Integración del proceso Kraft de obtención de pasta de celulosa en el esquema de una biorrefinería

El concepto de biorrefinería se basa en el uso eficiente de la biomasa lignocelulósica como materia prima en la producción integrada de combustibles, energía y productos químicos. Basándonos en este concepto, una fábrica de pastas celulósicas podría convertirse en una biorrefinería en la que, además de pasta, se obtendrían otros productos como etanol, bio-polímeros y otros compuestos químicos. Para conseguir dicho objetivo, se llevó a cabo un tratamiento de explosión por vapor previo al pasteado, que permitió la extracción del 50% de las hemicelulosas y su posterior hidrólisis enzimática. Dicho pre-tratamiento, además proporcionó una fracción sólida con una estructura más abierta, que facilita la difusión de los reactivos durante el pasteado, aumentando la deslignificación en un 70%. De esta forma, el tiempo de cocción pudo reducirse en un 60% para obtener pastas con una calidad similar a la comercial. Debido a la eliminación de hemicelulosas durante este pre-tratamiento, la energía consumida por las pastas durante el refino fue mayor y las propiedades mecánicas ligeramente inferiores a las de la pasta control. Sin embargo, las propiedades ópticas fueron mayores, mostrando además menor contenido en ácidos hexenurónicos. Por otro lado, al someter estas pastas pre-tratadas a una secuencia de bioblanqueo se observó una mayor blanqueabilidad de las mismas, reduciéndose además el consumo de peróxido de hidrógeno en un 20%. Por tanto, las pastas obtenidas mediante este esquema de biorrefinería podrían utilizarse para aplicaciones en las que las propiedades ópticas sean importantes y no se necesite una gran resistencia mecánica, consiguiendo además reducir el tiempo de cocción y el consumo de reactivos químicos y obteniendo como subproducto una corriente rica en hemicelulosas. Además, el pre-tratamiento de explosión por vapor hizo posible la aplicación directa de enzimas sobre las astillas explosionadas, suponiendo una buena alternativa al biopulpeo con hongos ligninolíticos. El concepto de biorrefinería se basa en el uso eficiente de la biomasa lignocelulósica como materia prima en la producción integrada de combustibles, energía y productos químicos. Basándonos en este concepto, una fábrica de pastas celulósicas podría convertirse en una biorrefinería en la que, además de pasta, se obtendrían otros productos como etanol, bio-polímeros y otros compuestos químicos. Para conseguir dicho objetivo, se llevó a cabo un tratamiento de explosión por vapor previo al pasteado, que permitió la extracción del 50% de las hemicelulosas y su posterior hidrólisis enzimática. Dicho pre-tratamiento, además proporcionó una fracción sólida con una estructura más abierta, que facilita la difusión de los reactivos durante el pasteado, aumentando la deslignificación en un 70%. De esta forma, el tiempo de cocción pudo reducirse en un 60% para obtener pastas con una calidad similar a la comercial. Debido a la eliminación de hemicelulosas durante este pre-tratamiento, la energía consumida por las pastas durante el refino fue mayor y las propiedades mecánicas ligeramente inferiores a las de la pasta control. Sin embargo, las propiedades ópticas fueron mayores, mostrando además menor contenido en ácidos hexenurónicos. Por otro lado, al someter estas pastas pre-tratadas a una secuencia de bioblanqueo se observó una mayor blanqueabilidad de las mismas, reduciéndose además el consumo de peróxido de hidrógeno en un 20%. Por tanto, las pastas obtenidas mediante este esquema de biorrefinería podrían utilizarse para aplicaciones en las que las propiedades ópticas sean importantes y no se necesite una gran resistencia mecánica, consiguiendo además reducir el tiempo de cocción y el consumo de reactivos químicos y obteniendo como subproducto una corriente rica en hemicelulosas. Además, el pre-tratamiento de explosión por vapor hizo posible la aplicación directa de enzimas sobre las astillas explosionadas, suponiendo una buena alternativa al biopulpeo con hongos ligninolíticos. [ABSTRACT] The concept of a forest biorefinery is based on the effective use of lignocellulosic biomass as feedstock in the integrated production of fuels, energy and chemical products. Based on this concept, a chemical pulp mill could be transformed into a forest biorefinery, where ethanol, bio-polymers and other chemical products could be produced in addition to pulp. To achieve this goal, a steam explosion treatment was carried out prior to kraft pulping, that allowed the extraction of 50% of the hemicelluloses and their subsequent enzymatic hydrolysis. This pre-treatment also yielded a solid fraction with a more open structure that favors an efficient diffusion of cooking liquor into the fibers during pulping, increasing the delignification by up to 70%. Thus, the cooking time could be shortened by 60% obtaining pulps of a quality similar to commercial standards. Due to the removal of hemicelluloses in the pre-treatment, the exploded pulp required more energy during refining and the mechanical properties were slightly worse than those of the control pulp. However, the optical properties were better, providing also a hexenuronic acid content. Moreover, when these pulps were subjected to a biobleaching sequence, exploded pulps proved to have more bleachability, allowing a reduction in hydrogen peroxide consumption of 20%. Therefore, pulps obtained by this biorefinery process could be used in applications for which optical properties are important but not so mechanical strength, achieving also a reduction in cooking time and chemical consumption and obtaining as a byproduct a liquid current rich in hemicelluloses. In addition, this steam explosion pre-treatment made possible the direct application of enzymes over exploded chips, obtaining in this way a viable alternative for conventional biopulping with ligninolytic fungi

