Studies on Production of Bacterial Xylanases

Xylanases with hydrolytic activity on xylan, one of the hemicellulosic materials present in plant cell walls, have been identified long back and the applicability of this enzyme is constantly growing. All these applications especially the pulp and paper industries require novel enzymes. There has been lot of documentation on microbial xylanases, however, none meeting all the required characteristics. The characters being sought are: higher production, higher pH and temperature optima, good stabilities under these conditions and finally the low associated cellulase and protease production. The present study analyses various facets of xylanase biotechnology giving emphasis on bacterial xylanases. Fungal xylanases are having problems like low pH values for both enzyme activity and growth. Moreover, the associated production of cellulases at significant levels make fungal xylanases less suitable for application in paper and pulp industries.Bacillus SSP-34 selected from 200 isolates was clearly having xylan catabolizing nature distinct from earlier reports. The stabilities at higher temperatures and pH values along with the optimum conditions for pH and temperature is rendering Bacillus SSP-34 xylanase more suitable than many of the previous reports for application in pulp and paper industries.Bacillus SSP-34 is an alkalophilic thertmotolerant bacteria which under optimal cultural conditions as mentioned earlier, can produce 2.5 times more xylanase than the basal medium.The 0.5% xylan concentration in the medium was found to the best carbon source resulting in 366 IU/ml of xylanase activity. This induction was subjected to catabolite repression by glucose. Xylose was a good inducer for xylanase production. The combination of yeast extract and peptone selected from several nitrogen sources resulted in the highest enzyme production (379+-0.2 IU/ml) at the optimum final concentration of 0.5%. All the cultural and nutritional parameters were compiled and comparative study showed that the modified medium resulted in xylanase activity of 506 IU/ml, 5 folds higher than the basal medium.The novel combination of purification techniques like ultrafiltraton, ammonium sulphate fractionation, DEAE Sepharose anion exchange chromatography, CM Sephadex cation exchange chromatography and Gel permeation chromatography resulted in the purified xylanase having a specific activity of 1723 U/mg protein with 33.3% yield. The enzyme was having a molecular weight of 20-22 kDa. The Km of the purified xylanase was 6.5 mg of oat spelts xylan per ml and Vmax 1233 µ mol/min/mg protein.Bacillus SSP-34 xylanase resulted in the ISO brightness increase from 41.1% to 48.5%. The hydrolytic nature of the xylanase was in the endo-form.Thus the organism Bacillus SSP-34 was having interesting biotechnological and physiological aspects. The SSP-34 xylanase having desired characters seems to be suited for application in paper and pulp industries.

Dieselmotor-Kraft-Wärme-Kopplungsanlagen im Kontext der Integration Erneuerbarer Energien in die Energieversorgung

