Displaying publications 1 - 20 of 39 in total

  1. Ahmad Rizal NFA, Ibrahim MF, Zakaria MR, Kamal Bahrin E, Abd-Aziz S, Hassan MA
    Molecules, 2018 Apr 02;23(4).
    PMID: 29614823 DOI: 10.3390/molecules23040811
    The combination of superheated steam (SHS) with ligninolytic enzyme laccase pretreatment together with size reduction was conducted in order to enhance the enzymatic hydrolysis of oil palm biomass into glucose. The oil palm empty fruit bunch (OPEFB) and oil palm mesocarp fiber (OPMF) were pretreated with SHS and ground using a hammer mill to sizes of 2, 1, 0.5 and 0.25 mm before pretreatment using laccase to remove lignin. This study showed that reduction of size from raw to 0.25 mm plays important role in lignin degradation by laccase that removed 38.7% and 39.6% of the lignin from OPEFB and OPMF, respectively. The subsequent saccharification process of these pretreated OPEFB and OPMF generates glucose yields of 71.5% and 63.0%, which represent a 4.6 and 4.8-fold increase, respectively, as compared to untreated samples. This study showed that the combination of SHS with laccase pretreatment together with size reduction could enhance the glucose yield.
    Matched MeSH terms: Laccase/metabolism*
  2. Moin SF, Omar MN
    Protein Pept Lett, 2014;21(8):707-13.
    PMID: 23855667
    Laccases belong to the multicopper binding protein family that catalysis the reduction of oxygen molecule to produce water. These enzymes are glycosylated proteins and have been isolated and purified from fungi, bacteria, plant, insects and lichens. The variety of commercial and industrial application of laccases has attracted much attention towards the research addressing different aspects of the protein characterization, production and fit for purpose molecule. Here we briefly discuss the purification, catalytic mechanism in light of available understanding of structure-function relationship and the tailoring side of the protein, which has been the subject of recent research. Purification strategy of laccases is a method of choice and is facilitated by increased production of the enzyme. The structure-function relationship has given insights to unfold the catalytic mechanism. Site directed mutagenesis and other modification at C-terminal end or surrounding environment of copper centres have shown promising results to fit for purpose aspect, with a lot remains to be explored in glycosylation status and its alteration.
    Matched MeSH terms: Laccase/genetics; Laccase/isolation & purification; Laccase/metabolism*; Laccase/chemistry*
  3. Mohidem NA, Mat HB
    Bioresour Technol, 2012 Jun;114:472-7.
    PMID: 22464060 DOI: 10.1016/j.biortech.2012.02.138
    The catalytic activity of free laccase and a novel sol-gel laccase (SOLAC) in ionic liquids and organic solvents was demonstrated by using 2,6-dimethoxyphenol (2,6-DMP) as a substrate. The enhancement of the catalytic activity of the SOLAC was observed and compared to the free laccase in both media. The oxidative biodegradation of o-chlorophenol as a model of phenolic environmental pollutants in organic media shows that the degradation was observed only when using water pre-saturated organic solvents or reverse micelle system. The SOLAC gave higher biodegradation rate in either aqueous or organic solvents, in which the optimum temperature was observed at 40 °C for the reverse micelle system as a reaction medium. All results demonstrated the potential use of the SOLAC for biodegradation of phenolic environmental pollutants in non-conventional media.
    Matched MeSH terms: Laccase/isolation & purification*; Laccase/chemistry*
  4. Vikineswary S, Abdullah N, Renuvathani M, Sekaran M, Pandey A, Jones EB
    Bioresour Technol, 2006 Jan;97(1):171-7.
