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1.
Int J Biol Macromol ; 263(Pt 1): 130111, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38346614

RESUMEN

Sugarcane bagasse was pretreated with dilute phosphoric acid or sulfuric acid to facilitate cellulose hydrolysis and lignin extraction. With phosphoric acid, only 8 % of the initial cellulose was lost after delignification, whereas pretreatment with sulfuric acid resulted in the solubilization of 38 % of the initial cellulose. After enzymatic hydrolysis, the process using phosphoric acid produced approximately 35 % more glucose than that using sulfuric acid. In general, the lignins showed 95-97 % purity (total lignin, w/w), an average molar mass of 9500-10,200 g mol-1, a glass transition temperature of 140-160 °C, and a calorific value of 25 MJ kg-1. Phosphoric acid lignin (PAL) was slightly more polar than sulfuric acid lignin (SAL). PAL had 13 % more oxidized units and 20 % more OH groups than SAL. Regardless of the acid used, the lignins shared similar properties, but differed slightly in the characteristics of their functional groups and chemical bonds. These findings show that pretreatment catalyzed with either of the two acids resulted in lignin with sufficiently good characteristics for use in industrial processes.


Asunto(s)
Celulosa , Saccharum , Celulosa/química , Lignina/química , Saccharum/química , Hidrólisis , Ácidos Fosfóricos , Ácidos Sulfúricos
2.
Acta fisiátrica ; 25(4)dez. 2018.
Artículo en Inglés, Portugués | LILACS | ID: biblio-1000038

RESUMEN

Objetivo: Avaliar a velocidade de movimento de extensão do tronco, em três fases angulares, dentro do intervalo de movimento de 15 graus por segundo (º/s) a 60º/s, em uma pessoa com dupla hemiparesia, após traumatismo crânio encefálico. Métodos: A amostra foi composta por um participante do sexo masculino, idade 18 anos, com dupla hemiparesia predominante à direita, limitação de amplitude de movimento de quadril e joelho direito após TCE causado por acidente automobilístico. A força muscular dos extensores do tronco foi verificada por meio da avaliação isocinética, em um dinamômetro da marca Cybex® modelo 6000. O programa de treinamento isocinético foi realizado duas vezes por semana, em sessões de 60 minutos, durante 35 semanas no Serviço de Condicionamento Físico - IMREA HCFMUSP, unidade Vila Mariana, São Paulo / SP. Resultados: Após 10 sessões, o pico do torque apresentou aumento de 193,0% e 160,0% na força muscular concêntrica dos extensores do tronco realizada em velocidade angular de 15 e 30 graus por segundo respectivamente e, após 70 sessões, a melhora apresentada foi de 102% para velocidade angular de 60 graus por segundo. Conclusão: O treinamento isocinético pode contribuir para melhora da força muscular dos extensores do tronco de um adulto jovem com sequela neurológica após traumatismo crânio-encefálico, contribuindo para melhora do equilíbrio, diminuição de dores e de riscos de futuras lesões musculoesqueléticas.


Objective: The objective of this study was to evaluate the velocity of trunk extension movement, in three angular phases, within the range of 15 degrees per second (º/s) at 60º/s, in a person with double hemiparesis after traumatic brain injury. Methods: The sample consisted of a male participant, 18 years old, with predominant right hemiparesis, limitation of range of motion of the hip and right knee after TBI caused by automobile accident. The muscle strength of the trunk extensors was verified by isokinetic evaluation in a Cybex® model 6000 dynamometer. The isokinetic training program was performed twice a week, in 60-minute sessions, for 35 weeks. Results: After 10 sessions, the peak torque increase 193.0% and 160.0% in the concentric muscle strength of the trunk extensors performed at angular velocity of 15 and 30 degree per second respectively and, after 70 sessions, the improvement presented was 102% for angular velocity of 60 degree per second. Conclusion: Isokinetic training may contribute to the improvement of the muscular strength of the trunk extensors of a young adult with a neurological sequel after traumatic brain injury, and contributes to an improvement in balance, a decrease in pain and risk of future musculoskeletal injuries.