In dieser Arbeit werden die sich abzeichnenden zukünftigen Möglichkeiten, Stärken und Schwächen der Kraft-Wärme-Kopplung (KWK) untersucht. Dies geschieht vor dem Hintergrund des Klimawandels, der Integration steigender Anteile Erneuerbarer Energien in die Stromerzeugung und unter Berücksichtigung der sich damit ergebenden Herausforderungen, eine sichere und nachhaltige Stromversorgung zu gestalten. Der Fokus liegt auf der Dieselmotor-KWK und der Nutzung nachwachsender Kraftstoffe. Es wird davon ausgegangen, dass der Übergang zu einer reinen Stromerzeugung aus Erneuerbaren Energiequellen in Deutschland unter erheblicher Einbindung des hohen Potentials der kostengünstigen, umweltfreundlichen, aber in der Leistung extrem fluktuierenden Windenergie erfolgen wird. Als dezentrales Integrationswerkzeug wurde die Kraft-Wärme-Kopplung mit Dieselmotoren untersucht. Sie entspricht aufgrund ihrer großen Flexibilität und ihrer hohen Wirkungsgrade mit vergleichsweise kleinen Leistungen sehr gut den Anforderungen der gleichzeitigen dezentralen Wärmenutzung. In der Dissertation werden die Randbedingungen der Dieselmotor-KWK untersucht und beschrieben. Darauf aufbauend werden unterschiedliche Modelle der Windintegration durch KWK erarbeitet und in diversen Variationen wird der Ausgleich der Stromerzeugung aus Windenergie durch KWK simuliert. Darüber hinaus werden dezentrale KWK-Anlagen hinsichtlich eines koordinierten gemeinsamen Betriebs und hinsichtlich der optimalen Auslegung für den Windenergieausgleich betrachtet. Es wird für den beschriebenen Kontext der Erneuerbaren Energien und der Kraft-Wärme-Kopplung das Thema „Umweltwirkungen“ diskutiert. Es wird dargelegt, dass die heute verwendeten Ansätze zur Bewertung der KWK zu einer Verzerrung der Ergebnisse führen. Demgegenüber wurde mit der so genannten Outputmethode eine Methode der Ökobilanzierung vorgestellt, die, im Gegensatz zu den anderen Methoden, keine verzerrenden Annahmen in die Wirkungsabschätzung aufnimmt und somit eine eindeutige und rein wissenschaftliche Auswertung bleibt. Hiermit ist die Grundlage für die Bewertung der unterschiedlichen Technologien und Szenarien sowie für die Einordnung der KWK in den Kontext der Energieerzeugung gegeben. Mit der Outputmethode wird u.a. rechnerisch bewiesen, dass die gekoppelte Strom- und Wärmeerzeugung in KWK-Anlagen tatsächlich die optimale Nutzung der regenerativen Kraftstoffe „Biogas“ und „Pflanzenöl“ im Hinblick auf Ressourceneinsatz, Treibhausgaseinsparung und Exergieerzeugung ist. Es wurde darüber hinaus die Frage untersucht woher die für die Stromerzeugung durch Dieselmotor-KWK-Anlagen notwendige Bioenergie genommen werden kann. Es ist erwiesen, dass die in Deutschland nutzbare landwirtschaftliche Fläche nur zur Deckung eines Teils der Stromerzeugung ausreichen würde. Einheimisches Biogas und nachhaltiges importiertes Pflanzenöl, das in hohem Maße auf degradierten Böden angebaut werden sollte, können die notwendige Brennstoffenergie liefern. Um im Ausland ausreichend Pflanzenöl herstellen zu können, wird eine landwirtschaftliche Fläche von 6 bis 12 Mio. ha benötigt. Das Ergebnis ist, dass ein voller Ausgleich von Windenergie-Restlast durch KWK mit Erneuerbaren Energieträgern sinnvoll und machbar ist! Dieses Wind-KWK-DSM-System sollte durch ein Stromnetz ergänzt sein, das Wasserkraftstrom für den Großteil der Regelenergieaufgaben nutzt, und das den großräumigen Ausgleich Erneuerbarer Energien in Europa und den Nachbarregionen ermöglicht.

The value of a saved tree : The lifecycle of CO2-emissions associated with the combination of printing paper and electricity production of wood in the U.S. and Sweden

The pulp- and paper production is a very energy intensive industry sector. Both Sweden and the U.S. are major pulpandpaper producers. This report examines the energy and the CO2-emission connected with the pulp- and paperindustry for the two countries from a lifecycle perspective.New technologies make it possible to increase the electricity production in the integrated pulp- andpaper mill through black liquor gasification and a combined cycle (BLGCC). That way, the mill canproduce excess electricity, which can be sold and replace electricity produced in power plants. In thisprocess the by-products that are formed at the pulp-making process is used as fuel to produce electricity.In pulp- and paper mills today the technology for generating energy from the by-product in aTomlinson boiler is not as efficient as it could be compared to the BLGCC technology. Scenarios havebeen designed to investigate the results from using the BLGCC technique using a life cycle analysis.Two scenarios are being represented by a 1994 mill in the U.S. and a 1994 mill in Sweden.The scenariosare based on the average energy intensity of pulp- and paper mills as operating in 1994 in the U.S.and Sweden respectively. The two other scenarios are constituted by a »reference mill« in the U.S. andSweden using state-of-the-art technology. We investigate the impact of varying recycling rates and totalenergy use and CO2-emissions from the production of printing and writing paper. To economize withthe wood and that way save trees, we can use the trees that are replaced by recycling in a biomassgasification combined cycle (BIGCC) to produce electricity in a power station. This produces extra electricitywith a lower CO2 intensity than electricity generated by, for example, coal-fired power plants.The lifecycle analysis in this thesis also includes the use of waste treatment in the paper lifecycle. Both Sweden and theU.S. are countries that recycle paper. Still there is a lot of paper waste, this paper is a part of the countries municipalsolid waste (MSW). A lot of the MSW is landfilled, but parts of it are incinerated to extract electricity. The thesis hasdesigned special scenarios for the use of MSW in the lifecycle analysis.This report is studying and comparing two different countries and two different efficiencies on theBLGCC in four different scenarios. This gives a wide survey and points to essential parameters to specificallyreflect on, when making assumptions in a lifecycle analysis. The report shows that there arethree key parameters that have to be carefully considered when making a lifecycle analysis of wood inan energy and CO2-emission perspective in the pulp- and paper mill in the U.S. and in Sweden. First,there is the energy efficiency in the pulp- and paper mill, then the efficiency of the BLGCC and last theCO2 intensity of the electricity displaced by BIGCC or BLGCC generatedelectricity. It also show that with the current technology that we havetoday, it is possible to produce CO2 free paper with a waste paper amountup to 30%. The thesis discusses the system boundaries and the assumptions.Further and more detailed research, including amongst others thesystem boundaries and forestry, is recommended for more specificanswers.

