Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,red...Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,reducing hydrophobicity and decreasing tensile strength.Additionally,pretreating LDPE enhanced microbial biodegradability to improve biofilm formation and significantly reduced the physical weight of LDPE film.AS3–8 consortia exhibited a maximum weight loss of 8.0%±0.5%after 45 days of incubation.While Bacillus sp.AS3 and Sphingobacterium sp.AS8 demonstrated LDPE weight loss of 5.03%±1.6%and 1.6%±0.5%,respectively.The structure of LDPE was altered after incubation with the bacterial strains,resulting in a reduction in the intensity of functional groups,including C=O,C=C,N–H,and C–N.The carbonyl index(CI)of LDPE also decreased by 7.17%after the consortia AS3–8 degradation.Consortia AS3–8 significantly impacted the physical properties of LDPE by reducing the water contact angle(WCA),decreasing to 64.21°±3.69°,and tensile strength(TS),decreasing to 17.97±0.3 MPa.Moreover,the esterase activity was measured through 45 days of incubation.SDS-PAGE analysis of the AS3–8 consortia revealed bands at 35,48,and 70 kDa molecular weights,similar to known enzymes like laccase and esterase.Furthermore,SEM observations showed rough,cracked surfaces on pretreated LDPE,with biofilms present after incubation with the bacterial strains.GC–MS analysis revealed that AS3–8 consortia produced depolymerized chemicals,including alkanes,aldehydes,and esters.The LDPE biodegradation pathway was elucidated.This study addresses critical knowledge gaps in improving plastic degradation efficiency.展开更多
The growing presence of emerging pollutants in the environment has led to a focus on developing new treatment technologies to address the limitations of traditional methods.Recent advancements in combining photocataly...The growing presence of emerging pollutants in the environment has led to a focus on developing new treatment technologies to address the limitations of traditional methods.Recent advancements in combining photocatalysis with biodegradation for pollutant treatment have garnered significant attention.This is due to the rapid and uncontrolled chemical reactions in single photocatalytic processes,which often result in the buildup of harmful by-products and over-oxidation residues.Additionally,relying solely on biodegradation is challenging for breaking down emerging pollutants that possess high concentrations and intricate structures.Therefore,the intimately coupled photocatalysis and biodegradation(ICPB)systems,along with the photocatalytic microbial fuel cells(PMFCs),as a new approach to treat pollutants.These systems combine the benefits of biodegradation and photocatalytic reactions,providing cost-effective,eco-friendly,and sustainable solutions with significant promise.In order to demonstrate the ICPB system and the PMFCs system as rational options for pollutant removal,the mechanisms of pollutant degradation by the two systems have been analyzed in depth,and recent advances in photocatalysts,biofilms,and carriers/configurations in the two systems have been summarized.Furthermore,the practical applications of the ICPB system versus the PMFCs system for pollutant removal are also summarized and highlighted.This review further points out the current limitations,such as photocatalytic materials that are still challenging in terms of commercial viability for practical applications,and looks forward to the prospects of the ICPB system versus the PMFCs system for the treatment of pollutants to promote practical applications.展开更多
The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and di...The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and dicalcium phosphate dihydrate(DCPD)in eye environment were evaluated,and uncoated Mg was used for comparison.It was found that uniform corrosion occurred macroscopically to the coated Mg samples in sodium lactate ringer’s injection(SLRI)as well as in the rabbit eyes.In micro-scale,the corrosion was characterized by local cracking and pitting primarily.Mg and calcium(Ca)were incorporated into the surface corrosion products and a multi-layer structure was formed.Compared to other samples,HA-coated Mg slowed down dramatically the alkalinity of the solution and the ion release of the sample,and exhibited the lowest corrosion rate in SLRI,which was about 0.22 mm/a.In terms of biocompatibility,fibroblasts demonstrated high viability in the HA-coated and DCPD-coated Mg groups(p<0.05)in vitro.In vivo,HA-coated Mg was found to show lower inflammatory response and fibrosis than the other groups did,as indicated by hematoxylin-eosin