Sophie Vanhulle

Catholic University of Louvain, Walloon Region, Belgium

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Publications (18)24.54 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Due to their low substrate specificity, fungal laccases have a great potential in industrial applications, including the bioremediation of colored wastewaters from textile industry. However, the presence of halides in these effluents (up to 1M NaCl) which inhibit laccases is a drawback for bioremediation processes. In order to develop an efficient enzymatic remediation process for textile dye effluent, the possibility to reduce this halide inhibition is conditioned by a better understanding of the phenomenon. The present study gives a detailed account of the kinetics of chloride inhibition of both ABTS (a model substrate) and ABu62 (an anthraquinonic acid dye) oxidations catalyzed by Trametes versicolor laccase (LacIIIb). Chloride inhibition can be described by a mixed model for ABTS and a non-competitive model for ABu62 and both inhibitions are linear suggesting a single inhibitory site for chloride. Experiments were also conducted in presence of both substrates. An apparent activation of laccase was observed in the presence of ABu62 leading to an enhancement of the oxidation rate of ABTS. The extent of activation increased in the presence of chloride anions. Finally, for the first time to our knowledge, we evidenced that inhibition of ABTS oxidation by chloride can be reduced in the presence of ABu62.
    Enzyme and microbial technology. 12/2011; 49(6-7):517-25.
  • Journal of Biotechnology - J BIOTECHNOL. 01/2010; 150:276-276.
  • Journal of Biotechnology - J BIOTECHNOL. 01/2010; 150:377-377.
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    ABSTRACT: The enzymatic synthesis of an azoanthraquinone by Perenniporia ochroleuca MUCL 41114 laccase was undertaken. The major product was purified and its structure identified by NMR, MS, IR analyses. In order to scale up the production of this azoanthraquinone named Laccase Acid Red 1, a commercial laccase from Trametes versicolor immobilised on perlite as an inexpensive carrier was used. Laccase Acid Red 1 showed lower toxicity than other commercial red dyes, was not mutagenic and displayed low ecotoxicity. In addition, its dyeing properties were assayed on polyamide and the industrial potential of the dye was demonstrated. To our knowledge, this is the first example of sulfonic azoanthraquinone production through enzymatic coupling of aromatic amine monomers. These results show promise for new, safer and environmental friendly routes to azo dye biosynthesis.
    Dyes and Pigments. 01/2010;
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    ABSTRACT: a b s t r a c t Laccase, isolated from Cerrena unicolor, is able to transform 3-amino-4-hydroxybenzensulfonic acid into a water soluble phenoxazine dye with an extinction coefficient (ε) of 8600 M −1 cm −1 . The dye has been characterized using a variety of different analytic and spectroscopic techniques like UV–vis spectroscopy, HPLC (High Performance Liquid Chromatography), ESI/MS (Electrospray Ionization Mass Spectrometry) and the following NMR experiments: 1 H, 13 C, TOCSY (Total Correlation Spectroscopy), HSQC (Heteronu-clear Single Quantum Coherence), HMBC (Heteronuclear Multiple Bond Coherence) showing the structure of 2-amino-3-oxo-3H-phenoxazine-8-sulfonic acid. The advantages of the presented biocatalytic system, in alignment with chemical system to obtain Curie 22, are eco-sustainability and one step performance.
    Journal of Molecular Catalysis B Enzymatic 01/2010; 63:116-120. · 2.82 Impact Factor
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    ABSTRACT: Inter-cell communication aided by released chemical signals when cell density reaches a critical concentration has been investigated for over 30 years as quorum sensing. Originally discovered in Gram-negative bacteria, quorum-sensing systems have also been studied extensively in Gram-positive bacteria and dimorphic fungi. Microbial communities communicating via quorum sensing employ various chemical signals to supervise their surrounding environment, alter genetic expression and gain advantage over their competitors. These signals vary from acylhomoserine lactones to small modified or unmodified peptides to complex gamma-butyrolactone molecules. The scope of this review is to give an insight into some of the quorum-sensing systems now known and to explore their role in microbial physiology and development of pathogenesis. Particular attention will be dedicated to the signalling molecules involved in quorum-sensing-mediated processes and the potential shown by some of their natural and synthetic analogues in the treatment of infections triggered by quorum sensing.
