Changes in chemical composition of cover crops residue during decomposition / Mudanças na composição química dos resíduos culturais de plantas de cobertura durante a decomposição

Crop residues decomposition are controlled by chemical tissue components. This study evaluated changes on plant tissue components, separated by the Van Soest partitioning method, during cover crop decomposition. The Van Soest soluble fraction was the first to be released from the crop residues, followed by cellulose and hemicellulose. Lignin was the crop residue component that suffered the least degradation, and for certain crop residue types, lignin degradation was not detected. The degradation of the main components of crop residues (soluble fraction, cellulose, hemicellulose and lignin) is determined by the chemical and structural composition of each fraction.

A decomposição de resíduos culturais é controlada pela composição química do tecido vegetal. O objetivo deste estudo foi avaliar as alterações que ocorrem nos componentes do tecido vegetal, separados pelo fracionamento de Van Soest, durante a decomposição de plantas de cobertura. A fração solúvel foi a primeira a ser liberada dos resíduos culturais, seguida pela celulose e hemicelulose. A lignina foi o componente dos resíduos culturais de menor degradação, sendo que em alguns resíduos culturais não foi possível detectar a degradação deste componente. A degradação dos principais componentes dos resíduos culturais (fração solúvel, celulose, hemicelulose e lignina) é determinada pela composição química e estrutural de cada uma destas frações.

Comparative study on infection and degradation of Armillaria gallica and Phallus impudicus to fungus-growing materials / 中国中药杂志

The phenomenon that waste of fungus-growing materials in the planting process of Gastrodia elata is very common. It has been proved by practice that the used fungus-growing materials planted with G. elata can be used to plant Phallus impudicus. But the mechanism is unclear. In this study, we compared the different infested-capacity of Armillaria gallica and Phallus impudicus by morphological anatomy of the used fungus-growing materials. We also compared the differences on the two fungi consumed the main contents of fungus-growing materials, cellulose, lignin and hemicellulose, by using nitric acid-95% ethanol method, sulfuric acid method and tetrabromide method respectively, so that to explore the mechanism of A. gallica and P. impudicus recycle the fungus-growing materials, and to provide scientific basis for recycling the used fungus-growing materials of G. elata. The results showed that A. gallica had a strong ability to invade some parts outside the vascular cambium, but it had a weak ability to invade some parts inside the vascular cambium, while P. impudicus had a strong ability to invade the same parts. The contents of lignin and cellulose, which from inside and outside the vascular cambium of fungus-growing materials were significantly different. In the parts of outside the vascular cambium of fungus-growing materials, A. gallica degraded more lignin and cellulose, while P. impudicus degraded more hemicellulose. In the parts of inside the vascular cambium of fungus-growing materials, A. gallica degraded more cellulose, while P. impudicus degraded more hemicellulose. The present results suggested that A. gallica and P. impudicus made differential utilization of the carbon source in the fungus-growing materials to realize that P. impudicus recycle the used fungus-growing materials of G. elata. A. gallica used lignin and cellulose as the main carbon source, while P. impudicus used hemicellulose as the main carbon source.

Assessment of wasteland derived biomass for bioethanol production

Background: The bioethanol produced from biomass is a promising alternative fuel. The lignocellulose from marginal areas or wasteland could be a promising raw material for bioethanol production because it is present in large quantities, is cheap, renewable and has favorable environmental properties. Despite these advantages, lignocellulosic biomass is much more difficult to process than cereal grains, due to the need for intensive pretreatment and relatively large amounts of cellulases for efficient hydrolysis. Therefore, there is a need to develop an efficient and cost-effective method for the degradation and fermentation of lignocellulosic biomass to ethanol. Results: The usefulness of lignocellulosic biomass from wasteland for the production of bioethanol using pretreatment with the aid of ionic liquids of 1-ethyl-3-methylimidazolium acetate and 1-ethyl-3-methylimidazolium chloride was evaluated in this study. The pretreatment process, enzymatic hydrolysis and alcoholic fermentation lasted a total of 10 d. The largest amounts of bioethanol were obtained from biomass originating from agricultural wasteland, in which the dominant plant was fireweed (Chamaenerion angustifolium) and from the field where the common broom (Cytisus scoparius) was the dominant. Conclusions: The plants such as fireweed, common broom, hay and goldenrod may be useful for the production of liquid biofuels and it would be necessary in the further stage of research to establish and optimize the conditions for the technology of ethyl alcohol producing from these plant species. Enzymatic hydrolysis of biomass from agricultural wastelands results in a large increase in fermentable sugars, comparable to the enzymatic hydrolysis of rye, wheat, rice or maize straw.

