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1.
J Hazard Mater ; 439: 129674, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36104903

RESUMO

Antibiotic mixtures in the environment result in the development of bacterial strains with resistance against multiple antibiotics. Oxidases are versatile that can bio-remove antibiotics. Various laccases (LACs), manganese peroxidases (MNPs), and versatile peroxidase (VP) were reconstructed in Pichia pastoris. For the single antibiotics, over 95.0% sulfamethoxazole within 48 h, tetracycline, oxytetracycline, and norfloxacin within 96 h were bio-removed by recombinant VP with α-signal peptide, respectively. In a mixture of the four antibiotics, 80.2% tetracycline and 95.6% oxytetracycline were bio-removed by recombinant MNP2 with native signal peptide (NSP) within 8 h, whereas < 80.0% sulfamethoxazole was bio-removed within 72 h, indicating that signal peptides significantly impacted removal efficiencies of antibiotic mixtures. Regarding mediators for LACs, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) resulted in better removal efficiencies of multi-antibiotic mixtures than 1-hydroxybenzotriazole or syringaldehyde. Furthermore, artificial microbial consortia (AMC) producing LAC2 and MNP2 with NSP significantly improved bio-removal efficiency of sulfamethoxazole (95.5%) in four-antibiotic mixtures within 48 h. Tetracycline and oxytetracycline were completely bio-removed by AMC within 48 and 72 h, respectively, indicating that AMC accelerated sulfamethoxazole, tetracycline, and oxytetracycline bio-removals. Additionally, transformation pathways of each antibiotic by recombinant oxidases were proposed. Taken together, this work provides a new strategy to simultaneously remove antibiotic mixtures by AMC.


Assuntos
Antibacterianos , Oxitetraciclina , Antibacterianos/metabolismo , Biotransformação , Lacase/metabolismo , Consórcios Microbianos , Sinais Direcionadores de Proteínas , Sulfametoxazol , Tetraciclina
2.
Int J Mol Sci ; 23(17)2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36077196

RESUMO

Herein, a novel laccase gene, Melac13220, was amplified from Methylobacterium extorquens and successfully expressed in Escherichia coli with a molecular weight of approximately 50 kDa. The purified Melac13220 had no absorption peak at 610 nm and remained silent within electron paramagnetic resonance spectra, suggesting that Melac13220 belongs to the non-blue laccase group. Both inductively coupled plasma spectroscopy/optical emission spectrometry (ICP-OES) and isothermal titration calorimetry (ITC) indicated that one molecule of Melac13220 can interact with two iron ions. Furthermore, the optimal temperature of Melac13220 was 65 °C. It also showed a high thermolability, and its half-life at 65 °C was 80 min. Melac13220 showed a very good acid environment tolerance; its optimal pH was 1.5. Cu2+ and Co2+ can slightly increase enzyme activity, whereas Fe2+ could increase Melac13220's activity five-fold. Differential scanning calorimetry (DSC) indicated that Fe2+ could also stabilize Melac13220. Unlike most laccases, Melac13220 can efficiently decolorize Congo Red and Indigo Carmine dyes even in the absence of a redox mediator. Thus, the non-blue laccase from Methylobacterium extorquens shows potential application value and may be valuable for environmental protection, especially in the degradation of dyes at low pH.


Assuntos
Lacase , Methylobacterium extorquens , Corantes/química , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Índigo Carmim , Lacase/metabolismo , Methylobacterium extorquens/metabolismo , Temperatura
3.
Nature ; 609(7926): 348-353, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35978195