    Biotechnology and Applied Biochemistry 11/2009; 54(2):65-84. · 1.35 Impact Factor
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    ABSTRACT: Laccases (benzenediol:oxygen oxidoreductases, EC 1.10.3.2) are blue multicopper oxidases that catalyze the oxidation of an array of aromatic substrates concomitantly with the reduction of molecular oxygen to water. In fungi, laccases carry out a variety of physiological roles during their life cycle. These enzymes are being increasingly evaluated for a variety of biotechnological applications due to their broad substrate range. In this review, the most recent studies on laccase structural features and catalytic mechanisms along with analyses of their expression are reported and examined with the aim of contributing to the discussion on their structure-function relationships. Attention has also been paid to the properties of enzymes endowed with unique characteristics and to fungal laccase multigene families and their organization.
    Cellular and Molecular Life Sciences CMLS 10/2009; 67(3):369-85. · 5.62 Impact Factor
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    ABSTRACT: BACKGROUND: The ability of the fungi Pleurotus ostreatus and Phanerochaete chrysosporium to decolourize and detoxify 11 (mono-, dis-, poly- azo, and anthraquinonic type) dyes, widely used across the textile and leather industries, was tested.RESULTS: Different substrate specificities were revealed between P. ostreatus and P. chrysosporium in decolourization experiments. The latter fungus provided almost complete decolourization of the tested azo dyes up to 600 ppm and dis-azo dyes up to 1000 ppm, and 80% decolourization of the tris-azo dye DBU1L38 at 1000 ppm, after 6 days. P. ostreatus provided almost total decolourization of the anthraquinone type dye ABU62 (1000 ppm) after just 1 day. P. ostreatus also showed the ability to decolourize the tested dis-azo and tris-azo dyes, giving the best performances against the dis-azo DBU1U1 (600 ppm) dye, which was 100% decolourized after 6 days. Laccases proved to be the main enzymatic activities acting in P. ostreatus decolourization.CONCLUSION: The potential of the fungi P. ostreatus and P. chrysosporium as efficient bio-systems for decolourization and detoxification of several toxic industrial dyes was demonstrated. The role of laccases in the decolourization of dis-azo dyes by P. ostreatus was demonstrated for the first time. Copyright © 2008 Society of Chemical Industry
    Journal of Chemical Technology & Biotechnology 02/2009; 84(3):414 - 419. · 2.50 Impact Factor
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    ABSTRACT: Only few data exist on the metabolites produced during the biotransformation of anthraquinonic dyes by white rot fungi (WRF). During the biotransformation of an anthraquinonic dye Acid Blue 62 (ABu62) using Pycnoporus sanguineus MUCL 41582 strain, it was previously demonstrated that the blue colour of the medium turned to red before complete dye decolourisation. To better understand the phenomenon, this study carried out ABu62 biotransformation with five different WRF strains (Coriolopsis polyzona MUCL 38443, Perenniporia ochroleuca MUCL 41114, Perenniporia tephropora MUCL 41562, P. sanguineus MUCL 38531 and Trametes versicolor MUCL 38412) and compared with P. sanguineus MUCL 41582 previously described. A multi-methodological approach (using capillary electrophoresis, mass spectrometry, HPLC, UV, NMR and IR spectroscopies) was developed to characterise the metabolites involved and monitor their apparition. Seven metabolites were commonly found with all strains, suggesting a common metabolic pathway for ABu62 biotransformation. During the first days, dimer and oligomers of the initial ABu62 molecule were observed: the main one absorbed in the 500nm region, explaining the red colour appearance of the medium. This main metabolite was made up of two molecules of ABu62 linked by an azo bond, minus a cyclohexyl moiety. After a longer incubation time, breakdown products were observed. Based on these products characterizations, a bioconversion pathway was proposed.
