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Relvas, Frederico Miguel Horta de Albuquerque Moura. "Kinetic study of biomass hydrolysis under high pressure conditions." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13848.
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Mestrado em Engenharia QuímicaThis study was focused on the kinetics of lignocellulosic biomass pre-treatment, in particular CO2-assisted autohydrolysis. The temperature was fixed at 180 ºC, varying pressure from 0 (CO2-free autohydrolysis), 20, 35 to 50 bar. For every pressure, a set of isothermal reactions was performed for various reaction times from 0 and 45 minutes. The pre-treatment resulted in a liquid, solid and gas phases, which were analyzed by HPLC. The liquid phase is essentially composed by sugars both in oligomer and monomer forms, mainly from xylan, also containing acetic acid and degradation products such as furfural and formic acid. In turn, there was an improvement of lignin and glucan’s fraction in the solid residue, being more pronounced for longer treatments. Regarding gas phase collected during depressurization, no traces of products from biomass hydrolysis were found. Basing on the literature and experimental results, 4 kinetic models were developed to predict the behavior of the biomass hydrolysis. Models for xylan, arabinoxylan, glucan and another for acetyl groups were presented. According to the results, the use of CO2 is beneficial for the selective fractionation of biomass, including hemicellulose and amorphous cellulose fractions. Beside, CO2 favors the production of xylooligosaccharides (XOS) achieving a maximum concentration of 14.76 g·L-1 at 50 bar assay vs 13.62 g·L-1 in case of autohydrolysis. Furthermore the conversion of oligomers to monomers is directly proportional to pressure and is enhanced by CO2 presence. With respect to the developed kinetic models, all showed good correlation with experimental data, with R2 as high as 0.9986. In the worst case, the R2 was 0.7865 what considering the so complex multistep analysis process can be acknowledge as a good result. Despite kinetic constants showed an increase of hydrolysis rate of xylan and arabinan in the presence of CO2, they decreases for higher pressures used. In turn, the model for acetyl groups also shows very consistent results with the lowest R2 of 0.9491. The removal of acetyl groups seems to be impaired by the carbon dioxide presence. With respect to glucan, the obtained data shows that reactions are close to zero order as they are independent on the products’ concentrations.
O presente trabalho focou-se no estudo cinético do pré-tratamento de biomassa lignocelulósica, em particular no processo de autohidrólise assistido com dióxido de carbono. O estudo foi feito fixando a temperatura em 180 ºC, variando a pressão entre 0 (ausência de CO2), 20, 35 e 50 bar. Para todas as gamas de pressão foram feitos ensaios isotérmicos entre 0 e 45 minutos. Os pré-tratamentos resultaram em 3 fases, líquida, sólida e gasosa, que foram analisadas por HPLC. A fase líquida é consituída essencialmente por açúcares (monómeros e oligómeros) provenientes maioritariamente do xilana, encontrando-se também ácido acético e produtos de degradação, tais como furfural e ácido fórmico. Por sua vez, as fracções de lignina e celulose na fase sólida aumentaram, sendo mais evidente para tratamentos mais longos. Em relação à fase gasosa, não foram encontrados quaisquer produtos de hidrólise da biomassa. Com base na literatura e nos resultados experimentais, foram desenvolvidos 4 modelos cinéticos para prever o comportamento da hidrólise da biomassa, correspondentes à fracção de xilana, arabinoxilana, celulose e grupos acetilo. De acordo com os resultados obtidos, concluiu-se que o uso de CO2 é útil para fraccionamento selectivo da biomassa, nomeadamente da fracção de hemicelulose e de celulose amorfa, apresentando também melhores resultados do que a autohidrólise na produção de xilooligossacarídeos (XOS), com um máximo de concentração de 14.76 g·L-1 para 50 bar vs. 13.62 g·L-1 na autohidrólise. Além disso, a conversão de oligomeros em monómeros é proporcional à pressão e favorecida pela presença de CO2. Quanto aos modelos cinéticos apresentam uma boa correlação com os dados experimentais, com um R2 mais alto de 0.9986. No pior caso, o R2 foi de 0.7865 que, tratando-se de uma reacção complexa, pode ser considerado um boa resultado. Apesar das constantes cinéticas mostrarem um aumento da hidrólise de xilana e arabinana na presença de CO2, estas decrescem em pressões mais elevadas. Por sua vez, os grupos acetilo também mostram resultados bastante consistentes, com o R2 mais baixo de 0.9491. A remoção de ácido acético parece ser prejudicada pela presença de CO2, enquanto os resultados da hidrólise de glucano sugerem uma cinética de ordem zero, uma vez que a concentração dos produtos aparenta ser independente da concentração dos diferentes produtos.