RESUMO

The mammalian immune system uses various pattern recognition receptors to recognize invaders and host damage and transmits this information to downstream immunometabolic signalling outcomes. Laccase domain-containing 1 (LACC1) protein is an enzyme highly expressed in inflammatory macrophages and serves a central regulatory role in multiple inflammatory diseases such as inflammatory bowel diseases, arthritis and clearance of microbial infection1-4. However, the biochemical roles required for LACC1 functions remain largely undefined. Here we elucidated a shared biochemical function of LACC1 in mice and humans, converting L-citrulline to L-ornithine (L-Orn) and isocyanic acid and serving as a bridge between proinflammatory nitric oxide synthase (NOS2) and polyamine immunometabolism. We validated the genetic and mechanistic connections among NOS2, LACC1 and ornithine decarboxylase 1 (ODC1) in mouse models and bone marrow-derived macrophages infected by Salmonella enterica Typhimurium. Strikingly, LACC1 phenotypes required upstream NOS2 and downstream ODC1, and Lacc1-/- chemical complementation with its product L-Orn significantly restored wild-type activities. Our findings illuminate a previously unidentified pathway in inflammatory macrophages, explain why its deficiency may contribute to human inflammatory diseases and suggest that L-Orn could serve as a nutraceutical to ameliorate LACC1-associated immunological dysfunctions such as arthritis or inflammatory bowel disease.


Assuntos
Artrite , Doenças Inflamatórias Intestinais , Animais , Humanos , Doenças Inflamatórias Intestinais/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lacase/metabolismo , Macrófagos/metabolismo , Mamíferos/metabolismo , Camundongos , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Ornitina/metabolismo , Poliaminas/metabolismo , Salmonella typhimurium
4.
J Hazard Mater ; 440: 129709, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35939906

RESUMO

Polyethylene (PE) is one of the most widely used plastics. However, the chemical inertness, inefficient recycling, and random landfilling of PE waste have caused serious pollution to the natural environment. In this study, a series of laccase-mediator systems (LMS) were constructed by combination of two laccases from Botrytis aclada (BaLac) and Bacillus subtilis (BsLac) with three synthetic mediators (ABTS, HBT, and TEMPO) to oxidize LDPE films (UVPE) pretreated with high-temperature UV irradiation. Scanning electron microscopy showed aging phenomena such as etching, fragmentation, and cracking on the surface of the UVPE films after LMS incubation. The FTIR results showed that LMS-UVPE added new oxygen-containing functional groups such as -OH, -CO, and CC. High-temperature gel chromatography confirmed that the average reduction in weight-average molecular weight (Mw) was approximately 40% for the BaLac experimental group. GC-MS analysis showed the presence of oxygen-containing products, such as aldehydes, ketones, and alcohols, in the reaction mixture. To verify the oxidation process UVPE degradation by LMS, we inferred three possible pathways by combined analysis of the oxidation products of LMS on UVPE and model substrates oleic acid and squalene.


Assuntos
Lacase , Polietileno , Álcoois , Aldeídos , Biodegradação Ambiental , Cetonas , Lacase/metabolismo , Ácido Oleico , Estresse Oxidativo , Oxigênio , Plásticos/metabolismo , Polietileno/metabolismo , Esqualeno
5.
Int J Mol Sci ; 23(16)2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-36012620

RESUMO

The high demand for food and energy imposed by the increased life expectancy of the population has driven agricultural activity, which is reflected in the larger quantities of agro-industrial waste generated, and requires new forms of use. Brazil has the greatest biodiversity in the world, where corn is one of the main agricultural genres, and where over 40% of the waste generated is from cobs without an efficient destination. With the aim of the valorization of these residues, we proposed to study the immobilization of laccase from Aspergillus spp. (LAsp) in residual corn cob and its application in the degradation of Remazol Brilliant Blue R (RBBR) dye. The highest yields in immobilized protein (75%) and residual activity (40%) were obtained at pH 7.0 and an enzyme concentration of 0.1 g.mL-1, whose expressed enzyme activity was 1854 U.kg-1. At a temperature of 60 °C, more than 90% of the initial activity present in the immobilized biocatalyst was maintained. The immobilized enzyme showed higher efficiency in the degradation (64%) of RBBR dye in 48 h, with improvement in the process in 72 h (75%). The new biocatalyst showed operational efficiency during three cycles, and a higher degradation rate than the free enzyme, making it a competitive biocatalyst and amenable to industrial applications.


