Utilizing peanut husk (Arachis hypogaea L.) in the manufacture of medium-density fiberboards

The main objective of this study was to investigate the potential of peanut husk (Arachis hypogaea L.) as a fiber–peanut mixture to produce fiberboards for general purposes. For panel production, the addition of peanut husk at various percentages to the wood fiber was the only variable. Panels produced utilizing peanut husk were compared to panels produced using 100% wood fiber. The chemical properties of peanut husk; holocellulose and lignin content, alcohol–benzene, hot and cold water, and dilute alkali (1% NaOH) solubility, were also determined. Results indicated that panels could be produced utilizing up to 30% peanut husk without affecting the usability of the panels. It was not possible to meet the minimum IB strength standards when peanut husk was added to the mixture. Higher additions resulted in panels having lower elastic and rupture moduli than the minimum requirements according to TS-EN standards.     

The potential for using the needle litter of Scotch pine (Pinus sylvestris L.) as a raw material for particleboard manufacturing

Particleboard panels were made from various wood particle/needle litter of Scotch pine (Pinus sylvestris L.) mixtures bonded with urea formaldehyde resin. Litter was characterized by having higher solubility's in alcohol-benzene, with diluting alkali and hot water, and resulted in lower pH values than those of wood particles. The mechanical properties (modulus of rupture, modulus of elasticity, and internal bond strength) of boards containing up to 6.25% litter were lower than those of panels made from wood particles. However, needle litter usage improved the physical property (thickness swelling) and decay resistance of the panels, significantly. Panels consist of 6.25% and 12.50% needle litter met the minimum EN standard requirements of mechanical properties for general-purposes. Particleboards contain more than 50% needle litter had the required level of thickness swelling for 24 h immersion.     

Effects of nanowollastonite on biological resistance of particleboard made from wood chips and chicken feather against Antrodia vaillantii

The effect of wollastonite nanofibers (NW) on biological resistance of particleboard, made from wood chips and chicken-feather fibers (CF), against Antrodia vaillantii was studied. 10% of NW, as well as 5 and 10% of CF, were applied to the particleboard-matrix based on the dry weight of wood chips. Then, as a complimentary study, 10% wood fibers were also added to the wood chips; totaling, 10 mixing treatments. Specimens were prepared and mass loss (ML) values were measured in accordance with the EN 113 specifications. Results indicated that the highest ML (37%) occurred in the control treatment without NW- or CF-content; the lowest ML was seen in panels with 10% of NW, CF, and wood fibers (2.5%). NW substantially decreased ML in all mixing ratios. CF also showed a significant decreasing effect on ML. No significant correlation was found between ML values with any of physical and mechanical properties; however, high significant correlations were found between most of the mechanical properties. It is concluded that NW may be considered an effective filler in wood-composite industry to increase the durability against fungal attack; however, more studies should first be conducted on different fungi and wood and wood-composite materials to finalize this conclusion.     

Evaluation of the mechanical, physical properties and decay resistance of particleboard made from particles impregnated with Pinus brutia bark extractives

The mechanical, physical properties and decay resistances of particleboard made from particles impregnated with Pinus brutia bark extractives were examined. Properties included were modulus of rupture, modulus of elasticity, internal bond, thickness swelling, and weight loss according to European standards. The results showed that particleboards made from particles impregnated with bark extractives had significantly lower mechanical values than those made from unimpregnated particles. Impregnating wood particles with bark extractives improved the decay resistance and thickness swelling of particleboard. Increasing concentration of the extractives decreased the mechanical properties and improved the thickness swelling and decay resistance of the panels. Particleboards made from 1% P. brutia bark extractives met the specifications for modulus of rupture and internal bond strength for general purposes.     

