Laccases are blue multicopper enzymes, capable of oxidizing diverse aromatic and non-aromatic compounds of industrial interest, concomitantly with reduction of molecular oxygen to water. Tolerance to extreme condition...Laccases are blue multicopper enzymes, capable of oxidizing diverse aromatic and non-aromatic compounds of industrial interest, concomitantly with reduction of molecular oxygen to water. Tolerance to extreme conditions, such as high temperature, salinity or extreme pH, is required for practical industrial applications. Here we focus on bacterial laccases from the phylum Actinobacteria, notably the order Actinomycetales. Currently, less than 10 enzymes have been properly characterized, all belonging to genus Streptomyces, but it is noteworthy that all of them have exhibited industrially important properties. Furthermore, studies with enzymes from this phylum revealed a novel molecular structure of laccases, providing the basis for a distinct family, the two-domain laccases. The relevant traits of actinomycetes laccases emphasize the need for more studies involving the isolation of this bacterial group from lignin-rich environmental samples, detection of their laccase activity and thereafter, characterization of the proteins and related genes. The nonhomogeneous responses of actinomycetes laccases to traditional inhibitors, substrates or metal ions have challenged the currently accepted “laccase concept”. Finally, considering that distinguishing laccase activity in vitro from other ligninolytic enzymes becomes a difficult task due to overlaps in catalytical properties of the enzymes, we proposed a simple flow chart to help experimental assays.展开更多
In recent years, there has been an upsurge of interest in enzyme treatment of textile fibres. Enzymes are globular proteins whose catalytic function is due to their three dimensional structure. For this reason, stabil...In recent years, there has been an upsurge of interest in enzyme treatment of textile fibres. Enzymes are globular proteins whose catalytic function is due to their three dimensional structure. For this reason, stability strategies make use of compounds that avoid dismantling or distorting protein 3D structures. This study is concerned with the use of microencapsulation techniques to optimize enzyme stabilization. Laccases were embedded in phophatidylcholine liposomes and their encapsulation capacity was assessed. Their enzymatic activity and stability were analyzed, comparing free-enzymes, enzymes in liposomes, and the lipid fraction separated from the aqueous fraction. An increase in their encapsulation efficiency was found at higher lipid/laccase ratios. Relative activity of enzyme-containing vesicles has also been shown to be retained much more than that of free native enzymes. The loss of activity of laccases entrapped in the vesicles in the total stability process is lower than 10% compared with 40% to 60% of loss of free-laccases after heating the samples for 3 days. Laccase stabilization could be of interest to future textile or cosmetic applications because of their potential for environmentally friendly oxidation technologies.展开更多
The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulf...The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.展开更多
Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant red...Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant reduction of 02 to H20. They are currently seen as highly interesting industrial enzymes because of their broad substrate specificity. The Phanerochaete flavido-alba laccase is expressed and secreted as a soluble active enzyme by Aspergillus niger （rLac-LPFA）. rLac-LPFA is easily purified to homogeneity. Metal ions like HgCI2, KC12, FeSO4 and MgSO4 at a concentration of 2 mM have inhibiting effect on recombinant and native laccase, whereas, CuSO4 and MnSO4 moderately increase both enzyme activities. Two potential inhibitors （sodium azide and EDTA） inhibited enzyme activity, whereas, urea and SDS have no effect on enzyme activity. The Km and V,,ax values for recombinant laccase are 0.65 mM and 300 U/mg respectively for 2,6-DMP as substrate.展开更多
Ochratoxin A is a metabolite of microbial origin with a negative biological activity on human health.The aim of this work was the evaluation of four recombinant bacterial laccases from Lactobacillus paracasei(syn.Lact...Ochratoxin A is a metabolite of microbial origin with a negative biological activity on human health.The aim of this work was the evaluation of four recombinant bacterial laccases from Lactobacillus paracasei(syn.Lacticaseibacillus paracasei)ENOLAB 4314,Lactococcus lactis ENOLAB 5298,Pediococcus parvulus ENOLAB 3909,and Companilactobacillus bobalius ENOLAB 4382 to degrade ochratoxin A(OTA)in wine.Several factors such as the presence and absence of redox mediators and copper,and the use of polyphenolic extracts from wine were addressed in sodium acetate buffer previously to the assays in wine.Ochratoxin A and oxidation products upon laccases action were analyzed by using high performance liquid chromatography coupled to mass spectrometry.Laccases were able to degrade ochratoxin A at different proportions depending on the enzyme origin and apparently its oxidation mechanism,rendering higher percentages of OTA oxidation in acetate buffer with(-)-epicatechin and copper than with ABTS,and without copper.In the experiments performed with natural red or white wines,the laccase of L.paracasei was the most OTA-degrading in red wine whereas in white wine was that of C.bobalius.Thus,the presence and absence of redox mediators and copper played a pivotal role in the oxidation reaction of OTA.To our knowledge,this is the first time that the degradation of OTA by lactic acid bacterial laccases has been reported,as well as the influence of different mediators and copper.These findings provided better understanding of the biological removal mechanism of this health-risk mycotoxin in wine.展开更多
