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1.
J Environ Sci (China) ; 147: 268-281, 2025 Jan.
Article in English | MEDLINE | ID: mdl-39003046

ABSTRACT

The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies. In this study, we evaluated the removal of a gaseous mixture containing toluene, m-xylene, ethylbenzene, cyclohexane, butane, pentane, hexane and heptane in aerated stirred bioreactors inoculated with Rhodococcus erythropolis and operated under non-sterile conditions. For the real-time measurement of hydrocarbons, a novel systematic approach was implemented using Selected-Ion Flow Tube Mass Spectrometry (SIFT-MS). The effect of the carbon source (∼9.5 ppmv) on (i) the bioreactors' performance (BR1: dosed with only cyclohexane as a single hydrocarbon versus BR2: dosed with a mixture of the 8 hydrocarbons) and (ii) the evolution of microbial communities over time were investigated. The results showed that cyclohexane reached a maximum removal efficiency (RE) of 53% ± 4% in BR1. In BR2, almost complete removal of toluene, m-xylene and ethylbenzene, being the most water-soluble and easy-to-degrade carbon sources, was observed. REs below 32% were obtained for the remaining compounds. By exposing the microbial consortium to only the five most recalcitrant hydrocarbons, REs between 45% ± 5% and 98% ± 1% were reached. In addition, we observed that airborne microorganisms populated the bioreactors and that the type of carbon source influenced the microbial communities developed. The abundance of species belonging to the genus Rhodococcus was below 10% in all bioreactors at the end of the experiments. This work provides fundamental insights to understand the complex behavior of gaseous hydrocarbon mixtures in bioreactors, along with a systematic approach for the development of SIFT-MS methods.


Subject(s)
Biodegradation, Environmental , Bioreactors , Hydrocarbons , Rhodococcus , Rhodococcus/metabolism , Bioreactors/microbiology , Hydrocarbons/metabolism , Carbon/metabolism , Air Pollutants/metabolism , Air Pollutants/analysis , Mass Spectrometry , Toluene/metabolism , Xylenes/metabolism , Butanes/metabolism , Benzene Derivatives , Pentanes
2.
J Hazard Mater ; 479: 135514, 2024 Nov 05.
Article in English | MEDLINE | ID: mdl-39243542

ABSTRACT

The extensive use of antibiotics has created an urgent need to address antibiotic wastewater treatment, posing significant challenges for environmental protection and public health. Recent advances in the efficacy and mechanisms of conductive materials (CMs) for enhancing the anaerobic biological treatment of antibiotic pharmaceutical wastewater are reviewed. For the first time, the focus is on the various application forms of iron-based and carbon-based CMs in strengthening the anaerobic methanogenic system. This includes the use of single CMs such as zero-valent iron (ZVI), magnetite, biochar (BC), activated carbon (AC), and graphene (GP), as well as iron-based and carbon-based composite CMs with diverse structures. These structures include mixed, surface-loaded, and core-shell combinations, reflecting the development of CMs. Iron-based and carbon-based CMs promote the rapid removal of antibiotics through adsorption and enhanced biodegradation. They also mitigate the inhibitory effects of toxic pollutants on microbial activity and reduce the expression of antibiotic resistance genes (ARGs). Additionally, as effective electron carriers, these CMs enrich microorganisms with direct interspecies electron transfer (DIET) functions, accelerate interspecies electron transfer, and facilitate the conversion of organic matter into methane. Finally, this review proposes the use of advanced molecular detection technologies to clarify microbial ecology and metabolic mechanisms, along with microscopic characterization techniques for the modification of CMs. These methods can provide more direct evidence to analyze the mechanisms underlying the cooperative anaerobic treatment of refractory organic wastewater by CMs and microorganisms.


