965 resultados para Wood-decaying fungi
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Seventy-five fungal strains from different groups of basidiomycetes, newly isolated from rotten wood, were screened for pectinolytic activity. Despite the fact that basidiomycetes are scarcely referred to as pectinase producers, the polygalacturonase (PG) activity was detected in 76 % of the strains; 16 % with activity higher than 40 nkat/g, 40 % between 13.3 and 40 nkat/g, and 44 % with activity lower than 13.3 nkat/g. The highest productions were obtained among the fungi from order Aphyllophorales, family Polyporaceae. The characterization of the enzymes from the highest PG producers (Lentinus sp., Gloeophyllum striatum, Pycnoporus sanguineus, Schizophyllum commune) showed optimum temperature for catalytic activity at 60-70°C and two peaks of pH optimum (3.5-4.5 and 8.5-9.5). The enzymes exhibited high pH stability (3.0-11.0) but after incubation at 40°C for 1 h their activity dropped by 18-73 %.
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Wood decay fungi belonging to the species complex Heterobasidion annosum sensu lato are among the most common and economically important species causing root rot and stem decay in conifers of the northern temperate regions. New infections by these pathogens can be suppressed by tree stump treatments using chemical or biological control agents. In Finland, the corticiaceous fungus Phlebiopsis gigantea has been formulated into a commercial biocontrol agent called Rotstop (Verdera Ltd.). This thesis addresses the ecological impacts of Rotstop biocontrol treatment on the mycoflora of conifer stumps. Locally, fungal communities within Rotstop-treated and untreated stumps were analyzed using a novel method based on DGGE profiling of small subunit ribosomal DNA fragments amplified directly from wood samples. Population analyses for P. gigantea and H. annosum s.l. were conducted to evaluate possible risks associated with local and/or global distribution of the Rotstop strain. Based on molecular community profiling by DGGE, we detected a few individual wood-inhabiting fungal species (OTUs) that seemed to have suffered or benefited from the Rotstop biocontrol treatment. The DGGE analyses also revealed fungal diversity not retrieved by cultivation and some fungal sequence types untypical for decomposing conifer wood. However, statistical analysis of DGGE community profiles obtained from Rotstop-treated and untreated conifer stumps revealed that the Rotstop treatment had not caused a statistically significant reduction in the species diversity of wood-inhabiting fungi within our experimental forest plots. Locally, ISSR genotyping of cultured P. gigantea strains showed that the Rotstop biocontrol strain was capable of surviving up to six years within treated Norway spruce stumps, while in Scots pine stumps it was sooner replaced by successor fungal species. In addition, the spread of resident P. gigantea strains into Rotstop-treated forest stands seemed effective in preventing the formation of genetically monomorphic populations in the short run. On a global scale, we detected a considerable level of genetic differentiation between the interfertile European and North American populations of P. gigantea. These results strongly suggest that local biocontrol strains should be used in order to prevent global spread of P. gigantea and hybrid formation between geographically isolated populations. The population analysis for H. annosum s.l. revealed a collection of Chinese fungal strains that showed a high degree of laboratory fertility with three different allopatric H. annosum s.l. taxa. However, based on the molecular markers, the Chinese strains could be clearly affiliated with the H. parviporum taxonomical cluster, which thus appears to have a continuous distribution range from Europe through southern Siberia to northern China. Keywords: Rotstop, wood decay, DGGE, ISSR fingerprinting, ribosomal DNA