Zearalenone(ZEN),a mycotoxin present in cereals,poses significant health risks to animals and humans due to its estrogenic effects.Numerous studies on the enzymatic detoxification of ZEN have predominantly focused on ...Zearalenone(ZEN),a mycotoxin present in cereals,poses significant health risks to animals and humans due to its estrogenic effects.Numerous studies on the enzymatic detoxification of ZEN have predominantly focused on reducing the parent toxin to assess the enzyme’s efficacy,yet there is limited research on the identification and toxicity evaluation of the enzymatic degradation products.This study investigated the enzymatic degradation mechanisms of ZEN using commercial peroxidase(POD)and laccase(LC),with a focus on identifying degradation products and assessing their hepatotoxicity effects.Molecular docking and dynamics simulations elucidated the binding mechanisms between these enzymes and ZEN,revealing strong interactions that facilitate efficient detoxification.Subsequent analysis employing ultra-high performance liquid chromatography-high resolution mass spectrometry(UHPLC-HRMS)successfully identified crucial degradation products.Hepatic toxicity of the enzymatic degradation products was comprehensively assessed in HepaRG liver cells through systematic measurements of cell viability,oxidative stress,apoptosis,mitochondrial membrane potential,and molecular metabolic profiles.Our findings demonstrate that both POD and LC exhibit significant efficacy in mitigating hepatocyte toxicity induced by ZEN,thereby highlighting their potential utility in enhancing food safety.This research provides essential data for safety evaluation regarding enzymatic detoxification of ZEN while offering theoretical and technical resources for risk assessment related to mycotoxin enzymatic detoxification.展开更多
Secondarily thickened cell walls of water-conducting vessels and tracheids and support-giving sclerenchyma cells contain lignin that makes the cell walls water impermeable and strong. To what extent laccases and perox...Secondarily thickened cell walls of water-conducting vessels and tracheids and support-giving sclerenchyma cells contain lignin that makes the cell walls water impermeable and strong. To what extent laccases and peroxidases contribute to lignin biosynthesis in muro is under active evaluation. We performed an in silico study of Norway spruce （Picea abies （L.） Karst.） laccases utilizing available genomic data. As many as 292 laccase encoding sequences （genes, gene fragments, and pseudogenes） were detected in the spruce genome. Out of the 112 genes annotated as laccases, 79 are expressed at some level. We isolated five fun-length laccase cDNAs from developing xylem and an extracellular lignin-forming cell culture of spruce. In addition, we purified and biochemically characterized one culture medium laccase from the lignin-forming cell culture. This laccase has an acidic pH optimum （pH 3.8-4.2） for coniferyl alcohol oxidation. It has a high affinity to coniferyl alcohol with an apparent Km value of 3.5μM; however, the laccase has a lower catalytic efficiency （Vmax/Km） for coniferyl alcohol oxidation compared with some purified culture medium peroxidases. The properties are discussed in the context of the information already known about laccases/coniferyl alcohol oxidases of coniferous plants.展开更多
2,6-Dimethoxyphenol (DMP) as a substrate was widely used in determination of laccase activity. It is surprising, however, that its catalyzed oxidation products have not been completely determined until now. Studies we...2,6-Dimethoxyphenol (DMP) as a substrate was widely used in determination of laccase activity. It is surprising, however, that its catalyzed oxidation products have not been completely determined until now. Studies were thus conducted on Rhus laccase (RL) and immobilized Rhus laccase (IRL)-catalyzed oxidation reactions of 2,6-dimethoxyphenol in water-organic solvent systems. These reactions proceeded well in water-(im)miscible organic solvent systems pre-saturated with water. Only one product, 3,3′,5,5′-tetramethoxy-1,1′biphenyl-4,4′-diol (TMBP), was produced by RL catalysis, and it was thoroughly characterized by FT-IR, NMR, GC-MS, etc. A simple enzymatic mechanism of this reaction is propos展开更多
Endocrine Disrupting Chemicals(EDCs)are a group of molecules that can influence hormonal balance,causing disturbance of the reproductive system and other health problems.Despite the efforts to eliminate EDC in the env...Endocrine Disrupting Chemicals(EDCs)are a group of molecules that can influence hormonal balance,causing disturbance of the reproductive system and other health problems.Despite the efforts to eliminate EDC in the environment,all current approaches are inefficient and expensive.In previous research,studies revealed that laccase-producing microorganisms may be a potential candidate for EDC degradation,as laccases have been found to be able to degrade many kinds of EDCs effectively and steadily.Here,we created two recombinant laccases,each fused with secretion peptide,Novel Signal Peptide 4(NSP4),and expressed them in Escherichia coli(E.coli,BL21),together with one laccase without secretion peptide.We first optimized the culture condition of expressing these laccases.Then,we test the activity of the recombinant laccases of decolorizing of a synthetic dye,indigo carmine.Finally,we confirmed the secreted can degrade one of the EDCs,β-estradiol,showing the potential of using the laccase secretion system to degrade toxic compounds.展开更多
Stem strength represents one of the most critical agronomic traits,as it enables plants to resist lodging and bending,thereby contributing to their overall yield and quality.Various transcription factors have been sho...Stem strength represents one of the most critical agronomic traits,as it enables plants to resist lodging and bending,thereby contributing to their overall yield and quality.Various transcription factors have been shown to regulate stem strength in crops;however,the mechanisms underlying stem strength formation and regulation remain largely unexplored,particularly in ornamental plants.This study identified a group IIe WRKY transcription factor PlWRKY29 in herbaceous peony.Tobacco plants overexpressing PlWRKY29 exhibited significantly enhanced stems,expanded xylem,thickened cell walls and elevated lignin content compared to wild-type specimens.Conversely,PlWRKY29-silenced herbaceous peony demonstrated opposite characteristics.Further investigation of the regulatory mechanism revealed that PlWRKY29 bound to the promoter of PlLAC15,which encodes a monolignol polymerization gene that facilitates lignin deposition.These findings demonstrate that PlWRKY29 positively regulates lignin biosynthesis and stem strength,advancing our understanding of lignin biosynthetic regulation in plants.展开更多
