Molecular characterization and biodiversity of wood-decaying fungi in French Guiana

Fungi from tropical regions are currently under-represented in the classification system. Indeed, difficult access to tropical forests and irregular occurrence carpophores make it complicated to study fungus species in such environments, unlike in European zones where fungal diversity and taxonomy are better known. The purpose of this work was to enhance classification by integrating new data that would bring out the importance of certain traits of these fungi, and provide a clearer understanding of how the biodiversity of fungi from the forest ecosystems of French Guiana is organized, particularly those causing wood decay through white rot, brown rot or soft rot. In our study, we chose to work in the zone comprising the internal transcribed spacers ITS1 and ITS2, which are relatively variable, and the 5.8 S small ribosomal subunit, which is not highly variable. The primers ITS 1(5'-TCCGTAGGTGAACCTGCGC-3') and ITS 4 (5'-TCCTCCGCTTATTGATATGC-3'), specific to fungi, were chosen for this taxonomic analysis of the studied species. This study was carried out on 101 fungus fruiting bodies at the Paracou forest site in French Guiana. Of those 101 fungi, 72 were identified by BLASTn. Four species were Ascomycetes of the genus Muscodor and Xylaria. The other 68 species, all in the class of the Basidiomycetes, were divided into the following orders: 31 Agaricales, 1 Atheliales, 2 Boletales, 1 Gomphales, 12 Polyporales, 1 Trechisporales and 1 Tremellales. There was also an indeterminate taxon very similar to the lichens. Within the order Polyporales, the main genera were found, such as Antrodiella, Coriolopsis, Fomitopsis, Ganoderma, Lentinus, Pycnoporus, Steccherinum, Trametes, Fomitoporia. All these fungi have the particularity of causing wood decay. (Résumé d'auteur

Assessing the ability of white-rot fungi to tolerate polychlorinated biphenyls using predictive mycology

The aim of the present study was to assess the ability of different white-rot fungi to tolerate polychlorinated biphenyls (PCBs) using predictive mycology, by relating fungal growth inhibition to ligninolityc enzyme secretion. Fungal strains were grown in the presence of PCBs in solid media and their radial growth values were modelled through the Dantigny-logistic like function in order to estimate the time required by the fungal colonies to attain half their maximum diameter. The principal component analysis (PCA) revealed an inverse correlation between strain tolerance to PCBs and the laccase secretion over time, being laccase production closely associated with fungal growth capacity. Finally, a PCA was run to regroup and split between resistant and sensitive fungi. Simultaneously, a function associated with a model predicting the tolerance to PCBs was developed. Some of the assayed isolates showed a promising capacity to be applied in PCB bioremediation. Abbreviations: Polychlorinated biphenyls (PCBs), white-rot fungi (WRF).Fil: Sadañoski, Marcela Alejandra. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Velázquez, Juan Ernesto. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Fonseca, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Zapata, Pedro Dario. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Levin, Laura Noemí. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Villalba, Laura. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentin

Effect of wood flour as carbon source on cellulases and xylanases production by white-rot-fungi native from Misiones