Synergic effect of inductors on laccase production by Pycnoporus sanguineus

As the fungal laccase production depends on some components which induce it, we have examined the independent effects of ethanol, wheat straw and copper sulphate and their combinations on the volumetric laccase activity of Pycnoporus sanguineus. Wheat straw and copper sulphate gave the best results showing a synergic effect after 13 days of incubation (laccaseactivity was 3 and 4.5 times greater than the activity generated when they were used alone). Ethanol on the contrary, was found to have a negative effect on laccase production. The laccase produced by the fungus  Pycnoporus sanguineusmaintains a good stability in a wide range of temperatures;a stability which also depends on the pH. By choosing the adequate pH, the level and stability of the laccase activity are satisfactory in a range of temperatures from 25 to 70ºC, which would allow the diversification of laccase use in industrial applications

Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic Biorefinery

The main source of cellulosic fibre used for pulp and paper production comes from wood, while non-wood fibres are used to a lesser extent. However, a renewed interest exists in the use of non-woody raw materials due to their abundance as source of low-cost fibres and because they are sometimes the only exploitable source of fibres in certain geographical areas, mainly in developing countries. Moreover, the great variety of characteristics, fibre dimensions and chemical composition of these alternative raw materials give them a great potential to produce different types of papers. On the other hand, the pulp and paper industry is an excellent starting point for the development of lignocellulosic biorefineries, possessing the necessary technology and infrastructure as well as extensive experience in lignocellulosic biomass transformation. Since its beginnings, the pulp and paper industry has been practicing certain aspects of the biorefinery concept, generating the energy necessary for the production of cellulosic pulp from the combustion of lignocellulosic waste and black liquors, recovering the chemical reagents used and generating high value-added products (e.g. tall oil) together with cellulosic pulp. However, the evolution of the pulp and paper industry to a lignocellulosic biorefinery requires technological innovations to make bioenergy and new bioproducts available alongside traditional products

Influence of Cellulose Characteristics on Pyrolysis Suitability

: Cellulose is the most abundant component of biomass and the one that requires the most activation energy (Ea) for pyrolysis. In this study, the dependence of Ea on the intrinsic cellulose characteristics, such as the degree of polymerization (DP), crystallinity, and crystal size, was studied in different cellulose samples, including samples from Eucalyptus globulus, Ulmus minor, Linun usitatissimum, Olea europaea, Robinia pseudoacacia, and Populus alba. Then, to describe the pyrolytic degradation of cellulose, the Ozawa–Flynn–Wall kinetic method was the most appropriate among the isoconversional models studied. An acceptable quadratic relationship of R2 > 0.9 between the Ea values of the different cellulose samples with their corresponding DP, crystallinity index, and crystal size values was found. Therefore, low crystallinity and low-to-medium crystal size values are desired to obtain lower Ea values for cellulose pyrolysis. On the other hand, DP did not present a clear effect on Ea in the studied DP rangeThis research was funded by Comunidad de Madrid and MCIU/AEI/FEDER, EU via Projects SUSTEC-CM S2018/EMT-4348 and RTI2018-096080-B-C22, respectively, and the Regional Ministry of Innovation, Science and Enterprise, Government of the Junta de Andalucía (Operational Programme FEDER Andalusia 2014-2020. Project UHU-1255540), Spain Universidad de Jaén is acknowledged for Olea europaea material. Silviculture and Forest Management Department (Forest Research Center, INIA, CSIC) is acknowledged for Robinia pseudoacacia and Populus alba materials. We thank the personnel at Puerta de Hierro Forest Breeding Centre (Ministerio para la Transición Ecológica y el Reto Demográfico) and the Spanish Elm Breeding Program for providing the Ulmus minor material. Finally, La Montañesa pulp mill (Lecta Group, Spain) and Celesa (Spain) are acknowledged for Eucalyptus globulus and Linun usitatissimum materials, respectivel

