Particleboards from Recycled Pallets

Worldwide production of wooden pallets continually increases, and therefore in future higher number of damaged pallets need to be recycled. One way to conveniently recycle pallets is their use for the production of particleboards (PBs). The 3-layer PBs, bonded with urea-formaldehyde (UF) resin, were prepared in laboratory conditions using particles from fresh spruce logs (FSL) and recycled spruce pallets (RSP) in mutual weight ratios of 100:0, 80:20, 50:50 and 0:100. Particles from RSP did not affect the moisture properties of PBs, i.e., the thickness swelling (TS) and water absorption (WA). The mechanical properties of PBs based on particles from RSP significantly worsened: the modulus of rupture (MOR) in bending from 14.6 MPa up to 10 MPa, the modulus of elasticity (MOE) in bending from 2616 MPa up to 2012 MPa, and the internal bond (IB) from 0.79 MPa up to 0.61 MPa. Particles from RSP had only a slight negative effect on the decay resistance of PBs to the brown-rot fungus Serpula lacrymans, while their presence in surfaces of PBs did not affect the growth activity of moulds at all.

Particleboards from Recycled Thermally Modified Wood

In recent years, the production and consumption of thermally modified wood (TMW) has been increasing. Offcuts and other waste generated during TMWs processing into products, as well as already disposed products based on TMWs can be an input recycled raw material for production of particleboards (PBs). In a laboratory, 16 mm thick 3-layer PBs bonded with urea-formaldehyde (UF) resin were produced at 5.8 MPa, 240 °C and 8 s pressing factor. In PBs, the particles from fresh spruce wood and mixed particles from offcuts of pine, beech, and ash TMWs were combined in weight ratios of 100:0, 80:20, 50:50 and 0:100. Thickness swelling (TS) and water absorption (WA) of PBs decreased with increased portion of TMW particles, i.e., TS after 24 h maximally about 72.3% and WA after 24 h maximally about 64%. However, mechanical properties of PBs worsened proportionally with a higher content of recycled TMW—apparently, the modulus of rupture (MOR) up to 55.5% and internal bond (IB) up to 46.2%, while negative effect of TMW particles on the modulus of elasticity (MOE) was milder. Decay resistance of PBs to the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F.Gray increased if they contained TMW particles, maximally about 45%, while the mould resistance of PBs containing TMW particles improved only in the first days of test. In summary, the recycled TMW particles can improve the decay and water resistance of PBs exposed to higher humidity environment. However, worsening of their mechanical properties could appear, as well.

FTIR Spectroscopy for Identification and Intra-Species Characterization of Serpula lacrymans

The dry rot fungus Serpula lacrymans is the most destructive fungal agent of wood building materials in Europe, Russia, North America, and Japan. The identification of this wood-deteriorating agent and the discrimination of different fungal isolates is very important for the control of buildings in general and for the preservation of cultural heritage in particular. The objective of the study was to develop a Fourier transform infrared (FTIR) method coupled with a partial least square discriminant analysis (PLS-DA) for the sample preparation and identification of S. lacrymans. Five distinct S. lacrymans strains were analysed and compared to two strains of unrelated fungal species. Different methods of mycelial growth, sample preparation, and FTIR spectral data normalisation were compared. FTIR analysis of a harvested mycelium grown on the surface of a polyether sulfone microfiltration membrane deposited on a malt extract agar medium, followed by vector normalization and PLS-DA statistical analysis, resulted in 100% correct attribution at phylum, species, and strain level, regardless of the type of standardization used. This study confirms the applicability of FTIR spectroscopy for the identification of S. lacrymans and the discrimination of different strains belonging to this species.

Use of thermal analysis for the detection of calcium oxalate in selected forms of plastering exposed to the effects of Serpula lacrymans

The article discusses the interaction of metabolic products of a wood-destroying fungus of the dry rot species (Serpula lacrymans (Wulfen) P. Karst.) with a commonly used lime mortar. Mortar samples used in the presented experiment were made mostly in laboratory conditions so as to make it possible to set input conditions and to determine initial properties of the examined samples. Matured lime mortar samples were placed in cultivation boxes with a growth of Serpula lacrymans and exposed to its action for a predetermined period of time. For a comparison, mortar samples taken “in situ” from real structures were also subjected to the experiment. The examined samples were subjected to a thermal analysis and a comparative measurement by infrared spectroscopy (FTIR). The results of the measurement of infected samples were compared with the results obtained in the reference (control) samples. The experiment carried out was focused on assessing the presence of calcium oxalate, which is secreted into the surroundings of the mycelium during the active growing of Serpula lacrymans.