Synthesis and characterization of starch based bioplatics using varying plant-based ingredients,plasticizers and natural fillers

With the ever-increasing demand of plastics in the world and their consequent disastrous effects on environment, a suitable environmental-friendly substitute like bioplastics/biodegradable plastics is the need time. This study centers on green-production of a variety of bioplastic samples from (1) banana peel starch (BPP) and (2) a composite of banana peel starch, cornstarch and rice starch (COM) with varying amounts of potato peel powder and wood dust powder as fillers, respectively. Two different plasticizers – Glycerol and Sorbitol – have been utilized separately and in a 1:1 combination. A total of 12 samples of each of two types of bioplastics were made using multiple amounts and combinations of the fillers and plasticizers, to test the differences in the physical and chemical characteristics (moisture content, absorption of water, solubility in water, solubility in alcohol, biodegradation in soil, tensile strength, Young’s modulus and FT-IR) of the produced samples due to their different compositions. The differences in the properties of the bioplastic samples produced make them suitable for usage in many different applications. All 24 of the samples produced were synthesized using natural and environmentally safe raw material and showed biodegradation, thus proving to be a good alternative to the conventional plastics.     

Influence of substrate wood-chip particle size on shiitake (Lentinula edodes) yield

Wood chips from four commercial hardwood sawmills were screened with 10 US standard sieves (4-0.21 mm) to assess particle size distributions. 96-98% of wood chips were < 4 mm while 95-99% of particles were > 0.21 mm. The majority (mean = 64.5%) of wood chips passed through US standard sieve size 14 (< 1.4 mm). Shiitake (Lentinula edodes) was grown in three crops to determine the effect of four particle size classes (1 = 2.8-4 mm; 2 = 1.7-2.8 mm; 3 = 0.85-1.7 mm; 4 = < 0.85 mm) on mushroom yield. Yields from substrates prepared with wood chips from class 4 (< 0.85 mm) were lower by 27.7%, 12.4% and 2% (mean = 14.9%) for Crops I, II, and III, respectively, when compared to controls. Profiling of wood chips may help growers optimize their production media and reduce production costs.     

Physical properties of peanut hull pellets

Peanut hull (peanut pods and waste materials from processing of peanuts) was pelleted through a 3/16-in. (4.76 mm) diameter die. The effect of change in moisture content (4.2-21.2%, wet basis) of the pellets (due to exposure of the pellets to low or high humidity storage environments) on physical properties were measured. Pelleting increased the bulk density of the peanut hull from 151 kg/m(3) to more than 600 kg/m(3). Bulk density, particle density and durability of the pelleted peanut hull of pellets were significantly affected by moisture content attained by the pellets during exposure to the low or high humidity environment. Air relative humidity significantly influenced the rate at which the pellets exchange moisture with the environment while air temperature did not. The values of the constants of the GAB model were obtained from moisture sorption isotherm at 25 degrees C.     

