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Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to investigate the fundamental interactions between wood extractives and surfaces used in papermaking. Experiments were carried out at 25 °C and 50 °C on a microcrystalline cellulose-coated surface (a surrogate for paper) and a chromium surface (a surrogate for metal surfaces in paper machines and printing presses) using colloids prepared from wood extractives and model compounds of the components in wood extractives. Differences in adsorption behaviour were observed between the two surfaces as a function of temperature. On both surfaces, triolein and abietic acid were found to deposit to a greater extent than wood extractives, mixed model compounds and oleic acid. At 25 °C the colloids were found to have two phases of adsorption onto cellulose surfaces, an initial rapid adsorption phase followed by a slower phase, compared to a single adsorption phase onto chromium. At 50 °C, only a single adsorption phase was observed on both surfaces. Abietic acid and oleic acid were found to desorb readily from both the cellulose and chromium substrates, while triolein remained strongly adsorbed. However significantly more abietic acid remained on the chromium surface at 25 °C compared to any other tested material, providing a possible explanation for the observed high rates of resin acid deposition onto metal surfaces during papermaking and printing. At 25 °C and 50 °C, less wood extractives and mixed model compound colloids were deposited onto cellulose than onto chromium, which may also explain the high rates of deposition on the metal surface. Stabilisation of the colloids due to interactions between different components within the colloid results in lower deposition of wood extractives and mixed model compound colloids compared to individual component colloids. [ABSTRACT FROM AUTHOR]

The study of decay resistance in wood is of interest for wood end-users but also for the global carbon balance since wood biodegradation is a key driver of forest ecosystem functioning through its impacts on carbon and nutrient cycling. We studied the density and wood extractive contents in order to understand decay resistance against soil microflora after 90 days exposure of sapwood and heartwood from three Neotropical wood species known for their decay resistance: Bocoa prouacensis, Vouacapoua americana, Inga alba. Decay resistance was correlated with density more than wood extractive content. The results highlighted different decay resistance strategies. In B. prouacensis, both sapwood and heartwood were highly resistant due to the high density and high content of antifungal wood extractives. In V. americana heartwood, decay resistance was due to the high synergistic-acting wood extractive content. Conversely, with the least dense wood species I. alba, we found that decay resistance was due to the antifungal wood extractives synthesized early in the sapwood. In conclusion, we showed that the three wood species with the same level of heartwood decay resistance performance had different decay resistance strategies according to the anatomic and defensive wood traits. [ABSTRACT FROM AUTHOR]

Abstract: Integrated kraft pulp and paper mill wastewater was characterized before (influent) and after (effluent) the activated sludge process by microfiltration (8, 3, 0.45 and 0.22μm) and ultrafiltration (100, 50, 30 and 3kDa) into different size fractions. Wood extractives, lignin, suspended solids and certain trace elements were determined in each fraction. Forty four percent of the resin and fatty acids in the influent (12.8mg/L) occurred in particles (>0.45μm), 20% as colloids (0.45μm–3kDa) and 36% in the <3kDa fraction. The corresponding values for sterols (1.5mg/L) were 5, 46 and 49%. In the effluent, resin and fatty acids (1.45mg/L) and sterols (0.26mg/L) were mainly present in the <3kDa fraction, as well as a small proportion in particles. β-sitosterol was present in particles in the effluent (88±50μg/L). Lignin in the influent was mainly in the colloidal and <3kDa fractions, whereas in the effluent it was mainly in the <3kDa fraction. Thus the decrease of lignin in the biological treatment was concentrated on the colloidal fraction. In the influent, Mn, Zn and Si were mainly present in the <3kDa fraction, whereas a significant proportion of Fe and Al were found also in the particle and colloidal fractions. In the effluent, Fe and Al were mainly present in the colloidal fraction; in contrast, Mn, Zn and Si were mainly in the <3kDa fraction. The results indicated that the release of certain compounds and elements into the environment could be significantly decreased or even prevented simply by employing microfiltration as a final treatment step or by enhancing particle removal in the secondary clarifier. [Copyright &y& Elsevier]