Antimicrobial Efficacy of Vitellaria paradoxa fractions and compounds on some wood Fungi and Bacteria

This study examined antifungal efficacy of Vitellaria paradoxa fractions and compounds in the control of some wood degrading fungi. Stem bark and heartwood parts of Vitellaria paradoxa were collected, dried, pulverised and macerated sequentially in n- hexane, methanol and ethyl acetate solvents. The mixtures were filtered, evaporated and the dried samples were mixed and run over silica gel in column chromatography with a mixture of n -hexane and ethyl acetate solvents to obtain fractions. The fractions collected were evaporated and those with white needles were subjected to Magnetic Resonance (NMR) spectroscopic analysis. Spinasterol was isolated and characterised from the heartwood fraction while the stem bark fractions were fatty. Vitellaria paradoxa fractions were active against Serpula lacrymans, Sclerotium rolfsii, Aspergillus fumigatus, Fomitopsis pinicoca, Phaeolus schweinitzii, Rhizopus sp., Coniophora puteana, Gloeophyllum sepiarium, and Fibroporia vaillantii at zones of inhibition (ZOI) of 18 mm - 24 mm. Although the antibiotics were active (25 – 31 mm), they were found inactive against the Fomitopsis pinicoca fungus which was sensitive to all the V. paradoxa fractions at zones of inhibition of 18 - 24 mm. The minimum inhibitory concentrations (MIC) of the V. paradoxa fractions were active at 50 μg/mL against all test fungi. At minimum fungicidal concentration (MFC) of between 50 - 200 μg/mL, all the test fungi were killed. Based on the ZOI, MIC and MFC, the V. paradoxa stem bark heartwood fractions have been proven to be very efficient in inhibiting the growth of test wood rot fungi; hence the species could be explored as a potential source of bioactive fungicides.

Biodiversity of Fungi, Causing Wood Biodeterioration In Buildings In Poland Against The Background Of Research Conducted In Other European Countries.

The paper presents the results of surveys on the diversity of wood-destroying fungi in buildings and wooden engineering structures outdoors in Poland. The respondents reported a total of 48 species and genus of wood-degrading Basidiomycetes. The greatest species diversity of wood-degrading fungi was found on open-air engineering structures (33 species), the second location in terms of biodiversity was unused residential buildings (30 species), the lowest biodiversity was found in the used residential buildings (21 species).The most common fungi in the buildings were Serpula lacrymans (24.8%), Coniophora puteana (14.1%) and Fibroporia vaillantii (13.8%). The prevalence of S. lacrymans and C. puteana in buildings in Poland is similar to the European average. The occurrence of indoor polypores group (Amyloporia sinuosa, Fibroporia vaillantii, Neoantrodia serialis) in Poland is twice as high as the European average. Donkioporia expansa, which is numerous in buildings in Western Europe, is sporadically recorded in Poland (0.1%).

Microbiota Associated with Different Developmental Stages of the Dry Rot Fungus Serpula lacrymans

The dry rot fungus Serpula lacrymans causes significant structural damage by decaying construction timber, resulting in costly restoration procedures. Dry rot fungi decompose cellulose and hemicellulose and are often accompanied by a succession of bacteria and other fungi. Bacterial–fungal interactions (BFI) have a considerable impact on all the partners, ranging from antagonistic to beneficial relationships. Using a cultivation-based approach, we show that S. lacrymans has many co-existing, mainly Gram-positive, bacteria and demonstrate differences in the communities associated with distinct fungal parts. Bacteria isolated from the fruiting bodies and mycelia were dominated by Firmicutes, while bacteria isolated from rhizomorphs were dominated by Proteobacteria. Actinobacteria and Bacteroidetes were less abundant. Fluorescence in situ hybridization (FISH) analysis revealed that bacteria were not present biofilm-like, but occurred as independent cells scattered across and within tissues, sometimes also attached to fungal spores. In co-culture, some bacterial isolates caused growth inhibition of S. lacrymans, and vice versa, and some induced fungal pigment production. It was found that 25% of the isolates could degrade pectin, 43% xylan, 17% carboxymethylcellulose, and 66% were able to depolymerize starch. Our results provide first insights for a better understanding of the holobiont S. lacrymans and give hints that bacteria influence the behavior of S. lacrymans in culture.