    PMID: 15967661
    A comparative study on solid substrate fermentation (SSF) of sago 'hampas', oil palm frond parenchyma tissue (OPFPt) and rubberwood sawdust with Pycnoporus sanguineus for laccase production was carried out. Optimal mycelial growth of Pyc. sanguineus was observed on all the substrates studied over a 21 days time-course fermentation. Laccase productivity was highest during degradation of sago 'hampas' and OPFPt and a range from 7.5 to 7.6 U/g substrate on the 11th day of fermentation compared to degradation of rubberwood sawdust with a maximum laccase productivity of 5.7 U/g substrate on day 11 of SSF. Further optimization of laccase production was done by varying the inoculum age, density and nitrogen supplementation. SSF of OPFPt by Pyc. sanguineus gave maximum productivity of laccase of 46.5 U/g substrate on day 6 of fermentation with a 30% (w/w) of 4 weeks old inoculum and 0.92% nitrogen in the form of urea supplemented in the substrate. The extraction of laccase was also optimized in this study. Recovery of laccase was fourfold higher at 30.6 U/g substrate on day 10 of SSF using unadjusted tap water at pH 8.0 as extraction medium at 25+/-2 degrees C compared to laccase recovery of 7.46 U/g substrate using sodium acetate buffer at pH 4.8 at 4 degrees C. Further optimization showed that laccase recovery was increased by 50% with a value of 46.5 U/g substrate on day 10 of SSF when the extraction medium was tap water adjusted to pH 5.0 at 25+/-2 degrees C.
    Matched MeSH terms: Laccase/biosynthesis*; Laccase/isolation & purification
  5. Saat MN, Annuar MS, Alias Z, Chuan LT, Chisti Y
    Bioprocess Biosyst Eng, 2014 May;37(5):765-75.
    PMID: 24005762 DOI: 10.1007/s00449-013-1046-8
    Production of extracellular laccase by the white-rot fungus Pycnoporus sanguineus was examined in batch submerged cultures in shake flasks, baffled shake flasks and a stirred tank bioreactor. The biomass growth in the various culture systems closely followed a logistic growth model. The production of laccase followed a Luedeking-Piret model. A modified Luedeking-Piret model incorporating logistic growth effectively described the consumption of glucose. Biomass productivity, enzyme productivity and substrate consumption were enhanced in baffled shake flasks relative to the cases for the conventional shake flasks. This was associated with improved oxygen transfer in the presence of the baffles. The best results were obtained in the stirred tank bioreactor. At 28 °C, pH 4.5, an agitation speed of 600 rpm and a dissolved oxygen concentration of ~25 % of air saturation, the laccase productivity in the bioreactor exceeded 19 U L(-1 )days(-1), or 1.5-fold better than the best case for the baffled shake flask. The final concentration of the enzyme was about 325 U L(-1).
    Matched MeSH terms: Laccase/biosynthesis*
  6. Rajagopalu D, Show PL, Tan YS, Muniandy S, Sabaratnam V, Ling TC
    J Biosci Bioeng, 2016 Sep;122(3):301-6.
    PMID: 26922478 DOI: 10.1016/j.jbiosc.2016.01.016
    The feasible use of aqueous two-phase systems (ATPSs) to establish a viable protocol for the recovery of laccase from processed Hericium erinaceus (Bull.:Fr.) Pers. fruiting bodies was evaluated. Cold-stored (4.00±1.00°C) H. erinaceus recorded the highest laccase activities of 2.02±0.04 U/mL among all the processed techniques. The evaluation was carried out in twenty-five ATPSs, which composed of polyethylene glycol (PEG) with various molecular weights and potassium phosphate salt solution to purify the protein from H. erinaceus. Optimum recovery condition was observed in the ATPS which contained 17% (w/w) PEG with a molecular weight of 8000 and 12.2% (w/w) potassium phosphate solution, at a volume ratio (VR) of 1.0. The use of ATPS resulted in one-single primary recovery stage process that produced an overall yield of 99% with a purification factor of 8.03±0.46. The molecular mass of laccases purified from the bottom phase was in the range of 55-66 kDa. The purity of the partitioned laccase was confirmed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).
    Matched MeSH terms: Laccase/biosynthesis*; Laccase/isolation & purification*; Laccase/chemistry
  7. Subramaniam R, Siddiquee S, Aguol KA, Hoque MZ, Kumar SV
    Data Brief, 2019 Apr;23:103796.
