Vanessa Mendes - Academia.edu (original) (raw)

Papers by Vanessa Mendes

Research paper thumbnail of Análise histológica do Bio-Oss e Biogran em tíbia de ratos

Bci, Jun 1, 2002

Base de dados : LILACS. Pesquisa : 321851 [Identificador único]. Referências encontradas : 1 [ref... more Base de dados : LILACS. Pesquisa : 321851 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Carvalho, Paulo Sérgio Perri de. ...

Research paper thumbnail of Extraction of hemicelluloses prior to kraft cooking: a step for an integrated biorefinery in the pulp mill

O Papel Revista Mensal De Tecnologia Em Celulose E Papel, Sep 1, 2011

Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus glob... more Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus globulus wood chips prior to the cooking stage to extract the hemicellulosic fraction that otherwise would be dissolved in the black liquor and burnt in the recovery boiler. The obtained hydrolysates, rich in xylose, were detoxified by overliming and used for ethanolic fermentation. Impacts of each wood pretreatment on the kraft cooking process and on the quality of the produced pulp were evaluated. Both pretreatments promoted an increase in the cooking rate, but had a negative effect on pulp quality and overall yield. Autohydrolysis showed a less negative influence. However, autohydrolysates led to lower values of ethanol concentration, productivity and yield compared to the fermentation of acid hydrolysates. To get more profit from the autohydrolysates they were also submitted to secondary acid hydrolysis and vacuum evaporation processes. Overliming followed by evaporation (with a concentration factor of 3) gave better results than the inverse method. This procedure raised the fermentable sugar content and led to the production of ethanol with a concentration of ~10 g eth L -1 (productivity of 0.23 g eth L -1 h -1 and yield of 0.50 g eth g xyl eq -1 ) which compares well with the results obtained with the fermentation of acid hydrolysates.

Research paper thumbnail of Valorisation of lignocellulosic biomass for an integrated biorefinery in the pulp and paper industry

The current study evaluates the extension of the biorefinery concept in a Portuguese pulp and pap... more The current study evaluates the extension of the biorefinery concept in a Portuguese pulp and paper mill using two different strategies to optimize the lignocellulosic biomass conversion: i) the extraction of nearly 50% of Eucalyptus globulus hemicelluloses prior to cooking stage by introducing a pre-treatment to wood chips, instead of being dissolved in the black liquor and burnt in the recovery boiler; and ii) valorisation of the cellulosic fraction present in the pulp and paper mill primary sludge. In the first goal, hemicelluloses pre-extraction was carried out by acid- and auto-hydrolysis procedures. Extracted hemicelluloses were used as carbon feedstock for ethanolic fermentation. The effects of both pre-extraction methods on pulp production and fermentation process were studied, with acid-hydrolysis having higher negative influence on pulp production. In the second goal, enzymatic hydrolysis was used to convert the cellulosic fraction into fermentable monosaccharides. Enzymat...

Research paper thumbnail of Investigation of a Novel PLGA/CaP Scaffold in the Healing of Tooth Extraction Sockets to Alveolar Bone Preservation in Humans

Clinical Implant Dentistry and Related Research, 2015

It is expected that 40% to 60% of initial alveolar bone volume will be lost up to 6 months after ... more It is expected that 40% to 60% of initial alveolar bone volume will be lost up to 6 months after tooth extraction. OsteoScaf(TM) (TRT, Toronto, ON, Canada) (poly (DL-lactide-co-glycololide/calcium phosphate [PLGA/CaP] scaffold) is a novel bone substitute material and represents a promising alternative for maintaining alveolar bone integrity in this clinical scenario. Here it was hypothesized that OsteoScaf would reduce alveolar bone lost after tooth extraction in patient, acting as a clot-retention device. A total of 10 patients (32 sockets) were included in the study, of which 16 sockets were grafted with OsteoScaf and 16 were used as control (coagulum alone). Cone beam computed tomography (CBCT) was performed both immediately following extraction and also at 120 days postoperatively, at which time biopsy samples were also harvested for histological analyses. Quantitative analysis of CBCT showed less bone resorption in the OsteoScaf groups, being 10.5% to 14.4% less bone lost in the center of the socket, 15.4% in the buccal region, and 12.6% in the palatal. Qualitative histological analysis showed new bone tissue in direct apposition to the scaffold - demonstrating its osteoconductive nature. OsteoScaf diminished the expected bone lost during the postextraction remodeling of the alveolar bone ridge at 120 days postextraction.

Research paper thumbnail of APLICAÇÃO DA GEOESTATÍSTICA NO MONITORAMENTO DA DISPERSÃO DE POLUENTES

A poluição pode ser entendida como uma fonte de degradação ambiental, uma vez que altera de forma... more A poluição pode ser entendida como uma fonte de degradação ambiental, uma vez que altera de forma deletéria as características do meio. Dentre os principais tipos de poluição estão a hídrica e a atmosférica, que se relacionam entre si e com o solo, afetando todos os compartimentos ambientais. Para direcionar as ações de recuperação ambiental é fundamental entender como ocorre à dispersão dos poluentes. Os fenômenos naturais apresentam certo grau de dependência espacial, o que indica que a aplicação da geoestatística é mais adequada para estudos ambientais. O objetivo deste trabalho é apresentar as aplicações da geoestatística em estudos de dispersão de poluentes em meio hídrico, atmosférico e nos solos, além de demonstrar sua importância para o monitoramento da poluição ambiental. A contaminação dos corpos d'água por metais e outros elementos tóxicos tem aumentado consideravelmente, sobretudo em razão do despejo irregular de rejeitos industriais. Os sedimentos presentes nesses poluentes apresentam altas capacidades de sorção associadas, as quais permitem o seu uso como indicadores destes poluentes por meio de mapas gerados por interpolação espacial. Ainda quanto à poluição hídrica, as técnicas geoestatísticas podem ser aplicadas para se estabelecer o grau de susceptibilidade e a direção percorrida pelo poluente quando este atinge o lençol. Nos grandes centros urbanos a poluição do ar por monóxido de carbono tem sido um grave problema devido à presença crescente dos automóveis e das indústrias. O monitoramento deste poluente é realizado através de amostragens pontuais; no entanto, a concentração do CO varia grandemente conforme a localidade, sendo necessário o uso da geoestatística para predizer os teores desta substância em locais não amostrados. Da mesma forma, os óxidos de nitrogênio e enxofre são monitorados a fim de se predizerem os locais com maior ocorrência de chuva ácida. A contaminação do solo por metais e semimetais tem aumentado consideravelmente, uma vez que a tecnologia atual emprega cada vez mais os recursos minerais. A dispersão dos metais e semimetais é influenciada pelas características dos próprios elementos e do ambiente. Por meio da modelagem geoestatística é possível predizer a mobilidade de cada poluente e, assim, avaliar o risco estimar o tempo de contaminação de uma área devido à lixiviação destes compostos. A determinação das concentrações pontuais destes poluentes associadas às técnicas de interpolação é utilizada para elaborar mapas de risco à saúde pública. A partir do estudo realizado constata-se que a geoestatística constitui uma série de ferramentas e conceitos capazes de contemplar a concepção geográfica, quantitativa e dinâmica dos acontecimentos naturais, sendo de fundamental importância no monitoramento e controle da poluição ambiental.

