183 research outputs found
Understanding the mechanisms of cooperative physico-chemical treatment and mechanical disintegration of biomass as a route for enhancing enzyme saccharification
A novel chemico-kinetic disintegration model has been applied to study the cooperative relationship between physico-chemical treatment and supplementary wet-state milling of biomass, as an efficient process route to achieve high enzyme accessibility. Wheat straw, Miscanthus and short-rotation willow were studied as three contrasting biomass species, which were subjected to controlled hydrothermal pretreatment using a microwave reactor, followed by controlled wet-state ball-milling. Comparative particle disintegration behaviour and related enzyme digestibilities have been interpreted on the basis of model parameters and with evaluation of textural and chemical differences in tissue structures, aided by the application of specific material characterisation techniques. Supplementary milling led to a 1.3Ă, 1.6Ă and 3Ă enhancement in glucose saccharification yield after 24 h for straw, Miscanthus and willow, respectively, following a standardised 10-min hydrothermal treatment, with corresponding milling energy savings of 98, 97 and 91% predicted from the model, compared to the unmilled case. The results confirm the viability of pretreatment combined with supplementary wet-milling as an efficient process route. The results will be valuable in understanding the key parameters for process design and optimisation and also the key phenotypical parameters for feedstock breeding and selection for highest saccharification yield
High throughput screening of hydrolytic enzymes from termites using a natural substrate derived from sugarcane bagasse
<p>Abstract</p> <p>Background</p> <p>The description of new hydrolytic enzymes is an important step in the development of techniques which use lignocellulosic materials as a starting point for fuel production. Sugarcane bagasse, which is subjected to pre-treatment, hydrolysis and fermentation for the production of ethanol in several test refineries, is the most promising source of raw material for the production of second generation renewable fuels in Brazil. One problem when screening hydrolytic activities is that the activity against commercial substrates, such as carboxymethylcellulose, does not always correspond to the activity against the natural lignocellulosic material. Besides that, the macroscopic characteristics of the raw material, such as insolubility and heterogeneity, hinder its use for high throughput screenings.</p> <p>Results</p> <p>In this paper, we present the preparation of a colloidal suspension of particles obtained from sugarcane bagasse, with minimal chemical change in the lignocellulosic material, and demonstrate its use for high throughput assays of hydrolases using Brazilian termites as the screened organisms.</p> <p>Conclusions</p> <p>Important differences between the use of the natural substrate and commercial cellulase substrates, such as carboxymethylcellulose or crystalline cellulose, were observed. This suggests that wood feeding termites, in contrast to litter feeding termites, might not be the best source for enzymes that degrade sugarcane biomass.</p
Bringing the Tiger Back from the BrinkâThe Six Percent Solution
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An integrated approach for efficient biomethane production from solid bio-wastes in a compact system
Visualization of Miscanthus Ă giganteus cell wall deconstruction subjected to dilute acid pretreatment for enhanced enzymatic digestibility
Expressing accessory proteins in cellulolytic Yarrowia lipolytica to improve the conversion yield of recalcitrant cellulose
Pretreatment and enzymatic process modification strategies to improve efficiency of sugar production from sugarcane bagasse
New dry technology of environmentally friendly biomass refinery: glucose yield and energy efficiency
Acompanhamento de pacientes submetidos Ă cirurgia bariĂĄtrica : aspectos laboratoriais nos perĂodos prĂ© e pĂłs-operatĂłrio