Environmental performance assessment of hardboard manufacture

Background, aim and scope  The forest-based and related industries comprise one of the most important industry sectors in the European Union, representing some 10% of the EU's manufacturing industries. Their activities are based on renewable raw material resources and efficient recycling. The forest-based industries can be broken down into the following sectors: forestry, woodworking, pulp and paper manufacturing, paper and board converting and printing and furniture. The woodworking sector includes many sub-sectors; one of the most important is that of wood panels accounting for 9% of total industry production. Wood panels are used as intermediate products in a wide variety of applications in the furniture and building industries. There are different kinds of panels: particleboard, fibreboard, veneer, plywood and blockboard. The main goal of this study was to assess the environmental impacts during the life cycle of wet-process fibreboard (hardboard) manufacturing to identify the processes with the largest environmental impacts. Methods  The study covers the life cycle of hardboard production from a cradle-to-gate perspective. A hardboard plant was analysed in detail, dividing the process chain into three subsystems: wood preparation, board forming and board finishing. Ancillary activities such as chemicals, wood chips, thermal energy and electricity production and transport were included within the system boundaries. Inventory data came from interviews and surveys (on-site measurements). When necessary, the data were complemented with bibliographic resources. The life cycle assessment procedure followed the ISO14040 series. The life cycle inventory (LCI) and impact assessment database for this study were constructed using SimaPro Version 7.0 software. Results  Abiotic depletion (AD), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), ecotoxicity, photochemical oxidant formation (PO), acidification (AC) and eutrophication (EP) were the impact categories analysed in this study. The wood preparation subsystem contributed more than 50% to all impact categories, followed by board forming and board finishing, which is mainly due to chemicals consumption in the wood preparation subsystem. In addition, thermal energy requirements (for all subsystems) were fulfilled by on-site wood waste burning and, accordingly, biomass energy converters were considered. Several processes were identified as hot spots in this study: phenol-formaldehyde resin production (with large contribution to HT, fresh water aquatic ecotoxicity and PO), electricity production (main contributor to marine aquatic ecotoxicity), wood chips production (AD and OLD) and finally, biomass burning for heat production (identified as the largest contributor to AC and EP due to NO _X emissions). In addition, uncontrolled formaldehyde emissions from manufacturing processes at the plant such as fibre drying should be controlled due to relevant contributions to terrestrial ecotoxicity and PO. A sensitivity analysis of electricity profile generation (strong geographic dependence) was carried out and several European profiles were analysed. Discussion  Novel binding agents for the wood panel industry as a substitute for the currently used formaldehyde-based binders have been extensively investigated. Reductions of toxic emissions during drying, mat forming and binder production are desirable. The improved method would considerably reduce the contributions to all impact categories. Conclusions  The results obtained in this work allow forecasting the importance of the wood preparation subsystem for the environmental burdens associated with hardboard manufacture. Special attention was paid to the inventory analysis stage for each subsystem. It is possible to improve the environmental performance of the hardboard manufacturing process if some alternatives are implemented regarding the use of chemicals, electricity profile and emission sources in the production processes located inside the plant. Recommendations and perspectives  This study provides useful information for forest-based industries related to panel manufacture with the aim of increasing their sustainability. Our research continues to assess the use phase and final disposal of panels to complete the life cycle assessment. Future work will focus on analysing the environmental aspects associated with plywood, another type of commonly used wood panel.     

A biomechanical perspective on the role of large stem volume and high water content in baobab trees (Adansonia spp.; Bombacaceae)

The stems of large trees serve in transport, storage, and support; however, the degree to which these roles are reflected in their morphology is not always apparent. The large, water-filled stems of baobab trees (Adansonia spp.) are generally assumed to serve a water storage function, yet recent studies indicate limited use of stored water. Through an analysis of wood structure and composition, we examined whether baobab morphology reflects biomechanical constraints rather than water storage capacity in the six Madagascar baobab species. Baobab wood has a high water content (up to 79%), low wood density (0.09-0.17 g · cm(-3)), high parenchyma content (69-88%), and living cells beyond 35 cm into the xylem from the cambium. Volumetric construction cost of the wood is several times lower than in more typical trees, and the elastic modulus approaches that of parenchyma tissue. Safety factors calculated from estimated elastic buckling heights were low, indicating that baobabs are not more overbuilt than other temperate and tropical trees, yet the energy investment in stem material is comparable to that in temperate deciduous trees. Furthermore, the elastic modulus of the wood decreases with water content, such that excessive water withdrawal from the stem could affect mechanical stability.     

