Enset fiber is a promising feedstock for biofuel production with the potential to reduce carbon emissions and improve the sustainability of the energy system.This study aimed to maximize hydrogen and butanol productio...Enset fiber is a promising feedstock for biofuel production with the potential to reduce carbon emissions and improve the sustainability of the energy system.This study aimed to maximize hydrogen and butanol production from Enset fiber through simultaneous saccharification and fermentation(SSF)process in bottles as well as in bioreactor.The SSF process in bottles resulted in a higher butanol concentration of 11.36 g/L with a yield of 0.23 g/g and a productivity of 0.16 g/(L h)at the optimal process parameters of 5%(w/v)substrate loading,16 FPU/g cellulase loading,and 100 rpm agitation speed from pretreated Enset fiber.Moreover,a comparable result to the bottle experiment was observed in the bioreactor with pH-uncontrolled SSF process,although with a decreased in butanol productivity to 0.095 g/(L h).However,using the pre-hydrolysis simultaneous saccharification and fermentation(PSSF)process in the bioreactor with a 7%(w/v)substrate loading led to the highest butanol concentration of 12.84 g/L with a productivity of 0.104 g/(L h).Furthermore,optimizing the SSF process parameters to favor hydrogen resulted in an increased hydrogen yield of 198.27 mL/g-Enset fiber at atmospheric pressure,an initial pH of 8.0,and 37°C.In general,stirring the SSF process to shift the product ratio to either hydrogen or butanol was possible by adjusting temperature and pressure.At 37°C and atmospheric pressure,the process resulted in an e-mol yield of 12%for hydrogen and 38%for butanol.Alternatively,at 30°C and 0.55 bar overpressure,the process achieved a yield of 6%e-mol of hydrogen and 48%e-mol of butanol.This is the first study to produce hydrogen and butanol from Enset fiber using the SSF process and contributes to the development of a circular bioeconomy.展开更多
The anaerobic digestion of aqueous condensate from fast pyrolysis is a promising technology for enhancing carbon and energy recovery from waste.Syngas,another pyrolysis product,could be integrated as a co-substrate to...The anaerobic digestion of aqueous condensate from fast pyrolysis is a promising technology for enhancing carbon and energy recovery from waste.Syngas,another pyrolysis product,could be integrated as a co-substrate to improve process efficiency.However,limited knowledge exists on the co-fermentation of pyrolysis syngas and aqueous condensate by anaerobic cultures and the effects of substrate toxicity.This work investigates the ability of mesophilic and thermophilic anaerobic mixed cultures to co-ferment syngas and the aqueous condensate from either sewage sludge or polyethylene plastics pyrolysis in semi-batch bottle fermentations.It identifies inhibitory concentrations for carboxydotrophic and methanogenic reactions,examines specific component removal and assesses energy recovery potential.The results show successful co-fermentation of syngas and aqueous condensate components like phenols and N-heterocycles.However,the characteristics and load of the aqueous condensates affected process performance and product formation.The toxicity,likely resulting from the synergistic effect of multiple toxicants,depended on the PACs’composition.At 37°C,concentrations of 15.6 gCOD/gVSS and 7.8 gCOD/gVSS of sewage sludge-derived aqueous condensate inhibited by 50%carboxydotrophic and methanogenic activity,respectively.At 55°C,loads between 3.9 and 6.8 gCOD/gVSS inhibited by 50%both reactions.Polyethylene plastics condensate showed higher toxicity,with 2.8 gCOD/gVSS and 0.3 gCOD/gVSS at 37°C decreasing carboxydotrophic and methanogenic rates by 50%.At 55°C,0.3 gCOD/gVSS inhibited by 50%CO uptake rates and methanogenesis.Increasing PAC loads reduced methane production and promoted short-chain carboxylates formation.The recalcitrant components in sewage sludge condensate hindered e-mol recovery,while plastics condensate showed high e-mol recoveries despite the stronger toxicity.Even with challenges posed by substrate toxicity and composition variations,the successful conversion of syngas and aqueous condensates highlights the potential of this technology in advancing carbon and energy recovery from anthropogenic waste streams.展开更多
基金Open Access funding enabled and organized by Projekt DEALfunded by the DAAD-EECBP Homegrown Ph.D.Scholarship Program 2019,and the APC was funded by the Karlsruhe Institute of Technology(KIT)Publication Fund.
