Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separati...Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic efficiency.In this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic acid.Under light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted photooxidation.Herein,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of ·O_(2)^(-),thereby improving the selectivity toward xylonic acid over other by-products.This work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.展开更多
Highly efficient photon-to-electron conversion is crucial for achieving photocatalytic conversion.In this study,oxygen-doped carbon nitride nanocages(O@CNNCs)were engineered via dual strategies of morphology-controlle...Highly efficient photon-to-electron conversion is crucial for achieving photocatalytic conversion.In this study,oxygen-doped carbon nitride nanocages(O@CNNCs)were engineered via dual strategies of morphology-controlled heteroatom doping,which was successfully used in the photocatalytic selective oxidation of xylose/xylan to xylonic acid.The nanocage-shaped O@CNNCs had a larger surface area,which was 4.02 times of carbon nitride(CN).Furthermore,with the assistance of morphology regulation and O-doping,O@CNNCs exhibit highly efficient photon-to-electron conversion,enhanced visible-light utilization,high photocurrent,low resistance,and fast separation/migration of electron-hole pairs.Correspondingly,the photocatalytic oxidation of xylose to xylonic acid using O@CNNCs was successfully achieved under mild reaction conditions with a yield of 83.4%.O@CNNCs have excellent recyclability,in which the yield of xylonic acid in the 5th cycle was 98.2%of its initial use.The O@CNNC photocatalytic system was also suitable for macromolecular xylan,and a xylonic acid yield of 77.34 mg was obtained when 100 mg xylan was used.The oxidation-active species captured experiments indicated that holes were crucial for the selective oxidation of xylose to xylonic acid.Overall,this study provides a new strategy for the preparation of photocatalysts with excellent photon-to-electron conversion and selective oxidation of biomass-derived feedstocks to xylonic acid.展开更多
Xylonic acid is a versatile and valuable chemical with a range of industrial and potential health applications.The high demand for renewable energy and sustainable products has increased interest in xylonic acid as a ...Xylonic acid is a versatile and valuable chemical with a range of industrial and potential health applications.The high demand for renewable energy and sustainable products has increased interest in xylonic acid as a starting material for the production of variety of high value chemicals and biofuels.The production of xylonic acid from biomass have an added advantage that it provides an opportunity to utilize bio-waste materials that would otherwise be discarded,reducing environmental hazards and reducing waste disposal costs.The aim of this research was to establish a bioprocess for producing xylonic acid from acid pre-treated sawdust liquor via fermentation,utilizing metabolically engineered strain of Corynebacterium glutamicum ATCC 31831.A maximum titre of 48.5±0.2 g/L xylonic acid from 60 g/L xylose derived from biomass was obtained with a yield of 0.89 g/g xylose which corresponds to a conversion of 62%.30.8±0.4 g/L of xylonic acid crystals of 95.5%purity were successfully recovered from 1L sawdust APL(Acid Pre-treated Liquor)via solvent precipitation and crystallization.Purified xylonic acid crystals were checked for its antibacterial effect on Salmonella enterica MTCC 3224,Escherichia coli MTCC 443 and Staphylococcus aureus MTCC 96.展开更多
Fungal endophytes offer structurally diverse and unique secondary metabolites with interesting biological activities.Several reports have shown the potential of fungal endophytes as sources ofα-glucosidase inhibitors...Fungal endophytes offer structurally diverse and unique secondary metabolites with interesting biological activities.Several reports have shown the potential of fungal endophytes as sources ofα-glucosidase inhibitors to alleviate diabetes.In this study,the fungal endophyte Annulohypoxylon stygium(Xylariales,Ascomycota)was identified for the first time from the leaves of the endemic tropical plant,Pandanus simplex Merr.Crude extract was obtained by fermenting the fungal endophyte in Potato Dextrose Broth for 30 days at room temperature.The A.stygium crude extract exhibited good inhibition to theα-glucosidase enzyme with an IC_(50) of 31.88±2.86μg/mL.Purification of the crude extract afforded 8-methoxynaphthol with an IC_(50) value of 676.3±1.03μg/mL.The isolation of 8-methoxynaphthol from A.stygium is reported herein for the first time.This study highlights the ability of A.stygium to produce metabolites that may be useful as antidiabetic drugs.展开更多
A significant reaction in the synthesis of biomass-based chemicals is the catalyst-based and targeted oxidation of monosaccharides into valuable sugar acids.In this study,an activated carbon supported gold catalyst wa...A significant reaction in the synthesis of biomass-based chemicals is the catalyst-based and targeted oxidation of monosaccharides into valuable sugar acids.In this study,an activated carbon supported gold catalyst was used to oxidize glucose and xylose to gluconic acid and xylonic acid under neutral condition.Optimization of reaction conditions for the catalysts was performed using both a batch reactor and a flow-through reactor.In a batch reactor,the yields of gluconic and xylonic acid reached 93%and 92%,respectively,at 90℃ within 180 min.In a flow reactor,both reactions reached a similar yield at 80℃ with the weight hourly space velocity of 47.1 h^(-1).The reaction kinetics were explored in the flow reactor.The oxidation of glucose and xylose to gluconic and xylonic acid followed a first-order kinetics and the turnover frequency was 0.195 and 0.161 s^(-1),respectively.The activation energy was evaluated to be 60.58 and 59.30 kJ·mol^(-1),respectively.This study presents an environmentally friendly and feasible method for the selective oxidation of monosaccharides using an activated carbon supported gold catalyst,benefiting the high-value application of carbohydrates.展开更多
基金financial support by National Key Research and Development Project(Grant No.2023YFE0109600)Guangzhou Key Research and Development Program(Grant No.2023B03J1330)+5 种基金National Program for Support of Topnotch Young Professionals(Grant No.x2qsA4210090)Guangzhou Basic and Applied Basic Research Foundation(Grant No.2024A04J3413)National Natural Science Foundation of China(Grant No.32201499)State Key Laboratory of Pulp and Paper Engineering(Grant Nos.2023PY01 and 202215)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515012519 and 2023B1515040013)China Postdoctoral Science Foundation(Grant No.2023M732021).