    PMID: 31372442 DOI: 10.1016/j.dib.2019.103796
    Members of the genus Tinctoporellus, which belong to the wood-degrading basidiomycetes, possess the ability to synthesize an array of industrially potent enzymes and metabolites. Here, we present the draft genome sequence of the species Tinctoporellus epimiltinus strain RS1, which is the first to represent its genus. The genome was sequenced using Illumina's 2 × 150 bp paired-end Nextera protocol. The draft genome assembly was 46.2 Mb in size consisting of 13,791 protein coding genes. Identification of carbohydrate active enzymes and laccases from the data may be useful in order to harness the metabolic potentials of the fungi. The data can be accessed at ENA under the accession number FTLJ00000000.
    Matched MeSH terms: Laccase
  8. Gou Z, Ma NL, Zhang W, Lei Z, Su Y, Sun C, et al.
    Environ Res, 2020 09;188:109829.
    PMID: 32798948 DOI: 10.1016/j.envres.2020.109829
    Intensive studies have been performed on the improvement of bioethanol production by transformation of lignocellulose biomass. In this study, the digestibility of corn stover was dramatically improved by using laccase immobilized on Cu2+ modified recyclable magnetite nanoparticles, Fe3O4-NH2. After digestion, the laccase was efficiently separated from slurry. The degradation rate of lignin reached 40.76%, and the subsequent cellulose conversion rate 38.37% for 72 h at 35 °C with cellulase at 50 U g-1 of corn stover. Compared to those of free and inactivated mode, the immobilized laccase pre-treatment increased subsequent cellulose conversion rates by 23.98% and 23.34%, respectively. Moreover, the reusability of immobilized laccase activity remained 50% after 6 cycles. The storage and thermal stability of the fixed laccase enhanced by 70% and 24.1% compared to those of free laccase at 65 °C, pH 4.5, respectively. At pH 10.5, it exhibited 16.3% more activities than its free mode at 35 °C. Our study provides a new avenue for improving the production of bioethanol with immobilized laccase for delignification using corn stover as the starting material.
    Matched MeSH terms: Laccase
  9. Masran R, Zanirun Z, Bahrin EK, Ibrahim MF, Lai Yee P, Abd-Aziz S
    Appl Microbiol Biotechnol, 2016 Jun;100(12):5231-46.
    PMID: 27115758 DOI: 10.1007/s00253-016-7545-1
    Abundant lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products such as biofuel, animal feed, and paper pulping. However, low yield of sugar obtained from lignocellulosic hydrolysate is usually due to the presence of lignin that acts as a protective barrier for cellulose and thus restricts the accessibility of the enzyme to work on the cellulosic component. This review focuses on the significance of biological pretreatment specifically using ligninolytic enzymes as an alternative method apart from the conventional physical and chemical pretreatment. Different modes of biological pretreatment are discussed in this paper which is based on (i) fungal pretreatment where fungi mycelia colonise and directly attack the substrate by releasing ligninolytic enzymes and (ii) enzymatic pretreatment using ligninolytic enzymes to counter the drawbacks of fungal pretreatment. This review also discusses the important factors of biological pretreatment using ligninolytic enzymes such as nature of the lignocellulosic biomass, pH, temperature, presence of mediator, oxygen, and surfactant during the biodelignification process.
    Matched MeSH terms: Laccase/metabolism
  10. Mohamad SB, Ong AL, Ripen AM
    Bioinformation, 2008 Jun 18;2(9):369-72.
    PMID: 18795108
    Laccase belongs to the family of blue multi-copper oxidases and are capable of oxidizing a wide range of aromatic compounds. Laccases have industrial applications in paper pulping or bleaching and hydrocarbon bioremediation as a biocatalyst. We describe the design of a laccase with broader substrate spectrum in bioremediation. The application of evolutionary trace (ET) analysis of laccase at the ligand binding site for optimal design of the enzyme is described. In this attempt, class specific sites from ET analysis were mapped onto known crystal structure of laccase. The analysis revealed 162PHE as a critical residue in structure function relationship studies.
    Matched MeSH terms: Laccase
  11. Abdul Aziz Ahmad, Raihan Othman, Faridah Yusof, Mohd Firdaus Abdul Wahab
    Sains Malaysiana, 2014;43:459-465.