Optimization of Vanillin Extraction from Biodegradation of Oil Palm Empty Fruit Bunches by Serpula lacrymans

This research aims to determine the combination of the ethyl acetate solvent volume and the extraction time that resulted in the optimum response of vanillin content and vanillin yield from the degradation of lignocellulose components from oil palm empty fruit bunches (OPEFB). First, OPEFB degraded using Serpula lacrymans to break down lignocellulosic components. The research design used a centralized composite design with two factors, the volume of ethyl acetate solvent (ml) and the extraction time (minutes). The responses of the experiment are vanillin content and vanillin yields. The optimization analysis results showed that the volume of ethyl acetate solvent and extraction time have a quadratic effect on the vanillin content and vanillin yields. The optimal solution was obtained by treatment with ethyl acetate volume 101.1 ml and extraction time 123.5 minutes. The optimal solution prediction results obtained vanillin content 0.014% and vanillin yield 7.302 μg/g with desirability of 92.8%. Validation based on the optimal solution’s prediction brought response vanillin content 0.013% and vanillin yield 6.950 μg/g. The vanillin content and yield validation results differed respectively by 4.081% and 4.826% lower when compared to predictions on the optimal solution. Keywords: ethyl acetate, vanillin content, vanillin yield

Contrasting demographic histories revealed in two invasive populations of the dry rot fungus Serpula lacrymans

Globalization and international trade have impacted organisms around the world leading to a considerable number of species establishing in new geographic areas. Many organisms have taken advantage of human-made environments, including buildings. One such species is the dry rot fungus Serpula lacrymans, which is the most aggressive wood-decay fungus in indoor environments in temperate regions. By using population genomic analyses of 36 full genome sequenced isolates, we revealed that isolates from Europe and Japan are highly divergent and that these populations split 3,000 - 19,000 generations ago, probably predating human influence. Approximately 250 generations ago, the European population went through a tight bottleneck, likely corresponding to the time it colonized the built environment. Moreover, evidence of admixture between European and Japanese populations was shown in an isolate from New Zealand. Genomic analyses revealed that low differentiation appeared in genes with functions related to of growth and intracellular transport, possibly important to its ability to effectively decay large substrates. These functions may have enabled both populations to independently establish in the human-made environment. Further, selective sweep analyses identified rapid changes in genes possibly related to decay of various substrates in Japan and in genes involved DNA replication and protein modification in Europe. These two fungal populations were preadapted to the built environment, but have more recently and independently adapted to their local environment.

Screening of Antioxidant Activity of 20 Kinds of Mushrooms from Southwest of China

The ethanol and water extracts of 20 kinds of mushrooms from Sichuan Province, Southwest of China, were investigated for their antioxidant activity using DPPH assay. The results showed the ethanol extract of Serpula lacrymans, Daldinia concentrica, and Scleroderma verrucosum had well DPPH free radical scavenging activities 91.33%, 79.76% and 62.82%, respectively. Besides, the water extracts of Serpula lacrymans, Armillaria luteo-virens, and Lentinus edodes also possessed pretty high DPPH free radical scavenging activity were 95.59%, 88.76% and 86.93%, respectively. Based on the above comparison, the EC50 and total phenolic content of the ethanol extracts of Serpula lacrymans, Daldinia concentrica, and Scleroderma verrucosum were also measured. Their EC50 and total phenolic content valued of 17.87mg·mL-1, 11.19mg·mL-1 and 35.01mg·mL-1, as well as 0.0769μg·L-1, 0.0673μg·L-1 and 0.0545μg·L-1, respectively. The results showed there was a correlation between antioxidant activity and total phenolic content. Besides, the reaction time of the DPPH test affected the free radical scavenging, which reflected the difference of the extract component would impact the test method.