Screening of lignocellulolytic fungi for hydrolyzation of lignocellulosic materials in paddy straw for bioethanol production

Aims@#Paddy straw is known to have lignocellulosic materials such as cellulose and hemicellulose which can be readily converted into fermentable sugar for production of bioethanol via simultaneous saccharification and fermentation (SSF). In order to produce ethanol competently, the degradation of biomass by cellulase and highly ethanol-producing microorganism in fermentation process are necessarily needed. However, there is lacking in cellulose degrading organism in producing adequate amount of lignocellulosic enzyme. Therefore, the screening and selection for the best fungi to hydrolyze the lignocellulosic materials as well as forming consortium between two species of fungi has become the main focus. @*Methodology and results@#Thirteen strains of fast-growing fungi were tested qualitatively for cellulase (congo red staining) and polyphenol oxidase (Bavendamm test). All tested strains displayed lignocellulolytic fungi characteristics. The selection was narrowed down by quantitative assay on endoglucanase, exoglucanase, β-glucosidase and xylanase and the highest cellulases enzyme producer were Trichoderma asperellum B1581 (3.93 U/mL endoglucanase; 2.37 U/mL exoglucanase; 3.00 IU/mL β-glucosidase; 54.87 U/mL xylanase), followed by Aspergillus niger B2484 (5.60 U/mL endoglucanase; 1.08 U/mL exoglucanase; 1.57 IU/mL β-glucosidase; 56.85 U/mL xylanase). In compatibility test, both T. asperellum B1581 and A. niger B2484 were inoculated on the same Petri dish for 4 days and the interaction showed by the two species was mutual intermingling. @*Conclusions, significance and impact of study@#Both T. asperellum B1581 and A. niger B2484 produced the highest cellulase enzyme. Since both strains can co-exist and produce enzymes that complete each other, a fungal consortium was suggested to increase the yield of sugars in saccharification process.

Production optimization, purification, expression, and characterization of a novel α-L-arabinofuranosidase from Paenibacillus polymyxa

Background: α-L-Arabinofuranosidase (EC 3.2.1.55) catalyzes the hydrolysis of terminal α-L-1,2-, -1,3-, and -1,5- arabinofuranosyl residues in arabinose-containing polymers, and hence, it plays an important role in hemicellulose degradation. Herein, the bacterium Paenibacillus polymyxa, which secretes arabinofuranosidase with high activity, was selected for enzyme production, purification, and characterization. Results: Medium components and cultural conditions were optimized by the response surface method using shake flask cultures. Arabinofuranosidase production reached 25.2 U/mL under optimized conditions, which were pH 7.5, 28°C, and a basic medium supplemented with 1.5 g/L mannitol and 3.5 g/L soymeal. Furthermore, the arabinofuranosidase secreted by P. polymyxa, named as PpAFase-1, was partially purified from the supernatant using a DEAE Sepharose Fast Flow column and a hydroxyapatite column. The approximate molecular mass of the purified PpAFase-1 was determined as 56.8 kDa by SDS-PAGE. Protein identification by mass spectrometry analysis showed that the deduced amino acid sequence had significant similarity to the glycosyl hydrolase family 51. The deduced gene of 1515 bp was cloned and expressed in Escherichia coli BL21 (DE3) cells. Purified recombinant PpAFase-1 was active toward p-nitrophenyl-α-L-arabinofuranoside (pNPAraf). The Km and kcat values toward pNPAraf were 0.81 mM and 53.2 s−1 , respectively. When wheat arabinoxylan and oat spelt xylan were used as substrates, PpAFase-1 showed poor efficiency. However, a synergistic effect was observed when PpAFase-1 was combined with xylanase from Thermomyces lanuginosus. Conclusion: A novel GH51 enzyme PpAFase-1 was cloned from the genome of P. polymyxa and expressed in E. coli. This enzyme may be suitable for hemicellulose degradation on an industrial scale.