    A hybrid biofuel cell, a zinc-air cell employing laccase as the oxygen reduction catalyst is investigated. A simple cell design is employed; a membraneless single chamber and a freely suspended laccase in the buffer electrolyte. The cell is characterised based on its open-circuit voltage, power density profile and galvanostatic discharge at 0.5 mA. The activity of laccase as an oxidoreductase is substantiated from the cell discharge profiles. The use of air electrode in the cell design enhanced the energy output by 14%. The zinc-air biofuel cell registered an open-circuit voltage of 1.2 V and is capable to deliver a maximum power density of 1.1 mWcm-2 at 0.4 V. Despite its simple design features, the power output is comparable to that of biocatalytic cell utilising a much more complex system design.
    Matched MeSH terms: Laccase
  12. Sayyed RZ, Bhamare HM, Sapna, Marraiki N, Elgorban AM, Syed A, et al.
    PLoS One, 2020;15(6):e0229968.
    PMID: 32497077 DOI: 10.1371/journal.pone.0229968
    Although laccase has been recognized as a wonder molecule and green enzyme, the use of low yielding fungal strains, poor production, purification, and low enzyme kinetics have hampered its large-scale application. Thus,this study aims to select high yielding fungal strains and optimize the production, purification, and kinetics of laccase of Aspergillus sp. HB_RZ4. The results obtained indicated that Aspergillus sp. HB_RZ4 produced a significantly large amount of laccase under meso-acidophilic shaking conditions in a medium containing glucose and yeast extract. A 25 μM CuSO4 was observed to enhance the enzyme yield. The enzyme was best purified on a Sephadex G-100 column. The purified enzyme resembled laccase of A. flavus. The kinetics of the purified enzyme revealed high substrate specificity and good velocity of reaction,using ABTS as a substrate. The enzyme was observed to be stable over various pH values and temperatures. The peptide structure of the purified enzyme was found to resemble laccase of A. kawachii IFO 4308. The fungus was observed to decolorize various dyes independent of the requirement of a laccase mediator system.Aspergillus sp. HB_RZ4 was observed to be a potent natural producer of laccase, and it decolorized the dyes even in the absence of a laccase mediator system. Thus, it can be used for bioremediation of effluent that contains non-textile dyes.
    Matched MeSH terms: Laccase/antagonists & inhibitors; Laccase/metabolism*; Laccase/chemistry
  13. Mazlan SZ, Lee YH, Hanifah SA
    Sensors (Basel), 2017 Dec 09;17(12).
    PMID: 29232842 DOI: 10.3390/s17122859
    Laccase enzyme, a commonly used enzyme for the construction of biosensors for phenolic compounds was used for the first time to develop a new biosensor for the determination of the azo-dye tartrazine. The electrochemical biosensor was based on the immobilization of laccase on functionalized methacrylate-acrylate microspheres. The biosensor membrane is a composite of the laccase conjugated microspheres and gold nanoparticles (AuNPs) coated on a carbon-paste screen-printed electrode. The reaction involving tartrazine can be catalyzed by laccase enzyme, where the current change was measured by differential pulse voltammetry (DPV) at 1.1 V. The anodic peak current was linear within the tartrazine concentration range of 0.2 to 14 μM (R² = 0.979) and the detection limit was 0.04 μM. Common food ingredients or additives such as glucose, sucrose, ascorbic acid, phenol and sunset yellow did not interfere with the biosensor response. Furthermore, the biosensor response was stable up to 30 days of storage period at 4 °C. Foods and beverage were used as real samples for the biosensor validation. The biosensor response to tartrazine showed no significant difference with a standard HPLC method for tartrazine analysis.
    Matched MeSH terms: Laccase
  14. Mohd Syukri MS, A Rahman R, Mohamad Z, Md Illias R, Nik Mahmood NA, Jaafar NR
    Int J Biol Macromol, 2021 Jan 01;166:876-883.