Asunto(s)
Humanos , Masculino , Adolescente , Fuerza Muscular , Dinamómetro de Fuerza Muscular , Lesiones Traumáticas del Encéfalo/patología , Paresia/fisiopatología
3.
Bioresour Technol ; 257: 172-180, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29500951

RESUMEN

The full use of biomass in future biorefineries has stimulated studies on utilization of lignin from agricultural crops, such as coffee husk, a major residue from coffee processing. This study focuses on characterizing the lignin obtained from coffee husk and its further wet oxidation products as a function of alkali loading, temperature and residence time. The lignin fraction after diluted acid and alkali pretreatments is composed primarily of p-hydroxylphenyl units (≥49%), with fewer guaiacyl and syringyl units. Linkages appear to be mainly ß-O-4 ether linkages. Thermal degradation of pretreated lignin during wet oxidation occurred in two stages. Carboxylic acids were the main degradation product. Due to the condensed structure of this lignin, relatively low yields of aromatic aldehydes were achieved, except with temperatures over 210 °C, 5 min residence time and 11.7 wt% NaOH. Optimization of the pretreatment and oxidation parameters are important to maximizing yield of high-value bioproducts from lignin.


Asunto(s)
Coffea , Lignina , Álcalis , Café , Oxígeno
4.
Carbohydr Polym ; 167: 280-289, 2017 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-28433164

RESUMEN

The synthesis and application of cellulose acetate (CA) from sugarcane bagasse were investigated. Firstly, cellulose was extracted by a sequential treatment with H2SO4 (10% v/v), NaOH (5% w/v), EDTA (0.5% w/V), and H2O2 (5% v/v), and characterized by X-ray diffraction (DRX). After the acetylation of the extracted cellulose, CA was characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA), and was applied in the membrane production. The membranes were analyzed by DSC and atomic force microscopy (AFM), and tested in the flux of water vapor to determinate the best conditions for membrane manufacturing. FTIR analysis proved the replacement of free OH groups by acetyl groups, and the thermal analysis showed that sugarcane bagasse CA possessed thermal properties compared to commercial grade CA. The best conditions to prepare membrane were: 3% (w/v) of polymer/solvent relation, 10min of solvent evaporation time, and 20°C as temperature for the coagulation bath. These results show that CA can be successfully synthesized from sugarcane bagasse and applied in membrane preparation.

5.
J Agric Food Chem ; 61(24): 5841-7, 2013 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-23738592

RESUMEN

Plant cell walls contain water, especially under biological and wet processing conditions. The present work characterizes this water in tissues of sugarcane stalks. Environmental scanning electron microscopy shows tissue deformation upon drying. Dynamic vapor sorption determines the equilibrium and kinetics of moisture uptake. Thermoporometry by differential scanning calorimetry quantifies water in nanoscale pores. Results show that cell walls from top internodes of stalks are more deformable, slightly more sorptive to moisture, and substantially more porous. These differences of top internode are attributed to less lignified walls, which is confirmed by lower infrared spectral signal from aromatics. Furthermore, cell wall nanoscale porosity, an architectural and not directly compositional characteristic, is shown to be tissue-specific. Nanoscale porosities are ranked as follows: pith parenchyma > pith vascular bundles > rind. This ranking coincides with wall reactivity and digestibility in grasses, suggesting that nanoscale porosity is a major determinant of wall recalcitrance.