Agroindustrial biomass for xylanase production by Penicillium chrysogenum: purification, biochemical properties and hydrolysis of hemicelluloses

Background: In this work, the xylanase production by Penicillium chrysogenum F-15 strain was investigated using agroindustrial biomass as substrate. The xylanase was purified, characterized and applied in hemicellulose hydrolysis. Results: The highest xylanase production was obtained when cultivation was carried out with sugar cane bagasse as carbon source, at pH 6.0 and 20°C, under static condition for 8 d. The enzyme was purified by a sequence of ion exchange and size exclusion chromatography, presenting final specific activity of 834.2 U·mg·prot-1. T he molecular mass of the purified enzyme estimated by SDS-PAGE was 22.1 kDa. The optimum activity was at pH 6.5 and 45°C. The enzyme was stable at 40°C with half-life of 35 min, and in the pH range from 4.5 to 10.0. The activity was increased in the presence of Mg+2 and Mn+2 and reducing agents such as DTT and ßmercaptoethanol, but it was reduced by Cu+2 and Pb+2 . The xylanase presented Km of 2.3 mM and Vmax of 731.8 U·mg·prot-1 with birchwood xylan as substrate. This xylanase presented differences in its properties when it was compared to the xylanases from other P. chrysogenum strains. Conclusion: The xylanase from P. chrysogenum F-15 showed lower enzymatic activity on commercial xylan than on hemicellulose from agroindustry biomass and its biochemistry characteristics, such as stability at 40°C and pH from 4.0 to 10.0, shows the potential of this enzyme for application in food, feed, pulp and paper industries and for bioethanol production.

Ethanol production from Rice (Oryza sativa) straw by simultaneous saccharification and cofermentation.

Ethanol production from alkali treated rice straw was investigated by simultaneous saccharification and cofermentation (SSCF) using commercial cellulase and 3 different yeast strains viz., Saccharomyces cerevisiae HAU-1, Pachysolen tannophilus and Candida sp. individually as well as in combination at varied fermentation temperature and incubation time. Dilute alkali (2%) pretreatment of straw resulted in efficient delignification as observed by low residual lignin (12.52%) with 90.6% cellulose and 28.15% hemicellulose recovery. All the 3 yeast strains were able to produce ethanol form alkali treated rice straw and overall ethanol concentration varied from 5.30 to 24.94 g/L based on different fermentation time and temperature. Comparative analysis of ethanol production from different yeast strains combinations revealed maximum ethanol concentration of 23.48 g/L after 96 h incubation at 35ºC with P. tannophilus individually and 24.94 g/L when used as co-culture with Saccharomyces cerevisiae.

Quantitative and qualitative characteristics of elephant grass (Pennisetum purpureum Schum) clones in the semi-arid lands of Pernambuco (Brazil) / Características cuantitativas y cualitativas de clones pasto elefante (Pennisetum purpureum Schum) en las tierras semi-áridas de Pernambuco (Brasil) / Características quantitativas e qualitativas de clones de capim-elefante (Pennisetum purpureum Schum) no semi-árido pernambucano (Brasil)