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Molwantwa, Jennifer Balatedi. "The hydrolysis of primary sewage sludge under biosulphidogenic conditions." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1004020.
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The potential for using readily available and cost-effective complex carbon sources such as primary sewage sludge for a range of environmental remediation processes, including biological sulphate reduction, biological nutrient removal and the bioremediation of acid mine drainage, has been constrained by the slow rate of solubilization and low yield of soluble products, which drive the above mentioned processes. Previous work conducted by the Environmental Biotechnology Group at Rhodes University indicated that the degradation of primary sewage sludge was enhanced under sulphate reducing conditions. This was proven in both laboratory and pilot-scale (Reciprocating Sludge Bed Reactor) systems, where the particulate matter accumulated in the sludge bed and the molecules in smaller flocs were rapidly solubilized. The current study was aimed at investigating in more detail the factors that govern the enhanced hydrolysis under sulphate reducing conditions, and to develop a descriptive model to explain the underlying mechanism involved. The solubilization of primary sewage sludge under sulphate reducing conditions was conducted in controlled flask studies and previously reported findings of enhanced hydrolysis were confirmed. The maximum percentage solubilization obtained in this study was 31% and 63% for the methanogenic and sulphidogenic systems respectively, and this was achieved over a period of 10 days. A rate of reducing sugar production and complex molecule breakdown of 51 mg. L⁻¹.hr⁻¹ and 167 mg.L⁻¹.hr⁻¹ was observed for the methanogenic and sulphidogenic systems respectively. The flask studies revealed that during hydrolysis of primary sewage sludge under sulphidogenic conditions there was enhanced production of soluble products, specifically carbohydrates (reducing sugars) and volatile fatty acids, compared to methanogenic conditions. The rate at which these products were utilized was also found to be more rapid under sulphidogenic as compared to methanogenic conditions. A study of the distribution of volatile fatty acids indicated that acetate was utilized preferentially in the methanogenic system, and that propionate, butyrate and valerate accumulated with time. The converse was found to occur in the sulphidogenic system. The descriptive model developed from the results of this study was based on the fact that a consortium of bacteria, composed of hydrolytic, acidogenic and acetogenic species, carries out the solubilization of complex carbon sources. Furthermore, it is essential that equilibrium between product formation and utilization is maintained, and that accumulation of soluble end products impacts negatively on the rate of the hydrolysis step. It is therefore proposed that the relatively poor utilization of VFA and reducing sugars in the methanogenic system activates a negative feedback inhibition on the hydrolytic and/ or acidogenic step. This inhibition is reduced in the sulphidogenic system where the utilization of end products is higher.
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Awasume, Ignatius Ekwe, and Abel Prince Jabakumar Sathiyaraj. "Optimization of Pre-hydrolysis Conditions for the Production of Biogas." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-16495.
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Hydrolysis and solubilisation of organic material is known to be the rate limiting step during anaerobic digestion. In this study, the effect of pre-hydrolysis was investigated. The substrate had a composition of the following wastes streams: fish and slaughterhouse waste, cleaning waste, doggy meat, doggy sludge, doggy dry food, mink (fur), Norway slurry, SOR2-Industrial waste, and municipal solid waste (MSW) from households in Borås community.Analyses were made on two batches of experiments performed at two different mesophilic temperature conditions; 34 0C and 42 0C and with or without the addition of mesophilic sludge obtained from a waste water treatment plant. One of the substrate maintained the original carbon/nitrogen (C/N) ratio, and for the other substrate the carbon nitrogen ratio was then slightly increased by adding 7.98g of special shredded paper which contains 82% volatile solids (VS). The experiments were run for 7days with samples collected regularly after 0 day, 4 days, 5 days, 6 days and 7 days retention time. Chemical oxygen demand (COD), pH, total nitrogen, and volatile fatty acids (VFAs) as process indicators were analyzed.The results showed that at 42 0C the rate of hydrolysis was faster with a higher COD release and removal. The optimum retention time for hydrolysis was 4 days and any longer time caused some of the carbon to be lost to carbon dioxide. The effect of adding mesophilic sludge had no significant effect. An increased C/N ratio resulted in a balanced system with lower VFAs produced compared with that from the original substrate mixture.Acknowledgements: The authors are heartily thankful to their supervisor Ilona Sárvári Horváth whose guidance and support from the initial to the final level of this thesis work enabled us to gain a deeper understanding of the project.
