Volatile organic compound (VOC) emissions from Scots pine and Norway spruce wood were evaluated in green and kiln-dried conditions using Micro-Chamber (µ-CTE™) air-sampling, thermal desorption, and GC–MS. A total of 411 specimens were tested to evaluate sampling distributions, effect of kiln drying, and the chemical composition of VOC emissions in detail. There was no significant difference in emissions between spruce heartwood and sapwood. The median total VOC emission rate from spruce was 93% lower than that from pine heartwood in green condition, whereas in the kiln-dried state, the emission was 98% lower. Compared with pine sapwood, the median emissions from spruce were 85% and 94% lower in green and kiln-dried conditions, respectively. Pine sapwood emitted 55% and 79% less VOC than heartwood in green and kiln-dried conditions. Except for pine sapwood, all groups exhibited positively skewed distributions. The skewness was particularly noticeable in the green pine heartwood sample, where the top 10% of VOC scores increased the mean VOC emission by 67%. Kiln drying had a substantial impact on VOC emissions. The median emission reduction due to drying amounted to 93%, 79%, and 80% for spruce, pine heartwood, and pine sapwood, respectively. A strong positive linear relationship was observed between the emissions in the green condition and the emission reduction caused by drying. Except for 3-carene, the emission profiles were similar among the tested groups.

Sustainable utilization of waste streams from bioresources is a challenging opportunity for the future. This study investigated the potential of a seasonally varying process effluent stream from medium-density fiberboard production for a year-round cultivation process of Pseudomonas putida PX1 for reduction of volatile organic compounds (VOC) in pinewood strands. For four years, seasonal variations with abundant fermentable carbon sources during colder periods and few carbon sources during warmer periods were observed. Nitrogen sources present in process effluent required for optimal biomass production are insufficient when abundant carbon sources are available and should be supplemented. VOC reduction in pinewood strands with P. putida after mixed substrate fermentation showed very promising results for industrial applications. Total VOC emissions were reduced by more than 55% in only 3 h. Most aldehydes and terpenes were effectively reduced by 67%–100%, except for Δ-3-carene and α-terpinolene, which were reduced by 20%–22%.

Pitch oil production from Scots pine (Pinus sylvestris L.) resinous wood is an intangible cultural heritage in the Central European region including the Czech Republic, Northern Austria and South Eastern Germany, and is related to traditions in Finland and Southern France. The heating of wood in small kilns also fueled by wood produces liquid for collection. Our detailed investigations of three pitch oil kilns in Upper Austria led to the discovery of relationships to the production of pine and birch tar in Fennoscandia and black pine tar production in Western Anatolia. Our measurements of temperatures at the bases of the kilns revealed a slow temperature rise. We predicted maximum temperatures based on infrared spectra, and measured overall temperatures in the range of 250 degrees C-650 degrees C. With gas chromatographic analyses of pitch oil we detected a dominant proportion of resin components and only a minor proportion of compounds attributable to pyrolytic transformation of solid wood mass. In most pitch oil samples the extractives comprised 90 %. Most samples were similar and only the first samples at the starting outflow were systematically dominated by pyrolysis products. Tar runoff from a traditional circular charcoal kiln for charcoal production - used as a reference - had a strongly different composition, with a high proportion of pyrolysis compounds.

AbstractA scalable, fixed-bed adsorption system for the removal and selective recovery of polyphenols (lignans and stilbenes) from medium-density fiberboard (MDF) process waters was developed. Before adsorption, fibers and non-colloidal substances were removed from process water by centrifugation, while colloidal fatty and resin acids were removed by filtration through a 30-kDa cut-off membrane. Polyphenols were then isothermally adsorbed on a medium-pressure liquid chromatography (MPLC) column packed with Divergan® RS, a regenerable macroporous, cross-linked pyrrolidone-based [polyvinylpolypyrrolidone (PVPP)] resin. Loading at acidic pH and subsequent gradient elution of polyphenols with methanol were monitored at 280 nm, and elution conditions for selective polyphenol recovery were optimized based on gas chromatography/mass spectrometry (GC/MS) analyses of the obtained fractions. Lignans were eluted in successive fractions containing the individual lignans in different proportions, followed by pinosylvin in a separate fraction. The capacity of the PVPP for hydroxymatairesinol (HMR) as a model lignan was determined to be 37.4 mg g−1 at 1% breakthrough. Highly polar substances such as sugars and sugar alcohols, however, were not retained on the column and remained in the flow-through. The results revealed the benefits of PVPP for the recovery of potentially valuable polyphenols from MDF process waters while reducing carbon load and toxicity for subsequent biological treatment.