Subject(s)
Anti-Bacterial Agents , Iron , Wastewater , Water Pollutants, Chemical , Anti-Bacterial Agents/chemistry , Wastewater/chemistry , Anaerobiosis , Iron/chemistry , Water Pollutants, Chemical/chemistry , Carbon/chemistry , Waste Disposal, Fluid/methods , Biodegradation, Environmental , Water Purification/methods
3.
J Hazard Mater ; 479: 135755, 2024 Nov 05.
Article in English | MEDLINE | ID: mdl-39244986

ABSTRACT

Sulfachloropyridazine (SCP) is a common sulfonamide antibiotic pollutant found in animal excreta. Finding highly efficient degrading bacterial strains is an important measure to reduce SCP antibiotic pollution. Although some strains with degradation capabilities have been screened, the degradation pathways and biotransformation mechanisms of SCP during bacterial growth are still unclear. In this study, a strain capable of efficiently degrading SCP, named Bacillus sp. DLY-11, was isolated from pig manure aerobic compost. Under optimized conditions (5 % Vaccination dose, 51.5 â„ƒ reaction temperature, pH=7.92 and 0.5 g/L MgSO4), this strain was able to degrade 97.7 % of 20 mg/L SCP within 48 h. Through the analysis of nine possible degradation products (including a new product of 1,4-benzoquinone with increased toxicity), three potential biodegradation pathways were proposed. The biodegradation reactions include S-N bond cleavage, dechlorination, hydroxylation, deamination, methylation, sulfur dioxide release, and oxidation reactions. This discovery not only provides a new efficient SCP-degrading bacterial strain but also expands our understanding of the mechanisms of bacterial degradation of SCP, filling a knowledge gap. It offers important reference for the bioremediation of antibiotic pollutants in livestock and poultry farming.


Subject(s)
Bacillus , Biodegradation, Environmental , Manure , Sulfachlorpyridazine , Bacillus/metabolism , Animals , Sulfachlorpyridazine/metabolism , Manure/microbiology , Swine , Anti-Bacterial Agents/metabolism , Composting
4.
J Hazard Mater ; 479: 135756, 2024 Nov 05.
Article in English | MEDLINE | ID: mdl-39255668

ABSTRACT

The report demonstrated that a member of cockroach family, Blaptica dubia (Blattodea: Blaberidae) biodegraded commercial polystyrene (PS) plastics with Mn of 20.3 kDa and Mw of 284.9 kDa. The cockroaches digested up to 46.6 % of ingested PS within 24 h. The biodegradation was confirmed by the 13C isotopic shift of the residual PS in feces versus pristine PS (Δ Î´13C of 2.28 ‰), reduction of molecular weight and formation of oxidative functional groups in the residual PS. Further tests found that B.dubia cockroaches degraded all eight high purity PS microplastics with low to ultra-high molecular weights (MW) at 0.88, 1.20, 3.92, 9.55, 62.5, 90.9, 524.0, and 1040 kDa, respectively, with superior biodegradation ability. PS depolymerization/biodegradation pattern was MW-dependent. Ingestion of PS shifted gut microbial communities and elevated abundances of plastic-degrading bacterial genes. Genomic, transcriptomic and metabolite analyses indicated that both gut microbes and cockroach host contributed to digestive enzymatic degradation. PS plastic diet promoted a highly cooperative model of gut digestive system. Weighted gene co-expression network analysis revealed different PS degradation patterns with distinct MW profiles in B. dubia. These results have provided strong evidences of plastic-degrading ability of cockroaches or Blaberidae family and new understanding of insect and their microbe mediated biodegradation of plastics.


Subject(s)
Biodegradation, Environmental , Cockroaches , Gastrointestinal Microbiome , Polystyrenes , Animals , Polystyrenes/chemistry , Cockroaches/microbiology , Cockroaches/metabolism , Gastrointestinal Microbiome/drug effects , Feces/microbiology , Microplastics/toxicity
5.
Biotechnol Adv ; 77: 108439, 2024 Sep 04.
Article in English | MEDLINE | ID: mdl-39241969