We equally extend our sincere gratitude to the following persons who never ceased in helping until this work was complete.
Solmaz Aslanzadeh: For sharing her precious time and positive insight in coping with associated challenges of the project.
Hanson Jonas: Your assistance and patience over our laboratory experiments given the limited resources vis-a-vis students demand is quite reminding and saluted.
The support team at Sobacken Biogas plant: Your concern and timely assistance beginning from the supply of the substrate and the opportunity granted us to use your laboratory station greatly ensured results validation.
Program: MSc in Resource Recovery - Sustainable Engineering
Program: MSc in Resource Recovery - Industrial Biotechnology
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Ahuja, Nandita. "Impact of operating conditions on thermal hydrolysis pre-treated digestion return liquor." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56647.
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Return liquor from thermal hydrolysis process (THP) can significantly add to the nitrogen load of a wastewater treatment plant (WWTP) and introduce UV quenching substances to the wastewater stream when recycled. While there are mature technologies in place to handle the inorganic nitrogen produced due to the thermal pretreatment, organic nitrogen remains a parameter of concern for utilities employing THP pretreatment. The impact of operating conditions of the THP on dissolved organic nitrogen (DON) and UV absorbance in return liquor was investigated. Operating conditions studied were (1) operating temperature (2) solids retention time (SRT) in the anaerobic digester (3) THP flash pressure (4) the effect of co-digestion of sewage sludge with food waste and, (5) polymer conditioning. Operating temperature and polymer dose had the most significant impact on DON and UV quenching. It was found that an increase in operating temperature resulted in an increase in DON, which was primarily contributed by the hydrophilic fraction. An increase in temperature also resulted in increased UV254 absorbance. However, this trend was not linear and the increase was more pronounced when the temperature was increased from 150 C to 170 C. Increasing flash pressure from 25 psi to 45 psi did not have a significant impact on the return liquor. However, increasing the flash pressure to 75 psi increased the DON and UV254 absorbing compounds. Co-digesting the sludge with food waste resulted in a slight increase in DON and a decrease in dissolved organic carbon (DOC) and UV quenching compounds. Increasing the SRT from 10 days to 15 days resulted in a slight decrease in DON but did
not have any impact on UV254 absorbance. Overall, it can be concluded that optimizing operating conditions of thermal hydrolysis process can result in decreased DON and UV quenching compounds in the recycle stream.Master of Science
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Mirshokraie, S. Ahmad (Seyed Ahmad). "Reactions of a-substituted non-phenolic lignin model compounds under alkaline hydrolysis conditions." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75783.
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Side-chain ether groups in lignin model compounds of the general structure 1-(3$ sp prime$,4$ sp prime$-dimethoxyphenyl)-1,2-diaryloxyethane exhibited hydrolytic cleavage (the extent depending on the substituents on the 1-aryloxy groups) in aqueous 2N NaOH at 150$ sp circ$C (i.e. under wood pulping conditions). The level of hydrolysis increased in phenylpropane models (i.e. with $ gamma$-CH$ sb2$OH). Thus the commonly accepted generalization that 1,2-diethers of 3$ sp prime$,4$ sp prime$-dimethyoxyphenylpropane are stable in hot alkali is valid only for 1-alkoxy compounds. The newly observed hydrolytic cleavage is influenced by a combination of steric effects, electronic effects and solubility parameters. These observations now make it possible to consider alkaline delignification in the light of gel-degradation theory.A series of compounds of the general structure 1-(3$ sp prime$-4$ sp prime$,dimethoxyphenyl)-1-aryl-2-guaiacyloxyethane, where the 1-aryl group bore a hydroxy substituent, also exhibited alkaline hydrolysis, at 150$ sp circ$C, at the $ beta$-carbon. The extent was greater when the 1-aryl group bore an $o$-OH than when it bore a $p$-OH. Thus, the reaction was assisted by the nucleophilic attack of the $o$-phenoxide anion on the $ beta$-carbon.