Mechanical Properties of Black Locust (Robinia pseudoacacia) Wood: Correlations among Elastic and Rupture Moduli,Proportional Limit,and Tissue Density and Specific Gravity

The purpose of this paper is to determine the extent to which the physical and mechanical properties of dry and green wood samples are correlated. Samples of green (fresh) sap- and heartwood differing in density (ρ) were removed from the trunk of a black locust (Robinia pseudoacaciaL.) tree 30 years old and measuring 15 m in height. These samples were mechanically tested to determine their Young's elastic modulus (E), proportional (elastic) limit (σ_p), and modulus of rupture (σ_R). The Young's elastic modulus of green wood samples increased in magnitude to a limit with increasing cross-sectional area of the sample tested. The values of all three mechanical parameters measured for sapwood samples were consistently lower than those measured for heartwood samples with equivalent cross-sectional areas.Ewas linearly and positively correlated with the σ_pand σ_Rof heartwood tissue samples. All mechanical properties were highly correlated with the density of green heartwood. Likewise, these properties were highly correlated with the specific gravity of wood samples. Based on these results, it is concluded that either the density of fresh wood or the specific gravity of air-dried wood can be used to estimate the mechanical properties of black locust wood based on simple regression curves in the absence of extensive mechanical tests.     

Evaluating mulches together with Heterorhabditis zealandica (Rhabditida: Heterorhabditidae) for the control of diapausing codling moth larvae,Cydia pomonella (L.) (Lepidoptera: Tortricidae)

The potential of using an entomopathogenic nematode, Heterorhabditis zealandica Poinar, together with different test mulches (pine chips, wheat straw, pine wood shavings, blackwood and apple wood chips) to control diapausing codling moth, Cydia pomonella (L.) larvae was evaluated. Mesh cages were identified as a suitable larval-containment method. High levels of codling moth mortality were obtained when using pine wood shavings as mulch (88%) compared to pine chips, wheat straw, blackwood and apple wood chips (41–88%). Humidity (>95% RH) has to be maintained for at least 3 days to ensure nematode survival. It was also proven that nematodes had the ability to move out of infected soil into moist mulch, to infect the codling moth larvae residing at heights of up to 10 cm. Field experiments showed the importance of climatic conditions on nematode performance. Low temperatures (<15°C) recorded during the first trial resulted in low levels of control (48%), as opposed to the 67% mortality recorded during the second trial (temperatures ranged between 20 and 25°C). Low levels of persistence (<10%) were recorded in the mulches post-application. The study conclusively illustrated some of the baseline requirements fundamental to the success of entomopathogenic nematodes together with mulches for the control of codling moth.     

Biological protection of hardwood logs destined for panel manufacturing using <Emphasis Type="Italic">Gliocladium roseum</Emphasis> against biodegradation

The objective of the present study was to develop a biological technology that would protect logs destined for oriented strand board (OSB) manufacturing from biodegradation. Aspen, red maple, and yellow birch trees were felled in one summer and the logs either debarked or not debarked, and either treated or not treated with a biological product of Gliocladium roseum. The logs were piled in different treatment groups and stored in a yard for 5 months and 1 year before evaluation. The results showed that all untreated logs, with or without bark, were seriously degraded by moulds, stain and decay fungi after a summer storage period of 5 months. The logs with bark were more degraded than the debarked logs, and the log ends were more degraded than the middle sections. After 5 months, 55–83% of the surface area of the wood discs was degraded in untreated logs. The biological treatment was effective, and only 4–16% of the surface area of the wood discs in treated logs was infected by various fungi. Strands cut from untreated logs consisted of 50–75% grey- or blue-stained strands, whereas those cut from biologically treated logs consisted of 10–25% such strands. Panels made using biologically treated logs had a lower thickness swelling and water absorption values compared to panels made using freshly cut logs and untreated stored logs. The other physical and mechanical properties of the various panels made in this test were comparable. In terms of mould resistance, all panels made from fungal-treated logs had a better mould resistance than those made from freshly cut and untreated logs.     

