SD, 10% BiC, and 10% BC) and the T6 pellets (70% WS, 10% SD, 10% BiC, and 10% CS) provide suitable quality according to EN plus 2015 standard requirements. The ash content of produced pellet was higher than the recommended value, which suggests that further research onto the alternative additive use for ash reduction is needed.
An investigation was conducted to examine the impact of additive mixing with wheat straw (WS) for pellet making. This study manufactured seven types of pellets with different additive combinations to evaluate pellet quality characteristics and their relationships. A laboratory-type hammer mill and a pellet mill were used for feedstock preparation and pellet production. Experimental investigations showed that the lignin content increased from 7.0% to 13.1%, which was a primary need for pelletization. Also, the heating value rose from 17.02 to 20.36 MJ/kg. However, the ash content also increased from 7.09% to 16.2%. Results showed that dimension (length and diameter), durability, and tensile strength increased significantly with additives while the fines content decreased. The fines content had an inverse relationship with durability and strength. Wheat straw (60%), together with 10% sawdust (SD), 10% corn starch (CS), 10% bentonite clay (BC), and 10% biochar (BiC), was optimal with good pellet performance (T7). In addition, both the T5 pellets (70% WS, 10% SD, 10% BiC, and 10% BC) and the T6 pellets (70% WS, 10% SD, 10% BiC, and 10% CS) provide suitable quality according to EN plus 2015 standard requirements. The ash content of produced pellet was higher than the recommended value, which suggests that further research onto the alternative additive use for ash reduction is needed.
2023, 8(1): 59-65.
doi: 10.1016/j.jobab.2022.11.006
Abstract:
The Salvadora persica (S. persica) L. chewing stick, usually known as miswak, is still being employed as an oral hygiene agent for plaque and gingivitis prevention. This study aims to assess the antibacterial, antibiofilm, antioxidant, and phytochemical profile of S. persica extract. The S. persica was purchased from a local market, grinded and extracted with petroleum ether. The disk diffusion, microdilution, and micro-plate assays were performed to evaluate the antibacterial and antibiofilm activities of the prepared extract at different concentrations against β-lactam resistance Streptococcus species. Free radical scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and stable radical cationic chromophore, 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) methods were used to determine their antioxidant activity. Chromatographic and spectrometric analyses were performed using gas chromatography-mass (GC-MS) spectrometry. The minimum inhibitory concentration (MIC) of S. persica extract against β-lactam resistance Streptococcus species ranged from 6.25 to 12.5 mg/mL. The maximum suppression of biofilm formation by S. persica extract was observed at MIC with a percentage of 68.66%, against Streptococcus oralis. The S. persica extract exhibited antioxidant activity with IC50 of 20 µg/mL and 35 µg/mL from DPPH and ABTS, respectively. The phytochemical characterization showed the presence of 22 compounds with major compounds; benzyl isothiocyanate (36.21%) and n-hexadecanoic acid (27.62%). The S. persica extract exhibited antibacterial activity against β-lactam resistant Streptococcus species, showing a promising natural alternative that could be a treatment option.
The Salvadora persica (S. persica) L. chewing stick, usually known as miswak, is still being employed as an oral hygiene agent for plaque and gingivitis prevention. This study aims to assess the antibacterial, antibiofilm, antioxidant, and phytochemical profile of S. persica extract. The S. persica was purchased from a local market, grinded and extracted with petroleum ether. The disk diffusion, microdilution, and micro-plate assays were performed to evaluate the antibacterial and antibiofilm activities of the prepared extract at different concentrations against β-lactam resistance Streptococcus species. Free radical scavenging 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and stable radical cationic chromophore, 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) methods were used to determine their antioxidant activity. Chromatographic and spectrometric analyses were performed using gas chromatography-mass (GC-MS) spectrometry. The minimum inhibitory concentration (MIC) of S. persica extract against β-lactam resistance Streptococcus species ranged from 6.25 to 12.5 mg/mL. The maximum suppression of biofilm formation by S. persica extract was observed at MIC with a percentage of 68.66%, against Streptococcus oralis. The S. persica extract exhibited antioxidant activity with IC50 of 20 µg/mL and 35 µg/mL from DPPH and ABTS, respectively. The phytochemical characterization showed the presence of 22 compounds with major compounds; benzyl isothiocyanate (36.21%) and n-hexadecanoic acid (27.62%). The S. persica extract exhibited antibacterial activity against β-lactam resistant Streptococcus species, showing a promising natural alternative that could be a treatment option.