A relatively high release of guaiacol occurred on treatment of 1-(3$ sp prime$,4$ sp prime$-dimethoxyphenyl)-1-thio-2-guaiacyloxyethane with 2N NaOH at 150$ sp circ$C, and the yield of guaiacol was increased when the terminal sidechain carbon bore a $-$CH$ sb2$OH group. Analogous $ alpha$-thioaryl and $ alpha$-thioalkyl compounds also exhibited greater ether cleavage than their oxy counterparts. The hydrolysis of the $ beta$-guaiacyl group was also enhanced by the presence of $ alpha$-seleno-containing groups.
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Henry, Lucile. "Étude et développement d'un procédé propre et innovant de traitement de la surface de fibres céramiques en conditions hydrothermales." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0328.
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Cette thèse s’inscrit dans une volonté d’adapter un procédé hydrothermal au traitement de la surface de fibres céramiques utilisées lors de la fabrication des composites à matrice céramique (CMCs). Le procédé conventionnel développé par la société Safran Ceramics se réalise en plusieurs étapes dont la principale consiste à dissoudre les phases oxydées de la surface des fibres Nicalon dans des bains d’acides. En conséquence, leurs propriétés chimiques de surface sont homogènes et un film de carbone microporeux est généré à la surface des fibres afin d’améliorer sa compatibilité chimique avec l’interphase de pyrocarbone qui y est déposée. Nous avons proposé de substituer ce procédé par un traitement par voie hydrothermale. En effet, l’eau possédant des propriétés physicochimiques ajustables en fonction des paramètres pression et température, il a été possible de modifier les propriétés de surface des fibres Nicalon d’une manière identique être productible au procédé conventionnel. L’efficacité et la compétitivité de ce traitement ont pu être démontrées par l’obtention de fibres avec des propriétés de surface optimales en une seule étape. Par la suite, l’étude du mécanisme réactionnel a révélé une attaque sélective des atomes de Si de la fibre selon des réactions d’hydrolyse. Puis, l’étude thermodynamique réalisée a mis en avant un régime à dominante cinétique. Finalement, les propriétés mécaniques des composites fabriqués à partir de tissus de fibres traités selon ce nouveau procédé ont été conformes aux objectifs. Ceci nous a donc permis de qualifier le traitement des fibres Nicalon par voie hydrothermaleThis thesis project was carried out in order to develop a hydrothermal processfor the surface treatment of ceramic fibres which are integrated into the fabrication of ceramicmatrix composites (CMCs). A conventional process was developed by Safran Ceramics tomodify the surface chemistry of the Nicalon fibres following 3 steps. The main step consistsin dissolving the oxidised phases at the fibre surface by the use of strong acids. As aconsequence, the chemical homogeneity of the surface is enhanced and a microporouscarbon film is generated helping its compatibilization with the pyrocarbon interphase that isdeposited in between the fibres and the matrix. It was suggested to substitute thisconventional process by a hydrothermal treatment. Indeed, as water displays tunablephysico-chemical properties regarding the temperature and pressure conditions, it waspossible to recover fibres demonstrating reproducible and similar characteristics. Theefficiency and competitivity of the hydrothermal treatment have been assessed throughoptimised surface properties obtained after one single step. Next, the mechanisminvestigation revealed a selective attack of the Si atoms contained in the fibre via hydrolysisreactions. Then, the thermodynamic study pointed out the fact that the process wasdominated by a kinetic regim. Finally, the mechanical caracterisation of the CMCs made ofhydrothermal treated fibres showed results which met all the requirements. These finalobservations allowed us to complete the qualification of the hydrothermal process to treat thesurface of Nicalon fibres
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O'Neil, Joseph M. "Factors contributing to the degradation of poly(p-phenylene benzobisoxazole) (PBO) fibers under elevated temperature and humidity conditions." Thesis, Texas A&M University, 2006. http://hdl.handle.net/1969.1/4439.