Asunto(s)
Pared Celular/química , Productos Agrícolas/química , Tallos de la Planta/química , Saccharum/química , Agua/análisis , Brasil , Pared Celular/metabolismo , Pared Celular/ultraestructura , Fenómenos Químicos , Productos Agrícolas/metabolismo , Productos Agrícolas/ultraestructura , Tallos de la Planta/metabolismo , Tallos de la Planta/ultraestructura , Saccharum/metabolismo , Saccharum/ultraestructura , Agua/metabolismo
6.
Bioresour Technol ; 130: 168-73, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23306125

RESUMEN

Steam explosion at 180, 190 and 200°C for 15min was applied to sugarcane straw in an industrial sugar/ethanol reactor (2.5m(3)). The pretreated straw was delignificated by sodium hydroxide and hydrolyzed with cellulases, or submitted directly to enzymatic hydrolysis after the pretreatment. The pretreatments led to remarkable hemicellulose solubilization, with the maximum (92.7%) for pretreatment performed at 200°C. Alkaline treatment of the pretreated materials led to lignin solubilization of 86.7% at 180°C, and only to 81.3% in the material pretreated at 200°C. All pretreatment conditions led to high hydrolysis conversion of cellulose, with the maximum (80.0%) achieved at 200°C. Delignification increase the enzymatic conversion (from 58.8% in the cellulignin to 85.1% in the delignificated pulp) of the material pretreated at 180°C, but for the material pretreated at 190°C, the improvement was less remarkable, while for the pretreated at 200°C the hydrolysis conversion decreased after the alkaline treatment.


Asunto(s)
Biocombustibles , Celulosa/metabolismo , Etanol/metabolismo , Saccharum/metabolismo , Vapor , Hidrólisis
7.
Bioresour Technol ; 111: 447-52, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22391588

RESUMEN

Five pilot-scale steam explosion pretreatments of sugarcane bagasse followed by alkaline delignification were explored. The solubilised lignin was precipitated with 98% sulphuric acid. Most of the pentosan (82.6%), and the acetyl group fractions were solubilised during pretreatment, while 90.2% of cellulose and 87.0% lignin were recovered in the solid fraction. Approximately 91% of the lignin and 72.5% of the pentosans contained in the steam-exploded solids were solubilised by delignification, resulting in a pulp with almost 90% of cellulose. The acidification of the black liquors allowed recovery of 48.3% of the lignin contained in the raw material. Around 14% of lignin, 22% of cellulose and 26% of pentosans were lost during the process. In order to increase material recovery, major changes, such as introduction of efficient condensers and the reduction in the number of washing steps, should be done in the process setup.


Asunto(s)
Álcalis/química , Lignina/química , Proyectos Piloto , Solubilidad , Vapor
8.
J Ind Microbiol Biotechnol ; 38(7): 809-17, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20740373

RESUMEN

This work aims to evaluate the fermentability of cellulosic hydrolysates obtained by enzymatic saccharification of sugarcane bagasse pretreated by hydrothermal processing using Candida guilliermondii FTI 20037 yeast. The inoculum was obtained from yeast culture in a medium containing glucose as a carbon source supplemented with rice bran extract, CaCl(2)·2H(2)O and (NH(4))(2)SO(4) in 50 mL Erlenmeyer flasks, containing 20 mL of medium, initial 5.5 pH under agitation of an orbital shaker (200 rpm) at 30°C for 24 h. The cellulosic hydrolysates, prior to being used as a fermentation medium, were autoclaved for 15 min at 0.5 atm and supplemented with the same nutrients employed for the inoculum, except the glucose, using the same conditions for the inoculum, but with a period of 48 h. Preliminary results showed the highest consumption of glucose (97%) for all the hydrolysates, at 28 h of fermentation. The highest concentration of ethanol (20.5 g/L) was found in the procedure of sugarcane bagasse pretreated by hydrothermal processing (195°C/10 min in 20 L reactor) and delignificated with NaOH 1.0% (w/v), 100°C, 1 h in 500 mL stainless steel ampoules immersed in an oil bath.