Assuntos
Lacase , Zea mays , Antraquinonas/química , Corantes/química , Lacase/metabolismo , Zea mays/metabolismo
6.
Arch Microbiol ; 204(9): 562, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35980477

RESUMO

Statistical optimization of aeration conditions viz. aerobic, microaerobic and anaerobic, was performed using response surface methodology (RSM) utilizing soybean meal as medium to enhance the production of laccase from Rheinheimera sp. Maximum laccase yield (18.48 × 105 U/L) was obtained under microaerobic (static) conditions sustained for 12 h in tandem with 26 h aerobically (150 rpm) grown culture, which was 17.03-fold higher than laccase production in the starting M162 medium under aerobic conditions (150 rpm). The reduction in incubation time from 72 to 38 h and utilization of cost-effective soybean meal as medium, which is easily available from local market, have provided a promising, eco-friendly method of laccase enzyme production. Enhanced expression of laccase gene under microaerobic conditions corresponded to the increased expression of fnr (fumarate nitrate reductase) gene, the oxygen sensing global regulator. The putative FNR-binding site upstream of laccase transcription initiation site was predicted to play an imperative role in Rheinheimera sp. adaptation from aerobic to microaerobic conditions and for enhanced laccase production.


Assuntos
Chromatiaceae , Lacase , Lacase/genética , Lacase/metabolismo , Nitrato Redutase , Nitratos , Oxigênio
7.
Biodegradation ; 33(5): 489-508, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35809150

RESUMO

An efficient heterogeneous natural polymer-based biocatalyst was fabricated through the immobilization of laccase onto dialdehyde inulin (DAI)-coated silica-caped magnetic nanoparticles (laccase@DAI@SiO2@Fe3O4⋅MNPs). The carrier was developed using SiO2@Fe3O4⋅MNPs and functionalized with DAI. The construction of immobilized laccase was confirmed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Immobilization yield and efficiency were calculated as 61.0 ± 0.3% and 93.0 ± 0.6%, respectively. The immobilized laccase maintained 50% and 85% of its relative activity after 25 repeated cycles and 20 days of storage at 4 °C, respectively. The prepared biocatalyst effectively eliminated ofloxacin, a fluoroquinolone-type antibiotic, with a 63% removal capacity. Besides, antimicrobial activity study on some soil microorganisms involved in the biodegradation of xenobiotics revealed that the laccase-treated ofloxacin resulted in less toxic metabolites. The obtained data indicated that the fabricated biocatalyst is promising for the removal of ofloxacin or other analogs of fluoroquinolones in the environment.


Assuntos
Lacase , Nanopartículas , Biodegradação Ambiental , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Inulina/farmacologia , Lacase/química , Lacase/metabolismo , Fenômenos Magnéticos , Ofloxacino/farmacologia , Dióxido de Silício/química
8.
Sci Rep ; 12(1): 11932, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35831359

RESUMO

Laccases are multicopper oxidase family enzymes that can oxidize various substrates. In this study, we isolated laccase-producing Acinetobacter spp. from the environment, and one isolate of laccase-producing Acinetobacter baumannii, designated NI-65, was identified. The NI-65 strain exhibited constitutive production of extracellular laccase in a crude extract using 2,6-dimethoxyphenol as a substrate when supplemented with 2 mM CuSO4. Whole-genome sequencing of the NI-65 strain revealed a genome size of 3.6 Mb with 3,471 protein-coding sequences. The phylogenetic analysis showed high similarity to the genome of A. baumannii NCIMB8209. Three laccase proteins, PcoA and CopA, that belong to bacterial CopA superfamilies, and LAC-AB, that belongs to the I-bacterial bilirubin oxidase superfamily, were identified. These proteins were encoded by three laccase-coding genes (pcoA, copA, and lac-AB). The lac-AB gene showed a sequence similar to that of polyphenol oxidase (PPO). Gene clusters encoding the catabolized compounds involved in the utilization of plant substances and secondary metabolite biosynthesis gene clusters encoding antimicrobial compounds were identified. This is the first report of whole-genome sequencing of laccase-producing A. baumannii, and the data from this study help to elucidate the genome of A. baumannii to facilitate its application in synthetic biology for enzyme production.


