Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-b...Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-based process for enhanced lignin removal in wastewater using the fungus Neurospora discreta,which effectively degrades lignin and forms robust biofilms at the air–liquid interface under specific conditions.The process was optimised using the Taguchi design of experiments approach,and three factors including pH,copper sulphate concentration,and trace element concentration were evaluated at three levels.Experimental data were analysed against three responses:lignin degradation efficiency and the activities of two ligninolytic enzymes(polyphenol oxidase and versatile peroxidase).The results indicated that wastewater pH was the most significant parameter affecting lignin degradation efficiency and enzyme activities.Over 70%lignin degradation was achieved at pH levels of 5 and 6 with copper sulphate concentrations above 4 mg/L,while degradation efficiency drastically dropped to 45%at a pH value of 7.Reversed-phase high-performance liquid chromatography analysis demonstrated the effects of the three factors on the polar and non-polar components of lignin in wastewater,revealing a clear decrease in all peak areas after treatment.Additionally,significant relationships were observed between biofilm properties(including porosity,water retention value,polysaccharide content,and protein content)and lignin removal efficiency.This study also reported for the first time the presence of versatile peroxidase,a ligninolytic enzyme,in Neurospora sp.展开更多
Extensive use of lambda-cyhalothrin(LC)for agricultural and domestic pest control leads to the accumulation of its residues in soil and water,which poses a serious threat to the environment.Remediation of LC at the po...Extensive use of lambda-cyhalothrin(LC)for agricultural and domestic pest control leads to the accumulation of its residues in soil and water,which poses a serious threat to the environment.Remediation of LC at the point source is the most effective way to avoid its spread and harmful effects.Therefore,this study was planned to investigate the potential of indigenously isolated bacteria for the remediation of LC in cotton-vegetated soils.Three potent LC-degrading bacteria,Brucella intermedia Halol,Alcaligenes faecalis CH1S,and Aquamicrobium terrae CH1T,were isolated from a pyrethroid-contaminated soil.A consortium CHST comprising these three strains was found to exhibit a higher potential for LC degradation as compared to the individual strains.The degradation of LC by CHST was optimized for four varying factors,i.e.,pH,inoculum density(ID),carbon source(CS),and initial pesticide(i.e.,LC)concentration(PC),by applying Taguchi design of experiment.The contributions of these factors to the biodegradation of LC were found to be in the order of pH>CS>PC>ID.The enhanced degradation of LC(84%)was attained at pH 7.0 in minimum salt medium containing 10 mg L^(-1)LC and 3%inoculum.The consortium CHST was also augmented in sterilized and unsterilized soil microcosms at three PCs,i.e.,2,5,and 10 mg kg^(-1).After 21 d of incubation,complete LC degradation was achieved at 2 mg kg^(-1)PC in sterilized as well as unsterilized soil,whereas at higher PCs,the extent of degradation was comparatively less.At PC of 5 mg kg^(-1),88%and 96%LC degradation were observed in sterilized and unsterilized soils,respectively,compared to 79%and90%degradation at 10 mg kg^(-1),respectively.During biodegradation,the major metabolite of LC,i.e.,3-phenoxybenzoic acid,was produced and further degraded.In a cotton-planted soil spiked with 10 mg kg^(-1)LC,the consortium degraded 91.8%LC,as well as improving the agronomic parameters of the cotton plants.In a nutshell,the consortium CHST was found to be a promising candidate for the remediation of LC contamination at the point source.展开更多
The rates of maize breakage and entrainment loss are high in the harvest of high-moisture maize,which remains an issue with the development of agricultural mechanization.In order to reduce the maize breakage and entra...The rates of maize breakage and entrainment loss are high in the harvest of high-moisture maize,which remains an issue with the development of agricultural mechanization.In order to reduce the maize breakage and entrainment loss rates,the correlations among key factors,such as the threshing cylinder speed,concave clearance and feeding rate,and the rates of breakage and entrainment loss during high-moisture maize harvesting were studied in this paper.A single-factor experiment was carried out using a single-longitudinal-axial flow maize harvester,and an orthogonal experiment was carried out using single-and double-longitudinal-axial flow maize harvesters with the Taguchi experimental design method.The single-factor experiment revealed that when the cylinder speed increased,the breakage rate of maize decreased first and then increased,while the entrainment loss rate decreased.The breakage rate of maize decreased as the concave clearance increased,while the entrainment loss rate decreased first and then increased.The optimum value of the concave clearance was positively correlated with the ear diameter of maize;Additionally,the minimum breakage rate of maize occurred when the feeding rate was at the rated value,and the entrainment loss rate increased as the feeding rate increased.The orthogonal experiments revealed that the importance of cylinder speed,feeding rate,concave clearance on the maize breakage and entrainment loss rates were in descending order.The optimum values of parameters for the single-longitudinal-axial flow maize harvester were 370 r/min cylinder speed,40 mm concave clearance and 10 kg/s feeding rate.The optimum values of parameters the double-longitudinal-axial flow maize harvester were 550 r/min cylinder speed,35 mm concave clearance and 10 kg/s feeding rate.The research can provide a reference for parameter configuration and control strategy for the longitudinal-axial flow maize harvester with high-moisture maize.展开更多
基金supported by the Leverhulme Trust Research Project(Grant No.RPG-2020-021).