2023, 8(1): 66-77.
doi: 10.1016/j.jobab.2022.11.002
Abstract:
Activated carbon (AC) was synthesized from palm kernel shell (PKS) using different activating agents, i.e., steam, carbon dioxide (CO2), and CO2-steam, in order to analyze the impact of activating agents on the pore opening of AC. In this study, AC produced from PKS was found to have great potential as an adsorbent for methane storage. The different molecular diffusivity and reactivity of the combination of CO2 and steam succeeded in producing AC with the highest burn-off of 78.57%, a surface area of 869.82 m2/g, a total pore volume of 0.47 cm3/g, and leading to maximum methane gas adsorption capacity of 4.500 mol/kg. All types of ACs exhibited the best fit with the Freundlich isotherm model, with the correlation coefficient (R2) ranging from 0.997 to 0.999, indicating the formation of multilayer adsorption. In addition, the adsorption kinetic data for all ACs followed the pseudo-first-order model showing that the rate of adsorption was dependent on both the adsorbent and the adsorbate and was governed primarily by physical adsorption between the pore surface and methane gas. The results of intraparticle diffusion model indicated that the adsorption of methane was affected by both pore diffusion and exterior layer diffusion due to the different adsorption rates.
Activated carbon (AC) was synthesized from palm kernel shell (PKS) using different activating agents, i.e., steam, carbon dioxide (CO2), and CO2-steam, in order to analyze the impact of activating agents on the pore opening of AC. In this study, AC produced from PKS was found to have great potential as an adsorbent for methane storage. The different molecular diffusivity and reactivity of the combination of CO2 and steam succeeded in producing AC with the highest burn-off of 78.57%, a surface area of 869.82 m2/g, a total pore volume of 0.47 cm3/g, and leading to maximum methane gas adsorption capacity of 4.500 mol/kg. All types of ACs exhibited the best fit with the Freundlich isotherm model, with the correlation coefficient (R2) ranging from 0.997 to 0.999, indicating the formation of multilayer adsorption. In addition, the adsorption kinetic data for all ACs followed the pseudo-first-order model showing that the rate of adsorption was dependent on both the adsorbent and the adsorbate and was governed primarily by physical adsorption between the pore surface and methane gas. The results of intraparticle diffusion model indicated that the adsorption of methane was affected by both pore diffusion and exterior layer diffusion due to the different adsorption rates.
2023, 8(1): 78-89.
doi: 10.1016/j.jobab.2022.11.005
Abstract:
Mycelium bio-composites was developed by incubating Pleurotus ostreatus fungi on different substrates from agricultural residual byproducts, including rice straw, bagasse, coir-pith, sawdust, and corn straw. The scanning electron microscope (SEM) results showed that the hypha of composite derived from bagasse was the densest, and the diameter of hypha was the biggest (0.77 µm), which was presumably due to the existence of cellulose in bagasse in the form of dextran and xylan. The maximum and minimum compression strength for sawdust substrate and corn straw substrate were 456.70 and 270.31 kPa, respectively. The flexural strength for bagasse substrate and rice straw substrate were 0.54 and 0.16 MPa, respectively. The two composites derived from rice straw and bagasse exhibited higher hydrophobic properties than others. In comparison, mycelium bio-composite derived from bagasse showed the best comprehensive properties. Except for a little worse anti-creep ability and waterproof performance, other properties of mycelium bio-composites could be comparable to commercially expanded polystyrene (EPS) packaging material. Derived from this study, mycelium material provided a good way to use agricultural residual byproducts and could be a good alternative to non-biodegradable materials for packaging applications.
Mycelium bio-composites was developed by incubating Pleurotus ostreatus fungi on different substrates from agricultural residual byproducts, including rice straw, bagasse, coir-pith, sawdust, and corn straw. The scanning electron microscope (SEM) results showed that the hypha of composite derived from bagasse was the densest, and the diameter of hypha was the biggest (0.77 µm), which was presumably due to the existence of cellulose in bagasse in the form of dextran and xylan. The maximum and minimum compression strength for sawdust substrate and corn straw substrate were 456.70 and 270.31 kPa, respectively. The flexural strength for bagasse substrate and rice straw substrate were 0.54 and 0.16 MPa, respectively. The two composites derived from rice straw and bagasse exhibited higher hydrophobic properties than others. In comparison, mycelium bio-composite derived from bagasse showed the best comprehensive properties. Except for a little worse anti-creep ability and waterproof performance, other properties of mycelium bio-composites could be comparable to commercially expanded polystyrene (EPS) packaging material. Derived from this study, mycelium material provided a good way to use agricultural residual byproducts and could be a good alternative to non-biodegradable materials for packaging applications.
2023, 8(1): 90-92.
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2023, 8(1): 93-95.
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2023, 8(1): 96-97.
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2023, 8(1): 98-99.
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