Assuntos
Acinetobacter baumannii , Antibacterianos , Genômica , Lacase/metabolismo , Família Multigênica , Filogenia
9.
Colloids Surf B Biointerfaces ; 217: 112660, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35777167

RESUMO

Achieving fast electron transfer process between oxidoreductase and electrodes is pivotal for the biocathode of enzymatic biofuel cells (EBFCs). However, in-depth understanding of the interplay mechanism between enzymes and electrode materials remains challenging when designing and constructing EBFCs. Herein, atomic-scale insight into the direct electron transfer (DET) behavior of Thermus thermophilus laccase (TtLac) with a special methionine-rich ß-hairpin motif adsorbed on the carboxyl-functionalized carbon nanotube (COOH-CNT) and amino-functionalized carbon nanotube (NH2-CNT) surfaces were disclosed by multi-scale molecular simulations. Simulation results reveal that electrostatic modification is an effective way to tune the DET behavior for TtLac on the modified-CNTs electrode surface. Surprisingly, the positively charged TtLac can be attracted by both negatively charged COOH-CNT and positively charged NH2-CNT surfaces, yet only the latter is capable to trigger the DET process due to the 'lying-on' adsorption orientation. Specifically, the T1 copper site is near the methionine-rich ß-hairpin motif, which is the key binding site for TtLac binding onto the NH2-CNT surface via electrostatic interaction, π-π stacking and cation-π interaction. Moreover, TtLac on the NH2-CNT surface undergoes less conformational changes than those on the COOH-CNT surface, which allows the laccase stability and catalytic efficiency to be well preserved. These findings provide a fundamental guidance for future design and fabrication of methionine-rich laccase-based EBFCs with high power output and long lifespan.


Assuntos
Lacase , Nanotubos de Carbono , Adsorção , DEET , Eletrodos , Lacase/metabolismo , Metionina , Nanotubos de Carbono/química
10.
Colloids Surf B Biointerfaces ; 217: 112675, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35792528

RESUMO

The promising potentials of biocatalytic treatment processes in the removal of micropollutants whilst eliminating health and environmental hazards have attracted great attention in recent years. This current work investigated the biotransformation efficiency of a novel laccase from Xylaria polymorpha (XPL) in comparison with commercial laccases from Trametes versicolor (TVL) and Aspergillus sp. (ASL). XPL exhibited better oxidation performance (95.7%) on AMX than TVL (92.8%) and ASL (90.5%). Optimization of operational conditions revealed that AMX was best oxidized at pH 5, temperature (30 °C), and concentration (1.0 mg L-1). The investigation carried out to determine the effect of redox mediators revealed violuric acid (VLA) as the best redox mediator. The laccase stability experiments elucidated that the oxidation of AMX is time and mediator concentration dependent with ABTS exhibiting highest deactivation of XPL active sites. Two metabolic products; amoxicillin penilloic acid and 5-hydroxy-6-(4-hydroxyphenyl)- 3-(1,3-thiazolidin-2-yl)piperazin-2-one of AMX were obtained through Liquid Chromatography-Mass Spectrometry (LC-MS) analyses. The toxicity assessments carried out after oxidation of AMX by XPL showed 94% and 97% reduced toxicity on Artemia salina and Aliivibrio fischeri respectively. The study further underscored the efficiency of biocatalytic-mediator technology in the transformation of complex micropollutants into less toxic substances in an eco-friendly way.


Assuntos
Lacase , Trametes , Ascomicetos , Biotransformação , Lacase/metabolismo , Oxirredução , Preparações Farmacêuticas , Trametes/metabolismo
11.
Bioresour Technol ; 361: 127699, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35905874

RESUMO

Lignin of high purity and structural integrity was isolated from the enzymatic residue of corn stover. Degradation of the lignin by laccase, lignin peroxidase, and manganese peroxidase was investigated. Structural changes in the lignin after degradation were characterized by scanning electron microscopy, nitrogen adsorption and Fourier transform infrared spectroscopy, and the enzymatic products were systematically analyzed by gas chromatography mass spectrometry. The highest percentage of lignin degradation was obtained with a mixture of three enzymes (25.79%): laccase (Lac), the starting enzyme of the mixed enzyme reaction, worked with lignin peroxidase (LiP), and manganese peroxidase (MnP) to further degrade lignin. This degradation destroyed the macromolecular structure of lignin, broke its key chemical bonds, and opened benzene rings, thus producing more acidic compounds. This study elucidated the concept of degrading lignin from corn stover using the Lac, LiP and MnP enzymes synergistically, thus providing a theoretical basis for the biodegradation of lignin.