ABSTRACT

Polyurethanes (PUR) are durable synthetic polymers widely used in various industries, contributing significantly to global plastic consumption. PUR pose unique challenges in terms of degradability and recyclability, as they are characterised by intricate compositions and diverse formulations. Additives and proprietary structures used in commercial PUR formulations further complicate recycling efforts, making the effective management of PUR waste a daunting task. In this review, we delve into the complex challenge of enzymatic degradation of PUR, focusing on the structural and functional attributes of both enzymes and PUR. We also present documented native enzymes with reported efficacy in hydrolysing specific bonds within PUR, analysis of these enzyme structures, reaction mechanisms, substrate specificity, and binding site architecture. Furthermore, we propose essential features for the future redesign of enzymes to optimise PUR biodegradation efficiency. By outlining prospective research directions aimed at advancing the field of enzymatic biodegradation of PUR, we aim to contribute to the development of sustainable solutions for managing PUR waste and reducing environmental pollution.

6.
Environ Pollut ; 362: 125002, 2024 Sep 20.
Article in English | MEDLINE | ID: mdl-39307340

ABSTRACT

Glyphosate is one of the most widely used pesticides globally. The environmental micro-molar hydrogen peroxide (H2O2)-driven Fenton reaction has been reported to degrade herbicides in natural water. However, the impact of micro-molar H2O2 (50 µM) on the degradation of glyphosate in soil and glyphosate-degrading bacteria remains unclear. In this study, degradation of glyphosate in the sterilized and unsterilized soil system and MSM medium under micro-molar H2O2 was investigated; bacterial diversity, enzyme activity and gene abundance in the soil following micro-molar H2O2 addition were also investigated. The results indicated that the addition of micro-molar H2O2 facilitated the degradation of glyphosate in a sterilized environment, resulting in a 76.30% decrease in glyphosate within 30 days. The degradation of glyphosate increased by 52.32% compared to the control treatment. However, in an unsterilized environment, the addition of micro-molar H2O2 leads to a reduction in the biodegradation efficiency of glyphosate. Bacteria, enzymes and specific genes were found to be affected to varying degrees. Firstly, micro-molar H2O2 affects the relative abundance of functional bacteria related to glyphosate degradation, such as Afipia, Microcoleus and Pseudomonas. Secondly, micro-molar H2O2 resulted in a decrease in soil phosphatase activity. Thirdly, the expression of resistance genes was affected, particularly the glyphosate resistance gene aroA. The findings presented a novel research perspective on the degradation of soil glyphosate by micro-molar H2O2.

7.
Environ Sci Technol ; 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39315846

ABSTRACT

Mealworms (Tenebrio molitor) larvae can degrade both plastics and lignocellulose through synergistic biological activities of their gut microbiota because they share similarities in chemical and physical properties. Here, a total of 428 genes encoding lignocellulose-degrading enzymes were screened from the gut microbiome of T. molitor larvae to identify poly(ethylene terephthalate) (PET)-degrading activities. Five genes were successfully expressed in E. coli, among which a feruloyl esterase-like enzyme named TmFae-PETase demonstrated the highest PET degradation activity, converting PET into MHET (0.7 mgMHETeq ·h-1·mgenzyme-1) and TPA (0.2 mgTPAeq ·h-1·mgenzyme-1) at 50 °C. TmFae-PETase showed a preference for the hydrolysis of ferulic acid methyl ester (MFA) in the presence of both PET and MFA. Site-directed mutagenesis and molecular dynamics simulations of TmFae-PETase revealed similar catalytic mechanisms for both PET and MFA. TmFae-PETase effectively depolymerized commercial PET, making it a promising candidate for application. Additionally, the known PET hydrolases IsPETase, FsC, and LCC also hydrolyzed MFA, indicating a potential origin of PET hydrolytic activity from its lignocellulosic-degrading abilities. This study provides an innovative strategy for screening PET-degrading enzymes identified from lignocellulose degradation-related enzymes within the gut microbiome of plastic-degrading mealworms. This discovery expands the existing pool of plastic-degrading enzymes available for resource recovery and bioremediation applications.

