Orientador: Rodrigo Fernando Costa Marques / Resumo: A biomassa lignocelulósica vem se destacando como uma matéria-prima essencial para a produção de muitos produtos químicos de interesse industrial em áreas como a produção de energia, alimentos, fármacos, agricultura, meio ambiente e assim por diante. Apesar disso, muitas aplicações vêm esbarrando em uma série de dificuldades encontradas nos processos de conversão enzimática, como instabilidade operação das enzimas, alto custo de produção e purificação, reações de inibição e problemas de recuperação e reciclo. Para contornar esses problemas, muitos métodos de imobilização enzimática têm surgido, entre os quais, destaca-se a obtenção de agregados enzimáticos reticulados magnéticos (MCLEAs). Esta classe de materiais é obtida a partir da reação de reticulação entre agregados físicos de enzimas e suportes magnéticos, o qual pode unir as importantes propriedades catalíticas dos agregados físicos (como resultado da manutenção da estrutura nativa da enzima) à capacidade de recuperação e reciclo do suporte magnético (devido suas propriedades magnéticas intrínsecas). Frente a isso, esse trabalho relata a síntese, caracterização e potencial aplicação de MCLEAs de enzimas celulases em processos de conversão de celulose. Dividido em três capítulos, primeiramente é apresentado um review sobre o estado da arte no que diz respeito a obtenção de produtos de valor agregado a partir da biomassa lignocelulósica utilizando MCLEAs. No segundo capítulo, diferentes MCLEAs foram preparados na presenç... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Lignocellulosic biomass has highlighted as an essential renewable raw material for production of many value-added chemicals of industrial interest in field as energy production, food, pharmaceutical, agriculture, environment and so on. Despite it, many applications have wrought with a series of difficulties in regarding enzymatic conversion processes, as enzyme operational instability, high production and purification cost, inhibition reactions, and issues of recovery and recycle. To overcome these issues, many enzyme immobilization methods have emerged, among which highlights the obtention of magnetic-cross linked enzyme aggregates (MCLEAs). This materials class is obtained from cross-linking reaction between enzyme physical aggregates and magnetic supports, which can gather the important catalytic properties of the physical aggregates (as a result of enzyme native structure maintenance) to recovery and recycle capacity of magnetic nanoparticles (as result of its intrinsic magnetic properties). Faced it, this work reports the synthesis, characterization and potential application of different cellulases MCLEAs in the cellulose enzymatic conversion process. Sectioned in three chapters, firstly is presented a review about the state of art in concern to obtention of value-added chemicals from lignocellulosic biomass using MCLEAs. In the second chapter, different MCLEAs were prepared in the presence of quitosana-coated magnetic nanoparticles with three different precipitation age... (Complete abstract click electronic access below) / Doutor

Release of nociceptin-like substances from the dorsal horn of rat spinal cords in situ was measured by the immobilized-antibody microprobe technique. Spinal cords removed from anesthetized 4-6 week-old rats were superfused with oxygenated Krebs solution at room temperature (21 ± 1°C). Glass microelectrodes, coated with antibodies to nociceptin, were inserted into the dorsal horn of the lumbar spinal cord (1.9 mm lateral to the midline to a depth 2.5 mm below the surface of the cord) for 15 rain periods before, during and after electrical stimulation applied to the dorsal root entry zone of the same segment. There was a basal release of immunoreactive nociceptin- like substance (irNC) from the dorsal horns during the pre-stimulation period. A significant increase in irNC release was detected during the period of electrical stimulation and this increase was maintained for at least 15 min following the cessation of electrical stimulation. These results provide the first evidence on the release of irNC, albeit non-quantitative, from the in situ rat spinal cord dorsal horn and an enhanced release upon electrical stimulation.

No description available.

No description available.