Effects of chipping, grinding, and heat on survival of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), in chips

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), a phloem-feeding insect from Asia, was identified in 2002 as the cause of widespread ash (Fraxinus sp.) mortality in southeastern Michigan and Essex County, Ontario. Most larvae overwinter as nonfeeding prepupae in the outer sapwood or thick bark of large trees. In a series of studies, we evaluated effects of grinding, chipping, and heat treatment on survival of A. planipennis prepupae in ash material. Heavily infested ash bolts containing roughly 8,700 prepupae were processed by a horizontal grinder with either a 2.5- or 10-cm screen. There was no evidence of A. planipennis survival in chips processed with the 2.5-cm screen, but eight viable prepupae were recovered from chips processed with the 10-cm screen. We chiseled additional sentinel chips with prepupae from ash logs and buried 45 in each chip pile. In total, six prepupae in sentinel chips survived the winter, but we found no sign of adult A. planipennis emergence from the processed chips. Subsequently, we assessed prepupal survival in chips processed by a chipper or a horizontal grinder fit with 5-, 10-, or 12.7-cm screens. An estimated 1,565 A. planipennis prepupae were processed by each treatment. Chips from the chipper were shorter than chips from the grinder regardless of the screen size used. No live prepupae were found in chips produced by the chipper, but 21 viable prepupae were found in chips from the grinder. Infested wood and bark chips chiseled from logs were held in ovens at 25, 40, or 60 degrees C for 8, 24, or 48 h. Prepupal survival was consistently higher in wood chips than bark chips at 40 degrees C, whereas no prepupae survived exposure to 60 degrees C for eight or more hours. In a second study, prepupae in wood chips were exposed to 40, 45, 50, 55, or 60 degrees C for 20 or 120 min. Some prepupae survived 20 min of exposure to all temperatures. No prepupae survived exposure to 60 degrees C for 120 min, but 17% survived exposure to 55 degrees C for 120 min, suggesting that some fraction of the population may survive internationally recognized phytosanitary standards (ISPM-15) for treatment of wood packing material.     

Sulfite pretreatment (SPORL) for robust enzymatic saccharification of spruce and red pine

This study established a novel process using sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust and efficient bioconversion of softwoods. The process consists of sulfite treatment of wood chips under acidic conditions followed by mechanical size reduction using disk refining. The results indicated that after the SPORL pretreatment of spruce chips with 8–10% bisulfite and 1.8–3.7% sulfuric acid on oven dry (od) wood at 180 °C for 30 min, more than 90% cellulose conversion of substrate was achieved with enzyme loading of about 14.6 FPU cellulase plus 22.5 CBU β-glucosidase per gram of od substrate after 48 h hydrolysis. Glucose yield from enzymatic hydrolysis of the substrate per 100 g of untreated od spruce wood (glucan content 43%) was about 37 g (excluding the dissolved glucose during pretreatment). Hemicellulose removal was found to be as critical as lignin sulfonation for cellulose conversion in the SPORL process. Pretreatment altered the wood chips, which reduced electric energy consumption for size reduction to about 19 Wh/kg od untreated wood, or about 19 g glucose/Wh electricity. Furthermore, the SPORL produced low amounts of fermentation inhibitors, hydroxymethyl furfural (HMF) and furfural, of about 5 and 1 mg/g of untreated od wood, respectively. In addition, similar results were achieved when the SPORL was applied to red pine. By building on the mature sulfite pulping and disk refining technologies already practiced in the pulp and paper industry, the SPORL has very few technological barriers and risks for commercialization.     

Conversion of Japanese red pine wood (Pinus densiflora) into valuable chemicals under subcritical water conditions