8.
Environ Technol ; : 1-11, 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39292531

ABSTRACT

This work evaluated the effects of cobalt nanoparticles (CoNPs) (0.025-7 mg/gVS) on the intensification of sewage sludge anaerobic digestion (AD) using biochemical methane potential (BMP) tests. This study was motivated by the need to improve the efficiency and stability of anaerobic digestion of sewage sludge, a critical process in waste management and renewable energy production. The effects at doses less than 2 mg/gVS were not substantial, but 3-7 mg/gVS improved the performance. The maximum biogas yield was 232 mL/gVS (at a dose of 7 mg/gVS), whereas it was 132 mL/gVS in the control (zero dose). Similarly, the reductions in the volatile solids and methane contents reached maxima of 16 and 74.3%, respectively. The analyses of volatile fatty acids, redox potential, and electron transfer system activity indicated that the addition of CoNPs stimulated the early stages of AD. Finally, acetate consumption and the increase in CH4 content suggested that CoNPs positively affected system stability and acetoclastic methanogenesis. That is, CoNPs effectively intensified the behaviour and stability of the anaerobic process. The novelty of this research lies in the comprehensive evaluation of the effects of CoNPs across a wide range of doses on sewage sludge AD, providing new insights into the optimisation of this process for increased biogas production and organic matter reduction.

9.
Environ Sci Technol ; 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39292649

ABSTRACT

Offshore oil platforms discharge enormous volumes of produced water that contain mixtures of petrochemicals and production chemicals. It is crucial to avoid the discharge of particularly those chemicals that are persistent in the marine environment. This study aims to (1) develop a biodegradation testing approach for discharged chemicals by native marine microorganism, (2) determine how dilution affects biodegradation, and (3) determine biodegradation kinetics for many discharged chemicals at low and noninhibitory concentrations. Produced water from an offshore oil platform was diluted in the ratio of 1:20, 1:60, and 1:200 in seawater from the same location and incubated for 60 days at 10 °C. Automated solid-phase microextraction GC-MS was used as a sensitive analytical technique, and chemical-specific primary degradation was determined based on peak area ratios between biotic test systems and abiotic controls. Biodegradation was inhibited at lower dilutions, consistent with ecotoxicity tests. Biodegradation kinetics were determined at the highest dilution for 139 chemicals (43 tentatively identified), and 6 chemicals were found persistent (half-life >60 days). Nontargeted analysis by liquid chromatography-high-resolution MS was demonstrated as a proof-of-principle for a comprehensive assessment. Biodegradation testing of chemicals in discharges provides the possibility to assess hundreds of chemicals at once and find the persistent ones.

10.
Article in English | MEDLINE | ID: mdl-39258936

ABSTRACT

In this study, horseradish peroxidase (HRP) enzyme was immobilized on Pd(II) containing polymeric microspheres by adsorption method and used for the decolourisation of Methyl Orange (MO) and Rhodamine B (RB) dyes. The synthesized microspheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM/EDX), Thermal Gravimetric Analysis (TGA). The effects of pH, dye concentration, temperature, and H2O2 concentration on the decolourisation of MO and RB were determined. According to the results of various parameters studied, when 2-AEPS-napht-HRP support was used, MO and RB were biodegraded to 69.72% and 80.65%, respectively, within 60 min. When 2-AEPS-napht-Pd-HRP support was used, MO and RB were biodegraded to 58.35% and 90.81%, respectively, under optimum conditions. When the reproducibility results of the immobilized supports were examined, it was observed that they remained efficient during the first five reusability cycles and even reached 65% decolourisation efficiency after the 9th reuse. The immobilized enzyme (2AEPS-npht-HRP and 2AEPS-npht-Pd-HRP) showed remarkable resistance to higher temperatures compared to the free enzyme.