Asunto(s)
Celulosa/metabolismo , Etanol/metabolismo , Fermentación , Saccharum/metabolismo , Candida/metabolismo , Metabolismo de los Hidratos de Carbono , Celulosa/química , Calor , Hidrólisis , Agua
9.
Appl Biochem Biotechnol ; 154(1-3): 38-47, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19214797

RESUMEN

Ethanol/water organosolv pulping was used to obtain sugarcane bagasse pulp that was bleached with sodium chlorite. This bleached pulp was used to obtain cellulosic films that were further evaluated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). A good film formation was observed when temperature of 74 degrees C and baths of distilled water were used, which after FTIR, TGA, and SEM analysis indicated no significant difference between the reaction times. The results showed this to be an interesting and promising process, combining the prerequisites for a more efficient utilization of agro-industrial residues.


Asunto(s)
Celulosa/química , Óxidos N-Cíclicos/química , Morfolinas/química , Saccharum/química , Celulosa/ultraestructura , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
10.
Appl Biochem Biotechnol ; 147(1-3): 85-96, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18401755

RESUMEN

The effects of alkaline treatments of the wheat straw with sodium hydroxide were investigated. The optimal condition for extraction of hemicelluloses was found to be with 0.50 mol/l sodium hydroxide at 55 degrees C for 2 h. This resulted in the release of 17.3% of hemicellulose (% dry starting material), corresponding to the dissolution of 49.3% of the original hemicellulose. The yields were determined by gravimetric analysis and expressed as a proportion of the starting material. Chemical composition and physico-chemical properties of the samples of hemicelluloses were elucidated by a combination of sugar analyses, Fourier transform infrared (FTIR), and thermal analysis. The results showed that the treatments were very effective on the extraction of hemicelluloses from wheat straw and that the extraction intensity (expressed in terms of alkali concentration) had a great influence on the yield and chemical features of the hemicelluloses. The FTIR analysis revealed typical signal pattern for the hemicellulosic fraction in the 1,200-1,000 cm(-1) region. Bands between 1,166 and 1,000 cm(-1) are typical of xylans.


Asunto(s)
Residuos Industriales/prevención & control , Componentes Aéreos de las Plantas/química , Polisacáridos/química , Polisacáridos/aislamiento & purificación , Hidróxido de Sodio/química , Triticum/química , Agricultura/métodos , Portugal
11.
Appl Biochem Biotechnol ; 148(1-3): 151-61, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18418748

RESUMEN

Agricultural residues as sugarcane straw and bagasse are burned in boilers for generation of energy in sugar and alcohol industries. However, excess of those by-products could be used to obtain products with higher value. Pulping process generates cellulosic pulps and lignin. The lignin could be oxidized and applied in effluent treatments for heavy metal removal. Oxidized lignin presents very strong chelating properties. Lignins from sugarcane straw and bagasse were obtained by ethanol-water pulping. Oxidation of lignins was carried out using acetic acid and Co/Mn/Br catalytical system at 50, 80, and 115 degrees C for 5 h. Kinetics of the reaction was accomplished by measuring the UV-visible region. Activation energy was calculated for lignins from sugarcane straw and bagasse (34.2 and 23.4 kJ mol(-1), respectively). The first value indicates higher cross-linked formation. Fourier-transformed infrared spectroscopy data of samples collected during oxidation are very similar. Principal component analysis applied to spectra shows only slight structure modifications in lignins after oxidation reaction.


Asunto(s)
Ácido Acético/química , Celulosa/química , Residuos Industriales/prevención & control , Lignina/química , Metales Pesados/química , Saccharum/química , Agricultura/métodos , Oxidación-Reducción , Componentes Aéreos de las Plantas/química
12.
Rev. bras. med. esporte ; 13(1): 6-10, jan.-fev. 2007. tab
Artículo en Portugués | LILACS | ID: lil-461044