and immunofluorescence staining.During the degrading process of HA-coated Mg in the rabbits’eyes,no inflammation was found in the anterior chamber,lens,and vitreous body.HA-coated Mg was fully biodegraded fifteen weeks post-operation,and the scleral drainage channel(SDC)was formed without obvious scarring.It is concluded that HA-coated Mg implantation is a promising adjunctive procedure to improve the success rate of trabeculectomy.Statement of significance:Magnesium(Mg)has shown to be a potential biomaterial for ophthalmic implants in our previous work.However,inflammatory response resulted from the low corrosion resistance of Mg is a major concern.It is shown here that Mg coated with different calcium phosphates can improve these properties in varying degrees and keep the scleral drainage channel unobstructed and unscarred.Based on our in vitro and in vivo studies,HA-coated Mg exhibited a better degradation behavior and excellent biocompatibility.The scleral drainage channel still exists and aqueous humor flows out smoothly after the full degradation of the implant.It is concluded that HA-coated Mg is a promising biomaterial to increase the therapeutic efficiency of trabeculectomy for glaucoma.展开更多
Insects have become an efficient and eco-friendly bioreactor for plastics and even micro/nano-plastics biodegradation.However,the optimal conditions for rearing insects to maximize plastic biodegradation and the under...Insects have become an efficient and eco-friendly bioreactor for plastics and even micro/nano-plastics biodegradation.However,the optimal conditions for rearing insects to maximize plastic biodegradation and the underlying mechanisms remain unclear,hindering its practical applications.We investigated the effects of multiple rearing factors on plastics degradation efficiency of Tenebrio molitor larvae,including larval instar,water addition frequency,plastic specific surface area and plastic types.The functional gut microbes and enzymes associated with the improved efficiency were further explored.Our findings revealed that adult larvae achieved the highest plastics degradation efficiency when receiving regular water additions without causing drowning of insects on hydrophobic plastics.Additionally,they effectively ingested foam plastics of polystyrene,polyethylene and polyurethane without prior comminution and densification.The biodegradation processes involving oxidation,cleavage and depolymerization of plastics were all demonstrated.Furthermore,foam plastic type-dependent functional microbes and enzymes that contributed to the efficient plastic degradationwere identified.Thiswork provides valuable insights into the practical applications of insects for sustainable plastics biodegradation.展开更多
Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution...Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution.Biodegradation demonstrates substantial potential for CDP removal from the environment.This study investigated the biodegradation mechanisms of CDP using anaerobic activated sludge(AnAS).The biodegradation of 1-mg/L CDP followed a first-order kinetic model with a degradation kinetic constant of 0.943 d^(-1),and the addition of different electron acceptors affected the degradation rate.High-resolution mass spectrometry identified seven transformation products(TPs)of CDP.The pathways of CDP degradation in anaerobic conditions were proposed,with carboxylation products being the most dominant intermediate products.The structure of the anaerobic microbial community at different degradation time points in CDP-amended microcosms was examined.The linear discriminant analysis(LDA)of effect size(LEfSe)potentially underscored the pivotal role of Methyloversatilis in CDP biodegradation.Zebrafish embryotoxicity experiments revealed both lethal and morphogenetic impacts of CDP on zebrafish embryos.The survival rate,hatching rate,and body length indicators of zebrafish embryos underscored the detoxification of CDP and its resultant intermediates by AnAS.This study offers new insights into the fate and biodegradation mechanisms of CDP in wastewater treatment plants.展开更多