Background: the efficient use of good quality forage represents one of many ways to improve animal productivity and, consequently, reduce the feed costs of dairy farming. Between the wide variety of studies aiming to improve the nutritional value of forage, histological studies, allow for both the comparison of species or cultivars and the monitoring of tissue aging within the plant. Objective: the present work aimed to characterize the stem morphology of Pennisetum clones (Itambé IV-46, Itambé I-1.20, Itambé I-1.4, Milheto x Buaçu/112-23.4, Cuba-116-29.3, CAC-262-12.102, Roxo of Botucatu x CAC-282-18.29, Taiwan-146-2.6, Itambé I-1.5, Pusa Napier or 419-76 x Buaçu/122-11.2, Taiwan-146-2.03, Taiwan-146-2.85, Itambé II-2.46, Pusa Napier or 419-76 x Cuba-116-12.3 and Pusa Napier or 412-76 x Buaçu/122-8.22) into three strata (basal, medium and apical) and three tillers of the plant using histological sections. Methods: the material was collected in a previously established area at the Experimental Station of São Bento do Una at the Agronomic Institute of Pernambuco. The materials were distributed in a completely randomized 15 x 3 x 3 factorial design (14 clones and one hybrid, three layers of stem and three tillers). The samples were collected during the dry season beginning in August 2008. Results: there were significant differences (p<0.05) among the clones evaluated, and the average values for the lignified cells in the cortex region ranged from 2.21 to 4.21 for the Taiwan-146-2.6 and Roxo of Botucatu x CAC-282-18.29 clones; however, this was not different from the other clones in the medullary region. The Itambé II-2.46 clone showed the highest absolute value in the percentage of phloem in the cortex region (2.32%) and a high value, with significant differences, in the medullary region (1.59%) compared to the other clones. Conclusion: the highest values of cellulose in the medium and apical regions of the studied stems represent a benefit to grazing animals.

Antecedentes: el uso eficiente de forraje de buena calidad es una de las muchas maneras de mejorar la productividad animal y por lo tanto reducir el costo de la alimentación del ganado lechero. Entre la variedad de estudios que permiten mejorar el valor nutritivo del forraje, los estudios histológicos se destacan, porque permiten tanto la comparación de especies o cultivares y el seguimiento del envejecimiento de los tejidos con la madurez de la planta. Objetivo: el presente trabajo tuvo como objetivo caracterizar la morfología del tallo de los clones de Pennisetum (Itambé IV-46, I-Itambé 1.20, Itambé I-1.4, Milheto x Buaçu/112-23.4, Cuba- 116-29.3, el CAC-262-12.102, Roxo de Botucatu x CAC-282-18.29, Taiwán-146-2.6, Itambé I-1.5, Pusa Napier o 419-76 x Buaçu/122-11.2, Taiwan-146-2.03, Taiwán-146-2.85, Itambé II-2.46 , Pusa Napier 419-76 x Cuba-116-12.3 y Napier Pusa o 412-76 x Buaçu/122-8.22) en tres estratos (basal, medio y apical) y tres tallos de la planta con los cortes histológicos. Métodos: el material se recogió en una zona ya establecida en la Estación Experimental de São Bento do Una en el Instituto Agronómico de Pernambuco. Los materiales se distribuyeron en un diseño factorial completamente al azar de 15 x 3 x 3 (14 clones y un híbrido, tres capas de la madre y los tallos de tres). Las muestras fueron recolectadas durante la estación seca comenzando en agosto de 2008. Resultados: hubo diferencias significativas (p<0,05) entre los clones evaluados, y los valores promedio de las células lignificadas en la región de la corteza variaron desde 2,21 hasta 4,21 para los clones Taiwán-146-2.6 y Roxo de Botucatu X CAC-282-18.29, sin embargo, esto no fue diferente de los otros clones en la región medular. El clon Itambé II-2.46 mostró el mayor valor absoluto en el porcentaje de floema en la región de la corteza (2,32%) y un alto valor, con diferencias significativas, en la región medular (1,59%) en comparación con los otros clones. Conclusión: los valores más altos de celulosa en las regiones media y apical de los tallos estudiados representa un beneficio para los animales de pastoreo.