This study focused on the utilization of medium-density fiberboard (MDF) effluent as a culture medium for Pseudomonas putida for reduction of volatile organic compounds (VOC) in pinewood. P. putida was successfully cultivated in the residual carbohydrate-rich effluent after purification by centrifugation, 30 kDa membrane filtration and recovery of bioactive compounds via adsorption onto polyvinyl polypyrrolidone (PVPP). Besides monosaccharides, P. putida can metabolize glycerol, acetate, succinate, and citrate present in MDF effluent without addition of other nutrients. P. putida cultures applied to pinewood reduced emissions of α-pinene and Δ3-carene by 80% and 50%, respectively, and β-pinene and α-terpinolene were reduced by 100% within 4 days. The valorization of industrial process effluents for VOC reduction could assist the wood processing industry in sustainably lowering VOC emissions of their products.

Lignocellulosic plant biomass is the world's most abundant carbon source and has consequently attracted attention as a renewable resource for production of biofuels and commodity chemicals that could replace fossil resources. Due to its recalcitrant nature, it must be pretreated by chemical, physical or biological means prior to hydrolysis, introducing additional costs. In this paper, we tested the hypothesis that fungi which thrive on lignocellulosic material (straw, bark or soil) would be efficient in degrading untreated lignocellulose. Wheat straw was used as a model. We developed a fast and simple screening method for cellulase producers and tested one hundred Trichoderma strains isolated from wheat straw. The most potent strain-UB483FTG2/ TUCIM 4455, was isolated from substrate used for mushroom cultivation and was identified as T. guizhouense. After optimization of growth medium, high cellulase activity was already achieved after 72 h of fermentation on raw wheat straw, while the model cellulase overproducing strain T. reesei QM 9414 took 170 h and reached only 45% of the cellulase activity secreted by T. guizhouense. Maximum production levels were 1.1 U/mL (measured with CMC as cellulase substrate) and 0.7 U/mL (β-glucosidase assay). The T. guizhouense cellulase cocktail hydrolyzed raw wheat straw within 35 h. Our study shows that screening for fungi that successfully compete for special substrates in nature will lead to the isolation of strains with qualitatively and quantitatively superior enzymes needed for their digestion which could be used for industrial purposes.

Nitrogen (N) exerts strong effects on litter decomposition through altering microbial abundance and community composition. However, the effect of N addition on plant–soil interactions such as home-field advantage (HFA: enhanced decomposition at a home environment compared to a guest environment) in relation to litter decomposition remains unclear. To fill this knowledge gap, we conducted a reciprocal litter transplant plus N addition experiment in Mytilaria laosensis and Cunninghamia lanceolata plantations for two years in subtropical China where anthropogenic N input is amongst the highest in the world. We found positive HFA effects (in which the calculation incorporates litter of both species) with litter mass loss 11.2% faster at home than in the guest environment in the N addition (50 kg N ha−1 yr−1) treatment, but no significant HFA effects were found in the control treatment. The magnitude of the HFA effect on carbon (C) release increased with N addition, while that on N release decreased. The HFA effects on phosphorus, potassium, calcium, sodium, and magnesium release were positive overall, but varied through time and the magnitude of the effects were different among elements. The greater HFA effects in the N addition treatment were associated with greater differences in microbial biomass and community composition between home and guest environments than in the control treatment. Our results indicate that anthropogenic N enrichment could lead to enhanced HFA effects, through modification of microbial communities, and thereby affect C sequestration and N cycling in subtropical forests.