Research paper thumbnail of Valorization of Residual Streams from Pulp and Paper Mills: Pretreatment and Bioconversion of Primary Sludge to Bioethanol

Industrial & Engineering Chemistry Research, 2014

ABSTRACT Primary sludge is a lignocellulosic residue from pulp and paper mills consisting of cell... more ABSTRACT Primary sludge is a lignocellulosic residue from pulp and paper mills consisting of cellulosic fibers and ash. However, the high ash content (35%, mainly CaCO3) and pH value affect the enzymatic hydrolysis of cellulosic fibers. Several pretreatments were used to reduce the CaCO3 content and to adjust the pH. Enzymatic hydrolysis of primary sludge was enhanced when it was pretreated with HCl or spent acid (another residual stream of the same plant). Cellulosic fibers were converted to monomeric sugars by Cellic CTec2 cellulase with a dosage of 35 FPU gCH−1 for a carbohydrate concentration of 46 g L−1. This conversion was enhanced from 20% to 88% for primary sludge pretreated with HCl and to 72% for samples pretreated with spent acid. The fermentation of 27 g L−1 of available sugars with Pichia stipitis led to ethanol concentrations of up to 10.5 g L−1 with a yield of 0.39 gEtOH gsug−1.

Research paper thumbnail of Xylose from Eucalyptus globulus wood as a raw material for bioethanol production

Current research topics in applied microbiology and microbial biotechnology, 2009

ABSTRACT Extracts from auto- and acid-hydrolysis of Eucalyptus globulus wood Chips Were Used as f... more ABSTRACT Extracts from auto- and acid-hydrolysis of Eucalyptus globulus wood Chips Were Used as fermentation media to produce ethanol by the yeast Pichia stipitis. pH adjustment with Ca(OH)(2) led to higher yeast activity than with NaOH, probably due to a detoxification effect. Furfural, in the range 0.1 to 0.8 g L(-1), did not act as an inhibitor of yeast growth. Substrate inhibition did not occur as well for xylose concentration as high as 60 g L-1. Auto-hydrolysis extracts were submitted to a secondary hydrolysis. The use of different contents of auto- and acid-hydrolysis extracts as natural media, with the yeast previously adapted, showed that 75% (v/v) of acid-hydrolysis extract neutralized with Ca(OH)(2), led to 10 g L(-1) ethanol concentration and a yield of 0.36 g(bioethanol) G(sugars)(-1) micro-aerobic conditions, at 30 degrees C and pH 6.0. Although the maximum ethanol concentration reached was still very low, these results compare well to those obtained When Using a synthetic medium with an equivalent concentration of xylose.

Research paper thumbnail of Hemicelluloses: from wood to the fermenter

Current research topics in applied microbiology and microbial biotechnology, 2009

ABSTRACT The valorisation of hemicelluloses, as a subproduct of the pulping process, can be achie... more ABSTRACT The valorisation of hemicelluloses, as a subproduct of the pulping process, can be achieved with extraction of wood chips by primary hydrolysis (auto or acid catalysed) before cooking, where part of them are dissolved. However, the extracts of the hardwood used in this work (Eucalyptus globulus) could contain oligomers, mainly Xylose based, that Must be further hydrolysed to become a raw material for fermentation to produce e.g. bioethanol, The primary extract from an acid hydrolysis can be directly metabolised by microorganisms being a secondary hydrolysis worthless. On the other hand, twice the monosaccharicds concentration was obtained when a secondary hydrolysis was performed, over the extracts obtained from the primary auto-hydrolysis. The best conditions for that reaction include 3 h of hydrolysis, with 4 %(w/w) Of H(2)SO(4) and the highest concentration of solids (i.e. avoiding the dilution of primary extracts), which led to a secondary hydrolysis yield as high as 84 %.

Research paper thumbnail of Prebiliary Right Hepatic Artery Resulting in Common Hepatic Duct Compression and Subsequent Intrahepatic Stone Formation: Myth or Reality?

Case Reports in Medicine, 2014

The vascular anatomy of the liver is subjected to many variations. Aberrant hepatic artery is not... more The vascular anatomy of the liver is subjected to many variations. Aberrant hepatic artery is not an uncommon finding during visceral surgery; however, topographic variations are less reported in the literature. Prebiliary artery crossing anteriorly to the common hepatic duct was firstly reported in 1984. We present here a case of a 52-year-old lady who presented with obstructive jaundice and right upper quadrant pain. Paraclinical investigations were consistent with intrahepatic stones and a benign stricture on the CBD. During surgery, a prebiliary right hepatic artery compressing the CHD was noted. The liver pedicle was dissected and a hepaticojejunostomy was performed that resulted in a good outcome after 24 months of followup.

Research paper thumbnail of Stranding of Masturus lanceolatus (Actinopterygii: Molidae) in the estuary of the Una River, Pernambuco, Brazil: natural and anthropogenic causes

Marine Biodiversity Records, 2010

Molidae are tropical marine teleosts that occur in all oceans. Among the species described, Mastu... more Molidae are tropical marine teleosts that occur in all oceans. Among the species described, Masturus lanceolatus is considered rare on the Brazilian coast, with only four records found in scientific publications. The present study reports the first occurrence of this species for the coast of the State of Pernambuco (north-eastern Brazil) and discusses the possible causes of its being stranded. The specimen was found alive in the estuary of the Una River in the city of São José da Coroa Grande on the southern coast of the state. The fish was unknown to the local community of fishermen, who considered it a 'bad omen'. The occurrence led to an environmental education project in the community carried out by members of the Tropical Marine Ichthyology Group, which carried out an inspection, documentation, analysis of external injuries and collection of viscera for the subsequent histological analysis. After undergoing taxidermy, the specimen was donated to the Una Museum. Analysis revealed that the fish suffered from an intense inflammatory process of the liver caused by polycystosis of nematodes and Trypanorhyncha, which resulted in malnutrition, as observed by the low body weight. Moreover, a likely stranding left the specimen more vulnerable to different species of shark, which mutilated it, hindering its locomotion. This fish appears to have drifted and was thrown against the reefs near the estuary before its stranding. . (2009) Ocorrência de parasitismo em Mola mola (Linnaeus, 1758) por metazoários no litoral do Rio Grande do Norte, Brasil. Acta Veterinaria Brasilica 3, 43-47. Akiol O., Erdem M., Unal V. and Ceyham T. (2005) Investigations on drift-net fishery for swordfish (Xiphias gladius L.) in the Aegean Sea. Molicola horridus in Luvaris imperialis and Mola mola. Bollettino della Societa Italiana di Patologia Ittica 5, 89-91. Bass A.L., Dewar H., Thys T., Streelman J.T. and Karl S.A. (2005) Evolutionary divergence among lineages of the ocean sunfish family, Molidae (Tetraodontiformes). Marine Biology 148, 405-414.

