Published by De Gruyter

Volume 71 Issue 10

Issue of Holzforschung

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Contents
Journal Overview

Publicly Available September 29, 2017

Original Articles

Publicly Available May 25, 2017

Determination of uronic acids and neutral carbohydrates in pulp and biomass by hydrolysis, reductive amination and HPAEC-UV

Dominic Lorenz, Ron Janzon, Bodo Saake

Page range: 767-775

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Abstract

The exact quantification of all carbohydrate constituents in wood and pulp is a challenge because of the various glycosidic linkages of the polysaccharides with different stabilities. The individual detector responses for the compounds in the hydrolysates additionally complicate the quantification as pure standards for 4- O -methyl-α-D-glucuronic acid (meGlcA) and related oligosaccharides are not commercially available for calibration. In the present paper, a new analytical procedure is presented, based on the reductive amination of the carbohydrates obtained via acidic and enzymatic hydrolysis of the polysaccharides before quantification by means of high performance anion exchange chromatography (HPAEC) and UV-detection. This approach was suitable for the analysis of neutral carbohydrates and uronic acids obtained via enzymatic hydrolysis from bleached pulps. In the case of unbleached pulps, the enzymatic hydrolysis was not complete and unhydrolyzed nano-scaled and micro-scaled particles remained in the hydrolysates as detected by dynamic light scattering (DLS) measurements. The new HPAEC-UV methodology was also applied to kraft pulps and a sulfite pulp; six different kinds of wood as well as wheat straw and bagasse. All relevant monosaccharides and the dimer of meGlcA and xylose could be detected in the hydrolysates. Accordingly, significantly higher yields of meGlcA were found compared to literature data.

June 2, 2017

Influence of epoxidation conditions on the rheological properties of gel-like dispersions of epoxidized kraft lignin in castor oil

Esperanza Cortés-Triviño, Concepción Valencia, José M. Franco

Page range: 777-784

Abstract

The modification of castor oil (CO) with lignin was the focus of this research to create a lubricating medium with improved gel-like properties. Namely, an alkali lignin (L) was epoxidized with epichlorohydrin (EP) and the resulting L EP s were dispersed in CO. The parameters of L EP synthesis were varied and the epoxidation index (EPI) of the L EP s was determined. The L EP s were also submitted to thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. Rheological responses of the L EP /CO dispersions were investigated through small-amplitude oscillatory shear (SAOS) tests. Linear viscoelasticity functions are quantitatively affected by the epoxidation parameters, such as temperature, reaction time and L/EP and L/NaOH ratios. In general, lignins with higher EPI show higher values of the SAOS functions, which are indicative of better gel-strength due to a higher cross-linking density between the L EP s and CO. A power-law equation describes well the evolution of the complex modulus, G*, with frequency of gel-like dispersions, where the power-law parameters were found to increase almost linearly with the EPI. The thermo-rheological characterization provides a softening temperature beyond 50°C.

June 2, 2017

Isolation and structural elucidation of heartwood extractives of Juglans sigillata

Liqiu Hu, Kai Wang, Guangbi Li, Rongyan Zhang, Yanyan Luo, Chuan-Ling Si, Junhui Wang

Page range: 785-791

Abstract

Juglans sigillata is a deciduous tree in Juglandaceae that grows native in southwestern China. The extracts of J. sigillata are used extensively in folk medicines to treat or prevent various diseases. However, the individual components of J. sigillata heartwood are not known. In this work, the following substances have been isolated from the heartwood: a new trans -feruloyl isoflavone glycoside, namely 3′-methoxy-5′-hydroxy-isoflavone-7-O-(4′′- trans -feruloyl)-β-D-glucoyranoside ( I ), a known isoflavone glucoside, i.e. 3′-methoxy-5′-hydroxy-isoflavone-7-O-β-D-glucoyranoside ( II ), and two known flavonol glycosides: kaempferol-3-O- α -L-rhamnopyranoside ( III ) and myricetin-3-O- α -L-rhamnopyranoside ( IV ). Chemical structures of extractives I ~ IV were elucidated mainly based on their spectroscopic [nuclear magnetic resonance (NMR), mass spectroscopy (MS), ultraviolet (UV) and infrared (IR)] and chemical analysis, as well as by comparison with literature data. Compound I was never isolated from any other plant, and it is described the first time in this work. Compound II was not found before in extracts of the genus Juglans , and the compounds III and IV are the first time described as components of J. sigillata extractives.