The arbitrary discharge of tetracycline(TC)residuals has seriously influenced the ecosystem and human health.Laccase(Lac)-based biodegradation technology is considered a more effective way to remove TC due to its high...The arbitrary discharge of tetracycline(TC)residuals has seriously influenced the ecosystem and human health.Laccase(Lac)-based biodegradation technology is considered a more effective way to remove TC due to its high catalytic efficiency and less by-product.Nevertheless,free Lac suffers from poor stability,easy inactivation and difficult recovery,restricting its application.Immobilization of Lac is considered an efficient strategy for addressing these obstacles.In this study,a magnetic metal-organic framework of Fe_(3)O_(4)@SiO_(2)@UiO-66-NH_(2)(MMOF)was prepared and used as a carrier to immobilize Lac(Lac@MMOF)for TC degradation.Benefiting from the multiple binding sites,adsorption,and protection effect of MMOF,Lac@MMOF displayed a wider pH application range(2–7)and better thermal(15–85℃),repeatability,and storage stability than free Lac.Furthermore,owing to the synergism of MOF adsorption and Lac biocatalysis,the removal rate of Lac@MMOF for TC could be up to 98%at pH=7 within 1 hr,which was 1.29 and 1.24 times that of free Lac and MMOF,respectively.More importantly,Lac@MMOF could easily be separated from aqueous solution under a magnetic field and maintained good removal performance(80%)after five cycles.The degradation products were identified by applying LC-MS/MS,and possible degradation mechanisms and pathways were proposed.Finally,the antibacterial activity of intermediate products was evaluated using Escherichia coli,which revealed that the toxicity of TC was reduced effectively by the degradation of Lac@MMOF.Overall,Lac@MMOF is a green alternative for residual antibiotic removal in water.展开更多
Endocrine disruptors such as bisphenol A(BPA)adversely affect the environment and human health.Laccases are used for the efficient biodegradation of various persistent organic pollutants in an environmentally safe man...Endocrine disruptors such as bisphenol A(BPA)adversely affect the environment and human health.Laccases are used for the efficient biodegradation of various persistent organic pollutants in an environmentally safe manner.However,the direct application of free laccases is generally hindered by short enzyme lifetimes,non-reusability,and the high cost of a single use.In this study,laccases were immobilized on a novel magnetic threedimensional poly(ethylene glycol)diacrylate(PEGDA)-chitosan(CS)inverse opal hydrogel(LAC@MPEGDA@CS@IOH).The immobilized laccase showed significant improvement in the BPA degradation performance and superior storage stability compared with the free laccase.91.1%of 100 mg/L BPA was removed by the LAC@MPEGDA@CS@IOH in 3 hr,whereas only 50.6%of BPA was removed by the same amount of the free laccase.Compared with the laccase,the outstanding BPA degradation efficiency of the LAC@MPEGDA@CS@IOH was maintained over a wider range of pH values and temperatures.Moreover,its relative activity of was maintained at 70.4%after 10 cycles,and the system performed well in actual water matrices.This efficientmethod for preparing immobilized laccases is simple and green,and it can be used to further develop ecofriendly biocatalysts to remove organic pollutants from wastewater.展开更多
Background AflatoxinB1(AFB_(1))is a prevalent contaminant in agricultural products,presenting significant risks to animal health.CotA laccase from Bacillus licheniformis has shown significant efficacy in degrading myc...Background AflatoxinB1(AFB_(1))is a prevalent contaminant in agricultural products,presenting significant risks to animal health.CotA laccase from Bacillus licheniformis has shown significant efficacy in degrading mycotoxins in vitro test.The efficacy of Bacillus CotA laccase in animals,however,remains to be confirmed.A 2×2 factorial design was used to investigate the effects of Bacillus CotA laccase level(0 or 1 U/kg),AFB_(1) challenge(challenged or unchal-lenged)and their interactions on ducks.The purpose of this study was to evaluate the efficacy of Bacillus CotA laccase in alleviatingAFB_(1) toxicosis of ducks.Results Bacillus CotA laccase alleviatedAFB_(1)-induced declines in growth performance of ducks accompanied by improved average daily gain(ADG)and lower feed/gain ratio(F/G).Bacillus CotA laccase amelioratedAFB_(1)-induced gut barrier dysfunctions and inflammation testified by increasing the jejunal villi height/crypt depth ratio(VH/CD)and the mRNA expression of tight junction protein 1(TJP1)and zonula occluden-1(ZO-1)as well as decreasing the expression of inflammation-related genes in the jejunum of ducks.Amino acid metabolome showed that Bacillus CotA laccase amelioratedAFB_(1)-induced amino acid metabolism disorders evidenced by increasing the level of glu-tamic acid in serum and upregulating the expression of amino acid transport related genes in jejunum of ducks.Bacil-lus CotA laccase amelioratedAFB_(1)-induced liver injury testified by suppressing oxidative stress,inhibiting apoptosis,and downregulating the expression of hepatic metabolic enzyme related genes of ducks.Moreover,Bacillus CotA laccase degradedAFB_(1) in digestive tract of ducks,resulting in the reduced absorption level ofAFB_(1) across intestinal epithelium testified by the decreased level ofAFB_(1)-DNA adduct in the liver,and the reduced content ofAFB_(1) residues in liver and feces of ducks.Conclusions Bacillus CotA laccase effectively improved the growth performance,intestinal health,amino acid metabolism and hepatic aflatoxin metabolism of ducks fedAFB_(1) diets,highlighting its potential as an efficient and safe feed enzyme forAFB_(1) degradation in animal production.展开更多
2,4,6-trinitrotoluene(TNT) and its derivatives are nitrogen-containing aromatic compounds having chemical and thermal stability at ambient temperature and pressure. TNT has high toxicity and mutagenic activity to huma...2,4,6-trinitrotoluene(TNT) and its derivatives are nitrogen-containing aromatic compounds having chemical and thermal stability at ambient temperature and pressure. TNT has high toxicity and mutagenic activity to humans, plants and animals, thus decontamination processes are necessary. Many microorganisms are capable to bioremediate TNT such as bacteria from the genera Pseudomonas,Enterobacter, Rhodococcus, Mycobacterium, Clostridium and Desulfovibrio: fungus such as Phanerochate and Stropharia species are able to perform TNT biotransformation under aerobic and anaerobic conditions. In this work we review the state of TNT biodegradation by various routes: aerobic, anaerobic,combined, fungal, enzymatic, and bio-electrochemical.展开更多
To achieve effective decolorization of reactive dyes,laccase immobilization was investigated.Laccase 0.2%(m/V)(Denilite IIS) was trapped in beads of alginate/gelatin blent with polyethylene glycol(PEG),and then the su...To achieve effective decolorization of reactive dyes,laccase immobilization was investigated.Laccase 0.2%(m/V)(Denilite IIS) was trapped in beads of alginate/gelatin blent with polyethylene glycol(PEG),and then the supporters were activated by cross-linking with glutaraldehyde.The results of repeated batch decolorization showed that gelatin and appropriate concentration of glutaraldehyde accelerated the decolorization of Reactive Red B-3BF(RRB);PEG had a positive effect on enzyme stability and led to an inc...展开更多