Research paper thumbnail of Neurologic manifestations of AIDS: a review of fifty cases in Santos

Sao Paulo Medical Journal, 1998

To review the neurologic manifestations of AIDS in patients who were admitted to Hospital Guilher... more To review the neurologic manifestations of AIDS in patients who were admitted to Hospital Guilherme Alvaro (HGA) due to any clinical manifestation of the disease. Case series. All HIV+ patients admitted to the Faculty Hospital (HGA) between July 96 and April 97 were included in this review. From the 117 HIV+ patients admitted to hospitalization due to AIDS-related symptoms, 50 (42.7%) presented neurologic manifestations. The most prevalent of these was neurotoxoplasmosis (68%), but a variety of other neurologic diseases were observed. Only 36% of these 50 patients had neurological signs and symptoms as the main complaint for admission, 12% of the patients had at least complained of some neurologic dysfunction at the time of admission and 10% had no neurologic complaints at all. The remaining 42% (21 patients) only complained of neurologic manifestations of AIDS when specifically asked. The prevalence of neurologic manifestations of AIDS is very high in patients admitted to hospital. Even in the absence of neurologic-related complaints, these patients have to be carefully questioned and examined in the search for an underlying neurologic complication which may present high morbidity and mortality.

Research paper thumbnail of Mapeamento das áreas de preservação permanente e identificação dos conflitos de uso da terra na sub-bacia hidrográfica do Rio Camapuã/Brumado

Revista Árvore, 2012

RESUMO -O objetivo deste trabalho foi mapear e quantificar as áreas de preservação permanente (AP... more RESUMO -O objetivo deste trabalho foi mapear e quantificar as áreas de preservação permanente (APPs) de acordo com a Resolução n o 303/02 do CONAMA para, então, com base no mapa de uso da terra e cobertura vegetal, identificar e quantificar os eventuais conflitos de uso da terra, com vistas a nortear o cumprimento da lei e promover o uso adequado dos recursos da sub-bacia hidrográfica do rio Camapuã/Brumado, MG. Utilizaram-se uma imagem digital do sensor ETM+/LANDSAT 7, bases cartográficas planialtimétricas do IBGE para a área de estudo, e os softwares Anudem 5.2, Erdas Imagine 9.2 e ArcGIS 9.3. As APPs ocuparam 63.095 ha, representando 57,0% da área total da sub-bacia (110.711,9 ha). Com relação às categorias de APPs, o terço superior da bacia, ao longo das linhas de cumeada, correspondeu a 52,6% dos 63.095 ha; as zonas de proteção às margens dos cursos d´água, a 31,4%; a proteção das nascentes, a 15,6%; e as encostas com declividade superior a 45° e o terço superior de morros totalizaram 0,4%. As áreas de terço superior da bacia, ao longo das linhas de cumeada, foram as mais desrespeitadas (55,9%), seguidas das margens de curso d´água (23,12%), proteção de nascentes (20,83%), encostas com declividade superior a 45° (0,3%) e terço superior de morros (0,1%). Foram identificados 21.939,3 ha de APPs sendo explorados por atividades agropecuárias, o que representa 34,8% do total de APPs. Entretanto, constatou-se que 30.734,3 ha dos 47.616,9 ha situados fora das áreas de APP, i.e., 64,5% das áreas legalmente passíveis de conversão de uso da terra, estavam cobertos por vegetação nativa. Encontraram-se sólidas evidências de que a falta de conhecimento a respeito da espacialização das APPs dentro da propriedade é a principal causa do descumprimento da lei. A delimitação e espacialização das APPs pelo geoprocessamento viabilizam a aplicação da legislação florestal, contribuindo notoriamente para minimizar os conflitos de uso da terra e evitar a degradação dos remanescentes florestais pela formação de corredores ecológicos naturais que mitiguem os efeitos deletérios da fragmentação de habitats.

Research paper thumbnail of Development, characterization and clinical use of a biodegradable composite scaffold for bone engineering in oro-maxillo-facial surgery

Organogenesis, 2010

We have developed a biodegradable composite scaffold for bone tissue engineering applications wit... more We have developed a biodegradable composite scaffold for bone tissue engineering applications with a pore size and interconnecting macroporosity similar to those of human trabecular bone. The scaffold is fabricated by a process of particle leaching and phase inversion from poly(lactideco-glycolide) (PLGA) and two calcium phosphate (CaP) phases both of which are resorbable by osteoclasts; the first a particulate within the polymer structure and the second a thin ubiquitous coating. The 3-5 µm thick osteoconductive surface CaP abrogates the putative foreign body giant cell response to the underlying polymer, while the internal CaP phase provides dimensional stability in an otherwise highly compliant structure. The scaffold may be used as a biomaterial alone, as a carrier for cells or a three-phase drug delivery device. Due to the highly interconnected macroporosity ranging from 81% to 91%, with macropores of 0.8∼1.8 mm, and an ability to wick up blood, the scaffold acts as both a clot-retention device and an osteoconductive support for host bone growth. As a cell delivery vehicle, the scaffold can be first seeded with human mesenchymal cells which can then contribute to bone formation in orthotopic implantation sites, as we show in immune-compromised animal hosts. We have also employed this scaffold in both lithomorph and particulate forms in human patients to maintain alveolar bone height following tooth extraction, and augment alveolar bone height through standard sinus lift approaches. We provide a clinical case report of both of these applications; and we show that the scaffold served to regenerate sufficient bone tissue in the wound site to provide a sound foundation for dental implant placement. At the time of writing, such implants have been in occlusal function for periods of up to 3 years in sites regenerated through the use of the scaffold.