    PMID: 33144251 DOI: 10.1016/j.ijbiomac.2020.10.244
    Enzyme immobilization has been known to be one of the methods to improve the stability and reusability of enzyme. In this study, a strategy to optimize laccase immobilization on polyethylene terephthalate grafted with maleic anhydride electrospun nanofiber mat (PET-g-MAH ENM) was developed. The development involves the screening and optimization processes of the crucial factors that influence the immobilization yield such as enzyme concentration, pH values, covalent bonding (CV) time, CV temperature, crosslinking (CL) time, CL temperature and glutaraldehyde concentration using two-level factorial design and Box-Behnken design (BBD), respectively. It was found that laccase concentration, pH values and glutaraldehyde concentration play important role in enhancing the immobilization yield of laccase on PET-g-MAH ENM in the screening process. Subsequently, the optimization result showed at 0.28 mg/ml laccase concentration, pH 3 and 0.45% (v/v) glutaraldehyde concentrations gave the highest immobilization yield at 87.64% which was 81.2% increment from the immobilization yield before optimization. Under the optimum condition, the immobilized laccase was able to oxidize 2, 2-azino-bis 3-ethylbenzothiazoline-6- sulfonic acid (ABTS) in a broad range of pH (pH 3-6) and temperature (20- 70 °C). Meanwhile, the kinetic parameters for Km and Vmax were 1.331 mM and 0.041 mM/min, respectively. It was concluded that the optimization of immobilized laccase on PET-g-MAH ENM enhance the performance of this biocatalyst.
    Matched MeSH terms: Laccase/metabolism; Laccase/chemistry*
  15. Karimi S, Abdulkhani A, Karimi A, Ghazali AH, Ahmadun FL
    Environ Technol, 2010 Apr 1;31(4):347-56.
    PMID: 20450108 DOI: 10.1080/09593330903473861
    The efficiency of advanced oxidation processes (AOPs), enzymatic treatment and combined enzymatic/AOP sequences for the colour remediation of soda and chemimechanical pulp and paper mill effluent was investigated. The results indicated that under all circumstances, the AOP using ultraviolet irradiation (photo-Fenton) was more efficient in the degradation of effluent components in comparison with the dark reaction. It was found that both versatile peroxidase (VP) from Bjerkandera adusta and laccase from Trametes versicolor, as pure enzymes, decolorize the deep brown effluent to a clear light-yellow solution. In addition, it was found that in the laccase treatment, the decolorization rates of both effluents were enhanced in the presence of 2, 2'-azinobis (3-ethylbenzthiazoline-6-sulfonate), while in the case of VP, Mn(+2) decreased the efficiency of the decolorization treatment. The concomitant use of enzymes and AOPs imposes a considerable effect on the colour remediation of effluent samples.
    Matched MeSH terms: Laccase/metabolism; Laccase/chemistry*
  16. Mohamad SB, Ong AL, Khairuddin RF, Ripen AM
    In Silico Biol. (Gedrukt), 2010;10(3):145-53.
    PMID: 22430288 DOI: 10.3233/ISB-2010-0423
    Laccases are industrially attractive enzymes and their applications have expanded to the field of bioremediation. The challenge of today's biotechnology in enzymatic studies is to design enzymes that not only have a higher activity but are also more stable and could fit well with the condition requirements. Laccases are known to oxidize non-natural substrates like polycyclic aromatic hydrocarbons (PAHs). We suppose by increasing the hydrophobicity of laccase, it would increase the chance of the enzyme to meet the hydrophobic substrates in a contamination site, therefore increasing the bioremediation efficacy of PAHs from environment. In this attempt, the applications of evolutionary trace (ET), molecular surface accessibility and hydrophobicity analysis on laccase sequences and laccase's crystal structure (1KYA) are described for optimal design of an enzyme with higher hydrophobicity. Our analysis revealed that Q23A, Q45I, N141A, Q237V, N262L, N301V, N331A, Q360L and Q482A could be promising exchanges to be tested in mutagenesis experiments.
    Matched MeSH terms: Laccase/genetics; Laccase/chemistry*
  17. Chan KG, Chong TM, Adrian TG, Kher HL, Hong KW, Grandclément C, et al.
    Genome Announc, 2015;3(6).