Effect of different nitrogen concentration in the mediums on growth and enzyme production of Phanerochaete chrysosporium was studied when glucose concentration was 10 g/L. The results showed that the medium contained ...Effect of different nitrogen concentration in the mediums on growth and enzyme production of Phanerochaete chrysosporium was studied when glucose concentration was 10 g/L. The results showed that the medium contained 0.8 g/L ammonium tartrate is the best. It not only supply abundant nutrients for the growth of Phanerochaete chrysosporium, which make mycelia the best grow compared with the other medium, but also produce higher manganese-dependent peroxidase(Mnp) and laccase(Lac) activity. In addition, it is observed that the variation of mycelia surface is related to ligninolytic enzyme secreted by Phanerochaete chrysosporium. When the surface of mycelium pellets appeared burs, it predicts secondary metabolism begin. This experimentation demonstrated that when the ratio of carbon and nitrogen in nitrogen limited medium is equal to 100∶8, growth and enzyme production of Phanerochaete chrysosporium is the best, it could achieve the maximum Mnp and Lac activity.展开更多
Pestalotiopsis sp. J63, producing a high activity of laccase, is a new marine-derived fungus isolated from the oceanic sediment of the East China Sea. Since the marine environment is oligotrophic nutrient, marine deri...Pestalotiopsis sp. J63, producing a high activity of laccase, is a new marine-derived fungus isolated from the oceanic sediment of the East China Sea. Since the marine environment is oligotrophic nutrient, marine derived fungi may use small amount of nutrients to grow and produce laccases. Agricultural residues that are mainly composed of lignin, cellulose and hemicellulose are difficult to be degraded and few microbes can take them as substrates, so they are considered as oligotrophic nutrient and have the potential to be used to produce value added products. In this study, the ability of Pestalotiopsis sp. J63 to use agricultural residues to produce laccases was tested in the submerged fermentation. The combination of 3 g·L 1maltose and 20 g·L 1rice straw was the best carbon sources and 8 g·L 1ammonium sulfate was the best nitrogen source under the condition without inducers. The effects of five inducers, the feeding time and concentration of inducer on laccase production were investigated.Adding 0.09 mmol·L 1phenol after 24 h of incubation led to high laccase activity(5089 U·L 1), while with 0.09mmol·L 1phenol in the medium and wheat bran as the nitrogen source, the laccase activity could reach 5791.7U·L 1. Native-PAGE results showed that two laccase isozymes were present in the cultures. One existed in both induced and non-induced culture filtrates, while the other was only found in the fermentation with the addition of phenol, guaiacol and veratryl alcohol.展开更多
Biodegradation of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane(DDT)in soil by laccase extract from white rot fungi under different experimental conditions was investigated.DDTs,which stands for the sum of p,p′-DDE,...Biodegradation of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane(DDT)in soil by laccase extract from white rot fungi under different experimental conditions was investigated.DDTs,which stands for the sum of p,p′-DDE,o,p′-DDT,p,p′-DDD and p,p′-DDT in soil was degraded efficiently,and the residue decreased rapidly during the first 15 days and then slowly during the period of 16-25 days.The biodegradation of DDTs in soil fitted the pseudo-first-order kinetics.For 5,10,15 and 25 days of incubation with laccase,the residue of DDTs in soil under different atmospheres was decreased by 20%-33%,34%-52%,41%-61%and 41%-69%respectively,under different flooding conditions that was decreased by 12%-17%,17%-30%,30%-45%and 35%-52%respectively, and for different soils that was decreased by 25%-34%,39%-53%,44%-58%and 47%-62%respectively.The half-life of DDTs in soil ranged from 15.07 to 32.95 days under O2,air or N2 atmospheres,23.07 to 40.71 days under different flooding conditions,and 18.78 to 28.88 days for different soils.Laccase is an efficient and safe agent for bioremediation of DDT-contaminated soil.展开更多
The capability of decolorization for commercial dyes by Coriolus versicolor fermentation broth containing laccase with or without immobilized mycelium was evaluated. With cell free fermentation broth containing l...The capability of decolorization for commercial dyes by Coriolus versicolor fermentation broth containing laccase with or without immobilized mycelium was evaluated. With cell free fermentation broth containing laccase, high decolorization ratio was achieved for acid orange 7, but not for the other dyes concerned. The immobilized mycelium was proved to be more efficient than the cell free system. All the four dyestuffs studied were found being decolourized with certain extent by immobilized mycelium. The repeated batch decolorization was carried out with satisfactory results. The experimental data showed that the continuous decolorization of wastewater from a printing and dyeing industry was possible by using the self immobilized C. Versicolor.展开更多
文摘Laccases are blue multicopper enzymes, capable of oxidizing diverse aromatic and non-aromatic compounds of industrial interest, concomitantly with reduction of molecular oxygen to water. Tolerance to extreme conditions, such as high temperature, salinity or extreme pH, is required for practical industrial applications. Here we focus on bacterial laccases from the phylum Actinobacteria, notably the order Actinomycetales. Currently, less than 10 enzymes have been properly characterized, all belonging to genus Streptomyces, but it is noteworthy that all of them have exhibited industrially important properties. Furthermore, studies with enzymes from this phylum revealed a novel molecular structure of laccases, providing the basis for a distinct family, the two-domain laccases. The relevant traits of actinomycetes laccases emphasize the need for more studies involving the isolation of this bacterial group from lignin-rich environmental samples, detection of their laccase activity and thereafter, characterization of the proteins and related genes. The nonhomogeneous responses of actinomycetes laccases to traditional inhibitors, substrates or metal ions have challenged the currently accepted “laccase concept”. Finally, considering that distinguishing laccase activity in vitro from other ligninolytic enzymes becomes a difficult task due to overlaps in catalytical properties of the enzymes, we proposed a simple flow chart to help experimental assays.