Glucose isomerase (GI) catalyzes the conversion of D-glucose to D-fructose in vitro. It is one of the bulkiest commercial enzymes, essential for the mass production of high-fructose corn syrup (HFCS) and crystalline fructose. / In this study, the effects of nitrogen sources, carbon sources, expression vectors, host strains, bacterial (Vitreoscilla) hemoglobin, selective pressure, plasmid stability and fermentation process on the GI production were investigated. The results showed that E. coli could express cloned thermostable GI at high expression level. E. coli transformed with the recombinant plasmid P-lac-GI gave the best result in term of total GI production and expression level. Corn steep liquor could be used as a cheap alternative nitrogen source for what was in LB medium. The concentration of glucose affected the expression level of GI significantly. Replacement of the ampicillin resistance gene by kanamycin resistance gene improved the plasmid stability leading to high productivity of GI in fed-batch fermentation. A suicide system could further improve the plasmid stability resulting in a high productivity of GI. A feeding strategy for fed-batch fermentation with the optimized parameters was developed to result in the production of up to 3g/L recombinant GI, which constituted 50% of the total soluble proteins. The total yield was 5-fold higher than that from flask experiments and 7-fold higher than the highest ever recorded. The expression level was also 100% higher than it was in other reports. / Liu Zhaoming. / "August 2005." / Advisers: J. Wang; W. P. Fong. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3780. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 129-154). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Glucose isomerase (GI) catalyzes the isomerization of glucose to fructose and consequently is one of the bulkiest industrial enzyme for the manufacture of high fructose corn syrup and crystalline fructose. The GI is used in industry mainly in the form of immobilized enzyme. / In this work, the immobilization of GI had been studied by several methods: ion exchange adsorption, covalent binding, alginate cells entrapment and cells cross-linking. Three kinds of carrier support (ion exchange resin, epoxy resin and amino resin) have been used in the immobilization of cells-free enzyme; the whole cells immobilization of GI by cross-linking agents polyethyleneimid and glutaraldehyde were critically examined. The results show that the cells cross-linking is the best method to prepare the immobilized GI products, as it is high in specific activity and thermostability, and low the cost. The method is likely to make significant contribution to the field of immobilization, its application has expanding rapidly in many walks of the society, including environment protection, food and pharmaceutical industries. / Jin, Caike. / "August 2005." / Adviser: Jun Wang. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3521. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 125-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Extraction of bitumen from Alberta oil sands produces 2 to 4 barrels of aqueous tailings per barrel of crude oil. Oil sands process water (OSPW) contains naphthenic acids (NAs), a complex mixture of carboxylic acids of the form CnH2n+ZOx that are persistent and toxic to aquatic organisms. Previous studies have demonstrated that aerobic biodegradation reduces NA concentrations and OSPW toxicity; however, treatment times are long. The objective of this study was to evaluate the feasibility of an immobilized soil bioreactor (ISBR) for treatment of NAs in OSPW and to determine the role of ammonium and ammonium oxidizing bacteria (AOB) in NA removal. ISBRs have been used to successfully remediate water contaminated with pollutants such as pentachlorophenol and petroleum hydrocarbons. A system of two ISBRs was operated continuously for over 2 years with OSPW as the sole source of carbon. Removal levels of 30-40% were consistently achieved at a residence time of 7 days, a significant improvement compared to half-lives of 44 to 240 days reported in the literature. However, similar to biodegradation experiments in the literature, a significant portion (~60%) of the NAs was not degraded. The role of AOB in NA removal was investigated by decreasing ammonium concentration and inhibiting AOB activity with allylthiourea, neither of which significantly affected removal, indicating that AOB did not enhance NA removal. Furthermore, high AOB populations actually inhibited the removal of a simple NA surrogate. Therefore, a moderate ammonium concentration of 0.3 g/L is recommended. NA degradation occurred with nitrate as the sole nitrogen source, however, removal levels were lower than those achieved with ammonium. Exploratory studies involving ozonation or biostimulation were conducted with the aim of increasing NA removal. Ozonation decreased NA concentration by 94% and total organic carbon (TOC) by 6%. Subsequent ISBR treatment removed ~30% of the remaining TOC. Addition of a NA surrogate increased heterotrophic NA-degrading populations due to the increase in available carbon, resulting in a significant increase in NA removal levels. However, use of a surrogate may result in a population that is only adapted to degradation of the NA surrogate. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-06-20 14:53:47.498