Research paper thumbnail of Intraosseous leiomyoma of the mandible

Oral Oncology Extra, 2006

The case of an intraosseous leiomyoma in a 57-year-old man is presented. The tumor was incidental... more The case of an intraosseous leiomyoma in a 57-year-old man is presented. The tumor was incidentally discovered during routine dental X-ray examination as a round, unilocular, radiolucency, measuring approximately 2 · 1.5 cm. Clinical examination revealed a slight swelling of the buccal cortical plate in the edentulous area of the posterior right mandible, and intra-operatively, perforation of the buccal cortical plate was seen. Histological and immunohistochemical examination was diagnostic of solid leiomyoma. One year after surgery the patient is free of residual or recurrent disease. This is the fifteen documented cases of intraosseous leiomyoma reported in the English literature.

Research paper thumbnail of Survival and initial growth of Euterpe edulis Mart. seedlings transplanted to gaps and undestory in a Semideciduous Forest, Viçosa, MG

Revista Árvore, 2011

RESUMO Este estudo teve como objetivos avaliar a sobrevivência e crescimento inicial de plântulas... more RESUMO Este estudo teve como objetivos avaliar a sobrevivência e crescimento inicial de plântulas de Euterpe edulis Mart. transplantadas para duas condições de luz: clareira e sub-bosque, além de discutir seu comportamento ecofisiológico. Foram transplantadas 90 ...

Research paper thumbnail of Complicated rectovaginal fistula secondary to Bartholin's cyst infection

Journal of Obstetrics and Gynaecology Research, 2014

Rectovaginal fistula formation secondary to Bartholin&amp... more Rectovaginal fistula formation secondary to Bartholin's cyst is a very rare complication, and to date only three cases were reported in the literature. We report a case of a 32-year-old woman who suffered recurrent episodes of Bartholin's cyst infection with subsequent abscess formation that resulted in rectovaginal fistula formation. We treated her initially with transperineal repair; however, the fistulous tract recurred a month later. A laparoscopic colostomy and transperineal repair using biological graft was then performed, with excellent results. The patient underwent reversal of colostomy after 2 months, and remained asymptomatic upon follow-up 12 months later.

Research paper thumbnail of Prehydrolysis of Eucalyptus globulus Labill. hemicelluloses prior to pulping and fermentation of the hydrolysates with the yeast Pichia stipitis 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung, 2000

ABSTRACT The aim of this work was to evaluate the potential of Eucalyptus globulus hemicelluloses... more ABSTRACT The aim of this work was to evaluate the potential of Eucalyptus globulus hemicelluloses, mainly xylan, for bioethanol production. Hemicelluloses have been removed prior to pulping by auto-hydrolysis and an acid-catalysed hydrolysis. As the hydrolysates obtained were rich in xylose, the yeast Pichia stipitis was selected for fermentation. It was confirmed that the yeast performance is strongly dependent on pH and the presence of inhibitors, such as lignin. The addition of Ca(OH)(2) was successful for lowering the concentration of inhibitors and adjusting the pH. The strain was grown in culture media with increasing volumetric percentages of treated hydrolysates up to 100% (v/v), supplemented with nutrients other than the carbon and energy source. This methodology shortened the lag phase of fermentation and improved the performance of yeast. Maximum ethanol concentration (12 g(eth) l(-1)), productivity (0.22 g(eth) l(-1) h(-1)), and yield (0.48 g(eth) g(xyl) eqs(-1)) were achieved with treated acid-hydrolysates. These results are similar to those obtained by a synthetic medium with an equivalent xylose concentration.

Research paper thumbnail of Valorisation of hardwood hemicelluloses in the kraft pulping process by using an integrated biorefinery concept

Food and Bioproducts Processing, 2009

ABSTRACT A primary hydrolysis treatment (auto or acid-catalysed) of Eucalyptus globulus wood was ... more ABSTRACT A primary hydrolysis treatment (auto or acid-catalysed) of Eucalyptus globulus wood was performed before the cooking stage to extract part of the hemicelluloses that otherwise would be dissolved in the kraft liquor and burned. As xylose was the main monosaccharide Pichia stipitis was selected to produce bioethanol. Two methods were tested, with different alkalis, to reduce hydrolysates toxicity and adjust pH. A two-step method using Ca(OH)2 leads to better fermentation results. Acid hydrolysates promoted higher ethanol concentrations (12 g L−1) with high productivity and yield values (0.22 geth L−1h−1 and 0.48 geth/gxyl eqs), whilst auto-hydrolysates, even after a secondary hydrolysis, gave low ethanol concentrations (2–4 g L−1). The impacts on kraft cooking and pulp quality were also studied in order to fully understand the feasibility of this biorefinery concept (combining ethanol production and hardwood pulping). A decrease of the overall pulp yield (10% for auto- and 15% for acid-hydrolysis) was observed. However, a decrease on bleaching requirements (up to 15%) and on brightness reversion was registered. Moreover, auto-hydrolysis improves pulp viscosity, whilst acid-hydrolysis is more efficient in metals leaching. Overall, from the pulp production point of view, auto-hydrolysis conditions are more attractive than the acid-catalysed ones.

Research paper thumbnail of Periodontal regeneration using a bilayered PLGA/calcium phosphate construct

Research paper thumbnail of EXTRACTION OF HEMICELLULOSES PRIOR TO KRAFT COOKING: A STEP FOR AN INTEGRATED BIOREFINERY IN THE PULP MILL

O PAPEL, 2011

Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus glob... more Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus globulus wood chips prior to the cooking stage to extract the hemicellulosic fraction that otherwise would be dissolved in the black liquor and burnt in the recovery boiler. The obtained hydrolysates, rich in xylose, were detoxified by overliming and used for ethanolic fermentation. Impacts of each wood pretreatment on the kraft cooking process and on the quality of the produced pulp were evaluated. Both pretreatments promoted an increase in the cooking rate, but had a negative effect on pulp quality and overall yield. Autohydrolysis showed a less negative influence. However, autohydrolysates led to lower values of ethanol concentration, productivity and yield compared to the fermentation of acid hydrolysates. To get more profit from the autohydrolysates they were also submitted to secondary acid hydrolysis and vacuum evaporation processes. Overliming followed by evaporation (with a concentration factor of 3) gave better results than the inverse method. This procedure raised the fermentable sugar content and led to the production of ethanol with a concentration of ~10 g eth L -1 (productivity of 0.23 g eth L -1 h -1 and yield of 0.50 g eth g xyl eq -1 ) which compares well with the results obtained with the fermentation of acid hydrolysates.