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Wood-degrading fungi are able to degrade a large range of recalcitrant pollutants which resemble the lignin biopolymer. This ability is attributed to the production of lignin-modifying enzymes, which are extracellular and non-specific. Despite the potential of fungi in bioremediation, there is still an understanding gap in terms of the technology. In this thesis, the feasibility of two ex situ fungal bioremediation methods to treat contaminated soil was evaluated. Treatment of polycyclic aromatic hydrocarbons (PAHs)-contaminated marsh soil was studied in a stirred slurry-phase reactor. Due to the salt content in marsh soil, fungi were screened for their halotolerance, and the white-rot fungi Lentinus tigrinus, Irpex lacteus and Bjerkandera adusta were selected for further studies. These fungi degraded 40 - 60% of a PAH mixture (phenanthrene, fluoranthene, pyrene and chrysene) in a slurry-phase reactor (100 ml) during 30 days of incubation. Thereafter, B. adusta was selected to scale-up and optimize the process in a 5 L reactor. Maximum degradation of dibenzothiophene (93%), fluoranthene (82%), pyrene (81%) and chrysene (83%) was achieved with the free mycelium inoculum of the highest initial biomass (2.2 g/l). In autoclaved soil, MnP was the most important enzyme involved in PAH degradation. In non-sterile soil, endogenous soil microbes together with B. adusta also degraded the PAHs extensively, suggesting a synergic action between soil microbes and the fungus. A fungal solid-phase cultivation method to pretreat contaminated sawmill soil with high organic matter content was developed to enhance the effectiveness of the subsequent soil combustion. In a preliminary screening of 146 fungal strains, 28 out of 52 fungi, which extensively colonized non-sterile contaminated soil, were litter-decomposing fungi. The 18 strains further selected were characterized by their production of lignin-modifying and hydrolytic enzymes, of which MnP and endo-1,4-β-glucanase were the main enzymes during cultivation on Scots pine (Pinus sylvestris) bark. Of the six fungi selected for further tests, Gymnopilus luteofolius, Phanerochaete velutina, and Stropharia rugosoannulata were the most active soil organic matter degraders. The results showed that a six-month pretreatment of sawmill soil would result in a 3.5 - 9.5% loss of organic matter, depending on the fungus applied. The pretreatment process was scaled-up for a 0.56 m3 reactor, in which perforated plastic tubes filled with S. rugosoannulata growing on pine bark were introduced into the soil. The fungal pretreatment resulted in a soil mass loss of 30.5 kg, which represents 10% of the original soil mass (308 kg). Despite the fact that Scots pine bark contains several antimicrobial compounds, it was a suitable substrate for fungal growth and promoter of the production of oxidative enzymes, as well as an excellent and cheap natural carrier of fungal mycelium. This thesis successfully developed two novel fungal ex situ bioremediation technologies and introduce new insights for their further full-scale application. Ex situ slurry-phase fungal reactors might be applied in cases when the soil has a high water content or when the contaminant bioavailability is low; for example, in wastewater treatment plants to remove pharmaceutical residues. Fungal solid-phase bioremediation is a promising remediation technology to ex situ or in situ treat contaminated soil.