文摘In recent years, there has been an upsurge of interest in enzyme treatment of textile fibres. Enzymes are globular proteins whose catalytic function is due to their three dimensional structure. For this reason, stability strategies make use of compounds that avoid dismantling or distorting protein 3D structures. This study is concerned with the use of microencapsulation techniques to optimize enzyme stabilization. Laccases were embedded in phophatidylcholine liposomes and their encapsulation capacity was assessed. Their enzymatic activity and stability were analyzed, comparing free-enzymes, enzymes in liposomes, and the lipid fraction separated from the aqueous fraction. An increase in their encapsulation efficiency was found at higher lipid/laccase ratios. Relative activity of enzyme-containing vesicles has also been shown to be retained much more than that of free native enzymes. The loss of activity of laccases entrapped in the vesicles in the total stability process is lower than 10% compared with 40% to 60% of loss of free-laccases after heating the samples for 3 days. Laccase stabilization could be of interest to future textile or cosmetic applications because of their potential for environmentally friendly oxidation technologies.
基金supported by the National Science and Technology Council of Mexico(CONACYT)(No.192118)
文摘The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.
文摘Laccases are blue copper oxidases （E.C. 1.10.3.2 benzenediol：oxygen oxidoreductase） that catalyze the one-electron oxidation of phenolics, aromatic amines and other electron-rich substrates with the concomitant reduction of 02 to H20. They are currently seen as highly interesting industrial enzymes because of their broad substrate specificity. The Phanerochaete flavido-alba laccase is expressed and secreted as a soluble active enzyme by Aspergillus niger （rLac-LPFA）. rLac-LPFA is easily purified to homogeneity. Metal ions like HgCI2, KC12, FeSO4 and MgSO4 at a concentration of 2 mM have inhibiting effect on recombinant and native laccase, whereas, CuSO4 and MnSO4 moderately increase both enzyme activities. Two potential inhibitors （sodium azide and EDTA） inhibited enzyme activity, whereas, urea and SDS have no effect on enzyme activity. The Km and V,,ax values for recombinant laccase are 0.65 mM and 300 U/mg respectively for 2,6-DMP as substrate.
基金funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No.[101022293]funding provided by the University of Castilla-La Mancha and its Own Research Plan 2022 for the implementation of applied research projects,85%co-financed by the European Regional Development Fund(ERDF)[Proyect number:2022-GRIN-34333]+2 种基金Spanish MINECO(AGL2015-71227-R)Spanish MICIU(RTI2018-095658-B-C31)to ENOLAB research group of University of Valencia(Spain).
文摘Ochratoxin A is a metabolite of microbial origin with a negative biological activity on human health.The aim of this work was the evaluation of four recombinant bacterial laccases from Lactobacillus paracasei(syn.Lacticaseibacillus paracasei)ENOLAB 4314,Lactococcus lactis ENOLAB 5298,Pediococcus parvulus ENOLAB 3909,and Companilactobacillus bobalius ENOLAB 4382 to degrade ochratoxin A(OTA)in wine.Several factors such as the presence and absence of redox mediators and copper,and the use of polyphenolic extracts from wine were addressed in sodium acetate buffer previously to the assays in wine.Ochratoxin A and oxidation products upon laccases action were analyzed by using high performance liquid chromatography coupled to mass spectrometry.Laccases were able to degrade ochratoxin A at different proportions depending on the enzyme origin and apparently its oxidation mechanism,rendering higher percentages of OTA oxidation in acetate buffer with(-)-epicatechin and copper than with ABTS,and without copper.In the experiments performed with natural red or white wines,the laccase of L.paracasei was the most OTA-degrading in red wine whereas in white wine was that of C.bobalius.Thus,the presence and absence of redox mediators and copper played a pivotal role in the oxidation reaction of OTA.To our knowledge,this is the first time that the degradation of OTA by lactic acid bacterial laccases has been reported,as well as the influence of different mediators and copper.These findings provided better understanding of the biological removal mechanism of this health-risk mycotoxin in wine.
基金financially supported by the National Key Research and Development Program of China(2022YFF1102500)the Key Research and Development Projects in Hubei Province,China(2021BCA113).