June 16, 2017

Preliminary analysis of amplicon high-throughput sequencing as a method for the assessment of fungal diversity in discolored wood

Xingxia Ma, Mingliang Jiang, Junliang Liu, Hao Deng, Shuangyong Wang

Page range: 793-800

Abstract

The diversity of stain fungi is important if wood is inhabited with various fungi, and the discoloration mechanism will be better understood. MiSeq amplicon high-throughput sequencing (Illumina ® ) is able to detect species richness (the number of species within a community) and species evenness (the sizes of species populations within a community). This study detected fungal diversity in discolored Mongolian pine for the first time by the MiSeq approach, focusing on the nuclear ribosomal internal transcribed spacer-1 (ITS1). The results show that the discolored wood was inhabited by a combination of microorganisms, more than 90% of which belong to Ascomycota fungi at the phylum level. The MiSeq method revealed not only all the inhabited fungal species but also their quantitative relation to each other. The dominant fungal species in sample A are Helotiales (34.1%) and Hypocreales (20.7%). The dominant fungal species in sample B is Nectriaceae (67.9%), while Hypocrea (34.7%) and Sporothrix (27.6%) are the dominant fungal species in sample C. It was confirmed via core microbiome analysis that the following fungi were common stain fungi in the three discolored samples: Fusarium spp., Aspergillus spp., Sporothrix spp., Penicillium spp., Trichoderma spp., Alternaria spp. and Cladophialophora spp.

June 16, 2017

Acoustic impact testing and waveform analysis for damage detection in glued laminated timber

Feng Xu, Xiping Wang, Marko Teder, Yunfei Liu

Page range: 801-811

Abstract

Delamination and decay are common structural defects in old glued laminated timber (glulam) buildings, which, if left undetected, could cause severe structural damage. This paper presents a new damage detection method for glulam inspection based on moment analysis and wavelet transform (WT) of impact acoustic signals. Acoustic signals were collected from a glulam arch section removed from service through impact testing at various locations. The presence and positions of internal defects were preliminarily determined by applying time centroid and frequency centroid of the first moment. Acoustic signals were then decomposed by wavelet packet transform (WPT) and the energy of the sub-bands was calculated as characteristics of the response signals. The sub-bands of 0–375 Hz and 375–750 Hz were identified as the most discriminative features that are associated with decay and delamination and therefore are indicative of the presence of delamination or decay defects. A defect diagnosis algorithm was tested for its ability to identify internal decay and delamination in glulam. The results show that depth of delamination in a glulam member can be determined with reasonable accuracy.

May 24, 2017

Sorption isotherms of waterlogged subfossil Scots pine wood impregnated with a lactitol and trehalose mixture

Jerzy Majka, Leszek Babiński, Wiesław Olek

Page range: 813-819

Abstract

A waterlogged subfossil Scots pine wood, 12 500-years-old, was impregnated with a mixture of lactitol and trehalose as well as with polyethylene glycol (PEG) mixtures, respectively, and the sorption properties of the impregnated samples were determined. All the impregnated wood samples were freeze-dried. The sorption isotherms were parameterized with the Guggenheim-Anderson-deBoer (GAB) and Generalized D’Arcy and Watt (GDW) models. Better hygroscopic properties were found for wood impregnated with the lactitol and trehalose mixture as compared to the PEG treatments. An anomalous increase of equilibrium moisture content (EMC) was found for PEG treated wood at a high relative humidity (RH) as compared to untreated wood at RH<80%. The lactitol and trehalose mixture significantly reduced this effect due to the decreased sorption of polymolecular water. Another positive effect of the alternative method is the ca. 50% reduction of the sorption hysteresis as compared to untreated wood. Moreover, the hysteresis was also much lower in the case of high RH as compared to PEG treated wood. The alternative treatment is also effective in terms of the dimensional stabilization of decayed wood.