Antecedentes: o uso eficiente de forragem de boa qualidade representa uma das muitas maneiras de melhorar a produtividade animal e, consequentemente, reduzir os custos de alimentação da pecuária leiteira. Entre a variedade de estudos com o objetivo de melhorar o valor nutritivo da forragem, os estudos histológicos destacam-se, o que permite tanto a comparação de espécies ou cultivares e acompanhamento do envelhecimento dos tecidos com a maturidade da planta. Objetivo: o presente trabalho teve como objetivo caracterizar a morfologia do caule de Pennisetum clones (IV-46 Itambé, Itambé I-1.20, Itambé I-1.4, Milheto x Buaçu/112-23.4, Cuba-116-29.3, CAC-262-12,102, Roxo de Botucatu x CAC-282-18,29, Taiwan-146-2.6, Itambé I-1.5, Pusa Napier ou 419-76 x Buaçu/122-11.2, Taiwan-146-2.03, Taiwan-146-2.85, Itambé II-2,46 , Pusa Napier ou 419-76 x Cuba-116-12.3 e Pusa Napier ou 412-76 x Buaçu/122-8.22) em três estratos (basal, média e apical) e três perfilhos da planta, utilizando cortes histológicos. Métodos: o material foi coletado em uma área já estabelecida na Estação Experimental de São Bento do Una, no Instituto Agronômico de Pernambuco). Os materiais foram distribuídos em um inteiramente casualizado 15 x 3 x fatorial 3 (14 clones e um híbrido, três camadas de tronco e três perfilhos). As amostras foram coletadas durante a estação seca início em agosto de 2008. Resultados: houve diferenças significativas (p<0,05) entre os clones avaliados, e os valores médios para as células lignificadas na região do córtex variou 2,21-4,21 para o Taiwan-146-2,6 e Roxo de Botucatu X CAC-282-18,29 clones, no entanto, isto não era diferente dos outros clones da região medular. O clone II-Itambé 2,46 apresentaram o maior valor absoluto da percentagem de floema na região córtex (2,32%) e um valor elevado, com diferenças significativas, na região medular (1,59%) em comparação com os outros clones. Conclusão: os valores mais elevados de celulose nas regiões média e apical das hastes estudadas contribuir para características positivas para animais em pastejo.

Evaluación del pretratamiento con ácido sulfúrico diluido del pasto maralfalfa (Pennisetum glaucum x Pennisetum purpureum) para la producción de etanol / Dilute sulfuric acid pretreatment of goliath grass (Pennisetum glaucum x Pennisetum purpureum) for ethanol cellulosic

Evaluar la producción de etanol a partir de cultivos lignocelulósicos, específicamente pastos de rápido crecimiento en la región, constituye una alternativa a la demanda de biocombustibles. En la presente investigación se seleccionó el pasto Maralfalfa (Pennisetum glaucum x Pennisetum purpureum) utilizando el pretratamiento con ácido sulfúrico diluido a diferentes temperaturas (110, 130, 150, 170 y 190 °C) y concentraciones de ácido (0.8, 1.2 y 2.0% (p/p)), seguido de un proceso de hidrólisis enzimática utilizando celulasas y celobiosas comerciales y un proceso de hidrólisis y fermentación simultanea. La máxima producción de etanol obtenido fue 117 mg etanol/ g biomasa pretratada a 190 °C y 1,2 %(p/p) de ácido sulfúrico. El líquido hidrolizado fue caracterizado calculando el porcentaje de glucosa, xilosa y lignina solubilizadas y degradadas durante el pretratamiento.

The goliath grass (Pennisetum glaucum x Pennisetum purpureum) was pretreated with different sulfuric acid concentrations (0.8, 1.2 y 2.0% (w/w)) from low to high temperatures (110, 130, 150, 170 y 190 °C) followed by enzymatic hydrolysis and SSF of remaining solids. The maximum yield was 117 mg of ethanol/g biomass to 190 °C and 1.2 % (w/w) of sulfuric acid.

Heterologous Expression of Endo-1,4-beta-xylanaseA from Phanerochaete chrysosporium in Pichia pastoris

The cDNA of endo-1,4-beta-xylanaseA, isolated from Phaenerocheate chrysosporium was expressed in Pichia pastoris. Using either the intrinsic leader peptide of XynA or the alpha-factor signal peptide of Saccharomyces cerevisiae, xylanaseA is efficiently secreted into the medium at maximum concentrations of 1,946 U/L and 2,496 U/L, respectively.

Sugar cane bagasse as feedstock for second generation ethanol production: part I: diluted acid pretreatment optimization

Tons of sugar cane bagasse are produced in Brazil as waste of the sugar and ethanol industries. This lignocellulosic material is a potential source for second-generation ethanol production. Diluted acid hydrolysis is one of the most efficient pretreatments for hemicellulosic solubilization. The hydrolysate obtained is rich in xylose, which can be converted to ethanol by Pichia stipitis. This work used a statistical approach and the severity factor to investigate the effects of factors associated with the diluted acid hydrolysis process (acid concentration, solid:liquid ratio and time of exposure) on various response variables (xylose concentration, hydrolysis yield, inhibitor concentration and hydrolysate fermentability). The severity factor had a strong influence on the generation of inhibitors. The statistical analysis was useful for determining the effects of the individual factors and their interactions on the response variables. An acid concentration of 1.09 percent (vv), an S:L ratio of 1:2.8 (g:ml), and an exposure time of 27 min were established and validated as the optimum pretreatment conditions for the generation of hydrolysates with high xylose concentration and low contents of inhibitors. In such conditions, hydrolysate with 50 g/l of xylose was obtained.

Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA

UDP-glucose dehydrogenase (UGDH) catalyzes the oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in the biosynthesis of plant cell wall polysaccharides. A full-length cDNA fragment coding for UGDH was cloned from the cambial region of 6-month-old E. grandis saplings by RT-PCR. The 1443-bp-ORF encodes a protein of 480 amino acids with a predicted molecular weight of 53 kDa. The recombinant protein expressed in Escherichia coli catalyzed the conversion of UDP-Glc to UDP-GlcA, confirming that the cloned cDNA encodes UGDH. The deduced amino acid sequence of the cDNA showed a high degree of identity with UGDH from several plant species. The Southern blot assay indicated that more than one copy of UGDH is present in Eucalyptus. These results were also confirmed by the proteomic analysis of the cambial region of 3- and 22-year-old E. grandis trees by 2-DE and LC-MS/MS, showing that at least two isoforms are present. The cloned gene is mainly expressed in roots, stem and bark of 6-month-old saplings, with a lower expression in leaves. High expression levels were also observed in the cambial region of 3- and 22-year-old trees. The results described in this paper provide a further view of the hemicellulose biosynthesis during wood formation in E. grandis.

Analysis of Microstructure of Plant Fibers with Different Hemicellulose Content by Solid State Nuclear Magnetic Resonance and Atomic Force Microscope / 分析化学

Fibers with different hemicellulose contents were produced using various degree removal of hemicellulose to obtain large differences in cellulose and hemicellulose proportions at a similar lignin content. Solid state cross polarisation magic angle spinning carbon-13 nuclear magnetic resonance(CP/MAS ~(13)C-NMR) and atomic force microscope(AFM) had been employed to investigate the microstructure of fibers. The results showed that there was an increase in relative content of para-crystalline cellulose with the decreas of hemicellulose content obtained by the spectral fitting for the cellulose C1-region(δ 102-108). The elementary fibril size was relatively constant between 4.0 and 4.3 nm for the three samples obtained by the spectral fitting for the cellulose C4-region(δ 80-92). The difference in elementary fibril size between the samples was not significant. However, the elementary fibril aggregate size increased from 17.9 to 22.2 nm with the decreas of hemicellulose content, which was a significant change. The results of AFM analysis showed that the fiber with a high hemicellulose content had a porous surface structure. In fibres with a low hemicellulose content, the elementary fibril aggregates formed a much more compact surface structure. Lower hemicellulose content can promote the partially irreversible microfibril aggregation, which caused tensions in the microfibrils due to the finite dimensions of the cell wall, amounting to stress in the microfibrils. However, the porous structure can be improved as hemicellulose content decreased to a certain extent.

Kinetics of high-level of ß-glucosidase production by a 2-deoxyglucose-resistant mutant of Humicola lanuginosa in submerged fermentation / Cinética de produção de ß-glucosidase por um mutante de Hemicola lanuginosa resistente a 2-deoxiglucose em fermentação submersa