There is a need to explore lignocellulosic materials to select an adequate substrate for lignocellulolytic enzyme production. Utilization of some residues provides an opportunity to produce high yields of lignocellulolytic enzymes in a simple medium. The aim of the present work was to study the effect of wood flour as a carbon source on the cellulolytic and xylanolytic secretion of white-rot fungi native from Misiones. Fungi were incubated with 5 g Pinus sp. wood flour/L and 5 g Eucalyptus sp. wood flour/L as carbon sources in a reciprocal shaker at 80 rpm and 29ºC for 15 days. Total cellulase, endo-1,4-β-glucanase, β-glucosidase, cellobiohydrolase and endo-1,4-β-xylanase activities were determined in culture supernatants. Tested fungi showed high endo-1,4-β-xylanase activity between 6 and 12 days. Total cellulase showed the highest activity between 12-15 culture days. The test did not show differences among Pycnoporus sanguineus LBM 014, P. sanguineus BAFC 2126, Irpex lacteus BAFC 1171, Irpex sp. LBM 032, Irpex sp. LBM 034 and Lenzites elegans BAFC 2127, showing the highest activity for this group regard the others strains. I. lacteus BAFC 1171 was the strain with major endo-1,4-β-glucanase activity at day 9 (847 U/L). In the case of β-glucosidase and cellobiohydrolase, P. sanguineus BAFC 2126 was the strain with the highest activity between 12-15 culture days (18 U/L), and between 9-15 culture days (39 U/L), respectively. Wood flour proved to be a suitable carbon source to produce hydrolytic enzymes. I. lacteus BAFC 1171 and P. sanguineus BAFC 2126 have potential for cellulase production whereas P. sanguineus LBM 008 is a good endo-1,4-β-xylanase producer.Fil: Rodríguez, María Daniela. Universidad Nacional de Misiones. Facultad de Cs.exactas Quimicas y Naturales. Departamento de Bioquimica Clinica. Laboratorio de Biotecnologia Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barchuk, Mónica Lucrecia. Universidad Nacional de Misiones. Facultad de Cs.exactas Quimicas y Naturales. Departamento de Bioquimica Clinica. Laboratorio de Biotecnologia Molecular; Argentina. Comision Nacional de Investigacion Cientifica y Tecnologica; ChileFil: Fonseca, Maria Isabel. Universidad Nacional de Misiones. Facultad de Cs.exactas Quimicas y Naturales. Departamento de Bioquimica Clinica. Laboratorio de Biotecnologia Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zapata, Pedro Dario. Universidad Nacional de Misiones. Facultad de Cs.exactas Quimicas y Naturales. Departamento de Bioquimica Clinica. Laboratorio de Biotecnologia Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villalba, Laura. Universidad Nacional de Misiones. Facultad de Cs.exactas Quimicas y Naturales. Departamento de Bioquimica Clinica. Laboratorio de Biotecnologia Molecular; Argentin

Tannin-boron wood preservatives

Tannin-boron wood preservatives are alternative products to replace water-borne formulations based on copper. Interesting results in protection against fungus (pycnoporus sanguineus) were achieved with formulations based of 20% tannin solutions containing boric acid (Thevenon et al. 2009). In this paper two upgrades are introduced: extension of preservation properties to softwood species (scots pine) and analysis of the side-properties achieved after treatment. A detailed study on tannin penetration in beech and scots pine is presented. Microscope analysis demonstrates that impregnation in scots pine have two preferential directions: Longitudinal through tracheids and radial through parenchyma rays, while in beech the liquid penetrates the wood cell mainly longitudinally through large and easy accessible vessels. Commercialization of exterior-door wood preservative will be also dependent on the side-properties derived from the treatment. For this reason, properties such as mechanical resistance and behavior against fire have been investigated. The mechanical tests have shown a strong increasing of compression resistance and surface hardness for beech and scots pine samples. The tests against fire have been monitored considering ignition, flame and ember time. A broad positive effect on fire-repellence is shown when wood is treated with tannin-boron formulations. (Résumé d'auteur

Production Of Laccase By A Locally Isolated Fungus For Biodegradation Of Selected Agrowastes

The present study was conducted to screen the significant laccase (ligninolytic enzyme) producers from locally isolated white-rot fungi using agitated and non-agitated culture conditions. The highest laccase producer, identified as Pycnoporus sp. (strain S16) was selected for the optimisation of laccase production with particular attention to the effect of physiological factors on laccase production using submerged culture technique. Laccase was characterised to assist in formulating the best condition for the bioconversion of agro-wastes. Significant laccase production was obtained under carbon-depleted condition and dependent on culture morphology. The culture with high laccase activity was observed with the presence of small mycelial pellets with 1−2 mm diameter. The pellet formation and optimum laccase production influenced by various physiological factors are investigated. The best culture condition obtained consisted of 5 g/L of glucose, 12 mM of nitrogen, inoculum concentration of 8 × 106 spores/mL, initial pH 5, incubation temperature of 37°C and agitation speed of 100 rpm. Under the above culture conditions, the time of fermentation was shortened from 16 days to 7 days with maximum laccase activity of 225 U/L. The characterisation study of concentrated laccase revealed the importance of an acidic condition for the highest laccase activity. The biodegradation study showed that some locally available agro-waste materials are suitable for soluble sugar production and that rice bran gave the best results with 1.90 g/L of soluble sugar produce