Research paper thumbnail of Análise histológica do Bio-Oss e Biogran em tíbia de ratos

Bci, Jun 1, 2002

Base de dados : LILACS. Pesquisa : 321851 [Identificador único]. Referências encontradas : 1 [ref... more Base de dados : LILACS. Pesquisa : 321851 [Identificador único]. Referências encontradas : 1 [refinar]. Mostrando: 1 .. 1 no formato [Detalhado]. página 1 de 1, 1 / 1, LILACS, seleciona. para imprimir. Fotocópia. Carvalho, Paulo Sérgio Perri de. ...

Research paper thumbnail of Extraction of hemicelluloses prior to kraft cooking: a step for an integrated biorefinery in the pulp mill

O Papel Revista Mensal De Tecnologia Em Celulose E Papel, Sep 1, 2011

Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus glob... more Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus globulus wood chips prior to the cooking stage to extract the hemicellulosic fraction that otherwise would be dissolved in the black liquor and burnt in the recovery boiler. The obtained hydrolysates, rich in xylose, were detoxified by overliming and used for ethanolic fermentation. Impacts of each wood pretreatment on the kraft cooking process and on the quality of the produced pulp were evaluated. Both pretreatments promoted an increase in the cooking rate, but had a negative effect on pulp quality and overall yield. Autohydrolysis showed a less negative influence. However, autohydrolysates led to lower values of ethanol concentration, productivity and yield compared to the fermentation of acid hydrolysates. To get more profit from the autohydrolysates they were also submitted to secondary acid hydrolysis and vacuum evaporation processes. Overliming followed by evaporation (with a concentration factor of 3) gave better results than the inverse method. This procedure raised the fermentable sugar content and led to the production of ethanol with a concentration of ~10 g eth L -1 (productivity of 0.23 g eth L -1 h -1 and yield of 0.50 g eth g xyl eq -1 ) which compares well with the results obtained with the fermentation of acid hydrolysates.

Research paper thumbnail of Valorisation of lignocellulosic biomass for an integrated biorefinery in the pulp and paper industry

The current study evaluates the extension of the biorefinery concept in a Portuguese pulp and pap... more The current study evaluates the extension of the biorefinery concept in a Portuguese pulp and paper mill using two different strategies to optimize the lignocellulosic biomass conversion: i) the extraction of nearly 50% of Eucalyptus globulus hemicelluloses prior to cooking stage by introducing a pre-treatment to wood chips, instead of being dissolved in the black liquor and burnt in the recovery boiler; and ii) valorisation of the cellulosic fraction present in the pulp and paper mill primary sludge. In the first goal, hemicelluloses pre-extraction was carried out by acid- and auto-hydrolysis procedures. Extracted hemicelluloses were used as carbon feedstock for ethanolic fermentation. The effects of both pre-extraction methods on pulp production and fermentation process were studied, with acid-hydrolysis having higher negative influence on pulp production. In the second goal, enzymatic hydrolysis was used to convert the cellulosic fraction into fermentable monosaccharides. Enzymat...

Research paper thumbnail of Investigation of a Novel PLGA/CaP Scaffold in the Healing of Tooth Extraction Sockets to Alveolar Bone Preservation in Humans

Clinical Implant Dentistry and Related Research, 2015

It is expected that 40% to 60% of initial alveolar bone volume will be lost up to 6 months after ... more It is expected that 40% to 60% of initial alveolar bone volume will be lost up to 6 months after tooth extraction. OsteoScaf(TM) (TRT, Toronto, ON, Canada) (poly (DL-lactide-co-glycololide/calcium phosphate [PLGA/CaP] scaffold) is a novel bone substitute material and represents a promising alternative for maintaining alveolar bone integrity in this clinical scenario. Here it was hypothesized that OsteoScaf would reduce alveolar bone lost after tooth extraction in patient, acting as a clot-retention device. A total of 10 patients (32 sockets) were included in the study, of which 16 sockets were grafted with OsteoScaf and 16 were used as control (coagulum alone). Cone beam computed tomography (CBCT) was performed both immediately following extraction and also at 120 days postoperatively, at which time biopsy samples were also harvested for histological analyses. Quantitative analysis of CBCT showed less bone resorption in the OsteoScaf groups, being 10.5% to 14.4% less bone lost in the center of the socket, 15.4% in the buccal region, and 12.6% in the palatal. Qualitative histological analysis showed new bone tissue in direct apposition to the scaffold - demonstrating its osteoconductive nature. OsteoScaf diminished the expected bone lost during the postextraction remodeling of the alveolar bone ridge at 120 days postextraction.

Research paper thumbnail of APLICAÇÃO DA GEOESTATÍSTICA NO MONITORAMENTO DA DISPERSÃO DE POLUENTES

A poluição pode ser entendida como uma fonte de degradação ambiental, uma vez que altera de forma... more A poluição pode ser entendida como uma fonte de degradação ambiental, uma vez que altera de forma deletéria as características do meio. Dentre os principais tipos de poluição estão a hídrica e a atmosférica, que se relacionam entre si e com o solo, afetando todos os compartimentos ambientais. Para direcionar as ações de recuperação ambiental é fundamental entender como ocorre à dispersão dos poluentes. Os fenômenos naturais apresentam certo grau de dependência espacial, o que indica que a aplicação da geoestatística é mais adequada para estudos ambientais. O objetivo deste trabalho é apresentar as aplicações da geoestatística em estudos de dispersão de poluentes em meio hídrico, atmosférico e nos solos, além de demonstrar sua importância para o monitoramento da poluição ambiental. A contaminação dos corpos d'água por metais e outros elementos tóxicos tem aumentado consideravelmente, sobretudo em razão do despejo irregular de rejeitos industriais. Os sedimentos presentes nesses poluentes apresentam altas capacidades de sorção associadas, as quais permitem o seu uso como indicadores destes poluentes por meio de mapas gerados por interpolação espacial. Ainda quanto à poluição hídrica, as técnicas geoestatísticas podem ser aplicadas para se estabelecer o grau de susceptibilidade e a direção percorrida pelo poluente quando este atinge o lençol. Nos grandes centros urbanos a poluição do ar por monóxido de carbono tem sido um grave problema devido à presença crescente dos automóveis e das indústrias. O monitoramento deste poluente é realizado através de amostragens pontuais; no entanto, a concentração do CO varia grandemente conforme a localidade, sendo necessário o uso da geoestatística para predizer os teores desta substância em locais não amostrados. Da mesma forma, os óxidos de nitrogênio e enxofre são monitorados a fim de se predizerem os locais com maior ocorrência de chuva ácida. A contaminação do solo por metais e semimetais tem aumentado consideravelmente, uma vez que a tecnologia atual emprega cada vez mais os recursos minerais. A dispersão dos metais e semimetais é influenciada pelas características dos próprios elementos e do ambiente. Por meio da modelagem geoestatística é possível predizer a mobilidade de cada poluente e, assim, avaliar o risco estimar o tempo de contaminação de uma área devido à lixiviação destes compostos. A determinação das concentrações pontuais destes poluentes associadas às técnicas de interpolação é utilizada para elaborar mapas de risco à saúde pública. A partir do estudo realizado constata-se que a geoestatística constitui uma série de ferramentas e conceitos capazes de contemplar a concepção geográfica, quantitativa e dinâmica dos acontecimentos naturais, sendo de fundamental importância no monitoramento e controle da poluição ambiental.