文摘Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic efficiency.In this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic acid.Under light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted photooxidation.Herein,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of ·O_(2)^(-),thereby improving the selectivity toward xylonic acid over other by-products.This work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.
基金supported by the National Natural Science Foundation of China(22008018)the China Postdoctoral Science Foundation(2020M670716).
文摘Highly efficient photon-to-electron conversion is crucial for achieving photocatalytic conversion.In this study,oxygen-doped carbon nitride nanocages(O@CNNCs)were engineered via dual strategies of morphology-controlled heteroatom doping,which was successfully used in the photocatalytic selective oxidation of xylose/xylan to xylonic acid.The nanocage-shaped O@CNNCs had a larger surface area,which was 4.02 times of carbon nitride(CN).Furthermore,with the assistance of morphology regulation and O-doping,O@CNNCs exhibit highly efficient photon-to-electron conversion,enhanced visible-light utilization,high photocurrent,low resistance,and fast separation/migration of electron-hole pairs.Correspondingly,the photocatalytic oxidation of xylose to xylonic acid using O@CNNCs was successfully achieved under mild reaction conditions with a yield of 83.4%.O@CNNCs have excellent recyclability,in which the yield of xylonic acid in the 5th cycle was 98.2%of its initial use.The O@CNNC photocatalytic system was also suitable for macromolecular xylan,and a xylonic acid yield of 77.34 mg was obtained when 100 mg xylan was used.The oxidation-active species captured experiments indicated that holes were crucial for the selective oxidation of xylose to xylonic acid.Overall,this study provides a new strategy for the preparation of photocatalysts with excellent photon-to-electron conversion and selective oxidation of biomass-derived feedstocks to xylonic acid.
基金The funding has been received from CSIR New Delhi.
文摘Xylonic acid is a versatile and valuable chemical with a range of industrial and potential health applications.The high demand for renewable energy and sustainable products has increased interest in xylonic acid as a starting material for the production of variety of high value chemicals and biofuels.The production of xylonic acid from biomass have an added advantage that it provides an opportunity to utilize bio-waste materials that would otherwise be discarded,reducing environmental hazards and reducing waste disposal costs.The aim of this research was to establish a bioprocess for producing xylonic acid from acid pre-treated sawdust liquor via fermentation,utilizing metabolically engineered strain of Corynebacterium glutamicum ATCC 31831.A maximum titre of 48.5±0.2 g/L xylonic acid from 60 g/L xylose derived from biomass was obtained with a yield of 0.89 g/g xylose which corresponds to a conversion of 62%.30.8±0.4 g/L of xylonic acid crystals of 95.5%purity were successfully recovered from 1L sawdust APL(Acid Pre-treated Liquor)via solvent precipitation and crystallization.Purified xylonic acid crystals were checked for its antibacterial effect on Salmonella enterica MTCC 3224,Escherichia coli MTCC 443 and Staphylococcus aureus MTCC 96.
基金RRL Rondilla acknowledges the Accelerated Science and Technology Human Resource Development Program of the Department of Science and Technology-Science Education Institute(DOST-SEI)for the graduate scholarship grant.
文摘Fungal endophytes offer structurally diverse and unique secondary metabolites with interesting biological activities.Several reports have shown the potential of fungal endophytes as sources ofα-glucosidase inhibitors to alleviate diabetes.In this study,the fungal endophyte Annulohypoxylon stygium(Xylariales,Ascomycota)was identified for the first time from the leaves of the endemic tropical plant,Pandanus simplex Merr.Crude extract was obtained by fermenting the fungal endophyte in Potato Dextrose Broth for 30 days at room temperature.The A.stygium crude extract exhibited good inhibition to theα-glucosidase enzyme with an IC_(50) of 31.88±2.86μg/mL.Purification of the crude extract afforded 8-methoxynaphthol with an IC_(50) value of 676.3±1.03μg/mL.The isolation of 8-methoxynaphthol from A.stygium is reported herein for the first time.This study highlights the ability of A.stygium to produce metabolites that may be useful as antidiabetic drugs.
基金support from the National Key Research and Development Program of China(Grant No.2021YFC2101604)the National Natural Science Foundation of China(Grant No.22108088)the Natural Science Foundation of Guangdong,China(Grant No.2023A1515012740)。
文摘A significant reaction in the synthesis of biomass-based chemicals is the catalyst-based and targeted oxidation of monosaccharides into valuable sugar acids.In this study,an activated carbon supported gold catalyst was used to oxidize glucose and xylose to gluconic acid and xylonic acid under neutral condition.Optimization of reaction conditions for the catalysts was performed using both a batch reactor and a flow-through reactor.In a batch reactor,the yields of gluconic and xylonic acid reached 93%and 92%,respectively,at 90℃ within 180 min.In a flow reactor,both reactions reached a similar yield at 80℃ with the weight hourly space velocity of 47.1 h^(-1).The reaction kinetics were explored in the flow reactor.The oxidation of glucose and xylose to gluconic and xylonic acid followed a first-order kinetics and the turnover frequency was 0.195 and 0.161 s^(-1),respectively.The activation energy was evaluated to be 60.58 and 59.30 kJ·mol^(-1),respectively.This study presents an environmentally friendly and feasible method for the selective oxidation of monosaccharides using an activated carbon supported gold catalyst,benefiting the high-value application of carbohydrates.