Abstract: An extracellular sterol esterase from Ophiostoma piceae efficiently hydrolyzes sterol esters, triglycerides and p-nitrophenol esters. cDNA was screened with a probe obtained by PCR using as primers oligonucleotides corresponding to the N-terminal and internal mature enzyme sequences and complete sequence was obtained by 3′ rapid amplification of cDNA end (RACE) and inverse PCR. The O. piceae esterase gene had a length of 1.8 kbp and lacked introns. A search for proteins with related amino acid sequences revealed around 40% identity with lipases from Candida rugosa and Geotrichum candidum. Modelling the O. piceae enzyme, using the crystal structures of Lip1 and Lip3 from C. rugosa as templates, revealed a similar substrate-binding site, but some changes affecting the flap zone and the aromatic region of the tunnel may be responsible for the wide substrate specificity of this interesting sterol esterase. The ability of the new fungal esterase to hydrolyze triglycerides and esters of p-nitrophenol and cholesterol was compared with those of commercial lipases and cholesterol esterases showing the new enzyme the highest efficiency hydrolyzing triglycerides and sterol esters in the conditions assayed (in presence of Genapol X-100). Finally, the O. piceae gene was successfully expressed in Pichia pastoris, as a model organism to express fungal enzymes, resulting in higher levels of esterase activity than those obtained in the O. piceae cultures. In spite of its higher glycosylation degree, the recombinant enzyme was able to hydrolyze more efficiently than native enzyme the assayed substrates. [Copyright &y& Elsevier]

The purpose of this research was to investigate the effectiveness of short-chain cationic polyelectrolytes of different molecular weights and charge densities in reducing turbidity and selectively removing toxic wood extractives from chemical birch pulp filtrate. The effects of chemical type, dosage and temperature were of interest. An effective performance was achieved with a copolymer of acrylamide and methacrylate of medium molecular weight and medium charge density at 72°C and pH 5–6. The dosage range optimum for reducing the turbidity was 102–142mg/L. Up to 92% of the wood extractives was selectively removed. [Copyright &y& Elsevier]

Abstract: Wood extractives are constituents of wood present in pulp and paper mill effluents, which may cause reproductive disturbances in fish. In the present study, we examined three cellular in vitro bioassays in order to assess (anti)estrogenic potencies of the wood extractives dehydroabietic acid (DHAA), isopimaric acid (IPA), betulinol (BET), hydroxymatairesinol (HMR), a phytosterol preparation (ULT), an oxidized phytosterol preparation (OX) and the model estrogen 17β-estradiol (E2). The test systems used were primary hepatocyte cultures from brown trout and two piscine liver cell lines, RTH-149 and ZF-L. Estrogenicity was measured as vitellogenin (Vtg) secretion in cell culture medium. The primary hepatocytes cultures responded to E2 in a dose-dependent way. Vtg induction was inhibited with a simultaneous exposure to 4-hydroxytamoxifen (4-HT) indicating an estrogen receptor mediated response. DHAA and ULT induced a weak statistically non-significant Vtg production, and weak additive effects were found in some combination treatments of wood extractives and E2. Additionally, a pulp mill effluent tested on primary hepatocytes induced Vtg production when exposed at a 1% dilution. The cell lines secreted negligible amounts of Vtg upon E2 stimulation, which was neither dose-dependent nor inhibited by 4-HT. In conclusion, trout primary hepatocytes could be useful for assessing (anti)estrogenic potencies of compounds, and the wood extractives and a pulp mill effluent showed only weak or no estrogenic activity in this model system. [Copyright &y& Elsevier]

Abstract: Two wood extractives, dehydroabietic acid (DHAA) and betulinol (BET), present in wood industry effluents were evaluated for their potential effects on the reproductive physiology of zebrafish. Adult zebrafish (F0) were exposed in a continuous flow-through system to 50μg/l DHAA, 5μg/l BET and 0.27μg/l (1nM) 17β-estradiol (E2) for 3 months. Eggs were collected from F0 fish and the following F1 generation was exposed for 6 months. Biomarkers analyzed in both F0 and F1 fish were plasma vitellogenin (Vtg), testosterone (T), E2 (only females) and gonadal histology. DHAA and BET affected growth in terms of increased condition factor, and spawning was stimulated in BET-exposed fish of the F0 generation. F0 males exposed to DHAA and F0 females exposed to BET showed lower plasma Vtg concentration, but F1 males exposed to BET showed an increase in Vtg. In fish exposed to E2, the positive control for estrogenic effects, a pronounced increase in Vtg concentration was observed. Plasma sex steroids were not significantly affected by the wood extractives. However, although not statistically significant, the T concentration tended to be lower in fish of all BET treatments. The histological study revealed alterations in spermatogenic stages of F0 males exposed to DHAA and BET, which were different from those caused by E2. In F1 females, the percentage of vitellogenic oocytes was decreased in DHAA, BET and E2 exposures. This study shows that DHAA and BET may contribute to growth alterations and reproductive disturbances reported in fish exposed to pulp and paper mill effluents. Further, these wood extractives may have different effects in F0 and F1 generation fish, which highlights the value of two-generation studies in investigations regarding endocrine disrupting compounds. [Copyright &y& Elsevier]