Publicly Available June 16, 2017

Topochemical analyses of furfuryl alcohol-modified radiata pine (Pinus radiata) by UMSP, light microscopy and SEM

Gabriele Ehmcke, Annica Pilgård, Gerald Koch, Klaus Richter

Page range: 821-831

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Abstract

Furfurylation is one of the wood modification techniques via catalytic polymerization of the monomeric furfuryl alcohol (FA) in the impregnated cell wall. Little is known about the topochemistry of this process. Brown rot degradation begins with lignin modification and therefore, the reactions between FA and lignin was one focus of this research. Furfurylated radiata pine ( Pinus radiata ) with three different weight percent gains (WPGs of 57%, 60% and 70%) after FA uptake was observed by cellular ultraviolet microspectrophotometry (UMSP) to analyze chemical alterations of the individual cell wall layers. Moreover, light microscopy (LM) and scanning electron microscopy (SEM) analyses were performed. The ultraviolet (UV) absorbance of the modified samples increased significantly compared to the untreated controls, indicating a strong polymerization of the aromatic compounds. Highest UV absorbances were found in areas with the highest lignin concentration. The UMSP images of individual cell wall layers support the hypothesis concerning condensation reactions between lignin and FA.

June 2, 2017

Zone line formation on artificial media and in hardwoods by basidiomycetes for production of spalted wood

Stephanie Gantz, Susanne Steudler, Hubertus Delenk, André Wagenführ, Thomas Bley

Page range: 833-841

Abstract

One of the visual modification of wood is the formation of dark zone lines (ZLs) via interaction of fungi. The result is called spalted wood, which has hitherto been produced mainly in small batches. The main goal of the present study is to further develop techniques for rapid formation of ZLs in hardwoods. Various white rot and brown rot fungi were tested to this purpose. Initially, interactions of 148 combinations of 17 basidiomycetes in malt extract agar were evaluated and their antagonistic interactions were characterised in order to identify fungal pairs capable of rapidly forming high-quality ZLs. Six types of interactions were observed, among others; antibiosis and inhibition in contact, which differ in terms of variables including mycelial overgrowth and zone line formation. Furthermore, 23 pairs of ZL forming fungi on malt extract agar were identified. Then the interactions of five selected pairs of fungi grown on the hardwood species Acer pseudoplatanus L., Betula pendula Roth. and Populus nigra L. were examined to assess their utility for controlled mycological wood modification, also in terms of a possible substrate dependency of their interactions. The results indicate that Lentinus tigrinus fungus is one of the best and quickest producer of ZLs in mycological wood modification.

About this journal

Objective
Holzforschung (HF) is an international scholarly journal that publishes cutting-edge research on the biology, chemistry, physics and technology of wood and wood components. High quality papers about biotechnology and tree genetics are also welcome. Rated year after year as one of the top scientific journals in the category of Pulp and Paper (ISI Journal Citation Index), Holzforschung represents innovative, high quality basic and applied research. The German title reflects the journal's origins in a long scientific tradition, but all articles are published in English to stimulate and promote cooperation between experts all over the world. Ahead-of-print publishing ensures fastest possible knowledge transfer.

Topics

Biology, chemistry, physics and technology of wood and wood components
Biotechnology and tree genetics

Article formats
Original articles, Reviews, Short notes

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Volume 71 Issue 10

Issue of Holzforschung

Frontmatter

Determination of uronic acids and neutral carbohydrates in pulp and biomass by hydrolysis, reductive amination and HPAEC-UV

Abstract

Influence of epoxidation conditions on the rheological properties of gel-like dispersions of epoxidized kraft lignin in castor oil

Abstract

Isolation and structural elucidation of heartwood extractives of Juglans sigillata

Abstract

Preliminary analysis of amplicon high-throughput sequencing as a method for the assessment of fungal diversity in discolored wood

Abstract

Acoustic impact testing and waveform analysis for damage detection in glued laminated timber

Abstract

Sorption isotherms of waterlogged subfossil Scots pine wood impregnated with a lactitol and trehalose mixture

Abstract

Topochemical analyses of furfuryl alcohol-modified radiata pine (Pinus radiata) by UMSP, light microscopy and SEM

Abstract

Zone line formation on artificial media and in hardwoods by basidiomycetes for production of spalted wood

Abstract