A comparative study on the decomposition of Japanese red pine wood under subcritical water conditions in the presence and absence of phosphate buffer was investigated in a batch-type reaction vessel. Since cellulose makes up more than 40-45% of the components found in most wood species, a series of experiments were also carried out using pure cellulose as a model for woody biomass. Several parameters such as temperature and residence time, as well as pH effects, were investigated in detail. The best temperature for decomposition and hydrolysis of pure cellulose was found around 270 °C. The effects of the initial pH of the solution which ranged from 1.5 to 6.5 were studied. It was found that the pH has a considerable effect on the hydrolysis and decomposition of the cellulose. Several products in the aqueous phase were identified and quantified. The conditions obtained from the subcritical water treatment of pure cellulose were applied for the Japanese red pine wood chips. As a result, even in the absence of acid catalyst, a large amount of wood sample was hydrolyzed in water; however, by using phosphate buffer at pH 2, there was an increase in the hydrolysis and dissolution of the wood chips. In addition to the water-soluble phase, acetone-soluble and water-acetone-insoluble phases were also isolated after subcritical water treatment (which can be attributed mainly to the degraded lignin, tar, and unreacted wood chips, respectively). The initial wood:acid ratio in the case of reactions catalyzed by phosphate buffer was also investigated. The results showed that this weight ratio can be as high as 3:1 without changing the catalytic activity. The size of the wood chips as one of the most important experimental parameters was also investigated.     

Fermentability of the hemicellulose‐derived sugars from steam‐exploded softwood (douglas fir)

Steam explosion ofDouglas fir wood chips under low‐severity conditions (log Ro = 3.08 corresponding to 175°C, 7.5 min, and 4.5% SO₂) resulted in the recovery of around 87% of the original hemicellulose component in the water‐soluble stream. More than 80% of the recovered hemicellulose was in a monomeric form. As the pretreatment severity increased from 3.08 to 3.76, hemicellulose recovery dropped to 43% of the original hemicellulose found in Douglas fir chips while the concentration of glucose originating from cellulose hydrolysis increased along with the concentration of sugar degradation products such as furfural and hydroxymethylfurfural. Despite containing a higher concentration of hexose monomers (mainly glucose originating from cellulose degradation), the water‐soluble fraction prepared under high‐severity conditions (log Ro = 3.73 corresponding to 215°C, 2.38 min, and 2.38% SO₂) was not readily fermented. Only the two hydrolyzates obtained at low and medium (195°C, 4.5 min, and 4.5% SO₂) severities were fermented to ethanol using a spent sulfur liquor adapted strain of Saccharomyces cerevisiae. High ethanol yields were obtained for these two hydrolyzates with 0.44 g of ethanol produced per gram of hexose utilized (86% of theoretical). However, the best results of hemicellulose recovery and fermentability were obtained for the low‐severity water‐soluble fraction which was fermented significantly faster than the fraction obtained after medium‐severity treatment probably because it contained higher amounts of fermentation inhibitors. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 64: 284–289, 1999.     

Ensiling corn stover: effect of feedstock preservation on particleboard performance

Ensilage is a truncated solid-state fermentation in which anaerobically produced organic acids accumulate to reduce pH and limit microbial activity. Ensilage can be used to both preserve and pretreat biomass feedstock for further downstream conversion into chemicals, fuels, and/or fiber products. This study examined the ensilage of enzyme-treated corn stover as a feedstock for particleboard manufacturing. Corn stover at three different particle size ranges (<100, <10, and <5 mm) was ensiled with and without a commercial enzyme mixture having a cellulase:hemicellulase ratio of 2.54:1, applied at a hemicellulase rate of 1670 IU/kg dry mass. Triplicate 20 L mini-silos were destructively sampled and analyzed on days 0, 1, 7, 21, 63, and 189. Analysis included produced organic acids and water-soluble carbohydrates, fiber fractions, pH, and microorganisms, including Lactobacillus spp. and clostridia were monitored. On days 0, 21, and 189, the triplicate samples were mixed evenly and assembled into particleboard using 10% ISU 2 resin, a soy-based adhesive. Particleboard panels were subjected to industry standard tests for modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), thickness swell (TS), and water absorption at 2 h boiling and 24 h soaking. Enzyme addition did improve the ensilage process, as indicated by sustained lower pH (P < 0.0001), higher water-soluble carbohydrates (P < 0.05), and increased lactic acid production (P < 0.0001). The middle particle size range (<10 mm) demonstrated the most promising results during the ensilage process. Compared with fresh stover, the ensilage process did increase IB of stover particleboard by 33% (P < 0.05) and decrease water adsorption at 2 h boiling and 24 h soaking significantly (P < 0.05). Particleboard panels produced from substrate ensiled with enzymes showed a significant reduction in water adsorption of 12% at 2 h boiling testing. On the basis of these results, ensilage can be used as a long-term feedstock preservation method for particleboard production from corn stover. Enzyme-amended ensilage not only improved stover preservation but also enhanced the properties of particleboard products.     