文摘Zearalenone(ZEN),a mycotoxin present in cereals,poses significant health risks to animals and humans due to its estrogenic effects.Numerous studies on the enzymatic detoxification of ZEN have predominantly focused on reducing the parent toxin to assess the enzyme’s efficacy,yet there is limited research on the identification and toxicity evaluation of the enzymatic degradation products.This study investigated the enzymatic degradation mechanisms of ZEN using commercial peroxidase(POD)and laccase(LC),with a focus on identifying degradation products and assessing their hepatotoxicity effects.Molecular docking and dynamics simulations elucidated the binding mechanisms between these enzymes and ZEN,revealing strong interactions that facilitate efficient detoxification.Subsequent analysis employing ultra-high performance liquid chromatography-high resolution mass spectrometry(UHPLC-HRMS)successfully identified crucial degradation products.Hepatic toxicity of the enzymatic degradation products was comprehensively assessed in HepaRG liver cells through systematic measurements of cell viability,oxidative stress,apoptosis,mitochondrial membrane potential,and molecular metabolic profiles.Our findings demonstrate that both POD and LC exhibit significant efficacy in mitigating hepatocyte toxicity induced by ZEN,thereby highlighting their potential utility in enhancing food safety.This research provides essential data for safety evaluation regarding enzymatic detoxification of ZEN while offering theoretical and technical resources for risk assessment related to mycotoxin enzymatic detoxification.
基金supported by University of Helsinki Research Funds (to A.K.)Academy of Finland (grant 251390 to A.K.)Societas pro Fauna et Flora Fennica (to H.A.M.)
文摘Secondarily thickened cell walls of water-conducting vessels and tracheids and support-giving sclerenchyma cells contain lignin that makes the cell walls water impermeable and strong. To what extent laccases and peroxidases contribute to lignin biosynthesis in muro is under active evaluation. We performed an in silico study of Norway spruce （Picea abies （L.） Karst.） laccases utilizing available genomic data. As many as 292 laccase encoding sequences （genes, gene fragments, and pseudogenes） were detected in the spruce genome. Out of the 112 genes annotated as laccases, 79 are expressed at some level. We isolated five fun-length laccase cDNAs from developing xylem and an extracellular lignin-forming cell culture of spruce. In addition, we purified and biochemically characterized one culture medium laccase from the lignin-forming cell culture. This laccase has an acidic pH optimum （pH 3.8-4.2） for coniferyl alcohol oxidation. It has a high affinity to coniferyl alcohol with an apparent Km value of 3.5μM; however, the laccase has a lower catalytic efficiency （Vmax/Km） for coniferyl alcohol oxidation compared with some purified culture medium peroxidases. The properties are discussed in the context of the information already known about laccases/coniferyl alcohol oxidases of coniferous plants.
文摘2,6-Dimethoxyphenol (DMP) as a substrate was widely used in determination of laccase activity. It is surprising, however, that its catalyzed oxidation products have not been completely determined until now. Studies were thus conducted on Rhus laccase (RL) and immobilized Rhus laccase (IRL)-catalyzed oxidation reactions of 2,6-dimethoxyphenol in water-organic solvent systems. These reactions proceeded well in water-(im)miscible organic solvent systems pre-saturated with water. Only one product, 3,3′,5,5′-tetramethoxy-1,1′biphenyl-4,4′-diol (TMBP), was produced by RL catalysis, and it was thoroughly characterized by FT-IR, NMR, GC-MS, etc. A simple enzymatic mechanism of this reaction is propos
文摘Endocrine Disrupting Chemicals(EDCs)are a group of molecules that can influence hormonal balance,causing disturbance of the reproductive system and other health problems.Despite the efforts to eliminate EDC in the environment,all current approaches are inefficient and expensive.In previous research,studies revealed that laccase-producing microorganisms may be a potential candidate for EDC degradation,as laccases have been found to be able to degrade many kinds of EDCs effectively and steadily.Here,we created two recombinant laccases,each fused with secretion peptide,Novel Signal Peptide 4(NSP4),and expressed them in Escherichia coli(E.coli,BL21),together with one laccase without secretion peptide.We first optimized the culture condition of expressing these laccases.Then,we test the activity of the recombinant laccases of decolorizing of a synthetic dye,indigo carmine.Finally,we confirmed the secreted can degrade one of the EDCs,β-estradiol,showing the potential of using the laccase secretion system to degrade toxic compounds.
基金supported by the National Natural Science Foundation of China(32302586,32330091)the China Postdoctoral Science Foundation(2023M732988,2022M722698)+1 种基金the National Forest and Grass Science and Technology Innovation and Development Research Project,China(2023132012)the Forestry Science and Technology Promotion Project of Jiangsu Province,China(LYKJ[2021]01)。
文摘Stem strength represents one of the most critical agronomic traits,as it enables plants to resist lodging and bending,thereby contributing to their overall yield and quality.Various transcription factors have been shown to regulate stem strength in crops;however,the mechanisms underlying stem strength formation and regulation remain largely unexplored,particularly in ornamental plants.This study identified a group IIe WRKY transcription factor PlWRKY29 in herbaceous peony.Tobacco plants overexpressing PlWRKY29 exhibited significantly enhanced stems,expanded xylem,thickened cell walls and elevated lignin content compared to wild-type specimens.Conversely,PlWRKY29-silenced herbaceous peony demonstrated opposite characteristics.Further investigation of the regulatory mechanism revealed that PlWRKY29 bound to the promoter of PlLAC15,which encodes a monolignol polymerization gene that facilitates lignin deposition.These findings demonstrate that PlWRKY29 positively regulates lignin biosynthesis and stem strength,advancing our understanding of lignin biosynthetic regulation in plants.
基金supported by the National Natural Science Foundation of China(No.U20A20133)the National Key Research and Development Program of China(No.2022YFF0606703).