文摘Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-based process for enhanced lignin removal in wastewater using the fungus Neurospora discreta,which effectively degrades lignin and forms robust biofilms at the air–liquid interface under specific conditions.The process was optimised using the Taguchi design of experiments approach,and three factors including pH,copper sulphate concentration,and trace element concentration were evaluated at three levels.Experimental data were analysed against three responses:lignin degradation efficiency and the activities of two ligninolytic enzymes(polyphenol oxidase and versatile peroxidase).The results indicated that wastewater pH was the most significant parameter affecting lignin degradation efficiency and enzyme activities.Over 70%lignin degradation was achieved at pH levels of 5 and 6 with copper sulphate concentrations above 4 mg/L,while degradation efficiency drastically dropped to 45%at a pH value of 7.Reversed-phase high-performance liquid chromatography analysis demonstrated the effects of the three factors on the polar and non-polar components of lignin in wastewater,revealing a clear decrease in all peak areas after treatment.Additionally,significant relationships were observed between biofilm properties(including porosity,water retention value,polysaccharide content,and protein content)and lignin removal efficiency.This study also reported for the first time the presence of versatile peroxidase,a ligninolytic enzyme,in Neurospora sp.
基金supported by the Higher Education Commission(HEC),Pakistan(No.NRPU 9570)。
文摘Extensive use of lambda-cyhalothrin(LC)for agricultural and domestic pest control leads to the accumulation of its residues in soil and water,which poses a serious threat to the environment.Remediation of LC at the point source is the most effective way to avoid its spread and harmful effects.Therefore,this study was planned to investigate the potential of indigenously isolated bacteria for the remediation of LC in cotton-vegetated soils.Three potent LC-degrading bacteria,Brucella intermedia Halol,Alcaligenes faecalis CH1S,and Aquamicrobium terrae CH1T,were isolated from a pyrethroid-contaminated soil.A consortium CHST comprising these three strains was found to exhibit a higher potential for LC degradation as compared to the individual strains.The degradation of LC by CHST was optimized for four varying factors,i.e.,pH,inoculum density(ID),carbon source(CS),and initial pesticide(i.e.,LC)concentration(PC),by applying Taguchi design of experiment.The contributions of these factors to the biodegradation of LC were found to be in the order of pH>CS>PC>ID.The enhanced degradation of LC(84%)was attained at pH 7.0 in minimum salt medium containing 10 mg L^(-1)LC and 3%inoculum.The consortium CHST was also augmented in sterilized and unsterilized soil microcosms at three PCs,i.e.,2,5,and 10 mg kg^(-1).After 21 d of incubation,complete LC degradation was achieved at 2 mg kg^(-1)PC in sterilized as well as unsterilized soil,whereas at higher PCs,the extent of degradation was comparatively less.At PC of 5 mg kg^(-1),88%and 96%LC degradation were observed in sterilized and unsterilized soils,respectively,compared to 79%and90%degradation at 10 mg kg^(-1),respectively.During biodegradation,the major metabolite of LC,i.e.,3-phenoxybenzoic acid,was produced and further degraded.In a cotton-planted soil spiked with 10 mg kg^(-1)LC,the consortium degraded 91.8%LC,as well as improving the agronomic parameters of the cotton plants.In a nutshell,the consortium CHST was found to be a promising candidate for the remediation of LC contamination at the point source.
基金The authors acknowledge that this work was financially supported by the 13th Five-year National Key Research and Development Program(Grant No.2016YFD0701901).
文摘The rates of maize breakage and entrainment loss are high in the harvest of high-moisture maize,which remains an issue with the development of agricultural mechanization.In order to reduce the maize breakage and entrainment loss rates,the correlations among key factors,such as the threshing cylinder speed,concave clearance and feeding rate,and the rates of breakage and entrainment loss during high-moisture maize harvesting were studied in this paper.A single-factor experiment was carried out using a single-longitudinal-axial flow maize harvester,and an orthogonal experiment was carried out using single-and double-longitudinal-axial flow maize harvesters with the Taguchi experimental design method.The single-factor experiment revealed that when the cylinder speed increased,the breakage rate of maize decreased first and then increased,while the entrainment loss rate decreased.The breakage rate of maize decreased as the concave clearance increased,while the entrainment loss rate decreased first and then increased.The optimum value of the concave clearance was positively correlated with the ear diameter of maize;Additionally,the minimum breakage rate of maize occurred when the feeding rate was at the rated value,and the entrainment loss rate increased as the feeding rate increased.The orthogonal experiments revealed that the importance of cylinder speed,feeding rate,concave clearance on the maize breakage and entrainment loss rates were in descending order.The optimum values of parameters for the single-longitudinal-axial flow maize harvester were 370 r/min cylinder speed,40 mm concave clearance and 10 kg/s feeding rate.The optimum values of parameters the double-longitudinal-axial flow maize harvester were 550 r/min cylinder speed,35 mm concave clearance and 10 kg/s feeding rate.The research can provide a reference for parameter configuration and control strategy for the longitudinal-axial flow maize harvester with high-moisture maize.