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The moisture absorption behavior of Zylon fibers was characterized in various high temperature and high humidity conditions in a controlled environment. The results of these thermal cycling tests show that PBO fibers not only absorb, but also retain moisture (approximately 0.5-3%) when exposed to elevated temperature and humidity cycles. Also, the impurities of Zylon fibers were characterized through the use of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and solid state Nuclear Magnetic Resonance (NMR). These tests demonstrated that, in addition to other impurities, PBO fibers may contain up to 0.55 weight percent phosphorus, and that this phosphorus is present in the form of phosphoric acid. It was also shown through accelerated hydrolytic degradation tests that production procedures used to neutralize the acid present in the fibers have a beneficial effect on the hydrolytic performance of the fiber. The data collected in this study was then compared and contrasted to known Kevlar studies, identifying similarities, differences, and potential trends. The results of these tests seem to indicate that there is accelerated acid catalyzed hydrolysis occurring in the fiber which is causing these fibers to degrade at an increased rate. This condition is further accelerated by heat and humidity induced permanent fiber swelling.
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Dong, Shuping. "Effects of acid hydrolysis conditions on cellulose nanocrystal yield and properties: A response surface methodology study." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/78102.
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Cellulose nanocrystals (CNCs) are frequently prepared by sulfuric acid hydrolysis of a purified cellulose starting material. CNC yields, however, are generally low, often below 20%. This study employs response surface methodology to optimize the hydrolysis conditions for maximum CNC yield. Two experimental designs were tested and compared: the central composite design (CCD) and the Box–Behnken design (BBD).
The three factors for the experimental design were acid concentration, hydrolysis temperature, and hydrolysis time. The responses quantified were CNC yield, sulfate group density, ζ-potential, z-average diameter, and Peak 1 value. The CCD proved suboptimal for this purpose because of the extreme reaction conditions at some of its corners, specifically (1,1,1) and (–1,–1, –1). Both models predicted maximum CNC yields in excess of 65% at similar sulfuric acid concentrations (~59 wt %) and hydrolysis temperatures (~65 °C).
With the BBD, the hydrolysis temperature for maximum yield lay slightly outside the design space. All three factors were statistically significant for CNC yield with the CCD, whereas with the BBD, the hydrolysis time in the range 60–150 min was statistically insignificant. With both designs, the sulfate group density was a linear function of the acid concentration and hydrolysis temperature and maximal at the highest acid concentration and hydrolysis temperature of the design space. Both designs showed the hydrolysis time to be statistically insignificant for the ζ-potential of CNCs and yielded potentially data-overfitting regression models. With the BBD, the acid concentration significantly affected both the z-average diameter and Peak 1 value of CNCs.
However, whereas the z-average diameter was more strongly affected by the hydrolysis temperature than the hydrolysis time, the Peak 1 value was more strongly affected by the hydrolysis time. The CCD did not yield a valid regression model for the Peak 1 data and a potentially data-overfitting model for the z-average diameter data. A future optimization study should use the BBD but slightly higher hydrolysis temperatures and shorter hydrolysis times than used with the BBD in this study (45–65 °C and 60–150 min, respectively).Master of Science
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Oyekola, Oluwaseun Oyekanmi. "The enzymology of sludge solubilisation under biosulphidogenic conditions : isolation, characterisation and partial purification of endoglucanases." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1003980.