This study investigated the reduction of terpene emissions from Oriented Strand Boards (OSB) by pre-treatment of pine wood strands with a mixed culture of Pseudomonas bacteria and the ascomycete Penicillium nigricans. While Pseudomonas alone efficiently degraded α-pinene and β-pinene, the combined action of both microorganisms was required for the simultaneous degradation of all three major terpenes in pine wood including Δ3-carene. Δ3-carene emissions from laboratory OSB were 60% and 35% lower than that of controls after 4 and 2 days of microbial pre-treatment, respectively. At the same time, α-pinene emissions were reduced by 85% and 45%, while β-pinene emissions were completely absent. Δ3-carene degradation was no longer observed at a short-term treatment of only 1 day. However, laccase in the presence of a redox mediator may overcome this limitation by oxidation of Δ3-carene to non-volatile carenones. The results revealed the potential of biotechnology for reducing potentially harmful terpene emissions from wood products.

In this study six common user scenarios putatively influencing indoor air quality were performed in a model room constructed according to the specifications of the European Reference Room given in the new horizontal prestandard prEN 16516 to gain further information about the influence of user activities on indoor air quality. These scenarios included the use of cleaning agent, an electric air freshener, an ethanol fireplace and cosmetics as well as cigarette smoking and peeling of oranges. Four common indoor air pollutants were monitored: volatile organic compounds (VOC), particulate matter (PM), carbonyl compounds and CO2. The development of all pollutants was determined during and after the test performance. For each measured pollutant, well-defined maximum values could be assigned to one or more of the individual user scenarios. The highest VOC concentration was measured during orange-peeling reaching a maximum value of 3547 μg m−3. Carbonyl compounds and PM were strongly elevated while cigarette smoking. Here, a maximum formaldehyde concentration of 76 μg m−3 and PM concentration of 378 μg m−3 were measured. CO2 was only slightly affected by most of the tests except the use of the ethanol fireplace where a maximum concentration of 1612 ppm was reached. Generally, the user scenarios resulted in a distinct increase of several indoor pollutants that usually decreased rapidly after the removal of the source.

The degradation of cellulose in wheat straw during aqueous ethanol organosolv (AEO) treatment under different pulping conditions was investigated. For this purpose, molecular weight distribution (MWD) and degree of polymerization (DP) of the resulting cellulose pulp were determined using high performance size exclusion chromatography (HPSEC). The most pronounced effects regarding cellulose degradation were observed when varying the ethanol-to-water ratio. UV detection in HPSEC indicated that residual lignin in wheat straw fibers from organosolv treatments does not occur in free form, but rather is associated with hemicellulose (xylan) and to a minor extent also with cellulose. The established method was suitable for relative comparisons of MWD of variously treated wheat straw fibers and hence for obtaining information regarding the severity of organosolv treatment in terms of cellulose degradation. In summary, AEO treatment at a low ethanol-to-water ratio favours the efficient delignification and removal of xylan from wheat straw, but this occurs at the price of a greatly reduced fiber quality in terms of DP.

Abstract A bacterial mixture of Pseudomonas putida and Pseudomonas fluorescens has recently shown the potential to completely reduce monoterpenes within pine wood particles on a laboratory scale. This bacterial combination was then applied onto pine wood strands to obtain emission-reduced oriented strand boards (OSB) produced on a technical scale. Laboratory tests with bacterial inoculated strands were carried out to optimise parameters such as aeration and incubation time. Residual terpene emissions were measured by solid-phase microextraction/ gas chromatography-mass spectrometry (SPME/GC-MS) analysis. Daily aeration, specific pre-cultivation, and increased inoculum size eventually resulted in a reduction of the major softwood terpenes α-pinene, β-pinene, and Δ3-carene by 60, 70, and 40%, respectively, after only 2 days of incubation. Based on these results, OSB were manufactured from strands after bacterial pre-treatment for 2 or 4 days. As expected, terpene emissions from OSB decreased with increasing incubation time. However, even after only 2 days of incubation, α-pinene and β-pinene emissions were appreciably reduced by 40 and 70%, respectively. The method developed here thus appears to be feasible for industrial application although a further reduction of pre-treatment time would be advantageous. The inoculation step will also have to be adapted for technical implementation into the OSB production process.