Research paper thumbnail of Valorization of Residual Streams from Pulp and Paper Mills: Pretreatment and Bioconversion of Primary Sludge to Bioethanol

Industrial & Engineering Chemistry Research, 2014

ABSTRACT Primary sludge is a lignocellulosic residue from pulp and paper mills consisting of cell... more ABSTRACT Primary sludge is a lignocellulosic residue from pulp and paper mills consisting of cellulosic fibers and ash. However, the high ash content (35%, mainly CaCO3) and pH value affect the enzymatic hydrolysis of cellulosic fibers. Several pretreatments were used to reduce the CaCO3 content and to adjust the pH. Enzymatic hydrolysis of primary sludge was enhanced when it was pretreated with HCl or spent acid (another residual stream of the same plant). Cellulosic fibers were converted to monomeric sugars by Cellic CTec2 cellulase with a dosage of 35 FPU gCH−1 for a carbohydrate concentration of 46 g L−1. This conversion was enhanced from 20% to 88% for primary sludge pretreated with HCl and to 72% for samples pretreated with spent acid. The fermentation of 27 g L−1 of available sugars with Pichia stipitis led to ethanol concentrations of up to 10.5 g L−1 with a yield of 0.39 gEtOH gsug−1.

Research paper thumbnail of Xylose from Eucalyptus globulus wood as a raw material for bioethanol production

Current research topics in applied microbiology and microbial biotechnology, 2009

ABSTRACT Extracts from auto- and acid-hydrolysis of Eucalyptus globulus wood Chips Were Used as f... more ABSTRACT Extracts from auto- and acid-hydrolysis of Eucalyptus globulus wood Chips Were Used as fermentation media to produce ethanol by the yeast Pichia stipitis. pH adjustment with Ca(OH)(2) led to higher yeast activity than with NaOH, probably due to a detoxification effect. Furfural, in the range 0.1 to 0.8 g L(-1), did not act as an inhibitor of yeast growth. Substrate inhibition did not occur as well for xylose concentration as high as 60 g L-1. Auto-hydrolysis extracts were submitted to a secondary hydrolysis. The use of different contents of auto- and acid-hydrolysis extracts as natural media, with the yeast previously adapted, showed that 75% (v/v) of acid-hydrolysis extract neutralized with Ca(OH)(2), led to 10 g L(-1) ethanol concentration and a yield of 0.36 g(bioethanol) G(sugars)(-1) micro-aerobic conditions, at 30 degrees C and pH 6.0. Although the maximum ethanol concentration reached was still very low, these results compare well to those obtained When Using a synthetic medium with an equivalent concentration of xylose.

Research paper thumbnail of Hemicelluloses: from wood to the fermenter

Current research topics in applied microbiology and microbial biotechnology, 2009

ABSTRACT The valorisation of hemicelluloses, as a subproduct of the pulping process, can be achie... more ABSTRACT The valorisation of hemicelluloses, as a subproduct of the pulping process, can be achieved with extraction of wood chips by primary hydrolysis (auto or acid catalysed) before cooking, where part of them are dissolved. However, the extracts of the hardwood used in this work (Eucalyptus globulus) could contain oligomers, mainly Xylose based, that Must be further hydrolysed to become a raw material for fermentation to produce e.g. bioethanol, The primary extract from an acid hydrolysis can be directly metabolised by microorganisms being a secondary hydrolysis worthless. On the other hand, twice the monosaccharicds concentration was obtained when a secondary hydrolysis was performed, over the extracts obtained from the primary auto-hydrolysis. The best conditions for that reaction include 3 h of hydrolysis, with 4 %(w/w) Of H(2)SO(4) and the highest concentration of solids (i.e. avoiding the dilution of primary extracts), which led to a secondary hydrolysis yield as high as 84 %.

Research paper thumbnail of Prebiliary Right Hepatic Artery Resulting in Common Hepatic Duct Compression and Subsequent Intrahepatic Stone Formation: Myth or Reality?

Case Reports in Medicine, 2014

The vascular anatomy of the liver is subjected to many variations. Aberrant hepatic artery is not... more The vascular anatomy of the liver is subjected to many variations. Aberrant hepatic artery is not an uncommon finding during visceral surgery; however, topographic variations are less reported in the literature. Prebiliary artery crossing anteriorly to the common hepatic duct was firstly reported in 1984. We present here a case of a 52-year-old lady who presented with obstructive jaundice and right upper quadrant pain. Paraclinical investigations were consistent with intrahepatic stones and a benign stricture on the CBD. During surgery, a prebiliary right hepatic artery compressing the CHD was noted. The liver pedicle was dissected and a hepaticojejunostomy was performed that resulted in a good outcome after 24 months of followup.

Research paper thumbnail of Stranding of Masturus lanceolatus (Actinopterygii: Molidae) in the estuary of the Una River, Pernambuco, Brazil: natural and anthropogenic causes

Marine Biodiversity Records, 2010

Molidae are tropical marine teleosts that occur in all oceans. Among the species described, Mastu... more Molidae are tropical marine teleosts that occur in all oceans. Among the species described, Masturus lanceolatus is considered rare on the Brazilian coast, with only four records found in scientific publications. The present study reports the first occurrence of this species for the coast of the State of Pernambuco (north-eastern Brazil) and discusses the possible causes of its being stranded. The specimen was found alive in the estuary of the Una River in the city of São José da Coroa Grande on the southern coast of the state. The fish was unknown to the local community of fishermen, who considered it a 'bad omen'. The occurrence led to an environmental education project in the community carried out by members of the Tropical Marine Ichthyology Group, which carried out an inspection, documentation, analysis of external injuries and collection of viscera for the subsequent histological analysis. After undergoing taxidermy, the specimen was donated to the Una Museum. Analysis revealed that the fish suffered from an intense inflammatory process of the liver caused by polycystosis of nematodes and Trypanorhyncha, which resulted in malnutrition, as observed by the low body weight. Moreover, a likely stranding left the specimen more vulnerable to different species of shark, which mutilated it, hindering its locomotion. This fish appears to have drifted and was thrown against the reefs near the estuary before its stranding. . (2009) Ocorrência de parasitismo em Mola mola (Linnaeus, 1758) por metazoários no litoral do Rio Grande do Norte, Brasil. Acta Veterinaria Brasilica 3, 43-47. Akiol O., Erdem M., Unal V. and Ceyham T. (2005) Investigations on drift-net fishery for swordfish (Xiphias gladius L.) in the Aegean Sea. Molicola horridus in Luvaris imperialis and Mola mola. Bollettino della Societa Italiana di Patologia Ittica 5, 89-91. Bass A.L., Dewar H., Thys T., Streelman J.T. and Karl S.A. (2005) Evolutionary divergence among lineages of the ocean sunfish family, Molidae (Tetraodontiformes). Marine Biology 148, 405-414.