Taxonomic Study of French Guiana Fungi to Identify and Isolate Pure Cultured Fungi for Oleoresin Production in Aquilaria: Use of Sequences from the Small Ribosomal DNA (R) Subunit (SSU) and the Two Primer Pairs SR6/SR10R and SR7/SR1R

Fungi from tropical regions are currently under-represented in the classification system. Indeed, difficult access to tropical forests makes it complicated to study fungus species in such environments, unlike in European zones where fungal diversity and taxonomy are much better known. The purposes of this work were: a) to enhance classification by integrating new data that would bring out the importance of certain traits of these fungi, and provide a clearer understanding of how the biodiversity of fungi from the forest ecosystems of French Guiana is organized, particularly those causing wood decay through white rot, brown rot or soft rot; b) to establish a collection of fungal isolates from fruiting bodies collected in French Guiana.This taxonomic study based on sequences of the small subunit (SSU) of ribosomal (r) DNA using the two primer pairs, SR6/SR10R and SR7/SR1R, was carried out on 39 fungus fruiting bodies from Cacao and Régina, in French Guiana. Our protocol enabled extraction, with good repeatability, of fungal DNA from a few mg of pure mycelium. With most of the strains studied we were able to obtain PCR products ranging in size from 376 to 625 base pairs.This study enabled to specify the taxa involved wood decay: 39 species were identified by BlastN. Most of them, in the class of the Basidiomycetes, were the main genera were found, such as Antrodia, Coriolopsis, Fomitopsis, Ganoderma,Poria, Lentinus, Pycnoporus, Auricularia, Gloeophyllum, Trametes, Fomitopsis, Rigidoporus.In addition to the above objectives, the production of pure mycelium from fruiting bodies identified in this study will be used to produce inoculum to test the ability of these fungal species in stimulating oleoresin production in Aquilaria trees from plantation established in French Guyana

Evaluation of the use of Pycnoporus sanguineus fungus for phenolics and genotoxicity decay of a pharmaceutical effluent treatment

If not properly and efficiently treated, wastes produced by the chemical industry can contaminate the environment. Using fungi able to degrade organic compounds (e.g. phenol) seems to be a prominent method to treat pharmaceutical wastewaters, in particular, the white-rot fungus. The aim of this work was to treat pharmaceutical effluent by the Pycnoporus sanguineus fungus. Three effluent samples were collected in a pharmaceutical industry. The production of enzymes such as laccase and manganese peroxidase was determined. Their production increased throughout the treatment with the P. sanguineus fungus, reaching maximum concentration of 4.48 U.mL-1 (Effluent 1), 8.16 U.mL-1 (Effluent 2), 2.8 U.mL-1 (Effluent 3) and 0.03 Abs.min-1 (Effluent 2), respectively, during 96 hours of biological treatment. Genotoxic effects of the raw and treated effluents were also investigated using the in vivo mouse bone marrow micronucleus (MN) assay. Results showed the biological treatment reduced the frequency of MN, in a dose-dependent manner, when compared to untreated sample. The decreasing of around 20% and 45% of phenolics concentration was observed throughout the treatment, confirming that laccase production can be related to the degradation of toxic compounds present in the effluent. Therefore, the biodegradation by the P. sanguineus fungus seems a promising method for the mineralization of recalcitrant compounds present in pharmaceutical effluent

