The influence of biochar-released dissolved organic matter(BDOM)on the transcription of gene(DEG)in Pseudomonas stutzeri and Shewanella putrefacien during sulfamethoxazole(SMX)and chloramphenicol(CAP)biodegradation un...The influence of biochar-released dissolved organic matter(BDOM)on the transcription of gene(DEG)in Pseudomonas stutzeri and Shewanella putrefacien during sulfamethoxazole(SMX)and chloramphenicol(CAP)biodegradation under visible light was investigated in this study.The results indicated that BDOM components would be nutrients for bacterial amplification and growth under the culture conditions of xenon lamp irradiation and avoiding light,especially BDOM from low temperatures.Additionally,visible light irradiation would improve the saturated fatty acid by stimulating the cell membrane of the microorganism,thus promoting the biodegradation of antibiotics through altering P.stutzeri and S.putrefaciens reoxidative and catabolism processes and significantly inhabiting the copy number of their genes.Moreover,the upregulated genes and enzymes related to SMX and CAP-metabolic and catabolic processes were enriched,which were involved in the pathways of biodegradation,further improving biodegradation efficiency.In particular,interaction network analysis between the top 100 dominant functional genes from P.stutzeri and S.putrefaciens and the molecular types of BDOM,e.g.,CHO,CHON,and CHOS(p<0.05),indicated that the genes of molecular function showed a high positive or negative correlation with the CHO type of BDOM.The results revealed that the CHO type of BDOM affected the functional genes of molecular function,cellular component,and biological process from P.stutzeri and S.putrefaciens,influencing the biodegradation of SMX and CAP.This study provided an basis for BDOM playing a role in antibiotic removal from the aqueous solution using biochar combined with photobiodegradation.展开更多
Biochar-derived dissolved organic matter(DOM)is a highly active component that plays a critical and complex role in the immobilization of heavy metals.This study systematically investigated the impact of DOM on Pb(Ⅱ)...Biochar-derived dissolved organic matter(DOM)is a highly active component that plays a critical and complex role in the immobilization of heavy metals.This study systematically investigated the impact of DOM on Pb(Ⅱ)adsorption by comparing the adsorption capacities of biochar before and after DOM removal,thereby unveiling the underlying mechanisms through advanced spectroscopic techniques.Adsorption experiments demonstrated that water-washed biochar(WBC)exhibited a markedly reduced adsorption capacity(35.0 mg g^(−1))compared to untreated biochar(BC)(96.2 mg g^(−1)),highlighting the essential role of DOM in enhancing Pb(Ⅱ)adsorption.Kinetic and isothermal analyses revealed that the adsorption process was predominantly chemical in nature,as evidenced by the excellent fit of experimental data to the pseudo-second-order,Freundlich,and Temkin models.FTIR and XPS analyses confirmed that oxygen-containing functional groups,including hydroxyl,carboxyl,carbonyl,and ether groups,actively participated in Pb(Ⅱ)complexation in BC,WBC,and DOM.Spectral shifts and changes in the relative abundance of C–O and C=O bonds further supported this conclusion.The Pb 4f spectra indicated that Pb(Ⅱ)was primarily retained as Pb_(3)(OH)_(2)(CO_(3))_(2),with complexation identified as the dominant mechanism,followed by co-precipitation.UV differential log-transformed absorption spectra derived from titration experiments,revealed the heterogeneity of Pb(Ⅱ)binding sites within DOM.Furthermore,excitation-emission matrix fluorescence spectroscopy coupled with parallel factor analysis(EEM-PARAFAC)identified three humic-like components.Among these,component C3(humic-like and tyrosine substance)exhibited the strongest binding affinity for Pb(Ⅱ).Hetero-2DCOS analysis,combined with additional spectroscopic techniques,demonstrated that carboxyl groups in humic-like substances were the most reactive sites for Pb(Ⅱ)binding.These findings provide molecular-level insights into the structural and functional characteristics of biochar-derived DOM-Pb(Ⅱ)complexes,offering a scientific basis for optimizing biochar-based strategies for heavy metal pollution remediation.展开更多