Bioremediation has gained significant attention due to its potential to remove azo dyes.However,the challenges microor-ganisms face in surviving when azo dyes are the sole carbon source limit its widespread applicatio...Bioremediation has gained significant attention due to its potential to remove azo dyes.However,the challenges microor-ganisms face in surviving when azo dyes are the sole carbon source limit its widespread application.This study aimed to improve the biodegradation of azo dyes by utilizing Baijiu distiller’s grains leachate(BDGL)as a co-substrate.The experimental results demon-strated that BDGL significantly enhanced Providencia rettgeri’s ability to degrade the model pollutant Acid Black 210(AB210),achieving a decolorization efficiency of 94.5%.This may be attributed to the nutrient-rich composition of BDGL,which includes ethanol and protein,providing a favorable substrate for bacterial growth and activity.The higher biomass and increased activities of azoreductase and quinone oxidoreductase in the BDGL group further supported these findings.Additionally,this method demonstra-ted broad-spectrum degradation of azo dyes(Direct Red 5B,Acid Red 73,and Congo Red)with different structures,highlighting its potential applicability.Metabolite assays combined with transcriptomics analyses revealed that the expression of functional genes re-lated to redox reactions,azo bond cleavage,and hydrolysis increased under the co-metabolic conditions of BDGL,resulting in stronger reducing power that further mineralized the dye into smaller metabolites.Our study offers a practical strategy for the simulta-neous treatment of dye-containing wastewater and Baijiu distiller’s grains,with significant environmental and industrial applications.展开更多
The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,mola...The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.展开更多
ObjectiveThis study aimed to investigate the biodegradation effect and biodegradation mechanism of aniline aerofloat wastewater. MethodSmall-scale processing of simulated aniline aerofloat wastewater was carried out w...ObjectiveThis study aimed to investigate the biodegradation effect and biodegradation mechanism of aniline aerofloat wastewater. MethodSmall-scale processing of simulated aniline aerofloat wastewater was carried out with SBR （Sequencing Batch Reactor） system; intermediate products in the process were analyzed using high-performance liquid chromatography. ResultAccording to the experimental results, the small-scale process was basically stably operated after 40 days of activation and regulation, leading to relatively ideal degradation effect on aniline aerofloat, the COD removal efficiency reached 64.3% , degradation rate of aniline aerofloat reached 93.4%, which could be applied in the treatment of mine flotation wastewater containing such pollutant. During the degradation process, pH increased from 5.83 to 6.60 and then dropped to 6.17, which might be caused by the thiocyanate ions and aniline generated in the degradation process. Aniline aerofloat mainly produced two preliminary products during the biodegradation process： aniline and a substance that was difficult to be biodegraded under aerobic conditions, which was the main reason for the relatively high COD value in effluent. Furthermore, aniline was eventually biodegraded. ConclusionThis study provided basis for the development of biological treatment of flotation wastewater in China and showed great significance for the improvement of ecological environment around the mines.展开更多
A new cell immobilization method based on the replacement of KCl by KCl+chitosan as the gelling agent was developed. The experimental results showed that through addition of chitosan into gelling agent, the mechanica...A new cell immobilization method based on the replacement of KCl by KCl+chitosan as the gelling agent was developed. The experimental results showed that through addition of chitosan into gelling agent, the mechanical strength and the thermal stability of the carrageenan gel were greatly improved. The new immobilization method was used to entrap a chlorophenol degrading microorganism. The immobilized microbial cells were applied for chlorophenol biodegradation. The experiments demonstrated that immobilized cells exhibit a higher bioactivity in the degradation of chlorophenol than free cells.展开更多
By using plate screening techniques with five phthalate esters （DMP, DEP, DBP, DEHP and DOP） as energy and carbon sources, an active strain was isolated from the sediments of Chaohu Lake, which was identified as Bur...By using plate screening techniques with five phthalate esters （DMP, DEP, DBP, DEHP and DOP） as energy and carbon sources, an active strain was isolated from the sediments of Chaohu Lake, which was identified as Burkholderia pickettil and named B. pickettii.z-1. The biodegradation of five phthalate esters by B. pick- ettii.z-1 strain was in accordance with the pseudo first-order kinetic equation： Ct = C0.e-kt. As the concentration of phthalate esters increased, the degradation rate of phthalate esters was reduced. B. pickettii.z-1 strain exhibited remarkably different degradation effects on various PAEs. Specifically, short-side-chain DMP and DEP were degraded rapidly, while long-side-chain DBP and DEHP were degraded slowly.展开更多