A influência dos ácidos hexenurônicos no rendimento e na branqueabilidade da polpa kraft

This study investigated the impact of pulp hexenuronic acids (HexAs) content on pulping yield by changing cooking reaction temperature. The bleachability of pulps containing variable amounts of HexAs was also investigated. The cooking at 170 degrees C produced pulp of kappa number, HexAs and screen yield of 16.2, 49.4 mmol/kg and 50.2%, respectively, whereas the cooking at 156 degrees C resulted pulp of kappa 17.0, 61.3 mmol/kg HexAs and 50.8% screened yield. The pulp produced at lower cooking temperature also showed better bleachability as evaluated by the total amount of active chlorine required to achieve 90% ISO. The sequence OAHTD(EP) DD showed the lowest bleaching performance among all.

Influência da densidade básica da madeira de clones de Eucalyptus grandis x Eucalyptus urophylla na qualidade da polpa branqueada.

The study analyzed the wood basic density effect in two Eucalyptus grandis x Eucalyptus urophylla hybrid clones (440 kg/m(3) e 508 kg/m(3)) on bleached pulp quality (fiber dimensions and physical-mechanical properties). The woods performance on pulping, bleaching and beating results were analyzed. The Kraft pulping was carried out in forced circulation digester in order to obtain 17 +/- 1 kappa number targets. The pulps were bleached to 90 +/- 1 using delignification oxygen and D0EOPD1 bleaching sequence. Bleached pulp of low basic density clone showed, significantly, lowest revolutions number in the PFI mill to reach tensile index of 70 N.m/g, low Schopper Riegler degree and generated sheets with higher values to bulk and opacity. These characteristics and properties allow concluding that bleached pulp of low basic density clone was the most indicated to produce printing and writing sheets. The bleached pulp of high basic density clone showed higher values of bulk and capillarity Klemm and lower water retention value when analyzed without beating. The bleached pulp of high basic density clone showed more favorable characteristics to the production of tissue papers.

Screening and Production Study of Microbial Xylanase Producers from Brazilian Cerrado

Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by beta-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 A degrees C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0-5.5. They were stable in the pH range 5.0-10.0 and 5.5-8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 A degrees C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 A degrees C.

Thermal and pasting properties of cassava starch-dehydrated orange pulp blends

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ontogenesis of the fruit pulp layer of Hymenaea stigonocarpa (Fabaceae : Caesalpinioideae)

Hymenaea, a genus of major economic importance, has been the subject of several botanical studies. However, there is disagreement over the origin of the edible fruit pulp of Hymenaea, as there are no ontogenetic studies on this organ. According to some authors, the edible layer results from transformations of the mesocarp and endocarp, while according to others, it is considered a seed aril. There are still others who regard this layer as originating from an undefined region of the pericarp. To understand the nature and origin of the pulp layer, Hymenaea stigonocarpa Mart. ex Hayne ovaries and fruit were processed according to standard techniques. The production of the fruit pulp layer starts immediately after anthesis. During anthesis, the inner epidermal cells of the ovary show periclinal division and form a new layer of cells towards the mesocarp; this remains meristematic and initiates cell production by predominantly periclinal divisions, producing a compact tissue towards the locule. This tissue will become the fruit pulp layer, the inner endocarp. The seed coat shows typical testal structure without evidence of aril formation. This allows us to conclude that the fruit pulp layers are exclusively made from part of the endocarp. We also observed resin cavities on outer mesocarp and outer endocarp.

INFLUENCE of ENCAPSULATING MATERIALS on WATER SORPTION ISOTHERMS of VACUUM-DRIED PERSIMMON PULP POWDER

Water sorption isotherms for vacuum-dried persimmon pulp (PP) powder were determined in the temperature range of 20-50C, and the effects of maltodextrin (MD) or gum arabic (GA) addition on the water sorption behavior of the dried powders were analyzed. Several models were evaluated to fit the experimental data and the Guggenheim-Anderson-de Boer model was selected as the most adequate to describe the observed behavior. Addition of encapsulants affected the isotherms: at the same water activity, PP powder with added GA (PP + GA) or MD (PP + MD) presented lower equilibrium water content than pure PP and were less affected by temperature variations. Samples of PP + MD presented lower equilibrium moisture content than those of PP + GA. The isosteric heats of sorption of pulp powders with encapsulants were higher (less negative) than those of PP, suggesting that there are more active polar sites in PP than in pulp powder containing encapsulants.PRACTICAL APPLICATIONSThe choice of persimmon to carry out this work was due to the large persimmon production available in Brazil; moreover, persimmon pulp is rich in vitamin C, vitamin A and iron, as well as in phenolic compounds. Drying of fruit pulps with high sugar content presents technical difficulties because the hygroscopicity and thermoplasticity of the resulting powders when exposed to high temperature and relative humidity. For this reason, addition of high-molar-mass biopolymers, such as maltodextrin or gum arabic, is a strategy to aid drying and to improve storage stability. Knowledge of water sorption isotherms and net isosteric heats of sorption is important to various food processing operations, including drying, storage and packaging. They are useful in calculating time and energy consumptions during drying, modeling moisture changes during storage and predicting shelf life of food products.