    Chemosphere 02/2008; 70(6):1097-107. · 3.14 Impact Factor
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    ABSTRACT: In view of compliance with increasingly stringent environmental legislation imposed by regional, national, and supranational (e.g., European Union) authorities, innovative environmental technologies for the treatment of dye-contaminated effluents are necessary in the color industry. In this study, effluents of an industrial dye producer were subjected to distinct treatment trains following an initial qualitative characterization. The effectiveness of ozonation and a treatment using white rot fungi (WRF) and their enzymes were compared with respect to parameters such as residual color, toxicity on human cells, and genotoxicity. A combined ozonation/WRF process was also investigated. The effluent exhibited significant toxicity that was reduced by only 10% through ozonation, whereas the fungal treatment achieved a 35% reduction. A combined treatment (ozone/WRF) caused an abatement of the toxicity by more than 70%. In addition, the initial genotoxicity of the effluent was still present after the ozone treatment, while it was completely removed through the fungal treatment.
    Environmental Science and Technology 02/2008; 42(2):584-9. · 5.26 Impact Factor
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    ABSTRACT: White Rot Fungi (WRF) are able to decolorize dyes through the use of relatively non-specific extracellular oxidative enzymes. Nevertheless, decolorization does not imply that the resulting metabolites are less toxic than the parent molecules. The aim of the present study was to evaluate the detoxification potential of six strains (Pycnoporus sanguineus, Perenniporia tephropora, Perenniporia ochroleuca, Trametes versicolor, Coriolopsis polyzona and Clitocybula dusenii) during decolorization of dyes. Cytotoxicity assays were carried out on human Caco-2 cells, which are considered as a validated model for the human intestinal epithelium, and the results were compared with those obtained on classical bacterial cells. Genotoxic character was monitored through VITOTOX® assays. The biotransformation of an anthraquinonic dye (CI Acid Blue 62, ABu62) was studied. All tested strains were able to decolorize extensively ABu62 (between 83 and 95% decolorization), however, different cytotoxicity reduction levels were reached (from 44 to 99%). Best results were achieved with P. sanguineus strain and the major role of laccases in cytotoxicity reduction was underlined. Based on this result, efficiency of P. sanguineus strain was further studied. Four azo and two anthraquinonic dyes were treated by this strain. After WRF treatment, two dyes were found to be more toxic in one or both toxicity assays. Genotoxic character appeared during biotransformation of one dye, however, it was removed by the addition of hepatic rat extract to mimic liver transformation. These results stress the importance of monitoring several parameters, such as colour, toxicity and mutagenicity, to ensure the efficiency of the bioremediation process.
    World Journal of Microbiology and Biotechnology 01/2008; 24(3):337-344. · 1.26 Impact Factor
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    ABSTRACT: A natural phenoxazinone derivative, cinnabarinic acid (2, CA, R = CO2H), could be obtained in vitro with the aid of purified laccase from the fungi Pycnoporus cinnabarinus by oxidative dimerization of 3-hydroxyanthranilic acid (1, 3-HAA, R = CO2H). With the aim of gaining access to a new class of water-soluble chromophores and potential bioactive molecules, the regioselective sulfonation of 2-hydroxyanihne was investigated. Straightforward insertion of a sulfonate group into a carbon-metal bond provided an efficient and selective process for the synthesis of 3-hydroxyorthanilic acid (3, 3-HOA, R = SO3H). This sulfonated compound was then subjected to laccase oxidation in order to mimic the cinnabarinic acid synthesis. A practical HPLC method to study the oxidized products was developed, and the major product of biotransformation - namely 2-aniino-3-oxo-3H-phenoxazin-1,9-disulfonic acid (4, LAO, R = SO3H) - was isolated and identified as the sulfonate analogue of cinnabarinic acid. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).