unaliella tertiolecta has an ability to biodegrade dimethyl phthalate(DMP) was found in this study, and the average of the biodegradation rates were 113 mg/(L·d) and 305 mg/(L·d), and the average of the ph...unaliella tertiolecta has an ability to biodegrade dimethyl phthalate(DMP) was found in this study, and the average of the biodegradation rates were 113 mg/(L·d) and 305 mg/(L·d), and the average of the phthalic acid (PA) production rates were 15 mg/(L·d) and 36 mg/(L·d), for initial 100 mg/L and 300 mg/L DMP, respectively. The larger amount of accumulation by D. tertiolecta under higher DMP concentration may be responsible for the increase of biodegradation rate, and one of products of DMP biodegradation by D. tertiolecta may be PA. By fitting the process of DMP biodegradation by D. tertiolecta with a kinetic equation newly suggested, the standard deviations between calculated and observed values were 25 mg/L and 57 mg/L, respectively.展开更多
文摘Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,reducing hydrophobicity and decreasing tensile strength.Additionally,pretreating LDPE enhanced microbial biodegradability to improve biofilm formation and significantly reduced the physical weight of LDPE film.AS3–8 consortia exhibited a maximum weight loss of 8.0%±0.5%after 45 days of incubation.While Bacillus sp.AS3 and Sphingobacterium sp.AS8 demonstrated LDPE weight loss of 5.03%±1.6%and 1.6%±0.5%,respectively.The structure of LDPE was altered after incubation with the bacterial strains,resulting in a reduction in the intensity of functional groups,including C=O,C=C,N–H,and C–N.The carbonyl index(CI)of LDPE also decreased by 7.17%after the consortia AS3–8 degradation.Consortia AS3–8 significantly impacted the physical properties of LDPE by reducing the water contact angle(WCA),decreasing to 64.21°±3.69°,and tensile strength(TS),decreasing to 17.97±0.3 MPa.Moreover,the esterase activity was measured through 45 days of incubation.SDS-PAGE analysis of the AS3–8 consortia revealed bands at 35,48,and 70 kDa molecular weights,similar to known enzymes like laccase and esterase.Furthermore,SEM observations showed rough,cracked surfaces on pretreated LDPE,with biofilms present after incubation with the bacterial strains.GC–MS analysis revealed that AS3–8 consortia produced depolymerized chemicals,including alkanes,aldehydes,and esters.The LDPE biodegradation pathway was elucidated.This study addresses critical knowledge gaps in improving plastic degradation efficiency.
文摘The growing presence of emerging pollutants in the environment has led to a focus on developing new treatment technologies to address the limitations of traditional methods.Recent advancements in combining photocatalysis with biodegradation for pollutant treatment have garnered significant attention.This is due to the rapid and uncontrolled chemical reactions in single photocatalytic processes,which often result in the buildup of harmful by-products and over-oxidation residues.Additionally,relying solely on biodegradation is challenging for breaking down emerging pollutants that possess high concentrations and intricate structures.Therefore,the intimately coupled photocatalysis and biodegradation(ICPB)systems,along with the photocatalytic microbial fuel cells(PMFCs),as a new approach to treat pollutants.These systems combine the benefits of biodegradation and photocatalytic reactions,providing cost-effective,eco-friendly,and sustainable solutions with significant promise.In order to demonstrate the ICPB system and the PMFCs system as rational options for pollutant removal,the mechanisms of pollutant degradation by the two systems have been analyzed in depth,and recent advances in photocatalysts,biofilms,and carriers/configurations in the two systems have been summarized.Furthermore,the practical applications of the ICPB system versus the PMFCs system for pollutant removal are also summarized and highlighted.This review further points out the current limitations,such as photocatalytic materials that are still challenging in terms of commercial viability for practical applications,and looks forward to the prospects of the ICPB system versus the PMFCs system for the treatment of pollutants to promote practical applications.
基金supported by the Natural Science Foundation of Chongqing(Grant No.csts2018jcyjAX0016)Funded by the Senior Medical Talents Program of Chongqing for Young and Middle-aged.