by Fung King-yuen Debera. / On t.p., "2+" is superscript. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 102-112). / Acknowledgement --- p.i / Abstract --- p.ii / Table of Content --- p.iv / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Literature review --- p.1 / Chapter 1.1.1 --- Problems of heavy metals in the environment --- p.1 / Chapter 1.1.2 --- Methods of removal of heavy metal from industrial effluent --- p.5 / Chapter 1.1.3 --- The properties of magnetites --- p.10 / Chapter 1.1.4 --- Role of magnetites in water treatment --- p.12 / Chapter 1.1.5 --- The advantages of using magnetites and further application of magnetites --- p.16 / Chapter 1.2 --- Objectives of the study --- p.21 / Chapter 2. --- Materials and methods --- p.23 / Chapter 2.1 --- Selection of the organisms --- p.23 / Chapter 2.2 --- Culture media and chemicals --- p.23 / Chapter 2.3 --- Growth of the bacterial cells --- p.25 / Chapter 2.4 --- Immobilization of the bacterial cells on magnetites --- p.27 / Chapter 2.4.1 --- Effects of chemical and physical factors on the immobilization of the bacterial cells on magnetites --- p.27 / Chapter 2.4.2 --- Effect of pH on the desorption of cells from magnetites --- p.28 / Chapter 2.5 --- Nickel ion uptake experiments --- p.28 / Chapter 2.6 --- Effects of operational conditions on the nickel removal capacity of the magnetite-immobilized bacterial cells --- p.29 / Chapter 2 .6.1 --- Effect of physical factors --- p.29 / Chapter 2.6.2 --- Effect of chemical factors --- p.30 / Chapter 2.7 --- Optimization of the nickel removal efficiency --- p.30 / Chapter 2.8 --- Nickel adsorption isotherm of the magnetite- immobilized cells of Enterobacter sp4-2 --- p.30 / Chapter 2.9 --- Recovery of adsorbed Ni2+ from the magnetite- immobilized cells of Enterobacter sp4-2 --- p.31 / Chapter 2.9.1 --- Multiple adsorption-desorption cycles of Ni2+ by using citrate buffer --- p.32 / Chapter 2.9.2 --- Multiple adsorption-desorption cycles of Ni2+ by using ethylenediaminetetraacetic acid (EDTA) --- p.33 / Chapter 2.10 --- Effect of acidic treatment --- p.33 / Chapter 2.10.1 --- Effect of acidic treatment on the nickel removal capacity of the magnetites and the magnetite- immobilized cells of Enterobacter sp4-2 --- p.33 / Chapter 2.10.2 --- Effect of acidic treatment on the recovery of the adsorbed Ni2+ from magnetites and the magnetite- immobilized cells Enterobacter sp4-2 --- p.34 / Chapter 2.11 --- Removal and recovery of Ni2+ from the electroplating effluent --- p.34 / Chapter 3. --- Results --- p.36 / Chapter 3.1 --- Effects of chemical and physical factors on the immobilization of the bacterial cells on magnetites --- p.36 / Chapter 3.1.1 --- Effect of pH --- p.36 / Chapter 3.1.2 --- Effect of cells to magnetites ratio --- p.36 / Chapter 3.1.3 --- Effect of temperature --- p.39 / Chapter 3.2 --- Effect of pH on the desorption of cells from magnetites --- p.39 / Chapter 3.3 --- Nickel ion uptake experiments --- p.44 / Chapter 3.4 --- Effects of operational conditions on the nickel removal capacity of the magnetite-immobilized bacterial cells --- p.44 / Chapter 3.4.1 --- Effect of reaction temperature --- p.44 / Chapter 3.4.2 --- Effect of retention time --- p.44 / Chapter 3.4.3 --- Effect of pH --- p.47 / Chapter 3.4.4 --- Effect of the presence of cations --- p.50 / Chapter 3.4.5 --- Effect of the presence of anions --- p.50 / Chapter 3.5 --- Optimization of the nickel removal efficiency --- p.55 / Chapter 3.6 --- Nickel adsorption isotherm of the magnetite- immobilized cells of Enterobacter sp4-2 --- p.55 / Chapter 3.7 --- Recovery of adsorbed Ni2+ from the magnetite- immobilized cells of Enterobacter sp4-2 --- p.59 / Chapter 3.7.1 --- Multiple adsorption-desorption cycles of Ni2+ by using citrate buffer --- p.59 / Chapter 3.7.2 --- Multiple adsorption-desorption cycles of Ni2+ by using ethylenediaminetetraacetic acid (EDTA) --- p.63 / Chapter 3.8 --- Effect of acidic treatment --- p.63 / Chapter 3.8.1 --- Effect of acidic treatment on the nickel removal capacity of the magnetites and the magnetite-immobilized cells of Enterobacter sp4-2 --- p.63 / Chapter 3.8.2 --- Effect of acidic treatment on the recovery of the adsorbed Ni2+ from the magnetites and the magnetite-immobilized cells of Enterobacter sp4-2 --- p.66 / Chapter 3.9 --- Removal and recovery of Ni2+ from the electroplating effluent --- p.69 / Chapter 4. --- Discussion --- p.72 / Chapter 4.1 --- Selection of the organisms --- p.72 / Chapter 4.2 --- Effects of chemical and physical factors on the immobilization of the bacterial cells on magnetites --- p.72 / Chapter 4.2.1 --- Effect of pH --- p.72 / Chapter 4.2.2 --- Effect of cells to magnetites ratio --- p.74 / Chapter 4.2.3 --- Effect of temperature --- p.75 / Chapter 4.2.4 --- Effect of pH on the desorption of cells from magnetites --- p.76 / Chapter 4.3 --- Nickel ion uptake experiments --- p.78 / Chapter 4.4 --- Effects of operational conditions on the nickel removal capacity of the magnetite-immobilized bacterial cells --- p.80 / Chapter 4.4.1 --- Effect of reaction temperature --- p.80 / Chapter 4.4.2 --- Effect of retention time --- p.81 / Chapter 4.4.3 --- Effect of pH --- p.82 / Chapter 4.4.4 --- Effect of the presence of cations --- p.83 / Chapter 4.4.5 --- Effect of the presence of anions --- p.84 / Chapter 4.5 --- Optimization of the nickel removal efficiency --- p.85 / Chapter 4.6 --- Nickel adsorption isotherm of the magnetite- immobilized cells of Enterobacter sp4-2 --- p.86 / Chapter 4.7 --- Recovery of adsorbed Ni2+ from the magnetite- immobilized cells of Enterobacter sp4-2 --- p.87 / Chapter 4.7.1 --- Multiple adsorption-desorption of Ni2+ --- p.89 / Chapter 4.7.2 --- Effect of acidic treatment on the nickel removal capacity and recovery --- p.91 / Chapter 4.8 --- Removal and recovery of Ni2+ from the electroplating effluent --- p.93 / Chapter 5. --- Conclusion --- p.96 / Chapter 6. --- Summary --- p.99 / Chapter 7. --- References --- p.102