    European Journal of Organic Chemistry. 01/2008;
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    ABSTRACT: A microtitre plate-based method was developed for a fast screening of numerous fungal strains for their ability to decolourise textile dyes. In 3 days, this method allowed to estimate significant fungal decolourisation capability by measuring the absorbance decrease on up to ten dyes. More than 325 white-rot fungi (WRF) strains belonging to 76 fungal genera were compared with regards to their capability to decolourise five azo and two anthraquinone dyes as well as the dyes mixture. The most recalcitrant dyes belonged to the azo group. Several new species unstudied in the bioremediation field were found to be able to efficiently decolourise all the dyes tested.
    Enzyme and Microbial Technology 01/2008; 42(2):97-106. · 2.59 Impact Factor
  • World Journal of Microbiology and Biotechnology. 01/2007; doi: 10.1007/s11274-007-9475-7.
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    ABSTRACT: In the frame of the development of a bioprocess using the competences of White Rot Fungi to decolourise and detoxify dye contaminated effluents, laccases were produced by the strain Pycnoporus sanguineus MUCL 41582 in a malt extract medium. Two isoenzymes were detected among which LAC-1 was concentrated. A survey of the composition of industrial effluents showed that wastewaters from textile industry usually contain high concentrations of Na2SO4 or NaCl. Regarding the activity profile of the biocatalyst against pH, salts, temperature and target substrates, LAC-1 appears to be a good candidate for application in acid dye bath treatments. Studying the model anthraquinonic dye ABu62 decolourisation, we proved that this dye was a good substrate for LAC-1. Furthermore, unusual kinetic behaviour was observed suggesting that LAC-1 was activated in presence of ABu62. On the contrary, a classical Michaelis-Menten behaviour was observed for the oxidation of ABTS and LAC-1 showed a high affinity for this substrate as compared to data available for other laccases. To our knowledge, this is the first report showing this atypical behaviour of a laccase in the presence of dyes.
    Enzyme and Microbial Technology. 01/2007;
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    ABSTRACT: The effects of mannan oligosaccharides preparation (MO), as elicitor, and ferulic acid inducer for enhancement in laccases production in liquid cultures of three strains of basidiomycetes, Pycnoporus sanguineus, Coriolopsis polyzona and Pleurotus ostreatus was studied using a full factorial 32 experimental design. MO, either individually or combined with ferulic acid, enhanced laccases levels in the three different strains of the white-rot fungi. The enhancement of laccases production was species specific with the highest increase in liquid cultures of P. sanguineus (88-fold) followed by P. ostreatus (3-fold) and C. polyzona (2-fold). Separate additions of 75 mg/l of MO to the cultures of P. sanguineus and P. ostreatus caused the increase while a combined addition of 150 mg/l of MO and 1 mM ferulic acid resulted in the optimal production of laccases in the cultures of C. polyzona.
    Enzyme and Microbial Technology. 01/2007;
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    ABSTRACT: Pycnoporus strains were used as model to understand the role of laccases in the in vivo decolourisation of three anthraquinonic dyes. The decolourisation capability of Pycnoporus sanguineus MUCL 41582 (PS7), which produces laccases as the main oxidative enzyme, was assayed and compared with the decolourisation capability of a control strain, Pycnoporus cinnabarinus MUCL 39533 (PC330) described as laccase-deficient strain. In absence of dye, laccase activity was observed during the trophophase and the idiophase with PS7, while no laccase activity was observed with PC330. Acid Blue 62 (ABu62), Acid Blue 281 (ABu281) and Reactive Blue 19 (RBu19) caused an increase in laccase activity and surprisingly laccase activity was detected with PC330. In vitro, oxidation of all three anthraquinones by a laccase preparation was obtained to a lesser extent than the whole cell process; suggesting that other factor(s) could be required for a complete decolourisation. As the time space of laccase production in the tested fungi was not perfectly coincidental with the decolourisation process, the activity of cellobiose dehydrogenase (CDH) was monitored. Present early in the broth during the growth of the fungi, CDH displayed in vitro a synergism with laccases in the decolourisation of ABu62, and an antagonism with laccases in the decolourisation of ABu281 and RBu19.
    Enzyme and Microbial Technology. 01/2007;
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