文摘The possible application of magnesium(Mg)in glaucoma surgical treatment has been investigated in our previous work.In this paper,the degradation behavior and biocompatibility of Mg coated with hydroxyapatite(HA)and dicalcium phosphate dihydrate(DCPD)in eye environment were evaluated,and uncoated Mg was used for comparison.It was found that uniform corrosion occurred macroscopically to the coated Mg samples in sodium lactate ringer’s injection(SLRI)as well as in the rabbit eyes.In micro-scale,the corrosion was characterized by local cracking and pitting primarily.Mg and calcium(Ca)were incorporated into the surface corrosion products and a multi-layer structure was formed.Compared to other samples,HA-coated Mg slowed down dramatically the alkalinity of the solution and the ion release of the sample,and exhibited the lowest corrosion rate in SLRI,which was about 0.22 mm/a.In terms of biocompatibility,fibroblasts demonstrated high viability in the HA-coated and DCPD-coated Mg groups(p<0.05)in vitro.In vivo,HA-coated Mg was found to show lower inflammatory response and fibrosis than the other groups did,as indicated by hematoxylin-eosin and immunofluorescence staining.During the degrading process of HA-coated Mg in the rabbits’eyes,no inflammation was found in the anterior chamber,lens,and vitreous body.HA-coated Mg was fully biodegraded fifteen weeks post-operation,and the scleral drainage channel(SDC)was formed without obvious scarring.It is concluded that HA-coated Mg implantation is a promising adjunctive procedure to improve the success rate of trabeculectomy.Statement of significance:Magnesium(Mg)has shown to be a potential biomaterial for ophthalmic implants in our previous work.However,inflammatory response resulted from the low corrosion resistance of Mg is a major concern.It is shown here that Mg coated with different calcium phosphates can improve these properties in varying degrees and keep the scleral drainage channel unobstructed and unscarred.Based on our in vitro and in vivo studies,HA-coated Mg exhibited a better degradation behavior and excellent biocompatibility.The scleral drainage channel still exists and aqueous humor flows out smoothly after the full degradation of the implant.It is concluded that HA-coated Mg is a promising biomaterial to increase the therapeutic efficiency of trabeculectomy for glaucoma.
基金supported by the National Natural Science Foundation of China(No.22241603).
文摘Insects have become an efficient and eco-friendly bioreactor for plastics and even micro/nano-plastics biodegradation.However,the optimal conditions for rearing insects to maximize plastic biodegradation and the underlying mechanisms remain unclear,hindering its practical applications.We investigated the effects of multiple rearing factors on plastics degradation efficiency of Tenebrio molitor larvae,including larval instar,water addition frequency,plastic specific surface area and plastic types.The functional gut microbes and enzymes associated with the improved efficiency were further explored.Our findings revealed that adult larvae achieved the highest plastics degradation efficiency when receiving regular water additions without causing drowning of insects on hydrophobic plastics.Additionally,they effectively ingested foam plastics of polystyrene,polyethylene and polyurethane without prior comminution and densification.The biodegradation processes involving oxidation,cleavage and depolymerization of plastics were all demonstrated.Furthermore,foam plastic type-dependent functional microbes and enzymes that contributed to the efficient plastic degradationwere identified.Thiswork provides valuable insights into the practical applications of insects for sustainable plastics biodegradation.
基金supported by the National Natural Science Foundation of China(Grants No.52270155 and 92047201).
文摘Cresyl diphenyl phosphate(CDP),an emerging aryl organophosphate ester(OPE),exhibits potential toxic effects and is frequently found in diverse environmental media,thereby raising concerns about environmental pollution.Biodegradation demonstrates substantial potential for CDP removal from the environment.This study investigated the biodegradation mechanisms of CDP using anaerobic activated sludge(AnAS).The biodegradation of 1-mg/L CDP followed a first-order kinetic model with a degradation kinetic constant of 0.943 d^(-1),and the addition of different electron acceptors affected the degradation rate.High-resolution mass spectrometry identified seven transformation products(TPs)of CDP.The pathways of CDP degradation in anaerobic conditions were proposed,with carboxylation products being the most dominant intermediate products.The structure of the anaerobic microbial community at different degradation time points in CDP-amended microcosms was examined.The linear discriminant analysis(LDA)of effect size(LEfSe)potentially underscored the pivotal role of Methyloversatilis in CDP biodegradation.Zebrafish embryotoxicity experiments revealed both lethal and morphogenetic impacts of CDP on zebrafish embryos.The survival rate,hatching rate,and body length indicators of zebrafish embryos underscored the detoxification of CDP and its resultant intermediates by AnAS.This study offers new insights into the fate and biodegradation mechanisms of CDP in wastewater treatment plants.
基金supported by the National Key Re-search and Development Project of China(No.2023YFC3108400).