Subject(s)
Azo Compounds , Coloring Agents , Enzymes, Immobilized , Horseradish Peroxidase , Microspheres , Rhodamines , Horseradish Peroxidase/chemistry , Horseradish Peroxidase/metabolism , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Coloring Agents/chemistry , Rhodamines/chemistry , Azo Compounds/chemistry , Hydrogen-Ion Concentration , Hydrogen Peroxide/chemistry , Spectroscopy, Fourier Transform Infrared , Temperature , Water Pollutants, Chemical/chemistry , Adsorption , Water Decolorization/methods , Polymers/chemistry
11.
J Pharm Sci ; 2024 Aug 31.
Article in English | MEDLINE | ID: mdl-39218154

ABSTRACT

Erosion of biodegradable polymeric excipients, such as polylactic acid (PLA) and polylactic-co-glycolic acid (PLGA), is generally characterized by microbalance for the remaining mass of PLA and/or PLGA and Gel Permeation Chromatography (GPC) for molecular weight (MW) decrease. For polymer erosion studies of intravitreal sustained release brimonidine implants, however, both microbalance and GPC present several challenges. Mass loss measurement by microbalance does not have specificity for excipient polymers and drug substances. Accuracy of the remaining mass by weighing could also be low due to sample mass loss through retrieval-drying steps, especially at later drug release (DR) time points. When measuring the decrease of polymer MW by GPC, trace amounts of polymeric degradants (oligomers and/or monomers) trapped inside the implants during DR tests may not be measurable due to sensitivity limitations of the GPC detector and column MW range. Previous efforts to measure remained PLGA weight of dexamethasone micro-implants using qNMR with external calibration have been performed, however, these measurements do not account for chemical structure changes (i.e. LA to GA ratio changes from time zero) of PLGA implants during drug release tests. Here, a qNMR method with an internal standard was developed to monitor the following changes in micro-implants during drug release tests: 1. The remaining overall PLA/PLGA mass. 2. The remaining lactic acid (LA), glycolic acid (GA) unit and PLGA's lauryl ester end group percentages. 3. The trace content of PLA/PLGA oligomers as degradants retained in the implants. Unlike microbalance analysis, qNMR has both specificity for drug substance, excipient polymer, and accuracy due to minimal implant loss during sample preparation. Compared to the overall PLA/PLGA remaining mass generally monitored in erosion studies, the percentage of remaining LA, GA, and the ester end group provide more information about the microstructure change (such as hydrophobicity) of PLA/PLGA. Additionally, the qNMR method can complement GPC methods by measuring the change of remaining PLA and PLGA oligomer concentrations in brimonidine implants, with tenfold less sample and no MW cutoff. The qNMR method can be used as a sensitive tool for both polymer excipient characterization and kinetics studies of brimonidine implant erosion.

12.
Sci Total Environ ; 954: 176270, 2024 Sep 14.
Article in English | MEDLINE | ID: mdl-39278506

ABSTRACT

Antibiotic contamination and eutrophication in mariculture have become problems that cannot be ignored, and enrofloxacin (ENR), as an example, is especially widely used in mariculture. This study firstly revealed that Sesuvium portulacastrum, a plant with world-wide distribution in coastal zones, with its rhizosphere microorganisms, could remove ENR as well as nutrients. The S. portulacastrum system could degrade ENR to small-molecule products 1,2,3,4-tetrahydroquinolin-4-ol and (2,4-dihydroxyphenyl)-cyclopropylamine. And there were 81.3-39.2 % removals of ENR with 0.01-100 mg/L. Although ENR significantly influenced functions of rhizosphere microbial community, like decreasing nitrogen fixation, shifting trophic strategies from phototrophy to chemoheterotrophy, nutrients (NH4+-N, NO2--N, NO3--N and total dissolved phosphorus) removal of S. portulacastrum system was essentially unaffected at low ENR concentration (< 1 mg/L). The removal mechanism of S. portulacastrum system was explored. Neither of the isolated root exudates and rhizosphere bacteria could degrade ENR, however, without rhizosphere bacteria, ENR removal rate would decrease. Root proteins including oxidase, decarboxylase, dehydrogenase, such as laccase, isocitrate dehydrogenase, delta-1-pyrroline-5-carboxylate dehydrogenase were overexpressed. Additionally, endocytosis is a pathway for antibiotics to enter S. portulacastrum. This study demonstrated that S. portulacastrum system could be used for remediation of antibiotics-nutrients combined pollution, and deepened understanding the antibiotic removal mechanism of macrophytes in mariculture, moreover, provided new macroplant species and a theoretical basis for antibiotics removal in aquatic systems.