Assuntos
Lacase , Lignina , Hidrólise , Lacase/metabolismo , Lignina/metabolismo , Peroxidases/metabolismo , Zea mays/química
12.
J Hazard Mater ; 438: 129525, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-35816800

RESUMO

Laccase has received extensive attention in pollutant degradation due to its high efficiency and environmental friendliness, but free laccase has poor stability, easy inactivation, and difficulty in recycling, which limited its application. It was a smart strategy to construct a synergistic system for the efficient adsorption and degradation of pollutants by enzyme immobilization to improve the stability and recyclability of the enzyme. In this study, the materials were synthesized by a one-step co-precipitation method. With Cu-MOF as the main body, Co2+ was introduced to construct bimetallic CoCu-MOF as the protective carrier of the enzyme. The enzyme-carrying capacity and enzyme activity of Lac@CoCu-MOF were 2-fold and 3.5-fold higher than those of Lac@Cu-MOF, respectively. Lac@MOF composites had a good protective effect on enzyme in various interfering environments. At pH = 7, free laccase was completely inactivated and Lac@CoCu-MOF maintained 51.76% enzyme activity. In addition, the removal rate of Congo red by Lac@CoCu-MOF reached 90 % in 1 h at pH = 4 % and 95 % in 5 h at pH = 7, and the final TOC mineralization rate reached 86.05 %. After six cycles, the degradation rate of Lac@CoCu-MOF remained above 75 %. Therefore, Lac@CoCu-MOF was constructed with the advantages of enzyme immobilization (enhanced stability and easy operation), material adsorption, and biocatalysis (fast diffusion and high activity), which has great guiding significance for the industrial application of enzyme.


Assuntos
Vermelho Congo , Lacase , Adsorção , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Lacase/metabolismo
13.
Sci Rep ; 12(1): 11170, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35778516

RESUMO

A laccase-producing hyper performer, Schizophyllum commune, a white-rot fungus, was evaluated for its ability to selectively degrade lignin of diverse crop residues in vitro. Relative analysis of crop residue treatment using laccase obtained from immobilized cells demonstrated degradation of 30-40% in finger millet straw and sorghum stover, 27-32% in paddy straw, 21% in wheat straw, and 26% in maize straw, while 20% lignin degradation was observed when purified and recombinant laccase was used. Further investigations into in vitro dry matter digestibility studies gave promising results recording digestibility of 54-59% in finger millet straw 33-36% in paddy straw and wheat straw, 16% in maize straw for laccase obtained from cell immobilization method, whereas 14% digestibility was observed when purified and recombinant laccase was used. Sorghum stover recorded digestibility of 13-15% across all straws treated with laccase. The results obtained elucidated the positive influence of laccase treatment on lignin degradation and in vitro dry matter digestibility. The present research gave encouraging figures confirming the production of laccase using the cell immobilization method to be an efficient production method commensurate with purified and recombinant laccase under conditions of submerged cultivation, proclaiming a cost-effective, environmentally safe green technology for effectual lignin depolymerization.