RESUMEN

INTRODUÇÃO: Fibromialgia é uma síndrome crônica, caracterizada por dor músculo-esquelética generalizada. A possibilidade de atenuação dos sintomas com a atividade física abriu novas perspectivas para o tratamento desta doença. OBJETIVO: Avaliar o efeito de um programa de condicionamento físico sobre a capacidade funcional, dor e qualidade de vida de pacientes com fibromialgia. MÉTODOS: Adotado o desenho de coorte para avaliar 18 mulheres, média de 46,4 ± 5,8 anos de idade, com a síndrome em média de 10,6 ± 5,7 anos, submetidas a um ano de condicionamento físico supervisionado, predominantemente aeróbio. No início do estudo e trimestralmente foram realizados: teste de esforço cardiopulmonar para determinação da capacidade funcional; avaliação da intensidade de dor empregando a escala analógica visual; contagem dos pontos dolorosos e determinação do limiar de dor à pressão com o uso do algômetro de pressão; aplicação do questionário de qualidade de vida Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) traduzido e adaptado para a população brasileira. RESULTADOS: A capacidade funcional melhorou a partir do terceiro mês (p < 0,05), o limiar de dor aumentou a partir do sexto mês (p < 0,05), houve diminuição da dor pós-esforço (p < 0,05) e do número de pontos sensíveis (p < 0,05) no nono mês. A intensidade de dor diminuiu no 12° mês (p < 0,05). Com exceção do item "estado geral de saúde" (p > 0,05), os demais domínios do questionário de qualidade de vida melhoraram em diferentes períodos do estudo (p < 0,05). CONCLUSÃO: As pacientes com fibromialgia submetidas ao programa de condicionamento físico supervisionado apresentaram melhora da capacidade funcional, da dor e da qualidade de vida.


INTRODUCTION: Fibromyalgia is a chronic syndrome characterized by widespread musculoskeletal pain. Possible symptom attenuation with physical exercise has opened new perspective for treatment. OBJECTIVE: This study aimed to assess the effects of a program of physical exercises (SPPE) on the functional ability, perceived pain and life quality of patients with fibromyalgia. METHODS: A cohort of eighteen female fibromyalgia patients, mean age 46,4 ± 5,8 years, having the syndrome for 10,6 ± 5,7 years, were studied along one year of supervised program of predominantly aerobic physical exercises. Patients underwent baseline and quarterly exercise stress tests (EST) to evaluate work capacity; clinical examinations to determine pain intensity through visual analogue scale; tender points count and pain threshold assessment by pressure algometer; as well as interviews using the "Medical Outcomes Study 36-Item Short-Form Health Survey" (SF-36) questionnaire. RESULTS: Work capacity improved from the third month (p < 0,05); pain threshold increased from the sixth month (p < 0,05); post-exertion pain improved (p < 0,05) and number of tender points decreased (p < 0,05) in the ninth month. Pain intensity decreased in the twelfth month (p < 0,05). Except for the "general health perceptions" domain (p > 0,05), all the remaining issues of the SF-36 improved at different periods of the study (p < 0,05). CONCLUSION: Work capacity, pain and life quality of female fibromyalgia patients improved over a 12-month program of supervised physical exercise.


INTRODUCCION: La fibromialgia es un síndrome crónico, caracterizado por dolor músculo-esquelético generalizado. La posibilidad de atenuación de los síntomas con la actividad física abrió nuevas perspectivas para el tratamiento de esta enfermedad. OBJETIVO: Evaluar el efecto de un programa de condicionamiento físico sobre la capacidad funcional, dolor y calidad de vida de pacientes con fibromialgia. MÉTODOS: Adoptado el método de aglomeración para evaluar 18 mujeres, con edad media de 46,4 ± 5,8 años, con el síndrome en media hace 10,6 ± 5,7 años, sometidas a un ano de condicionamiento físico supervisado, predominantemente aeróbico. Al iniciar el estudio y trimestralmente, fueron realizados: test de esfuerzo cardiopulmonar para determinar la capacidad funcional; evaluación de la intensidad de dolor empleando la escala analógica visual; contaje de puntos dolorosos y determinación del límite del dolor a la presión con el uso del algómetro de presión; aplicación de cuestionario de calidad de vida "Medical Outcomes Study 36-Item Short-Form Health Survey" (SF-36) traducido y adaptado para la población brasileña. RESULTADOS: La capacidad funcional mejoró a partir del tercer mes (p < 0,05), la resistencia al dolor aumentó a partir del sexto mes (p < 0,05), hubo disminución de dolor pos esfuerzo (p < 0,05) y el número de puntos sensibles (p < 0,05) al noveno mes. La intensidad de dolor disminuyó al décimo segundo mes (p < 0,05). Con excepción del ítem "estado general de salud" (p > 0,05), los demás dominios del cuestionario de calidad de vida mejoraron en diferentes periodos del estudio (p < 0,05). CONCLUSION: Las pacientes con fibromialgia sometidas al programa de condicionamiento físico supervisado presentaron mejora de la capacidad funcional, dolor y calidad de vida.


Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Dolor Musculoesquelético/terapia , Ejercicio Físico , Prueba de Esfuerzo , Fibromialgia , Calidad de Vida , Dimensión del Dolor
13.
Appl Biochem Biotechnol ; 137-140(1-12): 501-13, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18478412

RESUMEN

The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 2(2) design was applied for temperatures of 185 and 215 degrees C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200 degrees C cooking temperature for 2 h with 50% ethanol-water concentration, and 1:10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50 degrees C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp.


Asunto(s)
Bacillus/enzimología , Técnicas Químicas Combinatorias/métodos , Endo-1,4-beta Xilanasas/química , Etanol/química , Componentes Aéreos de las Plantas/química , Saccharum/química , Agua/química
14.
Appl Biochem Biotechnol ; 137-140(1-12): 573-82, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18478417

RESUMEN

Sugar cane bagasse pulps were obtained by ethanol/water organosolv process under acid and alkaline conditions. The best condition of acid pulping for the sugarcane bagasse was 0.02 mol/L sulfuric acid at 160 degrees C, for 1 h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160 degrees C, for 3 h. For the residual lignin removal, the acid and alkaline pulps were submitted to a chemical bleaching using sodium chlorite. Pulps under acid and alkaline conditions bleached with sodium chlorite presented viscosities of 3.6 and 7.8 mPa x s, respectively, and mu-kappa numbers of 1.1 and 2.4, respectively. The pulp under acid condition, bleached with sodium chlorite was used to obtain carboxymethylcellulose (CMC). CMC yield was 35% (pulp based), showing mass gain after the carboxymethylation reaction corresponding to 23.6% of substitution or 0.70 groups -CH(2) COONa per unit of glucose residue. The infrared spectra showed the CMC characteristic bands and by the infrared technique it was possible to obtain a substitution degree (0.63), similar to the substitution degree calculated by mass gain (0.70).


Asunto(s)
Ácidos/química , Carboximetilcelulosa de Sodio/síntesis química , Etanol/química , Compuestos Orgánicos/química , Componentes Aéreos de las Plantas/química , Saccharum/química , Solventes/química , Agua/química , Álcalis/química , Concentración de Iones de Hidrógeno
15.
Appl Biochem Biotechnol ; 129-132: 320-5, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16915650

RESUMEN

Oxidation of lignin obtained from acetosolv and ethanol/water pulping of sugarcane bagasse was performed by phenol oxidases: tyrosinase (TYR) and laccase (LAC), to increase the number of carbonyl and hydroxyl groups in lignin, and to improve its chelating capacity. The chelating properties of the original and oxidized lignins were compared by monitoring the amount of Cu2+ bound to lignin by gel permeation chromatography. The Acetosolv lignin oxidized with TYR was 16.8% and with LAC 21% higher than that of the original lignin. For ethanol/water lignin oxidized with TYR was 17.2% and with LAC 18% higher than that of the original lignin.