Cytotoxicity and genotoxicity of pulp capping materials in two cell lines

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acerola: importance, culture conditions, production and biochemical aspects

Origin and importance. Acerola, or Malpighia emarginata D. C., is native to the Caribbean islands, Central America and the Amazonian region. More recently, it has been introduced in subtropical areas (Asia, India and South America). The vitamin C produced by acerola is better absorbed by the human organism than synthetic ascorbic acid. Exportation of acerola crops is a potential alternative source of income in agricultural businesses. In Brazil, the commercial farming of acerola is quite recent. Climatic conditions. Acerola is a rustic plant. It can resist temperatures close to 0 degrees C, but it is well adapted to temperatures around 26 degrees C with rainfall between (1200 and 1600) mm per year. Fruit characteristics. Acerola fruit is drupaceous, whose form can vary from round to conic. When ripe, it can be red, purple or yellow. The fruit weight varies between (3 and 16) g. Maturation. Acerola fruit presents fast metabolic activity and its maturation occurs rapidly. When commercialised in ambient conditions, it requires fast transportation or the use of refrigerated containers to retard its respiration and metabolism partially. Production and productivity. Flowering and fruiting are typically in cycles associated with rain. Usually, they take place in 25-day cycles, up to 8 times per year. The plant can be propagated by cuttings, grafting or seedlings. Harvest. Fruits produced for markets needs to be harvested at its optimal maturation stage. For distant markets, they need to be packed in boxes and piled up in low layers; transportation should be done in refrigerated trucks in relatively high humid conditions. Biochemical constituents. Acerola is the most important natural source of vitamin C [(1000 to 4500) mg.100(-1) g of pulp], but it is also rich in pectin and pectolytic enzymes, carotenoids, plant fibre, vitamin B, thiamin, riboflavin, niacin, proteins and mineral salts. It has also shown active anti-fungal properties. Products and market. Acerola is used in the production of juice, soft drinks, gums and liqueurs. The USA and Europe are great potential markets. In Europe, acerola extracts are used to enrich pear or apple juices. In the USA, they are used in the pharmaceutical industry. Conclusions. The demand for acerola has increased significantly in recent years because of the relevance of vitamin C in human health, coupled with the use of ascorbic acid as an antioxidant in food and feed. Acerola fruit contains other significant components, which are likely to lead to a further increase in its production and trade all over the world.

A Simple and Fast Method for the Production and Characterization of Methylic and Ethylic Biodiesels from Tucum Oil via an Alkaline Route

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Screening of filamentous fungi for production of enzymes of biotechnological interest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study of adsorption isotherms of green coconut pulp

O Brasil é considerado um dos maiores produtores e consumidores de frutas tropicais. O coco verde (Cocos nucifera L.) se destaca tanto em termos de produção e consumo quanto em quantidade de resíduos gerada por indústrias de água de coco e pelo consumo in natura. Portanto, existe uma necessidade de aproveitamento deste subproduto. Este trabalho teve por objetivo estudar as isotermas de adsorção da polpa de coco verde e determinação do calor isostérico de sorção. As isotermas de adsorção para as temperaturas de 30, 40, 50, 60 e 70 °C foram analisadas e evidenciaram curvas do tipo III, típicas de alimentos ricos em açúcares. Os dados experimentais de umidade de equilíbrio foram correlacionados por modelos da literatura. O modelo de GAB apresentou melhor concordância com os dados experimentais, entre os modelos avaliados. O calor isostérico de sorção é considerado um indicativo de forças atrativas intermoleculares entre os sítios de sorção de vapor de água, consequentemente, um importante fator para predizer a vida de prateleira de produtos desidratados.

Pectinolytic enzyme production by Bacillus species and their potential application on juice extraction

Five Bacillus strains isolated from decaying vegetable material were cultivated on wheat bran and endo-polygalacturonases, exo-polygalacturonase and pectin lyase activities in the crude enzymatic solution obtained were determined. Highest activity was observed for all enzymes when fermentation was carried out at 28 degreesC, the highest activity values were obtained after 120 h of cultivation for exo-PG and after 48 h for endo-PG and PL. The use of the enzymatic solution for treatment of fruits and vegetable mash afforded a high juice extraction and a pulp with good pressing characteristics.