13.
Indian J Microbiol ; 64(3): 1290-1300, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39282174

ABSTRACT

Polyhydroxyalkanoates (PHAs) constitute a principal group of bio-degradable polymers that are produced by certain microbes under limited supply of nutrients. PHA is a linear polyester that comprises of 3-hydroxy fatty acid monomers. Triacylglycerol acylhydrolases are known to catalyze the hydrolysis of ester linkages and in turn they are beneficial in the degradation of PHA. In present study, lipase-catalyzed degradation of PHA synthesized by Priestia megatarium POD1 was monitored. A gene from thermotolerant Bacillus subtilis TTP-06 that was capable of expressing lipase enzyme was amplified by PCR, cloned into a pTZ57R/T-vector, transferred to an expression vector pET-23a (+) and expressed in Escherichia coli BL21 (DE3) cells. The recombinant enzyme purified to 19.37-fold had a molecular weight of 30 kDa (SDS-PAGE analysis). Scanning Electron Microscopy (SEM) revealed changes in the surface morphology of native and treated PHA films. Further, changes in molecular vibrations were confirmed by Fourier Transform Infrared Spectroscopy. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-024-01329-z.

14.
Article in English | MEDLINE | ID: mdl-39288080

ABSTRACT

The biodegradation of therapeutic magnetic-oxide nanoparticles (MONPs) in the human body raises concerns about their lifespan, functionality, and health risks. Interactions between apoferritin proteins and MONPs in the spleen, liver, and inflammatory macrophages significantly accelerate nanoparticle degradation, releasing metal ions taken up by apoferritin. This can alter the protein's biological structure and properties, potentially causing health hazards. This study examines changes in apoferritin's shape, electrical surface potential (ESP), and protein-core composition after incubation with cobalt-ferrite (CoFe2O4) oxide nanoparticles. Using atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM), we observed changes in the topography and ESP distribution in apoferritin nanofilms over time. After 48 h, the characteristic apoferritin hole (∼1.35 nm) vanished, and the protein's height increased from ∼3.5 to ∼7.5 nm due to hole filling. This resulted in a significant ESP increase on the filled-apoferritin surface, attributed to the formation of a heterogeneous chemical composition and crystal structure (γ-Fe2O3, Fe3O4, CoO, CoOOH, FeOOH, and Co3O4). These changes enhance electrostatic interactions and surface charge between the protein and the AFM tip. This approach aids in predicting and improving the MONP lifespan while reducing their toxicity and preventing apoferritin deformation and dysfunction.

15.
Water Res ; 266: 122431, 2024 Sep 11.
Article in English | MEDLINE | ID: mdl-39298898

ABSTRACT

Trace organic contaminants (TrOCs) are omnipresent in wastewater treatment plants (WWTPs), yet, their removal during wastewater treatment is oftentimes incomplete and underlying biotransformation mechanisms are not fully understood. In this study, we elucidate how different factors, including pre-exposure levels and duration, influence microbial adaptation towards catabolic TrOC biodegradation and its potential role in biological wastewater treatment. Four sequencing batch reactors (SBRs) were operated in parallel in three succeeding phases, adding and removing a selection of 26 TrOCs at different concentration levels. After each phase of SBR operation, a series of batch experiments was conducted to monitor biotransformation kinetics of those same TrOCs across various spike concentrations. For half of our test TrOCs, we detected increased biotransformation in sludge pre-exposed to TrOC concentrations ≥5 µg L-1 over a 30-day period, with most significant differences observed for the insect repellent DEET and the artificial sweetener saccharin. Accordingly, 16S rRNA amplicon sequencing revealed enrichment of taxa that have previously been linked to catabolic biodegradation of several test TrOCs, e.g., Bosea sp. and Shinella sp. for acesulfame degradation, and Pseudomonas sp. for caffeine, cyclamate, DEET, metformin, paracetamol, and isoproturon degradation. We further conducted shotgun metagenomics to query for gene products previously reported to be involved in the TrOCs' biodegradation pathways. In the future, directed microbial adaptation may be a solution to improve bioremediation of TrOCs in contaminated environments or in WWTPs.