Assuntos
Basidiomycota , Schizophyllum , Animais , Basidiomycota/metabolismo , Lacase/metabolismo , Lignina/metabolismo , Ruminantes/metabolismo , Triticum/metabolismo , Zea mays/metabolismo
14.
Environ Pollut ; 309: 119729, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35809710

RESUMO

The treatment of contaminants from lignocellulosic biorefinery effluent has recently been identified as a unique challenge. This study focuses on removing phenolic contaminants and polycyclic aromatic hydrocarbons (PAHs) from lignocellulosic biorefinery wastewater (BRW) applying a laccase-assisted approach. Cassava waste was used as a substrate to produce the maximum yield of laccase enzyme (3.9 U/g) from Pleurotus ostreatus. Among the different inducers supplemented, CuSO4 (0.5 mM) showed an eight-fold increase in enzyme production (30.8 U/g) after 240 h of incubation. The catalytic efficiency of laccase was observed as 128.7 ± 8.47 S-1mM-1 for syringaldazine oxidation at optimum pH 4.0 and 40 °C. Laccase activity was completely inhibited by lead (II) ion, mercury (II) ion, sodium dodecyl sulphate, sodium azide and 1,4 dithiothretiol and induced significantly by manganese (II) ion and rhamnolipid. After treating BRW with laccase, the concentrations of PAHs and phenolic contaminants of 1144 µg/L and 46160 µg/L were reduced to 96 µg/L and 16100 µg/L, respectively. The ability of laccase to effectively degrade PAHs in the presence of different phenolic compounds implies that phenolic contaminants may play a role in PAHs degradation. After 240 h, organic contaminants were removed from BRW in the following order: phenol >2,4-dinitrophenol > 2-methyl-4,6-dinitrophenol > 2,3,4,6-tetrachlorophenol > acenaphthene > fluorine > phenanthrene > fluoranthene > pyrene > anthracene > chrysene > naphthalene > benzo(a)anthracene > benzo(a)pyrene > benzo(b)fluoranthene > pentachlorophenol > indeno(1,2,3-cd)pyrene > benzo(j) fluoranthene > benzo[k]fluoranthène. The multiple contaminant remediation from the BRW by enzymatic method, clearly suggests that the laccase can be used as a bioremediation tool for the treatment of wastewater from various industries.


Assuntos
Manihot , Pleurotus , Hidrocarbonetos Policíclicos Aromáticos , Lacase/metabolismo , Lignina , Manihot/metabolismo , Fenóis/metabolismo , Pleurotus/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/análise , Águas Residuárias
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 281: 121606, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-35839694

RESUMO

2-Methylimidazole (MIM) is a classic organic ligand that shows excellent thermal stability and chemical robustness and is widely used in ZIFs. Recently, transformations of MOFs have been realized by using metals or ligands. In this study, we propose a new strategy-adjusting MIM by extending the alkyl chain length -to change the properties of related MOFs. Furthermore, we used copper as the metal core to replace zinc to mimic the active sites of laccases (electron transfer between copper and imidazole ring). As a result, the nanostructures transformed from nanoleaves to nanovesicles, which changed the Cu(II)/Cu(I) ratio from 3.7 to 1.7, as well as the lattice constant (decreased the diffraction angle) and enzyme-like activity (inhibition). In addition, we revealed that superoxidase anions were the main factors responsible for its laccase-like activity. We applied it to detect and discriminate phenolics. Laccase-mimicking activity was best at pH 7.0. When compared to protein laccase, the Cu-MeIm nanozyme had a greater Vmax at the same mass concentration. It was used to identify and distinguish phenolics. In the presence of Cu-MeIm nanozymes, the linear range is 0.1-2 mM and the detection limit of 2,4-DCP is 0.034 mM.


Assuntos
Lacase , Nanoestruturas , Cobre/química , Lacase/química , Lacase/metabolismo , Ligantes , Compostos Orgânicos , Fenóis
16.
Cell Mol Biol (Noisy-le-grand) ; 67(5): 439-450, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35818224

RESUMO

Laccase producing fungus Pleurotus floridanus was isolated from Siruvani forest, Tamil Nadu, India. The potential of P. floridanus to produce laccase by using various lignocellulosic substrates was screened under submerged fermentation. Laccase production in the presence of lignocellulosic substrates such as rice, wheat and maize bran as a sole source of carbon as well as an additional supplement was examined. Laccase activity of P. floridanus using varied substrates was observed in the order of rice bran > wheat bran > maize bran. The isolate showed maximum laccase activity of 13.29±0.01 U/mL using rice bran as a carbon source within 11 days. This was 18 fold higher than the control media that lacks lignocellulosic substrates. The diclofenac tolerance was assessed in solid media at various concentrations and the results showed that the mycelia growth is not significantly affected by the drug. Finally, the laccase mediated degradation of diclofenac at a concentration of 10 mg/L showed 98% degradation in 2 h. The phytotoxicity of the crude laccase treated diclofenac was lower than the untreated diclofenac. In conclusion, findings suggested direct application of crude laccase produced from P. floridanus using agro-residues as ideal substrate for environmental applications.