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Endoglucanases play an important function in cellulose hydrolysis and catalyse the initial attack on the polymer by randomly hydrolysing the β-1,4 glucosidic bonds within the amorphous regions of cellulose chains. Cellulolytic bacteria have been isolated and characterised from the sewage sludge and the activation of several hydrolytic enzymes under biosulphidogenic conditions of sewage hydrolysis has been reported. The aims of this study were to: identify, induce production, locate and isolate, characterise (physicochemical and kinetic) and purify endoglucanases from anaerobic biosulphidogenic sludge. The endoglucanase activities were shown to be associated with the pellet particulate matter and exhibited a pH optimum of 6 and temperature optimum of 50 °C. The enzymes were thermally more stable when immobilised to the floc matrix of the sludge than when they were released into the aqueous solution via sonication. For both immobilised and released enzymes, sulphate was slightly inhibitory; activity was reduced to 84 % and 77.5 % of the initial activity at sulphate concentrations between 200 and 1000 mg/l, respectively. Sulphite was stimulatory to the immobilised enzymes between 200 and 1000 mg/l. Sulphide stimulated the activities of the immobilised endoglucanases, but inhibited activities of the soluble enzymes above 200 mg/l. The enzyme fraction did not hydrolyse avicel (a crystalline substrate), indicating the absence of any exocellulase activity. For CMC (carboxymethylcellulose) and HEC (hydroxylethylcellulose) the enzyme had K_m,app_ values of 4 and 5.1 mg/ml respectively and V_max,app_ values of 0.297 and 0.185 μmol/min/ml respectively. Divalent ions (Cu²⁺, Ni²⁺ and Zn²⁺) proved to be inhibitory while Fe²⁺, Mg²⁺ and Ca²⁺ stimulated the enzyme at concentrations between 200 and 1000 mg/l. All the volatile fatty acids studied (acetic acid, butyric acid, propionic acid and valeric acid) inhibited the enzymes, with acetic acid eliciting the highest degree of inhibition. Sonication released ~74.9 % of the total enzyme activities into solution and this was partially purified by PEG 20 000 concentration followed by DEAE-Cellulose ion exchange chromatography, which resulted in an appreciable purity as measured by the purification factor, 25.4 fold.
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Chassery, Aurélien. "Étude expérimentale et modélisation phénoménologique de l’hydrolyse de sodium tritié : influence des conditions opératoires sur la distribution du tritium dans les effluents." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/13934/1/chassery.pdf.
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L’hydrolyse contrôlée et progressive est une des solutions technologiques pour traiter le sodium tritié présent dans divers composants d’un Réacteur à Neutrons Rapides. Une étude expérimentale a été réalisée pour analyser et comprendre les phénomènes physico-chimiques mis en jeu lors de cette hydrolyse, fortement exothermique, et étudier l’influence des paramètres opératoires sur la répartition HT /HTO au sein de l’effluent liquide et de l’effluent gazeux générés. Les deux facteurs prédominants sont l’activité totale du sodium traité et le flux énergétique (J/s) dégagée par la réaction. Un modèle phénoménologique de l’hydrolyse de sodium tritié est proposé pour synthétiser les connaissances acquises et servir d’aide à la prédiction de la composition en tritium dans les effluents générés en vue de leur traitement.
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Sun, Peizhe. "Transformation of veterinary ionophore antibiotics under conditions related to water-soil-litter systems." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51880.
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Veterinary pharmaceuticals are routinely used in livestock production to treat diseases, prevent infections, and promote growth. However, the potential release of pharmaceuticals from agricultural activities has raised concerns because they may pose detrimental effects to the ecosystems and human health, for example fostering the evolution of antibiotic-resistant bacteria in the natural environment. A better understanding of the environmental fate of veterinary pharmaceuticals is critical to properly assess and mitigate their risks. This dissertation focuses on a major group of veterinary pharmaceuticals, ionophore antibiotics (IPAs), which is sold at over 4 million kilograms per year and constitutes more than one third of the total antibiotic consumption by the livestock industry in the U.S. Despite the extensive usage of IPAs, their environmental fate was not well-understood. Therefore, this study aimed at achieving a comprehensive understanding of the occurrence, persistence, and transformation of IPAs from poultry litter before and after applications to the agricultural lands. Three of the most commonly used members of IPAs were investigated in this study: monensin (MON), salinomycin (SAL), and narasin (NAR). Based on the common management practices of poultry litter, the potential abiotic and biotic transformation reactions of IPAs were examined under varying conditions relevant to the water-soil-litter systems.