Different Kraft lignin sources for electrospun nanostructures production: Influence of chemical structure and composition

This work focuses on the structural features and physicochemical properties of different Kraft lignins and how they can influence the electrospinning process to obtain nanostructures. Structural features of Kraft lignins were characterized by nuclear magnetic resonance, size exclusion chromatography, fourier-transform infrared spectroscopy, and thermal analysis, whereas chemical composition was analyzed by standard method. The addition of cellulose acetate (CA) improves the electrospinning process of Kraft lignins (KL). Thus, solutions of KL/CA at 30 wt% with a KL:CA weight ratio of 70:30 were prepared and then physicochemical and rheologically characterized. The morphology of electrospun nanostructures depends on the intrinsic properties of the solutions and the chemical structure and composition of Kraft lignins. Then, surface tension, electrical conductivity and viscosity of eucalypt/CA and poplar/CA solutions were suitable to obtain electrospun nanostructures based on uniform cross-linked nanofibers with a few beaded fibers. It could be related with the higher purity and higher linear structure, phenolic content and S/G ratios of lignin samples. However, the higher values of electrical conductivity and viscosity of OTP/CA solutions resulted in electrospun nanostructure with micro-sized particles connected by thin fibers, due to a lower purity, S/G ratio and phenolic content and higher branched structure in OTP lignin.This work is part of two coordinated research projects (RTI2018-096080-B-C21 and RTI2018-096080-B-C22) funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. The authors also wish to thank the Comunidad de Madrid and MCIU/AEI/FEDER, EU for funding this study via Projects SUSTEC-CM S2018/EMT-4348. The authors also acknowledge the pre-doctoral grants from José Fernando Rubio Valle (Ref. PRE2019-090632). The contribution of COST Action LignoCOST (CA17128), supported by COST (European Cooperation in Science and Technology), in promoting interaction, exchange of knowledge and collaborations in the field of lignin valorization is gratefully acknowledged

Enzyme-Catalyzed Polymerization of Kraft Lignin from Eucalyptus globulus: Comparison of Bacterial and Fungal Laccases Efficacy

Kraft lignin, a side-stream from the pulp and paper industry, can be modified by laccases for the synthesis of high added-value products. This work aims to study different laccase sources, including a bacterial laccase from Streptomyces ipomoeae (SiLA) and a fungal laccase from Myceliophthora thermophila (MtL), for kraft lignin polymerization. To study the influence of some variables in these processes, a central composite design (CCD) with two continuous variables (enzyme concentration and reaction time) and three levels for each variable was used. The prediction of the behavior of the output variables (phenolic content and molecular weight of lignins) were modelled by means of response surface methodology (RSM). Moreover, characterization of lignins was performed by Fourier-transform infrared (FTIR) spectroscopy and different nuclear magnetic resonance (NMR) spectroscopy techniques. In addition, antioxidant activity was also analyzed. Results showed that lignin polymerization (referring to polymerization as lower phenolic content and higher molecular weight) occurred by the action of both laccases. The enzyme concentration was the most influential variable in the lignin polymerization reaction within the range studied for SiLA laccase, while the most influential variable for MtL laccase was the reaction time. FTIR and NMR characterization analysis corroborated lignin polymerization results obtained from the RSM.This research was funded by Comunidad de Madrid via Project SUSTEC-CM S2018/EMT-4348; MICINN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” via Project RTI2018-096080-B-C22; and MICINN via Project TED2021-132122B-C21

Endophytic Fungi as Pretreatment to Enhance Enzymatic Hydrolysis of Olive Tree Pruning

Olive tree pruning, as one of the most abundant lignocellulosic residues in Mediterranean countries, has been evaluated as a source of sugars for fuel and chemicals production. A mild acid pretreatment has been combined with a fungal pretreatment using either two endophytes (Ulocladium sp. and Hormonema sp.) or a saprophyte (Trametes sp. I-62). The use of endophytes is based on the important role that some of them play during the initial stages of wood decomposition. Without acid treatment, fungal pretreatment with Ulocladium sp. provided a nonsignificant enhancement of 4.6% in glucose digestibility, compared to control. When a mild acid hydrolysis was carried out after fungal pretreatments, significant increases in glucose digestibility from 4.9% to 12.0% (compared to control without fungi) were observed for all fungal pretreatments, with maximum values yielded by Hormonema sp. However, despite the observed digestibility boost, the total sugar yields (taking into account solid yield) were not significantly increased by the pretreatments. Nevertheless, based on these preliminary improvements in digestibility, this work proves the potential of endophytic fungi to boost the production of sugar from olive tree pruning, which would add an extra value to the bioeconomy of olive crops

Correction : Chaparro et al. Incidence, Clinical Characteristics and Management of Inflammatory Bowel Disease in Spain: Large-Scale Epidemiological Study. J. Clin. Med. 2021, 10, 2885

The authors wish to make the following corrections to this paper [...]