基金National Natural Science Foundation of China(42077320)Fundamental Research Funds for the Central Universities and 111 program,Ministry of Education,China(T2017002)。
文摘The influence of biochar-released dissolved organic matter(BDOM)on the transcription of gene(DEG)in Pseudomonas stutzeri and Shewanella putrefacien during sulfamethoxazole(SMX)and chloramphenicol(CAP)biodegradation under visible light was investigated in this study.The results indicated that BDOM components would be nutrients for bacterial amplification and growth under the culture conditions of xenon lamp irradiation and avoiding light,especially BDOM from low temperatures.Additionally,visible light irradiation would improve the saturated fatty acid by stimulating the cell membrane of the microorganism,thus promoting the biodegradation of antibiotics through altering P.stutzeri and S.putrefaciens reoxidative and catabolism processes and significantly inhabiting the copy number of their genes.Moreover,the upregulated genes and enzymes related to SMX and CAP-metabolic and catabolic processes were enriched,which were involved in the pathways of biodegradation,further improving biodegradation efficiency.In particular,interaction network analysis between the top 100 dominant functional genes from P.stutzeri and S.putrefaciens and the molecular types of BDOM,e.g.,CHO,CHON,and CHOS(p<0.05),indicated that the genes of molecular function showed a high positive or negative correlation with the CHO type of BDOM.The results revealed that the CHO type of BDOM affected the functional genes of molecular function,cellular component,and biological process from P.stutzeri and S.putrefaciens,influencing the biodegradation of SMX and CAP.This study provided an basis for BDOM playing a role in antibiotic removal from the aqueous solution using biochar combined with photobiodegradation.
基金supported by the National Key R&D Program of China(2024YFD1501700)the Distinguished Youth Science Foundation of Heilongjiang Province,China(JQ2023E001)the Young Leading Talents Project of Northeast Agricultural University,China(NEAU2023QNLJ-013,NEAU2024QNLJ-01).
文摘Biochar-derived dissolved organic matter(DOM)is a highly active component that plays a critical and complex role in the immobilization of heavy metals.This study systematically investigated the impact of DOM on Pb(Ⅱ)adsorption by comparing the adsorption capacities of biochar before and after DOM removal,thereby unveiling the underlying mechanisms through advanced spectroscopic techniques.Adsorption experiments demonstrated that water-washed biochar(WBC)exhibited a markedly reduced adsorption capacity(35.0 mg g^(−1))compared to untreated biochar(BC)(96.2 mg g^(−1)),highlighting the essential role of DOM in enhancing Pb(Ⅱ)adsorption.Kinetic and isothermal analyses revealed that the adsorption process was predominantly chemical in nature,as evidenced by the excellent fit of experimental data to the pseudo-second-order,Freundlich,and Temkin models.FTIR and XPS analyses confirmed that oxygen-containing functional groups,including hydroxyl,carboxyl,carbonyl,and ether groups,actively participated in Pb(Ⅱ)complexation in BC,WBC,and DOM.Spectral shifts and changes in the relative abundance of C–O and C=O bonds further supported this conclusion.The Pb 4f spectra indicated that Pb(Ⅱ)was primarily retained as Pb_(3)(OH)_(2)(CO_(3))_(2),with complexation identified as the dominant mechanism,followed by co-precipitation.UV differential log-transformed absorption spectra derived from titration experiments,revealed the heterogeneity of Pb(Ⅱ)binding sites within DOM.Furthermore,excitation-emission matrix fluorescence spectroscopy coupled with parallel factor analysis(EEM-PARAFAC)identified three humic-like components.Among these,component C3(humic-like and tyrosine substance)exhibited the strongest binding affinity for Pb(Ⅱ).Hetero-2DCOS analysis,combined with additional spectroscopic techniques,demonstrated that carboxyl groups in humic-like substances were the most reactive sites for Pb(Ⅱ)binding.These findings provide molecular-level insights into the structural and functional characteristics of biochar-derived DOM-Pb(Ⅱ)complexes,offering a scientific basis for optimizing biochar-based strategies for heavy metal pollution remediation.