Asunto(s)
Agaricales/enzimología , Celulosa/química , Quelantes/síntesis química , Lacasa/química , Lignina/química , Monofenol Monooxigenasa/química , Solanum tuberosum/enzimología , Oxidación-Reducción
16.
Appl Biochem Biotechnol ; 129-132: 326-33, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16915651

RESUMEN

In this work, pretreatment-enzymatic series of the bagasse-sugarcane pulp and alkaline extraction of enzyme treated pulp were carried out. In the pretreatment an enzyme dose was utilized and acetosolv pulp suspension of 3% (w/v) with different solvents (distilled water, 0.05 mol/L acetate buffer pH 5.5 and 0.05 mol/L phosphate buffer pH 7.25) stirred at 85 rpm for 2 or 4 h. The enzymes used were pulpzyme and cartazyme, both commercial. The accompaniment of the enzymatic activity was carried out through measurement in initial and finish of each enzymatic pretreatment. The xylanase-treated pulps and xylanase-alkaline-extracted pulps were analyzed regarding kappa number and viscosity. Pulpzyme recovery was better in phosphate buffered medium (84, 46, and 23% for first, second, and third enzymatic treatment, respectively) although in aqueous medium reached only 2% for every treatments. However, the improvement of pulp properties was evidenced only in aqueous medium for pulpzyme. Cartazyme recovery was similar for both solvents (water and acetate buffer), reaching values around 19% for first enzymatic treatment and 9% for second one. Nevertheless, the pulp properties increased only in acetate buffered medium.


Asunto(s)
Ácido Acético/química , Celulosa/química , Endo-1,4-beta Xilanasas/química , Endo-1,4-beta Xilanasas/aislamiento & purificación , Saccharum/química , Solventes/química
17.
Appl Biochem Biotechnol ; 121-124: 821-6, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15930561

RESUMEN

Sugarcane bagasse and straw can be converted into pulps, oils, controlled-release formulations, chelating agents, and composites. This article reviews bagasse and straw conversion efforts in Brazil. Laboratory-scale processes were developed aiming at the integral use of these biomass byprod ucts. Organosolv pulping and oxidation of lignin are the most promising processes for the rational use of sugarcane residues. Fungal pretreatment and spectroscopic characterization are also discussed.


Asunto(s)
Celulosa/química , Industria Química/métodos , Lignina/química , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/microbiología , Saccharum/química , Saccharum/microbiología , Brasil , Industria Química/tendencias , Integración de Sistemas
18.
Appl Biochem Biotechnol ; 121-124: 171-81, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15917597

RESUMEN

Organosolv (ethanol/water and acetosolv) pulps were treated with Bacillus pumilus xylanase for 4, 8, and 12 h and compared with commercial Cartazyme HS xylanase-treated pulps. Treatment of ethanol/water pulps with B. pumilus xylanase increased viscosity by 40% in 8 h of treatment compared with pulps treated without enzyme. However, acetosolv pulps treated with B. pumilus xylanase lost viscosity. Ethanol/water pulps treated with Cartazyme had a viscosity of 18.5 cP in 4 h of treatment. In the acetosolv pulps treated with commercial enzyme, the loss of viscosity was 20% compared with pulps treated without enzyme. Ethanol/water pulps treated with B. pumilus and Cartazyme had similar effects: a 44% reduction in kappa number for pulps treated with enzyme followed by alkaline extraction compared with pulps treated with alkaline extraction. In acetosolv pulps treated with B. pumilus, the kappa number was from 12 to 18, compared with pulps treated without enzyme, which had a 40% reduction in 4 and 12 h and a 60% reduction in 8 h. Cartazyme-treated acetosolv pulps had a kappa number of 14 in 4 and 8 h of treatment. For 12 h of treatment, the kappa number was 8. Fourier transform infrared spectra of the pulps showed that enzyme-treated pulps had changes in the 1000 cm-1 absorption owing to a C-O bond present in esters. Using principal component analysis, it is possible to differentiate the unbleached pulps and enzyme-treated pulps.