文摘Enset fiber is a promising feedstock for biofuel production with the potential to reduce carbon emissions and improve the sustainability of the energy system.This study aimed to maximize hydrogen and butanol production from Enset fiber through simultaneous saccharification and fermentation(SSF)process in bottles as well as in bioreactor.The SSF process in bottles resulted in a higher butanol concentration of 11.36 g/L with a yield of 0.23 g/g and a productivity of 0.16 g/(L h)at the optimal process parameters of 5%(w/v)substrate loading,16 FPU/g cellulase loading,and 100 rpm agitation speed from pretreated Enset fiber.Moreover,a comparable result to the bottle experiment was observed in the bioreactor with pH-uncontrolled SSF process,although with a decreased in butanol productivity to 0.095 g/(L h).However,using the pre-hydrolysis simultaneous saccharification and fermentation(PSSF)process in the bioreactor with a 7%(w/v)substrate loading led to the highest butanol concentration of 12.84 g/L with a productivity of 0.104 g/(L h).Furthermore,optimizing the SSF process parameters to favor hydrogen resulted in an increased hydrogen yield of 198.27 mL/g-Enset fiber at atmospheric pressure,an initial pH of 8.0,and 37°C.In general,stirring the SSF process to shift the product ratio to either hydrogen or butanol was possible by adjusting temperature and pressure.At 37°C and atmospheric pressure,the process resulted in an e-mol yield of 12%for hydrogen and 38%for butanol.Alternatively,at 30°C and 0.55 bar overpressure,the process achieved a yield of 6%e-mol of hydrogen and 48%e-mol of butanol.This is the first study to produce hydrogen and butanol from Enset fiber using the SSF process and contributes to the development of a circular bioeconomy.
基金Open Access funding enabled and organized by Projekt DEALThe authors would like to thank the Helmholtz Research Program“Materials and Technologies for the Energy Transition(MTET),Topic 3:Chemical Energy Carriers”and the support from the KIT-Publication Fund of the Karlsruhe Institute of Technology.Open access funding enabled and organized by Projekt DEAL.
文摘The anaerobic digestion of aqueous condensate from fast pyrolysis is a promising technology for enhancing carbon and energy recovery from waste.Syngas,another pyrolysis product,could be integrated as a co-substrate to improve process efficiency.However,limited knowledge exists on the co-fermentation of pyrolysis syngas and aqueous condensate by anaerobic cultures and the effects of substrate toxicity.This work investigates the ability of mesophilic and thermophilic anaerobic mixed cultures to co-ferment syngas and the aqueous condensate from either sewage sludge or polyethylene plastics pyrolysis in semi-batch bottle fermentations.It identifies inhibitory concentrations for carboxydotrophic and methanogenic reactions,examines specific component removal and assesses energy recovery potential.The results show successful co-fermentation of syngas and aqueous condensate components like phenols and N-heterocycles.However,the characteristics and load of the aqueous condensates affected process performance and product formation.The toxicity,likely resulting from the synergistic effect of multiple toxicants,depended on the PACs’composition.At 37°C,concentrations of 15.6 gCOD/gVSS and 7.8 gCOD/gVSS of sewage sludge-derived aqueous condensate inhibited by 50%carboxydotrophic and methanogenic activity,respectively.At 55°C,loads between 3.9 and 6.8 gCOD/gVSS inhibited by 50%both reactions.Polyethylene plastics condensate showed higher toxicity,with 2.8 gCOD/gVSS and 0.3 gCOD/gVSS at 37°C decreasing carboxydotrophic and methanogenic rates by 50%.At 55°C,0.3 gCOD/gVSS inhibited by 50%CO uptake rates and methanogenesis.Increasing PAC loads reduced methane production and promoted short-chain carboxylates formation.The recalcitrant components in sewage sludge condensate hindered e-mol recovery,while plastics condensate showed high e-mol recoveries despite the stronger toxicity.Even with challenges posed by substrate toxicity and composition variations,the successful conversion of syngas and aqueous condensates highlights the potential of this technology in advancing carbon and energy recovery from anthropogenic waste streams.