Alkaline extracted and untreated wheat straw were ball-milled with liquid nitrogen cooling rendering them completely soluble in the solvent system dimethylsulfoxide—aqueous tetrabutylammonium hydroxide for subsequent fractionation into two lignin-carbohydrate complex fractions termed glucan-lignin and xylan-lignin according to their preferred association with glucan or arabinoxylan, respectively. This is the first description using this fractionation protocol for wheat straw. Eventually, acidolysis lignins were prepared from both lignin-carbohydrate complexes and structurally characterized using wet chemistry and NMR spectroscopy methods. Using the novel procedure we could reveal differences regarding wheat straw lignin association with polysaccharides, p-hydroxycinnamic acids and tricin as well as in their monomer composition. In glucan-lignin the lignin moiety was found to be linked mainly to glucan but also to branched arabinoxylan. Xylan-lignin, however, was rich in structures creating cross-links between lignin and linear arabinoxylan via ether-ester bridges by bi-functional ferulic acid. Inter-molecular ether-ester-linkages by ferulic acid connecting the lignin moieties of the two LCC fractions glucan-lignin and xylan-lignin were proposed. Alkaline extraction of the straw resulted in a strikingly lower recovery of xylan-lignin in the subsequent fractionation which was attributed to cleavage of ester linkages between ferulic acid and arabinoxylan. Structural characteristics indicated glucan-lignin and xylan-lignin deriving from different morphological origins of the cell wall.

Abstract Aldehydes and terpenes are the most frequently emitted volatile organic compounds (VOCs) in the wood-processing industry. These emissions are classified as injurious to health and hazardous to the environment. To address this problem, the growth conditions have been identified under which bacteria extensively degrade both aldehydes and particularly terpenes in pine wood particles as a raw material for the production of particle boards. In this study, the focus was on pentanal and hexanal (aldehydes) as well as α- and β-pinene (terpenes). Bacterial strains were selected for their ability to metabolize α-pinene as single carbon source in liquid culture medium. α-Pinene degradation was then determined by gas chromatography (GC) analysis. Strains belonging to the genus Pseudomonas showed the best results (98% degradation after 72 h). Comparably good results were also achieved with the thermophilic strain Bacillus pallidus (90% degradation) at 55°C. Furthermore, an adapted mixed culture of Pseudomonas species was inoculated onto wood particles and incubated at room temperature for 3 days. Solid-phase microextraction (SPME) measurements of emitted volatiles and subsequent gas chromatography-mass spectrometry (GC-MS) analysis indicated a complete removal (100%) of aldehydes and, even more importantly, α- and β-pinene. Pre-treatment of unsterile pine wood particles with Pseudomonas species may have potential for industrial application.

Interior fitting was performed stepwise in two model rooms built from Oriented Strand Board (OSB) and Cross Laminated Timber (X-lam), respectively. The walls and ceiling of the OSB model room were covered with gypsum plasterboard, parquet flooring was laid and the room was finally equipped with office furniture and textiles. In the X-lam model room an acoustical ceiling and parquet were installed. The walls were painted with wood stain and the room was adapted as bed room and equipped with textiles. After each fitting step volatile organic compounds (VOC) samples were taken and analyzed. In the OSB model room, the total volatile organic compound (TVOC) concentration decreased throughout the whole fitting process from 119 µg m−3 prior to the interior fitting to a final value of 26 µg m−3. In the X-lam model room, a change of the VOC profile and/or concentration could be observed after each fitting step. The highest TVOC concentration (225 µg m−3) was reached seven days after the installation of the acoustical ceiling. Terpenes, aldehydes and acetic acid were the most abundant substances identified. It was shown for both model rooms that some of the applied building materials acted as diffusion barriers or as emission sinks.

Dioxane lignin was isolated from ball-milled wheat straw by neutral dioxane-water extraction and subsequently molar-mass-fractionated by flash chromatography in dimethylformamide. The eluted lignin containing material was pooled into six distinct molar mass fractions that were in turn structurally characterized in detail by wet chemistry and NMR spectroscopy methods. Fractions of higher molar mass were found to be enriched in p-hydroxyphenyl units and contained more p-hydroxycinnamic acid units. They were found mainly associated with linear arabinoxylan, while in low-molar-mass fractions additional glucan contributions were found. Fractions of lower molar mass consisted of relatively more guaiacyl units and showed exclusive association with tricin units. One distinct lignin fraction with lower lignin content supposedly contained high ratios of arabinoxylan chains esterified by ferulic acid and cross-linked via ferulic acid dimerization, structures which were considered to represent lignin nucleation sites. High abundance of dibenzodioxocin type structures in this fraction indicated that they could be involved in cross-linking hemicelluloses networks with lignin moieties.