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10 Pág. Instituto de Ciencias Forestales (ICIFOR), The high humidity produced by the ripening of fruit and vegetables during refrigerated storage and transport leads to a noticeable loss of strength of corrugated board packaging. Increasing use of recycled fibres in the manufacture of corrugated board further reduces box compression strength. Adding virgin fibres to the furnish composition of liner paper could solve this problem. Various proportions of unbleached virgin eucalyptus and pine fibres were added to a recycled furnish used to manufacture liner paper for corrugated board. Laboratory sheets of each fibre blend were characterised by tensile, bursting and compressive strength. The change in the strength properties and moisture content of the sheets during refrigerated storage at 6°C and high relative humidity (90% RH) was also studied. The results showed that paper strength improved with the proportion of virgin fibres added. Pine fibres yielded higher increments than eucalyptus fibres in tensile and burst indices, whereas both fibres improved compression strength at a similar rate. After 4 h of exposure at refrigerated storage, the paper strength properties decreased considerably, in particular compression strength, which showed a loss of about 70% compared to the reference value. The percentage of strength lost compared to the value in standard conditions was influenced only by exposure time at low temperature and high RH. However, an increase in the amount of pine fibres added enhanced the remaining tensile and burst indices., The authors wish to thank the Madrid Regional Government for funding through project RETO PROSOST P2013-MAE2907 and theIPT support foundation (FIPT) for subsidising the training project of the researcher Renato Fioritti in Spain (INIA-CIFOR). They are also grateful to Purificación Pereira for her contribution to the experimental work

This work proposes a sequential combination of steam explosion and organosolv delignification for Pinus radiata fractionation. An efficient pretreatment to fully optimize the use of lignocellulosic materials is the key to make a biorefinery profitable, especially for softwoods, known to be more recalcitrant than other lignocellulosic raw materials. Steam explosion has a dual effect on biomass as morphological and chemical changes are introduced. A delignifying stage has been stated to be necessary in order to ease hydrolytic enzymes accessibility to cellulose while avoiding non-productive bonds with the lignin present. Three steam explosion conditions were tested (170°C, 5 min; 180°C, 10 min; 170°C, 5+5 min) followed by an organosolv delignification stage, carried out at two different conditions (170°C, 60 min; 170°C, 90 min). All treatment yields, delignification extent, and hydrolysis yields were determined to evaluate each stage. The steam explosion treatment did not produce high delignification extent. Maximum global delignification (50.4%) was achieved when combining the two-cycle steam explosion with the most severe post-treatment condition tested. Enzymatic hydrolysis of the cellulosic residue improved after organosolv delignification; however, hydrolysis yields did not exceed 35%. The chemical changes undergone by softwood lignins are presumably responsible for the low digestibility. Fil: Imlauer Vedoya, Camila María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina Fil: Vergara Alarcón, Priscila. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria; España Fil: Area, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina Fil: Revilla, Esteban. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria. Centro de Investigación Forestal; España Fil: Felissia, Fernando Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina Fil: Villar, Juan Carlos. Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria. Centro de Investigación Forestal; España

(Figure Presented) Cardoon (Cynara cardunculus) stalks were submitted to steam explosion (183°C, 5 min) with a yield of 88% and a lignin loss of around 7%. Cardoon (C) and steam exploded cardoon (CSE) were characterized by wet chemical analysis and Py-GC/MS. Total lignin and its S/G ratio were 21.6% and 1.35 in C and 22.4% and 1.40 in CSE. These samples were delignified by kraft and organosolv processes. Cardoon pulps were obtained with different yields of 45.1% for kraft and 61.2% for organosolv. Kraft pulps yields were 45.1% and 50.9%, respectively, for Ck and CSE-K, corresponding to a lignin loss of 74.7% and 72.2%. The S/G ratio was similar 1.25 and 1.23. Organosolv pulps presented higher yields (61.2% vs 73.3%) and were less delignified (30.5% vs 13.8%), and the S/G ratio was 1.54 and 1.47, respectively, for Corg and CSE-org. Overall, the condition chosen for steam explosion allowed a low mass loss but did not promote delignification and neither enhanced lignin removal during kraft and organosolv processes. © 2016 American Chemical Society.

The fractionation of wheat straw by ethanol-water (EW) pre-treatment was studied regarding its main operating conditions: time, temperature, L/S ratio and ethanol percentage were optimized by using an orthogonal experimental design (Taguchi). Afterwards, diluted sulfuric acid (DSA) hydrolysis and EW treatments have been compared in terms of energy consumption and yield of a cellulosic solid residue able to be enzymatically hydrolyzed to glucose. Experimental results show that temperature is the only variable of EW with a significant effect on the quality of the pretreated solids. EW pre-treatment of wheat straw is more effective than DSA hydrolysis due to its higher capacity of delignification. Moreover, a high glucose yield (80%) can be obtained by enzymatic hydrolysis of a solid pretreated with a moderate energy input EW (160 °C, 45 min) while wheat straw needs of a higher energy input during DSA to produce a similar yield of glucose after saccharification.

Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3. min, at 183. °C. © 2014 Elsevier Ltd.

Growing interest in alternative and renewable energy sources has brought increasing attention to the integration of a pulp mill into a forest biorefinery, where other products could be produced in addition to pulp. To achieve this goal, hemicelluloses were extracted, either by steam explosion or by steam treatment, from Eucalyptus globulus wood prior to pulping. The effects of both pre-treatments in the subsequent kraft pulping and paper strength were evaluated. Results showed a similar degree of hemicelluloses extraction with both options (32-67% of pentosans), which increased with the severity of the conditions applied. Although both pre-treatments increased delignification during pulping, steam explosion was significantly better 12.9 kappa number vs 22.6 for similar steam unexploded pulps and 40.7 for control pulp. Finally, similar reductions in paper strength were found regardless of the type of treatment and conditions assayed, which is attributed to the increase of curled and kinked fibers. © 2013 Elsevier Ltd.

The aim of this work is to study the reinforcement capacity of pulps obtained from Hesperaloe funifera using a simple and low energy consumption process (chemi refiner mechanical pulping) once they are added in different percentages to recycled pulps from newspaper and from old corrugated containers (OCC). Pinus radiata kraft pulp was used as a referent reinforcement material. H. funifera acted as a reinforcement material in newspaper and OCC recycled pulps, improving their optical and mechanical properties. While a 25% of H. funifera was the optimal amount added to reinforce the OCC pulp, only a 10% was needed for newspaper pulp. However, the OCC optimal mixture was better reinforced as it showed higher increase in all properties than the optimal newspaper mixture, apart from tensile index. Finally, all mixtures with P. radiata kraft pulp produce handsheet with lower properties, apart from tear index, suggesting than H. funifera is a better reinforcement material. El objetivo de este trabajo es estudiar la capacidad de refuerzo de pastas de Hesperaloe funifera obtenidas mediante un proceso simple de bajo consumo energético (pasteado químico-mecánico de refino) una vez añadidas en diferentes porcentajes a pastas recicladas de periódicos y de cartón ondulado (OCC). Se utilizó como material de refuerzo de referencia pasta kraft de Pinus radiata. H. funifera mejoró las propiedades ópticas y mecánicas de todas las pastas recicladas estudiadas, demostrando su capacidad de refuerzo. Mientras que un 25% de H. funifera fue la cantidad óptima para reforzar la pasta de OCC, sólo un 10% fue necesario para la pasta de periódicos. Sin embargo, la mezcla óptima de OCC mostró un mayor incremento en todas las propiedades que la mezcla óptima de periódicos, a excepción del índice de tracción. Por último, todas las mezclas de pasta kraft de P. radiata proporcionaron hojas con menores propiedades mecánicas, a excepción del índice de desgarro, lo que sugiere que H. funifera es un material de refuerzo más eficaz.

Steam explosion has been proposed for a wide range of lignocellulosic applications, including fractionation of biomass, pre-treatment of biomass for ethanol production, or as an alternative to conventional mechanical pulping. Nevertheless, a steam explosion process could also be used as pretreatment before chemical pulping, expecting a reduction in cooking time due to the open structure of the exploded chips. Thus, to evaluate the effect of steam explosion as a pretreatment in the kraft pulping of Eucalyptus globulus, steam exploded chips and control chips were subjected to kraft cookings. Steam exploded chips provided pulps with reductions of kappa number by up to 70% with no significant change in viscosity. Therefore, the cooking time could be shortened by 60%, increasing the productivity and obtaining pulps with similar delignification degree to those of the control pulp. Furthermore, not only the production rate could be increased, but also most of the hemicelluloses could be recovered before pulping and converted to a value-added product. Finally, although exploded pulp had inferior mechanical strength, the optical properties, which are more important in eucalyptus pulps, were found to be better.

The actinobacteriumStreptomyces cyaneusCECT 3335 was evaluated for its ability to delignify spruce wood chips (Picea abies) after 2 weeks of incubation prior to refiner mechanical pulping. Weight loss of the chips during the treatment ranged from 2% to 3%. Chemicalanalysis of the treated wood showed an increase in acid-soluble lignin content concomitant with a notable increase in the acid/aldehyde+ketone [AC/(AL+KE)] ratio of the lignin compared with the control. Structural alterations in wood cell walls were observed by optical and scanning microscopy using astra blue-safranin staining and cryosections stained with gold/palladium, respectively. A gradual loss of lignin from the lumen towards the middle lamella and incipient defiberization could be observed. The estimation of specific energy for the defibration and refining stages of treated pulp showed a 24% reduction in the energy required, largely due to a 30% saving in the defibration of chips. The analysis of handsheets obtained from treated pulp showed a notable improvement in some strength properties, such as breaking length, tear index and stretch. In addition, the high Gurley air resistance value indicates more packing of the voids of the fiber network. These results demonstrate for the first time the suitability ofStreptomyces cyaneusfor biomechanical pulping purposes.