This dissertation consists of three sections. First, a robust analytical method was developed to quantify IPAs in various environmental compartments, especially in high organic-containing matrices such as poultry litter, and soil and runoff from litter-fertilized lands. Efforts were made to optimize the analytical method with respect to improving extraction recovery, reducing matrix effects, and validating a surrogate standard. Second, lab-scale experiments were set up to determine the chemical properties of IPAs in aqueous environments and to study the abiotic transformation of IPAs, including hydrolysis and photolysis. The results showed that IPAs are prone to hydrolytic transformation in acidic environments, which are likely to be encountered in acidic soils, alum-amended litter (alum: Al₂(SO₄)₃•12H₂O), and acidic runoff. Multiple transformation pathways were proposed based on the identified hydrolysis products. It is also noteworthy that the hydrolysis products of MON still exhibited a toxic effect on the selected microorganism (Bacillus subtilis). SAL and NAR were found to undergo direct photolysis under both UV light and sunlight irradiation. In natural water matrix, IPAs were also degraded by indirect photolysis with hydroxyl radicals generated by light-excited nitrate. Dissolved organic matter can shield IPAs from light and slow down their photolysis. Third, the biodegradation potential of IPAs was first tested in litter and soil microcosms. Factor analysis was conducted to delineate the interaction of water and temperature on IPA degradation in the litter. Litter-fertilized and non-fertilized soil microcosms were compared on the degradation of MON and SAL. Furthermore, the inhibition and biotransformation potential of IPAs were assessed under different redox conditions with litter-enriched cultures. Inhibition tests focused on examining IPAs’ impact on microbial community functions, including denitrification, sulfate-reduction, and methane production. Biodegradation tests were conducted with different electron acceptors, including oxygen, nitrate, sulfate, and organic carbons, with efforts to elucidate primary biotransformation products.
On the basis of the results obtained in this study, several recommendations on litter management and IPA selection were made to help mitigate the release and transport of IPAs, as well as enhance their degradation. Overall, this study significantly improved the understanding of the environmental fate of IPAs and the obtained knowledge can aid proper selection of IPAs and management strategies in future applications to minimize the risks of antibiotic micropollutants in the environment.
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Boutiche, Mohamed. "Stabilité physico-chimique des smectites et de l'illite en présence de solutions chargées en électrolytes : étude expérimentale à 150°C." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL057N.
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Les interactions chimiques entre des solutions utilisées dans les boues de forage, et différents types d'argiles ont été étudiées dans des conditions P, T proches de celles des forages (150°C) afin de déterminer les conséquences éventuelles sur la stabilité des argilites. Le travail a été conduit essentiellement de manière expérimentale, en utilisant différentes solutions: eau pure, NaOH (pH 8, 10, 12), KCl (0,1, 1, 2 mol. /l), eau de mer et K₂CO₃, et des argiles à forte et faible proportion de feuillets gonflants (smectite (Na, Na-Ca, Ca) interstratifiés illite-smectite). Les produits de réaction ont été étudiés par diffraction des rayons X, et microsonde électronique. Les feuillets de smectites montrent une série de transformations (échange en site interfoliaire, fermeture de feuillets, hydrolyse), qui ne conduisent pas cependant à la formation de nouveaux minéraux sauf dans le cas de traitement en présence de K₂CO₃ à 150°C (formation de zéolites). L’échange du cation interfoliaire est fonction de la nature du cation, de la concentration des cations dans les solutions, des constantes d'échange et du rapport liquide/solide. Dans les solutions diluées (<1 mol. /l), l'échange est partiel et a pour conséquence l'obtention de smectites à garnitures interfoliaires mixtes qui présentent des états d'hydratation variés. L'hydrolyse, plus forte pour la smectite sodique que la calcique, conduit à une perte du fer octaédrique
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Oliveux, Géraldine. "Influence des conditions d'hydrolyse sous-critique sur le recyclage des matériaux composites fibres de verre / résine polyester insaturé : influence des conditions et de la structure de la résine sur les cinétiques réactionnelles." Nantes, 2012. http://www.theses.fr/2012NANT2110.