Research paper thumbnail of Neurologic manifestations of AIDS: a review of fifty cases in Santos

Sao Paulo Medical Journal, 1998

To review the neurologic manifestations of AIDS in patients who were admitted to Hospital Guilher... more To review the neurologic manifestations of AIDS in patients who were admitted to Hospital Guilherme Alvaro (HGA) due to any clinical manifestation of the disease. Case series. All HIV+ patients admitted to the Faculty Hospital (HGA) between July 96 and April 97 were included in this review. From the 117 HIV+ patients admitted to hospitalization due to AIDS-related symptoms, 50 (42.7%) presented neurologic manifestations. The most prevalent of these was neurotoxoplasmosis (68%), but a variety of other neurologic diseases were observed. Only 36% of these 50 patients had neurological signs and symptoms as the main complaint for admission, 12% of the patients had at least complained of some neurologic dysfunction at the time of admission and 10% had no neurologic complaints at all. The remaining 42% (21 patients) only complained of neurologic manifestations of AIDS when specifically asked. The prevalence of neurologic manifestations of AIDS is very high in patients admitted to hospital. Even in the absence of neurologic-related complaints, these patients have to be carefully questioned and examined in the search for an underlying neurologic complication which may present high morbidity and mortality.

Research paper thumbnail of Mapeamento das áreas de preservação permanente e identificação dos conflitos de uso da terra na sub-bacia hidrográfica do Rio Camapuã/Brumado

Revista Árvore, 2012

RESUMO -O objetivo deste trabalho foi mapear e quantificar as áreas de preservação permanente (AP... more RESUMO -O objetivo deste trabalho foi mapear e quantificar as áreas de preservação permanente (APPs) de acordo com a Resolução n o 303/02 do CONAMA para, então, com base no mapa de uso da terra e cobertura vegetal, identificar e quantificar os eventuais conflitos de uso da terra, com vistas a nortear o cumprimento da lei e promover o uso adequado dos recursos da sub-bacia hidrográfica do rio Camapuã/Brumado, MG. Utilizaram-se uma imagem digital do sensor ETM+/LANDSAT 7, bases cartográficas planialtimétricas do IBGE para a área de estudo, e os softwares Anudem 5.2, Erdas Imagine 9.2 e ArcGIS 9.3. As APPs ocuparam 63.095 ha, representando 57,0% da área total da sub-bacia (110.711,9 ha). Com relação às categorias de APPs, o terço superior da bacia, ao longo das linhas de cumeada, correspondeu a 52,6% dos 63.095 ha; as zonas de proteção às margens dos cursos d´água, a 31,4%; a proteção das nascentes, a 15,6%; e as encostas com declividade superior a 45° e o terço superior de morros totalizaram 0,4%. As áreas de terço superior da bacia, ao longo das linhas de cumeada, foram as mais desrespeitadas (55,9%), seguidas das margens de curso d´água (23,12%), proteção de nascentes (20,83%), encostas com declividade superior a 45° (0,3%) e terço superior de morros (0,1%). Foram identificados 21.939,3 ha de APPs sendo explorados por atividades agropecuárias, o que representa 34,8% do total de APPs. Entretanto, constatou-se que 30.734,3 ha dos 47.616,9 ha situados fora das áreas de APP, i.e., 64,5% das áreas legalmente passíveis de conversão de uso da terra, estavam cobertos por vegetação nativa. Encontraram-se sólidas evidências de que a falta de conhecimento a respeito da espacialização das APPs dentro da propriedade é a principal causa do descumprimento da lei. A delimitação e espacialização das APPs pelo geoprocessamento viabilizam a aplicação da legislação florestal, contribuindo notoriamente para minimizar os conflitos de uso da terra e evitar a degradação dos remanescentes florestais pela formação de corredores ecológicos naturais que mitiguem os efeitos deletérios da fragmentação de habitats.

Research paper thumbnail of Development, characterization and clinical use of a biodegradable composite scaffold for bone engineering in oro-maxillo-facial surgery

Organogenesis, 2010

We have developed a biodegradable composite scaffold for bone tissue engineering applications wit... more We have developed a biodegradable composite scaffold for bone tissue engineering applications with a pore size and interconnecting macroporosity similar to those of human trabecular bone. The scaffold is fabricated by a process of particle leaching and phase inversion from poly(lactideco-glycolide) (PLGA) and two calcium phosphate (CaP) phases both of which are resorbable by osteoclasts; the first a particulate within the polymer structure and the second a thin ubiquitous coating. The 3-5 µm thick osteoconductive surface CaP abrogates the putative foreign body giant cell response to the underlying polymer, while the internal CaP phase provides dimensional stability in an otherwise highly compliant structure. The scaffold may be used as a biomaterial alone, as a carrier for cells or a three-phase drug delivery device. Due to the highly interconnected macroporosity ranging from 81% to 91%, with macropores of 0.8∼1.8 mm, and an ability to wick up blood, the scaffold acts as both a clot-retention device and an osteoconductive support for host bone growth. As a cell delivery vehicle, the scaffold can be first seeded with human mesenchymal cells which can then contribute to bone formation in orthotopic implantation sites, as we show in immune-compromised animal hosts. We have also employed this scaffold in both lithomorph and particulate forms in human patients to maintain alveolar bone height following tooth extraction, and augment alveolar bone height through standard sinus lift approaches. We provide a clinical case report of both of these applications; and we show that the scaffold served to regenerate sufficient bone tissue in the wound site to provide a sound foundation for dental implant placement. At the time of writing, such implants have been in occlusal function for periods of up to 3 years in sites regenerated through the use of the scaffold.