16.
Sheng Wu Gong Cheng Xue Bao ; 40(9): 2812-2830, 2024 Sep 25.
Article in Chinese | MEDLINE | ID: mdl-39319709

ABSTRACT

Polyethylene terephthalate (PET) is one of the widely used plastics, but its waste pollution has become a global environmental issue. The discovery of polyethylene terephthalate hydrolase (PETase) has provided a green and environmentally friendly approach for PET degradation. However, PETase produces intermediate products that inhibit the enzyme's further activity, leading to a decrease in enzyme efficiency. Mono(2-hydroxyethyl) terephthalate hydrolase (MHETase) works synergistically with PETase to further degrade the intermediate product MHET into ethylene glycol (EG) and terephthalic acid (TPA). MHETase exhibits extremely high specificity for MHET and is crucial for the complete degradation of PET. This article comprehensively reviews MHETase from various perspectives, including its three-dimensional structure, substrate binding, and catalytic mechanism. It demonstrates the structural features and key residues associated with the enzyme's degrading activity and discusses the progress in enzyme engineering modifications. Additionally, the study envisions the development of a two-enzyme PET degradation system by combining MHETase with PETase, aiming to provide valuable references for designing and developing more efficient PET hydrolytic enzyme systems.


Subject(s)
Hydrolases , Polyethylene Terephthalates , Polyethylene Terephthalates/chemistry , Polyethylene Terephthalates/metabolism , Hydrolases/metabolism , Hydrolases/chemistry , Phthalic Acids/chemistry , Phthalic Acids/metabolism , Substrate Specificity , Biodegradation, Environmental , Protein Engineering , Ethylene Glycol/chemistry , Ethylene Glycol/metabolism
17.
Bioresour Technol ; 413: 131520, 2024 Sep 23.
Article in English | MEDLINE | ID: mdl-39321942

ABSTRACT

This study showcased the antibiotic degradation abilities of laccase and catalase-peroxidase from Bacillus ligniniphilus L1, an extremophile, against 18 common antibiotics using computationally guided approach. Molecular docking and simulation identified six enzyme-antibiotic complexes for laccase and four for catalase-peroxidase, demonstrating significant binding affinity and stability. Enzyme activity assays corroborated computational results, indicating both enzymes could degrade all tested antibiotics with varying efficiencies. L1 laccase outperformed commercial laccase against five antibiotics, notably vancomycin, levofloxacin, tobramycin, linezolid, and rifamycin, with enhanced degradation potential upon ABTS addition. Catalase-peroxidase from L1 exhibited superior degradation efficiency over commercial peroxidase against vancomycin, linezolid, tobramycin, and clindamycin. Overall, this study underscores the computational approach's utility in understanding enzyme-mediated antibiotic degradation, offering insights into environmental contaminant remediation.

18.
Sci Total Environ ; : 176420, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39326745

ABSTRACT

Anticancer drugs show recalcitrance to conventional wastewater treatments; thus, they are present in aquatic systems and pose an environmental threat. Fungi represent a promising biological alternative for wastewater treatments. Therefore, the goals of this work were to assess the potential of white-rot fungi (Fomes fomentarius (CB13), Hypholoma fasciculare (CB15), Phyllotopsis nidulans (CB14), Pleurotus ostreatus (BWPH), and Trametes versicolor (CB8)) for removing bleomycin and vincristine, and to investigate the impacts of various conditions (shaking, aeration, or biomass immobilization) on the process. The removal capacities were measured using Ultra-Performance Liquid Chromatography (UPLC) coupled with Mass Spectrometry (MS) and preceded by Solid Phase Extraction (SPE). We further identified major drugs degradation products; determined the fungi's main enzyme activity profiles (laccase, manganese and lignin peroxidases); and examined the toxicities of post-processed samples against Lemna minor, Daphnia magna and Pseudomonas putida. In just 2 days, all strains (except for P. nidulans) removed >90 % of vincristine, nearly completely eliminating the drug over time. Bleomycin content reduction occurred with T. versicolor or H. fasciculare, respectively reaching 55 % and 83 % drug elimination after 9 days. Oxygen was found to be crucial for cytostatics degradation, with their highest removal rates occurring in samples with air supply (aeration or agitation). Laccase was the only tested enzyme associated with cytostatics elimination. Drug biodegradation was followed by detoxification, demonstrating the utility of fungi in cytostatics removal.