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de CiĂȘncias da SaĂșde, Programa de PĂłs-Graduação em FarmĂĄcia, FlorianĂłpolis, 2017A obesidade Ă© uma doença crĂŽnica e endĂłcrino-metabĂłlica caracterizada pelo acĂșmulo excessivo de triacilglicerĂłis no tecido adiposo, capaz de ser revertida ou amenizada atravĂ©s de intervenção cirĂșrgica. Epidemiologicamente tĂȘm sido descritas associaçÔes entre o excesso de peso, resistĂȘncia Ă insulina e processo inflamatĂłrio crĂŽnico. AlĂ©m disso, nas Ășltimas dĂ©cadas o sistema complemento foi associado a doenças metabĂłlicas e cardiovasculares e intimamente relacionado com a obesidade e resistĂȘncia Ă insulina. Sendo assim, a melhora do estado metabĂłlico e a remissĂŁo da inflamação em pacientes obesos submetidos Ă cirurgia bariĂĄtrica foram avaliadas, bem como a associação dos fatores 3 e 4 (C3 e C4) do sistema complemento com a sensibilidade Ă insulina e a perda de peso apĂłs a cirurgia bariĂĄtrica. Para isso, a presença de comorbidades e as concentraçÔes sĂ©ricas de leptina, adiponectina, resistina e grelina foram avaliados em pacientes obesos mĂłrbidos antes, 1, 3 e 6 meses apĂłs a cirurgia bariĂĄtrica. TambĂ©m foram medidas as concentraçÔes de IL-1Ă, IL-6, TNF-a, proteĂna amiloide sĂ©rica A (SAA), proteĂna quimiotĂĄtica de monĂłcitos 1 (MCP-1), C3, C4, glicose, insulina, colesterol total, triacilglicerol, LDL- colesterol, HDL-colesterol e foi realizado o cĂĄlculo do modelo de avaliação da homeostase da resistĂȘncia Ă insulina (HOMA-IR) durante o seguimento da cirurgia, bem como em comparação com um grupo de indivĂduos nĂŁo-obesos. Como resultado, observou-se uma redução significativa de peso acompanhada de melhora do perfil lipĂdico, da sensibilidade Ă insulina e das comorbidades. Ainda, houve diminuição de leptina e aumento de adiponectina no perĂodo pĂłs-cirĂșrgico. IL-1Ă, IL-6, TNF-a, MCP-1 e SAA nĂŁo mostraram diferença no acompanhamento da cirurgia, porĂ©m SAA correlacionou-se com o IMC e apresentou-se muito mais alto no grupo de pacientes obesos. AlĂ©m disso, C3 e C4 foram significativamente maiores em indivĂduos obesos quando comparados aos indivĂduos nĂŁo-obesos e C3 e C4 foram positivamente correlacionados com HOMA-IR e as concentraçÔes de C3 foram significativamente diminuĂdas apĂłs a cirurgia. Com base nesses resultados, a cirurgia bariĂĄtrica mostrou melhorar o estado metabĂłlico melhorando as comorbidades associadas Ă obesidade e os biomarcadores de adiposidade leptina e adiponectina, mas nĂŁo os demais hormĂŽnios e citocinas inflamatĂłrias e C3 e C4 foram fortemente associados Ă sensibilidade Ă insulina.Abstract: Obesity is a chronic and endocrine-metabolic disease characterized by triacylglycerol accumulation in the adipose tissue, which can be reversed or improved through surgical intervention. Epidemiologically, associations between overweight, insulin resistance and chronic inflammatory process have been described. Furthermore, in the last decades the complement system was associated with metabolic and cardiovascular diseases and related to obesity and insulin resistance. Thus, metabolic status improvement and inflammation remission in obese patients undergoing bariatric surgery were evaluated, as well as the association of complement system factors 3 and 4 (C3 and C4) with insulin sensitivity and weight loss after bariatric surgery. For this, comorbidities and leptin, adiponectin, resistin and ghrelin serum concentrations were evaluated in morbidly obese patients before, 1, 3 and 6 months after bariatric surgery. IL-1Ă, IL-6, TNF-a, serum amyloid A protein (SAA), monocyte chemotactic protein 1 (MCP-1), C3, C4, glucose, insulin, total cholesterol, triacylglycerol, LDL-cholesterol, HDL-cholesterol concentrations and the calculation of the homeostasis model of insulin resistance (HOMA-IR) were performed during the surgery follow-up, as well in a group of non-obese individuals. As a result, significant weight loss followed by improvement in lipid profile, insulin sensitivity and comorbidities were observed. Still, there was a decrease in leptin and an increase in adiponectin in the postoperative period. IL-1Ă, IL-6, TNF-a, MCP-1 and SAA showed no difference after surgery, but SAA correlated with BMI and was much higher in obese patients. In addition, both C3 and C4 were significantly higher in obese individuals when compared to lean individuals and positively correlated with HOMA-IR. C3 concentrations were significantly decreased after surgery. Based on these results, bariatric surgery has been shown to improve metabolic status by improving obesity-associated comorbidities and adiposity biomarkers leptin and adiponectin but not the other hormones and inflammatory cytokines and C3 and C4 were strongly associated with insulin sensitivity
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