文摘The arbitrary discharge of tetracycline(TC)residuals has seriously influenced the ecosystem and human health.Laccase(Lac)-based biodegradation technology is considered a more effective way to remove TC due to its high catalytic efficiency and less by-product.Nevertheless,free Lac suffers from poor stability,easy inactivation and difficult recovery,restricting its application.Immobilization of Lac is considered an efficient strategy for addressing these obstacles.In this study,a magnetic metal-organic framework of Fe_(3)O_(4)@SiO_(2)@UiO-66-NH_(2)(MMOF)was prepared and used as a carrier to immobilize Lac(Lac@MMOF)for TC degradation.Benefiting from the multiple binding sites,adsorption,and protection effect of MMOF,Lac@MMOF displayed a wider pH application range(2–7)and better thermal(15–85℃),repeatability,and storage stability than free Lac.Furthermore,owing to the synergism of MOF adsorption and Lac biocatalysis,the removal rate of Lac@MMOF for TC could be up to 98%at pH=7 within 1 hr,which was 1.29 and 1.24 times that of free Lac and MMOF,respectively.More importantly,Lac@MMOF could easily be separated from aqueous solution under a magnetic field and maintained good removal performance(80%)after five cycles.The degradation products were identified by applying LC-MS/MS,and possible degradation mechanisms and pathways were proposed.Finally,the antibacterial activity of intermediate products was evaluated using Escherichia coli,which revealed that the toxicity of TC was reduced effectively by the degradation of Lac@MMOF.Overall,Lac@MMOF is a green alternative for residual antibiotic removal in water.
基金supported by the National Key Research and Development Program of China(Nos.2022YFC3703700 and 2021YFA0910300)the National Natural Science Foundation of China(No.22125606)the Special Project of Ecological Environmental Technology for Carbon Dioxide Emissions Peak and Carbon Neutrality(No.RCEES-TDZ-2021-21).
文摘Endocrine disruptors such as bisphenol A(BPA)adversely affect the environment and human health.Laccases are used for the efficient biodegradation of various persistent organic pollutants in an environmentally safe manner.However,the direct application of free laccases is generally hindered by short enzyme lifetimes,non-reusability,and the high cost of a single use.In this study,laccases were immobilized on a novel magnetic threedimensional poly(ethylene glycol)diacrylate(PEGDA)-chitosan(CS)inverse opal hydrogel(LAC@MPEGDA@CS@IOH).The immobilized laccase showed significant improvement in the BPA degradation performance and superior storage stability compared with the free laccase.91.1%of 100 mg/L BPA was removed by the LAC@MPEGDA@CS@IOH in 3 hr,whereas only 50.6%of BPA was removed by the same amount of the free laccase.Compared with the laccase,the outstanding BPA degradation efficiency of the LAC@MPEGDA@CS@IOH was maintained over a wider range of pH values and temperatures.Moreover,its relative activity of was maintained at 70.4%after 10 cycles,and the system performed well in actual water matrices.This efficientmethod for preparing immobilized laccases is simple and green,and it can be used to further develop ecofriendly biocatalysts to remove organic pollutants from wastewater.
基金National Key Research and Development Program of China(2021YFC2103003)National Natural Science Foundation of China(31972604)+1 种基金Jinan Introductory Innovation Team Project(No.202228037)China Postdoctoral Science Foundation(2023M730998).
文摘Background AflatoxinB1(AFB_(1))is a prevalent contaminant in agricultural products,presenting significant risks to animal health.CotA laccase from Bacillus licheniformis has shown significant efficacy in degrading mycotoxins in vitro test.The efficacy of Bacillus CotA laccase in animals,however,remains to be confirmed.A 2×2 factorial design was used to investigate the effects of Bacillus CotA laccase level(0 or 1 U/kg),AFB_(1) challenge(challenged or unchal-lenged)and their interactions on ducks.The purpose of this study was to evaluate the efficacy of Bacillus CotA laccase in alleviatingAFB_(1) toxicosis of ducks.Results Bacillus CotA laccase alleviatedAFB_(1)-induced declines in growth performance of ducks accompanied by improved average daily gain(ADG)and lower feed/gain ratio(F/G).Bacillus CotA laccase amelioratedAFB_(1)-induced gut barrier dysfunctions and inflammation testified by increasing the jejunal villi height/crypt depth ratio(VH/CD)and the mRNA expression of tight junction protein 1(TJP1)and zonula occluden-1(ZO-1)as well as decreasing the expression of inflammation-related genes in the jejunum of ducks.Amino acid metabolome showed that Bacillus CotA laccase amelioratedAFB_(1)-induced amino acid metabolism disorders evidenced by increasing the level of glu-tamic acid in serum and upregulating the expression of amino acid transport related genes in jejunum of ducks.Bacil-lus CotA laccase amelioratedAFB_(1)-induced liver injury testified by suppressing oxidative stress,inhibiting apoptosis,and downregulating the expression of hepatic metabolic enzyme related genes of ducks.Moreover,Bacillus CotA laccase degradedAFB_(1) in digestive tract of ducks,resulting in the reduced absorption level ofAFB_(1) across intestinal epithelium testified by the decreased level ofAFB_(1)-DNA adduct in the liver,and the reduced content ofAFB_(1) residues in liver and feces of ducks.Conclusions Bacillus CotA laccase effectively improved the growth performance,intestinal health,amino acid metabolism and hepatic aflatoxin metabolism of ducks fedAFB_(1) diets,highlighting its potential as an efficient and safe feed enzyme forAFB_(1) degradation in animal production.