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木材腐朽菌是生物多样性的重要组成部分,在森林生态系统中起着关键的降解还原作用;同时,木材腐朽菌还是重要的生物资源,与人类的生产与生活密切相关,具有重要的经济价值。因此,木腐菌一直是真菌研究的重点领域之一,然而过去对华东地区木腐菌的研究还非常薄弱,对华东地区木腐菌的种类和资源还缺乏清晰的认识。本文对华东地区不同森林生态类型中的木腐菌进行了广泛的调查采样,通过形态学、分子系统学和单孢融合交配实验,对华东地区的木腐菌多样性与资源进行了系统的研究,同时对具有重要经济意义和潜在应用价值的种类进行了菌种的分离保藏,并初步分析了华东地区木腐菌的区系特点。通过本论文的研究,提高了对华东地区木腐菌资源与多样性的认识,丰富了我国木材腐朽菌的种类,为控制林木病原菌、开发利用有益真菌资源提供了基本信息和科学依据。本论文的主要研究结论如下: 1.华东地区的木腐菌有3目13科92属270种,其中真菌新种6个,分别是:铁杉集毛孔菌Coltricia tsugicola Y.C. Dai & B.K. Cui,香榧嗜蓝孢孔菌Fomitiporia torreyae Y.C. Dai & B.K. Cui,拟囊状体大孔菌Megasporoporia cystidiolophora B.K. Cui & Y.C. Dai,菌索多年卧孔菌Perenniporia rhizomorpha B.K. Cui, Y.C. Dai & Decock,微小硬孔菌Rigidoporus minutus B.K. Cui & Y.C. Dai,浅黄芮氏孔菌Wrightoporia luteola B.K. Cui & Y.C. Dai;中国新记录种9个,分别是:紫多孢孔菌Abundisporus violaceus (Wakef.) Ryvarden,卡玛蜡孔菌Ceriporia camaresiana (Bourdot & Galzin) Bondartsev & Singer,撕裂蜡孔菌Ceriporia lacerata N. Maek., Suhara & R. Kondo,塔斯马尼亚集毛孔菌Coltriciella tasmanica (Cleland & Rodway) D.A. Reid,瑞克纤孔菌Inonotus rickii (Pat.) D.A. Reid,骨质多年卧孔菌Perenniporia minutissima (Yasuda) T. Hatt. & Ryvarden,灰硬孔菌Rigidoporus cinereus Núñez & Ryvarden,凹形栓孔菌Trametes ectypus (Berk. & M.A. Curtis) Gilb. & Ryvarden,变形干酪菌Tyromyces transformatus Núñez & Ryvarden。 2.利用分子系统学方法,确定了一些通过形态学研究难以鉴定或容易混淆的种类的分类地位,并对嗜蓝孢孔菌属、彩孔菌属和多年卧孔菌属进行了系统发育分析,发现木腐菌新种3个:Fomitiporia sp.、Hapalopilus sp. 和Perenniporia sp.。 3.华东地区的异担子菌为岛生异担子菌,并且存在两个生物种:T生物种和Y生物种。T生物种为腐生菌,Y生物种为兼性腐生菌,华东地区不存在多年异担子菌这一严重的森林病原菌。 4.华东地区的木腐菌种类丰富,组成复杂多样。优势科为多孔菌科,其次为锈革孔菌科,这两科的种类构成了华东地区木腐菌类区系的主体;优势属主要有多年卧孔菌属、多孔菌属、针层孔菌属和泊氏孔菌属。 4.华东地区木腐菌科的地理成分分为3类:热带亚热带成分,北温带成分和世界广布成分,以世界广布成分为主。属的地理成分分为5类:世界广布属,北温带分布属,热带–亚热带分布属,东亚–北美分布属,大洋洲–北温带分布属,以世界广布属和北温带分布属为主。种的地理成分分为8类:世界广布种,北温带分布成分,泛热带分布成分,亚–欧共有成分,东亚–北美共有成分,东亚–澳大利亚共有成分,东亚成分,中国特有种,以北温带分布种和世界广布种为主。 5.华东地区木腐菌的各主要区系成分均有分布,以世界广布成分和北温带成分为主,表现出明显的北温带性质,可能起源于北半球,华东地区木腐菌类的区系地理成分与其所处的地理位置、气候特点与植物区系的组成密切相关。此外,华东地区的中国特有种类也较为丰富,说明了华东地区木腐菌类的区系具有一定的独特性,也在一定程度上反映了华东地区生态环境条件的特殊性,而木腐菌的生长与环境条件和寄主树木种类有很大的关系。 6.华东地区的木腐菌资源非常丰富,林木病原菌有36种,其中新发现的病原菌有3种;野生的食用木腐菌有11种,野生的药用木腐菌64种,工业用木腐菌有28种。对其中的一种重要经济真菌——黄白多年卧孔菌进行了分离培养,找出了最佳生长条件:最适生长温度为25℃左右,相对最适pH值为5.5,相对最好的碳源为可溶性淀粉和葡萄糖,相对最好的氮源为酵母汁。
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<正>INTRODUCTION One resupinate, poroid specimen of wood-inhabiting fungi was collected on angiosperm stump from
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<正>1 INTRODUCTION During the investigation on wood-inhabiting fungi in China, two species of the Hymenochaetaceae were found: Fomitiporia texana (Murrill) Nuss and Inonotus ochroporus (Van der Byl) Pegler. Because they were not recorded in the Chinese fungal flora (Dai, 1999; Dai et al., 2001; Dai & Niemel?, 2006; Nú?ez & Ryvarden, 2000; Ryvarden, 2005), and their illustrated descriptions are given according to our collections.
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I<正>NTRODUCTION Changbaishan Nature Reserve is one of the most important forest reserves in China and it is very rich in wood-rotting fungi (Dai, 1997, 2000, 2003; Dai et al., 2003). Nearly 100 species of the Corticiaceae sensu lato
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A series of twelve benzoate esters was metabolised, by species of the Phellinus genus of wood-rotting fungi, to yield the corresponding benzyl alcohol derivatives and eight salicylates. The isolation of a stable oxepine metabolite, from methyl benzoate, allied to evidence of the migration and retention of a carbomethoxy group ( the NIH Shift), during enzyme-catalysed ortho-hydroxylation of alkyl benzoates to form salicylates, is consistent with a mechanism involving an initial arene epoxidation step. This mechanism was confirmed by the isolation of a remarkably stable, optically active, substituted benzene oxide metabolite of methyl 2-( trifluoromethyl) benzoate, which slowly converted into the racemic form. The arene oxide was found to undergo a cycloaddition reaction with 4-phenyl-1,2,4-triazoline-3,5-dione to yield a crystalline cycloadduct whose structure and racemic nature was established by X-ray crystallography. The metabolite was also found to undergo some novel benzene oxide reactions, including epoxidation to give an anti-diepoxide, base-catalysed hydrolysis to form a trans-dihydrodiol and acid-catalysed aromatisation to yield a salicylate derivative via the NIH Shift of a carbomethoxy group.
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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)