Plasticizer Effects on Physical–Mechanical Properties of Solvent Cast Soluplus® Films

Soluplus® is a novel amphiphilic polymer that has been shown to enhance the solubility and drug dissolution rate of poorly soluble drugs. However, there still is a lack of information regarding the physical mechanical properties of Soluplus® with addition of the plasticizers. This study characterized the mechanical properties of Soluplus® with four different plasticizers. The plasticizers selected were polyethylene glycol 6, triethyl citrate, propylene glycol, and glycerin; they were studied at three different levels (15%, 20%, and 25% w/w). The effects of these plasticizers on the glass transition temperature, tensile strength, percent elongation, and Young’s modulus of free films made from Soluplus® were measured and the toughness and ratio of tensile strength to Young’s modulus were calculated. These results showed these four plasticizers are capable to plasticizing Soluplus® as indicated by the glass transition temperature lowering, tensile strength, and Young’s modulus while increasing the percent elongation and film toughness. Among the plasticizers tested, polyethylene glycol 6 showed greatest changed in the mechanical properties studied.     

Bioorganosolve pretreatments for simultaneous saccharification and fermentation of beech wood by ethanolysis and white rot fungi

Ethanol was produced by simultaneous saccharification and fermentation (SSF) from beech wood chips after bioorganosolve pretreatments by ethanolysis and white rot fungi, Ceriporiopsis subvermispora, Dichomitus squalens, Pleurotus ostreatus, and Coriolus versicolor. Beech wood chips were pretreated with the white rot fungi for 2-8 weeks without addition of any nutrients. The wood chips were then subjected to ethanolysis to separate them into pulp and soluble fractions (SFs). From the pulp fraction (PF), ethanol was produced by SSF using Saccharomyces cerevisiae AM12 and a commercial cellulase preparation, Meicelase, from Trichoderma viride. Among the four strains, C. subvermispora gave the highest yield on SSF. The yield of ethanol obtained after pretreatment with C. subvermispora for 8 weeks was 0.294 g g(-1) of ethanolysis pulp (74% of theoretical) and 0.176 g g(-1) of beech wood chips (62% of theoretical). The yield was 1.6 times higher than that obtained without the fungal treatments. The biological pretreatments saved 15% of the electricity needed for the ethanolysis.     

Decolourization of reactive azo dyes with microorganisms growing on soft wood chips

The decolourization of a mixture of 200 mg L⁻¹ each of Reactive Black 5 and Reactive Red 2 dye was studied in batch experiments using microorganisms growing on forest residue wood chips in combination with or without added white-rot fungus, Bjerkandera sp. BOL 13. The study was performed as a first stage in the development of a relatively simple treatment process for textile wastewater, designed to work in developing countries. Forest residue wood chips contain a mixture of fungi and bacteria which is an advantage when complex molecules should be degraded. The wood chips furthermore provide the microorganisms with carbon source which make the addition of e.g. glucose unnecessary. The results showed that the microorganisms growing on the forest residue wood chips decolourized the mixture of the two dyes; adding extra nutrients approximately doubled the decolourization rate. The time needed for decolourization was approximately 18 days when nutrients were added. Lignocellulosic material is complex and so were the analysis, microorganisms were therefore transferred to ordinary soft wood chips from forest residue wood chips. Decolourization was measured with spectrophotometer and in order to determine intermediates HPLC was used.