    PMID: 26659682 DOI: 10.1128/genomeA.01442-15
    Stenotrophomonas maltophilia ZBG7B was isolated from vineyard soil of Zellenberg, France. Here, we present the draft genome sequence of this bacterial strain, which has facilitated the prediction of function for several genes encoding biotechnologically important enzymes, such as xylosidase, xylanase, laccase, and chitinase.
    Matched MeSH terms: Laccase
  18. Lazim ZM, Hadibarata T
    Braz J Microbiol, 2016 Jul-Sep;47(3):610-6.
    PMID: 27287336 DOI: 10.1016/j.bjm.2016.04.015
    This study aimed to investigate the impact of nonionic surfactants on the efficacy of fluorine degradation by Polyporus sp. S133 in a liquid culture. Fluorene was observed to be degraded in its entirety by Polyporus sp. S133 subsequent to a 23-day incubation period. The fastest cell growth rate was observed in the initial 7 days in the culture that was supplemented with Tween 80. The degradation process was primarily modulated by the activity of two ligninolytic enzymes, laccase and MnP. The highest laccase activity was stimulated by the addition of Tween 80 (2443U/L) followed by mixed surfactant (1766U/L) and Brij 35 (1655U/L). UV-vis spectroscopy, TLC analysis and mass spectrum analysis of samples subsequent to the degradation process in the culture medium confirmed the biotransformation of fluorene. Two metabolites, 9-fluorenol (λmax 270, tR 8.0min and m/z 254) and protocatechuic acid (λmax 260, tR 11.3min and m/z 370), were identified in the treated medium.
    Matched MeSH terms: Laccase
  19. Kristanti RA, Fikri Ahmad Zubir MM, Hadibarata T
    J Environ Manage, 2016 May 1;172:107-11.
    PMID: 26922501 DOI: 10.1016/j.jenvman.2015.11.017
    Cresol Red, a commercial dye that used widely to color nylon, wool, cotton, and polyacrylonitrile-modified nylon in the massive textile manufacture is toxic recalcitrant. Absidia spinosa M15, a novel fungal strain isolated from a tropical rain forest, was found to decolorize Cresol Red 65% within 30 d under agitation condition. UV-Vis spectroscopy, TLC analysis and mass spectra of samples after decolorization process in culture medium confirmed final decolorization of Cresol Red. Two metabolites were identified in the treated medium: benzeneacetic acid (tR 9.6 min and m/z 136) and benzoic acid (tR 5.7 min and m/z 122). Laccase showed the significant activity (133.8 U/L) in biomass obtained at the end of experiment demonstrates role of the enzyme in the decolorization process.
    Matched MeSH terms: Laccase
  20. Morsy SAGZ, Ahmad Tajudin A, Ali MSM, Shariff FM
    Front Microbiol, 2020;11:572309.
    PMID: 33101245 DOI: 10.3389/fmicb.2020.572309
    The world today is in a quest for new means of environmental remediation as the methods currently used are not sufficient to halt the damage. Mostly, a global direction is headed toward a shift from traditional chemical-based methods to a more ecofriendly alternative. In this context, biocatalysis is seen as a cost-effective, energy saving, and clean alternative. It is meant to catalyze degradation of recalcitrant chemicals in an easy, rapid, green, and sustainable manner. One already established application of biocatalysis is the removal of dyes from natural water bodies using enzymes, notably oxidoreductases like laccases, due to their wide range of substrate specificity. In order to boost their catalytic activity, various methods of enhancements have been pursued including immobilization of the enzyme on different support materials. Aside from increased catalysis, immobilized laccases have the advantages of higher stability, better durability against harsh environment conditions, longer half-lives, resistance against protease enzymes, and the ability to be recovered for reuse. This review briefly outlines the current methods used for detoxification and decolorization of dye effluents stressing on the importance of laccases as a revolutionary biocatalytic solution to this environmental problem. This work highlights the significance of laccase immobilization and also points out some of the challenges and opportunities of this technology.
    Matched MeSH terms: Laccase
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