Incidence, Clinical Characteristics and Management of Inflammatory Bowel Disease in Spain : Large-Scale Epidemiological Study

(1) Aims: To assess the incidence of inflammatory bowel disease (IBD) in Spain, to describe the main epidemiological and clinical characteristics at diagnosis and the evolution of the disease, and to explore the use of drug treatments. (2) Methods: Prospective, population-based nationwide registry. Adult patients diagnosed with IBD-Crohn's disease (CD), ulcerative colitis (UC) or IBD unclassified (IBD-U)-during 2017 in Spain were included and were followed-up for 1 year. (3) Results: We identified 3611 incident cases of IBD diagnosed during 2017 in 108 hospitals covering over 22 million inhabitants. The overall incidence (cases/100,000 person-years) was 16 for IBD, 7.5 for CD, 8 for UC, and 0.5 for IBD-U; 53% of patients were male and median age was 43 years (interquartile range = 31-56 years). During a median 12-month follow-up, 34% of patients were treated with systemic steroids, 25% with immunomodulators, 15% with biologics and 5.6% underwent surgery. The percentage of patients under these treatments was significantly higher in CD than UC and IBD-U. Use of systemic steroids and biologics was significantly higher in hospitals with high resources. In total, 28% of patients were hospitalized (35% CD and 22% UC patients, p < 0.01). (4) Conclusion: The incidence of IBD in Spain is rather high and similar to that reported in Northern Europe. IBD patients require substantial therapeutic resources, which are greater in CD and in hospitals with high resources, and much higher than previously reported. One third of patients are hospitalized in the first year after diagnosis and a relevant proportion undergo surgery

IL-6 serum levels predict severity and response to tocilizumab in COVID-19: An observational study

Background: Patients with coronavirus disaese 2019 (COVID-19) can develop a cytokine release syndrome that eventually leads to acute respiratory distress syndrome requiring invasive mechanical ventilation (IMV). Because IL-6 is a relevant cytokine in acute respiratory distress syndrome, the blockade of its receptor with tocilizumab (TCZ) could reduce mortality and/or morbidity in severe COVID-19. Objective: We sought to determine whether baseline IL-6 serum levels can predict the need for IMV and the response to TCZ. Methods: A retrospective observational study was performed in hospitalized patients diagnosed with COVID-19. Clinical information and laboratory findings, including IL-6 levels, were collected approximately 3 and 9 days after admission to be matched with preadministration and postadministration of TCZ. Multivariable logistic and linear regressions and survival analysis were performed depending on outcomes: need for IMV, evolution of arterial oxygen tension/fraction of inspired oxygen ratio, or mortality. Results: One hundred forty-six patients were studied, predominantly males (66%); median age was 63 years. Forty-four patients (30%) required IMV, and 58 patients (40%) received treatment with TCZ. IL-6 levels greater than 30 pg/mL was the best predictor for IMV (odds ratio, 7.1; P < .001). Early administration of TCZ was associated with improvement in oxygenation (arterial oxygen tension/fraction of inspired oxygen ratio) in patients with high IL-6 (P = .048). Patients with high IL-6 not treated with TCZ showed high mortality (hazard ratio, 4.6; P = .003), as well as those with low IL-6 treated with TCZ (hazard ratio, 3.6; P = .016). No relevant serious adverse events were observed in TCZ-treated patients. Conclusions: Baseline IL-6 greater than 30 pg/mL predicts IMV requirement in patients with COVID-19 and contributes to establish an adequate indication for TCZ administrationThis study was funded by Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and Instituto de Salud Carlos III (grant nos. RD16/0011/0012 and PI18/ 0371 to I.G.A., grant no. PI19/00549 to A.A., and grant no. SAF2017-82886-R to F.S.-M.) and co-funded by the European Regional Development Fund. The study was also funded by ‘‘La Caixa Banking Foundation’’ (grant no. HR17-00016 to F.S.-M.) and ‘‘Fondos Supera COVID19’’ by Banco de Santander and CRUE. None of these sponsors have had any role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publicatio