Assuntos
Lacase , Pleurotus , Biotransformação , Carbono , Diclofenaco/toxicidade , Índia , Lacase/metabolismo , Pleurotus/metabolismo
17.
Molecules ; 27(12)2022 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-35744827

RESUMO

Naringenin is one of the flavonoids originating from citrus fruit. This polyphenol is mainly found in grapefruit, orange and lemon. The antioxidant and antimicrobial properties of flavonoids depend on their structure, including the polymeric form. The aim of this research was to achieve enzymatic polymerization of naringenin and to study the properties of poly(naringenin). The polymerization was performed by methods using two different enzymes, i.e., laccase and horseradish peroxidase (HRP). According to the literature data, naringenin had not been polymerized previously using the enzymatic polymerization method. Therefore, obtaining polymeric naringenin by reaction with enzymes is a scientific novelty. The research methodology included analysis of the structure of poly(naringenin) by NMR, GPC, FTIR and UV-Vis and its morphology by SEM, as well as analysis of its properties, i.e., thermal stability (DSC and TGA), antioxidant activity (ABTS, DPPH, FRAP and CUPRAC) and antimicrobial properties. Naringenin oligomers were obtained as a result of polymerization with two types of enzymes. The polymeric forms of naringenin were more resistant to thermo-oxidation; the final oxidation temperature To of naringenin catalyzed by laccase (poly(naringenin)-laccase) was 28.2 °C higher, and poly(naringenin)-HRP 23.6 °C higher than that of the basic flavonoid. Additionally, due to the higher molar mass and associated increase in OH groups in the structure, naringenin catalyzed by laccase (poly(naringenin)-laccase) showed better activity for scavenging ABTS+• radicals than naringenin catalyzed by HRP (poly(naringenin)-HRP) and naringenin. In addition, poly(naringenin)-laccase at a concentration of 5 mg/mL exhibited better microbial activity against E. coli than monomeric naringenin.


Assuntos
Citrus , Lacase , Antioxidantes/farmacologia , Citrus/metabolismo , Escherichia coli/metabolismo , Flavonoides/química , Peroxidase do Rábano Silvestre/metabolismo , Lacase/metabolismo , Oxirredução , Polímeros
18.
Int J Mol Sci ; 23(12)2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35742972

RESUMO

Plant laccase genes belong to a multigene family, play key roles in lignin polymerization, and participate in the resistance of plants to biotic and abiotic stresses. Switchgrass is an important resource for forage and bioenergy production, yet information about the switchgrass laccase gene family is scarce. Using bioinformatic approaches, a genome-wide analysis of the laccase multigene family in switchgrass was carried out in this study. In total, 49 laccase genes (PvLac1 to PvLac49) were identified; these can be divided into five subclades, and 20 of them were identified as targets of miR397. The tandem and segmental duplication of laccase genes on Chr05 and Chr08 contributed to the expansion of the laccase family. The laccase proteins shared conserved signature sequences but displayed relatively low sequence similarity, indicating the potential functional diversity of switchgrass laccases. Switchgrass laccases exhibited distinct tissue/organ expression patterns, revealing that some laccases might be involved in the lignification process during stem development. All five of the laccase isoforms selected from different subclades responded to heavy metal. The immediate response of lignin-related laccases, as well as the delayed response of low-abundance laccases, to heavy-metal treatment shed light on the multiple roles of laccase isoforms in response to heavy-metal stress.