A 2-deoxyglucose-resistant mutant (M7) of Humicola lanuginosa was obtained by exposing conidia to γ-rays and permitting expression in broth containing 0.6 percent 2-deoxyglucose (DG) and cellobiose (1 percent) before plating on DG esculin-ferric ammonium citrate agar medium from which colonies showing faster and bigger blackening zones were selected. Kinetic parameters for enhanced ß-glucosidase (BGL) synthesis by M7 were achieved when corncobs acted as the carbon source. The combination between corncobs and corn steep liquor was the best to support higher values of all product formation kinetic parameters. Effect of temperature on the kinetic and thermodynamic attributes of BGL production equilibrium in the wild organismand M7was studied using batch process at eight different temperatures in shake-flask studies. The best performance was found at 45ºC and 20 g L-1 corncobs in 64 h. Both growth and product formation (17.93 U mL-1) were remarkably high at 45ºC and both were coupled under optimum working conditions. Product yield of BGL from the mutant M7 (1556.5 U g-1 dry corncobs) was significantly higher than the values reported on all fungal and bacterial systems. Mutation had thermo-stabilization influence on the organism and mutant required lower activation energy for growth and lower magnitudes of enthalpy and entropy for product formation than those demanded by the wild organism, other mesophilic and thermo-tolerant organisms. In the inactivation phase, the organisms needed lower values of activation energy, enthalpy and entropy for product formation equilibrium, confirming thermophilic nature of metabolic network possessed by the mutant organism.

Um mutante de Hemicola lanuginosa resistente a 2-deoxiglucose(M7) foi obtido através de exposição de conídios a raios γ, permitindo a expressão em caldo contendo 0,6 por cento de 2-deoxiglucose (DG) e celobiose (1 por cento) antes da semeadura em ágar DG esculina citrato de ferro amoniacal, da qual foram selecionadas as colônias com halo negro. Os parâmetros cinéticos para produção aumentada de ß-glucosidase (BGL) foram obtidos empregando-se sabugo de milho como fonte de carbono. A combinação de espiga de milho com água de maceração de milho foi a que forneceu os valores mais altos nos parâmetros cinéticos de formação de todos os produtos. O efeito da temperatura na cinética e atributos termodinâmicos da produção de BGL pelas cepas selvagem e M7 foi avaliado empregando-se processo de batelada em oito temperaturas diferentes in frascos em agitação. O melhor desempenho foi observado a 45ºC e 20g.l-1 de espiga de milho em 64h. Tanto a multiplicação quanto a formação do produto foram muito altas a 45ºC e ambas estavam ligadas em condições ótimas de trabalho. O rendimento de BGL produzido pelo mutante M7 (1556 U.g-1 de espiga seca) foi significativamente superior aos valores reportados para todos os sistemas fúngicos e bacterianos. A mutação influenciou a termoestabilização no microrganismo, sendo que o mutante necessitou de energia de ativação mais baixa para multiplicação e valores mais baixos de entalpia e entropia para a formação do produto quando comparado à cepa selvagem e a outros microrganismos mesofilicos e termotolerantes. Na fase de inativação, os microrganismos necessitaram valores mais baixos de energia de ativação, entalpia e entropia para o equilíbrio da formação de produto, confirmando a natureza termofílica da máquina metabólica do mutante.

REVIEW OF STUDIES ON ARABINOFURANOSIDASES / 微生物学通报

Hemicellulose is a kind of very abundant carbohydrate,which is not y ot exploited Arabinofuranosidase is important enzyme in biodegradation of hemi cellulose Up to now many arabinofuranosidases and genes have been studied in t he world In this paper, we reviewed mainly on the classification, characterizati on, utility and gene expression of arabinofuranosidase

THE EFFECTS OF CARBOXYMETHYL .MODIFIED HEMICELLULOSE ON THE IMMUNE REACTION IN ANIMALS / 中国药理学通报

A study was made of the effects of carboxymethyl modified hemi-cellulose ( CMMH ) on the immune reaction in mice. When it was administered with 1.5% 300mg/kg ip daily for 5 d, CMMH remarkably enhanced the phagocytic activity of peritoneal exudate macro-phages(P

DIETARY FIBER CONTENTS AND ITS COMPONENTS IN FOODS / 营养学报

Dietary fiber contents in 34 common foods perchased in Beijing markets have been determined with detergent method, including neutral detergent fiber, acid detergent fiber, cellulose, hemicellulose and lignin. On dry basis, the dietary fiber contents of vegetables varied with kinds of food: the dietary fiber contents were higher in tender stems, leaves, stalks and flowers; lower in starchy tubers and roots; medium in non-starchy tubers and roots. The propotions of dietary fiber components were different in various categories of foods. Cellulose was the major component in vegetables and legumes, but in most cereals, hemicellulose content was higher than cellulose. All foods had the lowest lignin content with the exception of garlic bolt.