Asunto(s)
Bacillus/enzimología , Celulosa/química , Endo-1,4-beta Xilanasas/química , Endo-1,4-beta Xilanasas/clasificación , Etanol/química , Saccharum/química , Agua/química , Biotransformación , Celulosa/análisis , Residuos Industriales/prevención & control , Eliminación de Residuos/métodos , Viscosidad
19.
Appl Biochem Biotechnol ; 121-124: 195-203, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15917599

RESUMEN

Organosolv (ethanol/water and acetosolv) pulps were treated with Humicola grisea var. thermoidea and compared with Cartazyme HS xylanase-treated pulp. The ethanol/water pulps treated with H. grisea had the same viscosity as unbleached pulps (8 cP). Ethanol/water pulps treated with Cartazyme had higher viscosity than H. grisea-treated pulps (12 cP). Acetosolv pulps treated with H. grisea and Cartazyme presented a reduction in viscosity; however, the pulps treated with H. grisea had a lower reduction in viscosity than Cartazyme-treated pulps. Ethanol/water pulps treated with H. grisea had a 23% reduction in kappa number in 4 and 8 h of treatment, compared with the unbleached pulps. Cartazyme-treated pulps had a kappa number similar to that of the control pulps for 4 h of treatment. Extending the treatment time to 12 h resulted in a reduction of 33%. The acetosolv pulp treated with H. grisea had a kappa number reduced to 23% in 4 h. Cartazyme treatment resulted in a reduction of 55 and 44% in kappa number for 4 and 8 h of treatment, respectively, when compared with control pulp. Extending the treatment time to 12 h decreased the kappa number 72%. Fourier transform infrared spectra and principal component analysis showed differences among unbleached, H. grisea-treated, and Cartazyme-treated pulps.


Asunto(s)
Ascomicetos/enzimología , Bacillus/enzimología , Celulosa/química , Endo-1,4-beta Xilanasas/química , Etanol/química , Saccharum/química , Agua/química , Ascomicetos/genética , Biotransformación , Celulosa/análisis , Endo-1,4-beta Xilanasas/clasificación , Endo-1,4-beta Xilanasas/genética , Residuos Industriales/prevención & control , Proteínas Recombinantes/química , Eliminación de Residuos/métodos , Viscosidad
20.
Appl Biochem Biotechnol ; 121-124: 695-706, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15920273

RESUMEN

Sugarcane bagasse was pretreated with the white-rot fungus Ceriporiopsis subvermispora for 30 d of incubation. The solid-state fermentation of 800 g of bagasse was carried out in 20-L bioreactors with an inoculum charge of 250 mg of fungal mycelium/kg of bagasse. The oxidative enzymes manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase (Lac) and the hydrolytic enzyme xylanase (Xyl) were measured by standard methods and related to the fungus's potential for delignification. Among the lignocellulolytic assayed enzymes, Xyl was detected in larger quantity (4478 IU/kg), followed by MnP (236 IU/kg). LiP and Lac were not detected. The results of chemical analysis and mass component loss showed that C. subvermispora was selective to lignin degradation. Pretreated sugarcane bagasse and control pulps were obtained by soda/anthraquinone (AQ) pulping. Pulp yields, kappa number, and viscosity of all pulps were determined by chemical analysis of the samples. Yields of soda/AQ ranged from 46 to 54%, kappa numbers were 15-25, and the viscosity ranged from 3.6 to 7 cP for pulps obtained from pretreated sugarcane bagasse.


Asunto(s)
Antraquinonas/química , Basidiomycota/metabolismo , Reactores Biológicos/microbiología , Celulosa/química , Celulosa/metabolismo , Lignina/metabolismo , Modelos Biológicos , Saccharum/metabolismo , Basidiomycota/clasificación , Biodegradación Ambiental , Técnicas de Cultivo de Célula/métodos , Simulación por Computador , Residuos Industriales/prevención & control , Lignina/aislamiento & purificación , Eliminación de Residuos/métodos , Hidróxido de Sodio/química , Especificidad de la Especie
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