Production of two novel laccase isoforms by a thermotolerant strain of Pycnoporus sanguineus isolated from an oil-polluted tropical habitat

A thermotolerant and halotolerant strain of Pycnoporus sanguineus was isolated from an oil-polluted site in a tropical area located in Veracruz, Mexico. This strain was able to grow at 47ºC and in culture medium containing 500 mM NaCl. The strain was also tolerant to the presence of 30,000 ppm of crude Maya oil. A 68-kDa protein purified submerged cultures exhibited laccase activity towards 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), guaiacol, syringaldazine and o-dianisidine, for which it presented the highest affinity (Km = 43 µM). Two-dimensional gel electrophoresis analysis showed that, unusual for laccases, the enzyme has two active isoforms, with isoelectric points of 7.00 and 7.08. The purified enzyme showed high thermostability, retaining 40% of its original activity after 3 h at 60ºC. This property seems to correlate with a long “shelf-life”, given that at 40ºC enzyme activity was only gradually lost over a 5-day period incubation. Both, the fungus and its laccase aer likely to have high potential for biotechnological applications

Wood natural resistance of seven forest species to white rot caused by Pycnoporus sanguineus

This research evaluated the natural resistance of: Platanus x acerifolia, Luehea divaricate, Carya illinoinensis, Peltophorum dubium, Araucaria angustifolia, Eucalyptus grandis and Hovenia dulcis, to accelerated decay of the white-rot fungus Pycnoporus sanguineus. The Specific Density at 12% was determinated. The accelerated decay test was conducted with glass bottles (capacity of 500 mL) filled with 100 g of moist soil, autoclaved, and kept at 25 °C. The initial establishment of fungal colonies on plates was supported by samples of Pinus elliottii sapwood. In this study, three samples of dimensions 9.0 x 25.0 x 25.0 mm were used for each species evaluated and, after 16 weeks of incubation, the percentage loss of mass was calculated. The degree of natural resistance was performed according to the percentages of mass loss. The results obtained from weight loss were compared by Tukey test at 5%. The natural resistance of woods was not influenced by specific gravity. The wood of Carya illinoinensis, Eucalyptus grandis, Platanus x acerifolia, Luehea divaricata and Peltophorum dubium were classified as very resistant, Houvenia dulcis as resistant and Araucaria angustifolia as moderate resistant

Ketahanan Lima Jenis Kayu Asal Lengkong Sukabumi Terhadap Beberapa Jamur Pelapuk

Lima jenis kayu kurang dikenal yaitu ki lubang (Calophyllum grandiflorum JJS), ki kuya (Ficus vasculosa Wall. Ex Miq.), ki bulu (Gironniera subaequalis Planch), ki hantap (Sterculia oblongata R.Br.) dan ki bancet (Turpinia sphaerocarpa Hassk.), diuji ketahanannya terhadap jamur menggunakan metode Kolle-flash. Contoh uji setiap kayu diambil dari bagian tepi dan dalam dolok dari dua tegakan pohon berbeda. Hasil penelitian menunjukkan bahwa kayu ki lubang, ki bancet dan ki bulu termasuk kelompok kayu agak- tahan (kelas III), sedangkan kayu ki hantap dan ki kuya termasuk kelompok kayu tidak-tahan (kelas IV). Kehilangan berat contoh yang diambil dari tegakan pohon I lebih rendah dibandingkan dengan pohon II, walaupun keduanya termasuk kelompok kayu tidak-tahan (kelas IV). Sedangkan kehilangan berat kayu bagian dalam umumnya lebih rendah dibandingkan dengan kayu bagian tepi dolok, yang termasuk dalam kelompok kayu tidak-tahan (kelas IV). Kehilangan berat tertinggi terjadi pada ke dua bagian tepi dan tengah dolok pohon contoh I dan II kayu ki hantap dan ki kuya yang diuji dengan Pycnoporus sanguineus HHBI-324 yaitu > 40%