Assuntos
Metais Pesados , Panicum , Lacase/genética , Lacase/metabolismo , Lignina/metabolismo , Panicum/genética , Panicum/metabolismo , Filogenia , Isoformas de Proteínas/genética
19.
J Hazard Mater ; 436: 129269, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35739784

RESUMO

How humic acid (HA) modifies bisphenol A (BPA) conversion in exoenzyme-activated polyreaction is poorly understood. Herein, the influencing mechanism of HA on laccase-induced BPA self-polymerization was investigated, and the phytotoxicity of the produced BPA self/co-polymers was assessed for the first time. HA prominently boosted BPA elimination, and the rate constants of BPA conversion augmented from 0.61 to 1.43 h-1 as HA level raised from 0 to 50 mg·L-1. It is because the generated BPA-HA co-polymers promptly lowered the yields of long-chain BPA self-oligomers, consequently maintaining laccase activity through opening enzymatic substrate-binding pockets. Notably, a few BPA monomers were re-released from the loosely bound self-polymers and co-polymers, and the releasing amounts respectively were 13.9 - 22.4% and 0.3 - 0.5% at pH 2 - 11. Formation of self/co-polymers was greatly conducive to avoiding BPA biotoxicity. Compared with BPA self-polymers, the phytotoxicity of BPA co-polymers to germinated radish (Raphanus sativus L.) seeds was lower due to these covalently bound products were more complex and stable. It follows that laccase-mediated co-polymerization played a significant role in BPA conversion, contaminant detoxification, and carbon sequestration. These findings are not only beneficial to clarifying exoenzyme-activated the generation mechanism of BPA co-polymers in water, but to reusing these supramolecular aggregates in crop growth.


Assuntos
Substâncias Húmicas , Lacase , Compostos Benzidrílicos/química , Compostos Benzidrílicos/toxicidade , Substâncias Húmicas/análise , Cinética , Lacase/metabolismo , Fenóis , Polímeros/química
20.
Chemosphere ; 304: 135374, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35718027

RESUMO

Enzymatic membrane reactors equipped with multifunctional biocatalytic membranes are promising and sustainable alternatives for removal of micropollutants, including steroid estrogens, under mild conditions. Thus, in this study an effort was made to produce novel multifunctional biocatalytic polyelectrolyte multilayer membranes via polyelectrolyte layer-by-layer assembly with laccase enzyme immobilized between or into polyelectrolyte layers. In this study, multifunctional biocatalytic membranes are considered as systems composed of commercially available filtration membrane modified by polyelectrolytes and immobilized enzymes, which are produced for complex treatment of water pollutants. The multifunctionality of the proposed systems is related to the fact that these membranes are capable of micropollutants removal via simultaneous catalytic conversion, membrane adsorption and membrane rejection making remediation process more complex, however, also more efficient. Briefly, cationic poly-l-lysine and polyethylenimine as well as anionic poly(sodium 4-styrenesulfonate) polyelectrolytes were deposited onto NP010 nanofiltration and UFX5 ultrafiltration membranes to produce systems for removal of 17α-ethynylestradiol. Images from scanning electron microscopy confirm effective enzyme deposition, whereas results of zeta potential measurements indicate introduction of positive charge onto the membranes. Based on preliminary results, four membranes with over 70%, activity retention produced using polyethylenimine in internal and entrapped mode, were selected for degradation tests. Systems based on UFX5 membrane allowed over 60% 17α-ethynylestradiol removal within 100 min, whereas NP010-based systems removed over 75% of estrogen within 150 min. Further, around 80% removal of 17α-ethynylestradiol was possible from the solutions at concentration up to 0.1 mg/L at pH ranging from 4 to 6 and at the pressure up to 3 bar, indicating high activity of the immobilized laccase over wide range of process conditions. Produced systems exhibited also great long-term stability followed by limited enzyme elution from the membrane. Finally, removal of over 70% and 60% of 17α-ethynylestradiol, respectively by NP010 and UFX5 systems after 8 cycles of repeated use indicate high reusability potential of the systems and suggest their practical application in removal of micropollutants, including estrogens.


Assuntos
Lacase , Polietilenoimina , Enzimas Imobilizadas/metabolismo , Estrogênios , Etinilestradiol , Lacase/metabolismo , Preparações Farmacêuticas , Polieletrólitos
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