文摘Bioremediation has gained significant attention due to its potential to remove azo dyes.However,the challenges microor-ganisms face in surviving when azo dyes are the sole carbon source limit its widespread application.This study aimed to improve the biodegradation of azo dyes by utilizing Baijiu distiller’s grains leachate(BDGL)as a co-substrate.The experimental results demon-strated that BDGL significantly enhanced Providencia rettgeri’s ability to degrade the model pollutant Acid Black 210(AB210),achieving a decolorization efficiency of 94.5%.This may be attributed to the nutrient-rich composition of BDGL,which includes ethanol and protein,providing a favorable substrate for bacterial growth and activity.The higher biomass and increased activities of azoreductase and quinone oxidoreductase in the BDGL group further supported these findings.Additionally,this method demonstra-ted broad-spectrum degradation of azo dyes(Direct Red 5B,Acid Red 73,and Congo Red)with different structures,highlighting its potential applicability.Metabolite assays combined with transcriptomics analyses revealed that the expression of functional genes re-lated to redox reactions,azo bond cleavage,and hydrolysis increased under the co-metabolic conditions of BDGL,resulting in stronger reducing power that further mineralized the dye into smaller metabolites.Our study offers a practical strategy for the simulta-neous treatment of dye-containing wastewater and Baijiu distiller’s grains,with significant environmental and industrial applications.
基金financial support of this paper by the Ministry of Education and Science of Ukraine under grant(Biotherm/0124U000789).
文摘The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.
基金Supported by Major Special Science and Technology Project of Guangdong Province(2010B080703035)~~
文摘ObjectiveThis study aimed to investigate the biodegradation effect and biodegradation mechanism of aniline aerofloat wastewater. MethodSmall-scale processing of simulated aniline aerofloat wastewater was carried out with SBR （Sequencing Batch Reactor） system; intermediate products in the process were analyzed using high-performance liquid chromatography. ResultAccording to the experimental results, the small-scale process was basically stably operated after 40 days of activation and regulation, leading to relatively ideal degradation effect on aniline aerofloat, the COD removal efficiency reached 64.3% , degradation rate of aniline aerofloat reached 93.4%, which could be applied in the treatment of mine flotation wastewater containing such pollutant. During the degradation process, pH increased from 5.83 to 6.60 and then dropped to 6.17, which might be caused by the thiocyanate ions and aniline generated in the degradation process. Aniline aerofloat mainly produced two preliminary products during the biodegradation process： aniline and a substance that was difficult to be biodegraded under aerobic conditions, which was the main reason for the relatively high COD value in effluent. Furthermore, aniline was eventually biodegraded. ConclusionThis study provided basis for the development of biological treatment of flotation wastewater in China and showed great significance for the improvement of ecological environment around the mines.
文摘A new cell immobilization method based on the replacement of KCl by KCl+chitosan as the gelling agent was developed. The experimental results showed that through addition of chitosan into gelling agent, the mechanical strength and the thermal stability of the carrageenan gel were greatly improved. The new immobilization method was used to entrap a chlorophenol degrading microorganism. The immobilized microbial cells were applied for chlorophenol biodegradation. The experiments demonstrated that immobilized cells exhibit a higher bioactivity in the degradation of chlorophenol than free cells.
基金Supported by National High Technology Research and Development Program of China(2013AA102804B)Fund of Anhui Province Environmental Protection(2013-008)~~
文摘By using plate screening techniques with five phthalate esters （DMP, DEP, DBP, DEHP and DOP） as energy and carbon sources, an active strain was isolated from the sediments of Chaohu Lake, which was identified as Burkholderia pickettil and named B. pickettii.z-1. The biodegradation of five phthalate esters by B. pick- ettii.z-1 strain was in accordance with the pseudo first-order kinetic equation： Ct = C0.e-kt. As the concentration of phthalate esters increased, the degradation rate of phthalate esters was reduced. B. pickettii.z-1 strain exhibited remarkably different degradation effects on various PAEs. Specifically, short-side-chain DMP and DEP were degraded rapidly, while long-side-chain DBP and DEHP were degraded slowly.
文摘unaliella tertiolecta has an ability to biodegrade dimethyl phthalate(DMP) was found in this study, and the average of the biodegradation rates were 113 mg/(L·d) and 305 mg/(L·d), and the average of the phthalic acid (PA) production rates were 15 mg/(L·d) and 36 mg/(L·d), for initial 100 mg/L and 300 mg/L DMP, respectively. The larger amount of accumulation by D. tertiolecta under higher DMP concentration may be responsible for the increase of biodegradation rate, and one of products of DMP biodegradation by D. tertiolecta may be PA. By fitting the process of DMP biodegradation by D. tertiolecta with a kinetic equation newly suggested, the standard deviations between calculated and observed values were 25 mg/L and 57 mg/L, respectively.