19.
ACS Appl Mater Interfaces ; 16(38): 50344-50359, 2024 Sep 25.
Article in English | MEDLINE | ID: mdl-39265074

ABSTRACT

Subunit vaccines have emerged as a promising strategy in immunotherapy for combating viral infections and cancer. Nevertheless, the clinical application of subunit vaccines is hindered by limitations in antigen delivery efficiency, characterized by rapid clearance and inadequate cellular uptake. Here, a novel subunit vaccine delivery system utilizing ovalbumin@magnetic nanoparticles (OVA@MNPs) encapsulated within biodegradable gelatin methacryloyl (GelMA) microspheres was proposed to enhance the efficacy of antigen delivery. OVA@MNPs-loaded GelMA microspheres, denoted as OMGMs, can be navigated through magnetic fields to deliver subunit vaccines into the lymphatic system efficiently. Moreover, the biodegradable OMGMs enabled the sustained release of subunit vaccines, concentrating OVA around lymph nodes and enhancing the efficacy of induced immune response. OMGMs were produced through a microfluidic droplet generation technique, enabling mass production. In murine models, OMGMs successfully accumulated antigens in lymph nodes abundant in antigen-presenting cells, leading to enhanced cellular and humoral immunity and pronounced antitumor effects with a single booster immunization. In conclusion, these findings highlight the promise of OMGMs as a practical subunit vaccination approach, thus addressing the limitations associated with antigen delivery efficiency and paving the way for advanced immunotherapeutic strategies.


Subject(s)
Immunotherapy , Microspheres , Ovalbumin , Vaccines, Subunit , Animals , Mice , Ovalbumin/chemistry , Ovalbumin/immunology , Ovalbumin/administration & dosage , Vaccines, Subunit/chemistry , Vaccines, Subunit/immunology , Magnetite Nanoparticles/chemistry , Mice, Inbred C57BL , Female , Gelatin/chemistry , Cancer Vaccines/chemistry , Cancer Vaccines/immunology , Cancer Vaccines/administration & dosage , Drug Delivery Systems/methods
20.
J Hazard Mater ; 480: 135778, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39316919

ABSTRACT

Riparian sediment (RS) is a translational zone separating aquatic and terrestrial ecosystems. To this date, the bioplastic's UV ageing and biodegradation features in these contaminated sediments remain unknown. It is a considerable concern to investigate whether a food packaging film can interact with RS and riparian sediment-derived Dissolved Organic Matter (RS-DOM) during biodegradation and UV ageing respectively, after disposal in a natural environmental setting. To address this research gap, for the first time, this study investigates the biodegradation and UV ageing of starch/PPst/GTR films intended for food packaging applications in RS and RS-DOM respectively. The findings revealed that RS comprises major fulvic acid DOM components. Remarkably, research demonstrates the leaching of humic acid-like DOM from the film promotes aromaticity and humification as UV ageing progresses from the third to the tenth day. Comparable DOM samples were darkly analysed, revealing aromatic proteins I and II. Furthermore, an elevated carbonyl carboxyl index confirmed significant degradation of films during UV ageing. Lesser humification, aromaticity, and higher biological activity were confirmed by a HI < 10 and BIX > 0.6 respectively. In comprehension, these findings reveal that the starch/PPst/GTR food packaging film will have a lesser adverse environmental impact after disposal, offering a hopeful outlook for the future of bioplastics.

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