Research paper thumbnail of Intraosseous leiomyoma of the mandible

Oral Oncology Extra, 2006

The case of an intraosseous leiomyoma in a 57-year-old man is presented. The tumor was incidental... more The case of an intraosseous leiomyoma in a 57-year-old man is presented. The tumor was incidentally discovered during routine dental X-ray examination as a round, unilocular, radiolucency, measuring approximately 2 · 1.5 cm. Clinical examination revealed a slight swelling of the buccal cortical plate in the edentulous area of the posterior right mandible, and intra-operatively, perforation of the buccal cortical plate was seen. Histological and immunohistochemical examination was diagnostic of solid leiomyoma. One year after surgery the patient is free of residual or recurrent disease. This is the fifteen documented cases of intraosseous leiomyoma reported in the English literature.

Research paper thumbnail of Survival and initial growth of Euterpe edulis Mart. seedlings transplanted to gaps and undestory in a Semideciduous Forest, Viçosa, MG

Revista Árvore, 2011

RESUMO Este estudo teve como objetivos avaliar a sobrevivência e crescimento inicial de plântulas... more RESUMO Este estudo teve como objetivos avaliar a sobrevivência e crescimento inicial de plântulas de Euterpe edulis Mart. transplantadas para duas condições de luz: clareira e sub-bosque, além de discutir seu comportamento ecofisiológico. Foram transplantadas 90 ...

Research paper thumbnail of Complicated rectovaginal fistula secondary to Bartholin's cyst infection

Journal of Obstetrics and Gynaecology Research, 2014

Rectovaginal fistula formation secondary to Bartholin&amp... more Rectovaginal fistula formation secondary to Bartholin's cyst is a very rare complication, and to date only three cases were reported in the literature. We report a case of a 32-year-old woman who suffered recurrent episodes of Bartholin's cyst infection with subsequent abscess formation that resulted in rectovaginal fistula formation. We treated her initially with transperineal repair; however, the fistulous tract recurred a month later. A laparoscopic colostomy and transperineal repair using biological graft was then performed, with excellent results. The patient underwent reversal of colostomy after 2 months, and remained asymptomatic upon follow-up 12 months later.

Research paper thumbnail of Prehydrolysis of Eucalyptus globulus Labill. hemicelluloses prior to pulping and fermentation of the hydrolysates with the yeast Pichia stipitis 10th EWLP, Stockholm, Sweden, August 25–28, 2008

Holzforschung, 2000

ABSTRACT The aim of this work was to evaluate the potential of Eucalyptus globulus hemicelluloses... more ABSTRACT The aim of this work was to evaluate the potential of Eucalyptus globulus hemicelluloses, mainly xylan, for bioethanol production. Hemicelluloses have been removed prior to pulping by auto-hydrolysis and an acid-catalysed hydrolysis. As the hydrolysates obtained were rich in xylose, the yeast Pichia stipitis was selected for fermentation. It was confirmed that the yeast performance is strongly dependent on pH and the presence of inhibitors, such as lignin. The addition of Ca(OH)(2) was successful for lowering the concentration of inhibitors and adjusting the pH. The strain was grown in culture media with increasing volumetric percentages of treated hydrolysates up to 100% (v/v), supplemented with nutrients other than the carbon and energy source. This methodology shortened the lag phase of fermentation and improved the performance of yeast. Maximum ethanol concentration (12 g(eth) l(-1)), productivity (0.22 g(eth) l(-1) h(-1)), and yield (0.48 g(eth) g(xyl) eqs(-1)) were achieved with treated acid-hydrolysates. These results are similar to those obtained by a synthetic medium with an equivalent xylose concentration.

Research paper thumbnail of Valorisation of hardwood hemicelluloses in the kraft pulping process by using an integrated biorefinery concept

Food and Bioproducts Processing, 2009

ABSTRACT A primary hydrolysis treatment (auto or acid-catalysed) of Eucalyptus globulus wood was ... more ABSTRACT A primary hydrolysis treatment (auto or acid-catalysed) of Eucalyptus globulus wood was performed before the cooking stage to extract part of the hemicelluloses that otherwise would be dissolved in the kraft liquor and burned. As xylose was the main monosaccharide Pichia stipitis was selected to produce bioethanol. Two methods were tested, with different alkalis, to reduce hydrolysates toxicity and adjust pH. A two-step method using Ca(OH)2 leads to better fermentation results. Acid hydrolysates promoted higher ethanol concentrations (12 g L−1) with high productivity and yield values (0.22 geth L−1h−1 and 0.48 geth/gxyl eqs), whilst auto-hydrolysates, even after a secondary hydrolysis, gave low ethanol concentrations (2–4 g L−1). The impacts on kraft cooking and pulp quality were also studied in order to fully understand the feasibility of this biorefinery concept (combining ethanol production and hardwood pulping). A decrease of the overall pulp yield (10% for auto- and 15% for acid-hydrolysis) was observed. However, a decrease on bleaching requirements (up to 15%) and on brightness reversion was registered. Moreover, auto-hydrolysis improves pulp viscosity, whilst acid-hydrolysis is more efficient in metals leaching. Overall, from the pulp production point of view, auto-hydrolysis conditions are more attractive than the acid-catalysed ones.

Research paper thumbnail of Periodontal regeneration using a bilayered PLGA/calcium phosphate construct

Research paper thumbnail of EXTRACTION OF HEMICELLULOSES PRIOR TO KRAFT COOKING: A STEP FOR AN INTEGRATED BIOREFINERY IN THE PULP MILL

O PAPEL, 2011

Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus glob... more Two treatments, an induced autohydrolysis and an acid hydrolysis, were applied to Eucalyptus globulus wood chips prior to the cooking stage to extract the hemicellulosic fraction that otherwise would be dissolved in the black liquor and burnt in the recovery boiler. The obtained hydrolysates, rich in xylose, were detoxified by overliming and used for ethanolic fermentation. Impacts of each wood pretreatment on the kraft cooking process and on the quality of the produced pulp were evaluated. Both pretreatments promoted an increase in the cooking rate, but had a negative effect on pulp quality and overall yield. Autohydrolysis showed a less negative influence. However, autohydrolysates led to lower values of ethanol concentration, productivity and yield compared to the fermentation of acid hydrolysates. To get more profit from the autohydrolysates they were also submitted to secondary acid hydrolysis and vacuum evaporation processes. Overliming followed by evaporation (with a concentration factor of 3) gave better results than the inverse method. This procedure raised the fermentable sugar content and led to the production of ethanol with a concentration of ~10 g eth L -1 (productivity of 0.23 g eth L -1 h -1 and yield of 0.50 g eth g xyl eq -1 ) which compares well with the results obtained with the fermentation of acid hydrolysates.