基金the Director of the School of Engineering and Science, Tecnológico de Monterrey, Campus Monterrey for his encouragement and financial supportthe financial support from CONACYT(Mexico)PhD scholarship No. 309171 for CCZ, SNI-C fellowship to RC and MR, FRAavesh green sustainability solutions S. De R. L. De. C. V. for their support
文摘2,4,6-trinitrotoluene(TNT) and its derivatives are nitrogen-containing aromatic compounds having chemical and thermal stability at ambient temperature and pressure. TNT has high toxicity and mutagenic activity to humans, plants and animals, thus decontamination processes are necessary. Many microorganisms are capable to bioremediate TNT such as bacteria from the genera Pseudomonas,Enterobacter, Rhodococcus, Mycobacterium, Clostridium and Desulfovibrio: fungus such as Phanerochate and Stropharia species are able to perform TNT biotransformation under aerobic and anaerobic conditions. In this work we review the state of TNT biodegradation by various routes: aerobic, anaerobic,combined, fungal, enzymatic, and bio-electrochemical.
基金supported by the National Hi-Tech Research and Development Program(863)of China(No.2007AA02Z218)the Open Project Program of Key Lab-oratory of Eco-Textiles,Jiangnan University,Ministry of Education,China(No.KLET0625) the Youth Fundof Jiangnan University(No.2006LQN002).
文摘To achieve effective decolorization of reactive dyes,laccase immobilization was investigated.Laccase 0.2%(m/V)(Denilite IIS) was trapped in beads of alginate/gelatin blent with polyethylene glycol(PEG),and then the supporters were activated by cross-linking with glutaraldehyde.The results of repeated batch decolorization showed that gelatin and appropriate concentration of glutaraldehyde accelerated the decolorization of Reactive Red B-3BF(RRB);PEG had a positive effect on enzyme stability and led to an inc...
文摘Effect of different nitrogen concentration in the mediums on growth and enzyme production of Phanerochaete chrysosporium was studied when glucose concentration was 10 g/L. The results showed that the medium contained 0.8 g/L ammonium tartrate is the best. It not only supply abundant nutrients for the growth of Phanerochaete chrysosporium, which make mycelia the best grow compared with the other medium, but also produce higher manganese-dependent peroxidase(Mnp) and laccase(Lac) activity. In addition, it is observed that the variation of mycelia surface is related to ligninolytic enzyme secreted by Phanerochaete chrysosporium. When the surface of mycelium pellets appeared burs, it predicts secondary metabolism begin. This experimentation demonstrated that when the ratio of carbon and nitrogen in nitrogen limited medium is equal to 100∶8, growth and enzyme production of Phanerochaete chrysosporium is the best, it could achieve the maximum Mnp and Lac activity.
基金Supported by the National Natural Science Foundation of China （21036005） and Scientific and Technology Plan of Zhejiang Province （2011C33016）.
文摘Pestalotiopsis sp. J63, producing a high activity of laccase, is a new marine-derived fungus isolated from the oceanic sediment of the East China Sea. Since the marine environment is oligotrophic nutrient, marine derived fungi may use small amount of nutrients to grow and produce laccases. Agricultural residues that are mainly composed of lignin, cellulose and hemicellulose are difficult to be degraded and few microbes can take them as substrates, so they are considered as oligotrophic nutrient and have the potential to be used to produce value added products. In this study, the ability of Pestalotiopsis sp. J63 to use agricultural residues to produce laccases was tested in the submerged fermentation. The combination of 3 g·L 1maltose and 20 g·L 1rice straw was the best carbon sources and 8 g·L 1ammonium sulfate was the best nitrogen source under the condition without inducers. The effects of five inducers, the feeding time and concentration of inducer on laccase production were investigated.Adding 0.09 mmol·L 1phenol after 24 h of incubation led to high laccase activity(5089 U·L 1), while with 0.09mmol·L 1phenol in the medium and wheat bran as the nitrogen source, the laccase activity could reach 5791.7U·L 1. Native-PAGE results showed that two laccase isozymes were present in the cultures. One existed in both induced and non-induced culture filtrates, while the other was only found in the fermentation with the addition of phenol, guaiacol and veratryl alcohol.
基金Supported by the Science and Technology Planning Project of Guangdong Province of China(2008B080701012)the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Ministry of Education of Chinathe Leading Academic Discipline Program of Phase-3 of"Project-211"for South China Agricultural University(2009B010100001)
文摘Biodegradation of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane(DDT)in soil by laccase extract from white rot fungi under different experimental conditions was investigated.DDTs,which stands for the sum of p,p′-DDE,o,p′-DDT,p,p′-DDD and p,p′-DDT in soil was degraded efficiently,and the residue decreased rapidly during the first 15 days and then slowly during the period of 16-25 days.The biodegradation of DDTs in soil fitted the pseudo-first-order kinetics.For 5,10,15 and 25 days of incubation with laccase,the residue of DDTs in soil under different atmospheres was decreased by 20%-33%,34%-52%,41%-61%and 41%-69%respectively,under different flooding conditions that was decreased by 12%-17%,17%-30%,30%-45%and 35%-52%respectively, and for different soils that was decreased by 25%-34%,39%-53%,44%-58%and 47%-62%respectively.The half-life of DDTs in soil ranged from 15.07 to 32.95 days under O2,air or N2 atmospheres,23.07 to 40.71 days under different flooding conditions,and 18.78 to 28.88 days for different soils.Laccase is an efficient and safe agent for bioremediation of DDT-contaminated soil.
基金TheNationalNaturalScienceFoundationofChina (No .2 9976 0 38)
文摘The capability of decolorization for commercial dyes by Coriolus versicolor fermentation broth containing laccase with or without immobilized mycelium was evaluated. With cell free fermentation broth containing laccase, high decolorization ratio was achieved for acid orange 7, but not for the other dyes concerned. The immobilized mycelium was proved to be more efficient than the cell free system. All the four dyestuffs studied were found being decolourized with certain extent by immobilized mycelium. The repeated batch decolorization was carried out with satisfactory results. The experimental data showed that the continuous decolorization of wastewater from a printing and dyeing industry was possible by using the self immobilized C. Versicolor.