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Un procédé d’hydrolyse en conditions batch est étudié pour rompre les liaisons ester de résines polyester insaturé et réticulé au styrène, matrices de matériaux composites renforcés de fibres de verre. Des conditions sous-critiques biphasiques apparaissent adaptées compte tenu de la chimie en jeu. La réaction d’hydrolyse suit en effet un mécanisme Aac2 et nécessite donc des conditions favorables à la réalisation de réactions ioniques, à savoir en particulier un produit ionique et une constante diélectrique relative de l’eau suffisants. Elle permet de récupérer en particulier les monomères d’origine de la résine. Mais ceux-ci subissent également des réactions secondaires ioniques. Ce traitement par hydrolyse affecte par ailleurs la qualité des fibres de verre récupérées. Elles sont corrodées, perdant ainsi une partie de leurs propriétés mécaniques, et nécessitent une phase de rinçage pour les débarrasser des substances organiques résiduelles. Des conditions ont cependant pu être identifiées comme permettant de minimiser la dégradation de leurs propriétés mécaniques. Ces conditions permettent également un taux de récupération maximal en monomères de la résine. Ainsi en moins d’une heure à 275°C, il est possible de rompre quasiment toutes les liaisons ester de la résine. Prolonger la durée de traitement ne fait que permettre aux réactions secondaires de se poursuivre. Un fonctionnement semi-continu s’avère indispensable pour minimiser les réactions secondaires et éviter l’étape ultérieure de rinçage des fibres. Il peut permettre par ailleurs une dégradation moins importante de ces dernièresA hydrolysis process in batch conditions is applied to break ester bonds of unsaturated polyester resins, crosslinked with styrene, as matrices of composite materials reinforced with glass fibres. Subcritical two-phase conditions appear adapted in view of the involved chemistry. The hydrolysis reaction follows in fact an Aac2 mechanism and requires then conditions enhancing ionic reactions, that is to say in particular sufficient values of the ionic product and of the relative dielectric constant of water. It allows the recovery of the initial monomers of the resin. But the latter’s are subjected to secondary ionic reactions. This hydrolysis treatment also affects the quality of the recovered glass fibres. They are corroded, loosing thus some of their mechanical properties, and require a washing phase to remove residual organic components. Conditions have however been identified as allowing minimizing the degradation of their mechanical properties. Those conditions also allow a maximum recovery rate of the initial monomers of the resin. Thus in less than an hour, it is possible to break almost all the ester bonds of the resin. A longer treatment time only allows secondary reactions to continue. A semi-continuous process appears to be essential to minimize secondary reactions and avoid the washing post-treatment of the fibres. It can also allow a less important degradation of them
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Benyattou, Abdelkader. "Thermohydrolyse de solutions d'aluminium III, conditions d'apparition de phases solides : caractérisations physico-chimiques des précipités." Lyon 1, 1994. http://www.theses.fr/1994LYO10071.
Full textAbstract:
La thermohydrolyyse, obention d'une phase solide par ebullition prolongee d'une solution initialement homogene, peut etre une technique interessante. Elle assure une bonne reproductibilite et limite la dispersion des proprietes texturales des solides obtenus. Des hydroxysulfates appartenant a la famille des alunites peuvent se former par thermohydrolyse de solutions de sulfate d'aluminium. L'influence de la composition des solutions a ete etudiee. Il est clairement etabli que l'alunite se forme en presence des cations na#+ ou nh#4#+ mais non pas en presence de li#+. Le rendement de precipitation croit lorsque les rapports so#4#2#-/al#3#+ avec (na#+ -o) et na#+ (ounh#4#+)al#3#+ augmentent. Une diminution rapide du ph apparait en meme temps que la temperature augmente: a l'ebullition le ph se stabilise pendant toute la duree de l'hydrolyse. L'utilisation des constantes d'hydrolyse et de complexation generalement admises, l'exploitation des spectres de la rnn de #2#7 al qui montrent le role du complexe al(h#2o)#5so#4#+, ont conduit a proposer un mecanisme dans lequel se forme d'abord l'anion al#3(h#2o)#8(os)#6(so#4)#2#-. Ensuite il se deshydrate et precipite avec l'alcalin, si ce dernier est suffisamment volumineux. La composition des solides obtenus depend etroitement de celle de la solution mere, la variation des parametres cristallins peut etre directement lies a la concentration des ions sodium de la solution. Par pyrolyse a l'air a environ 900c, les alubates conduisent a l'oxyde d'aluminium, al#2o#3 pour la natroalunite et al#2o#3 pour l'ammonialunite. La precipitation simultanee des ions mg#2s+ et al#3#+ par cette technique conduit a ph 12, a l'hydroxyde double mg#4al#2(08)#1#4, 3h#2o. Les conditions de synthese tres dures entrainent la formation de phases parasites. La modification du rapport al#3/mgh#2#+ entre 0,5 et 0,8
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Brandam, Cédric. "Optimisation des conditions opératoires d'un procédé de brassage : étude expérimentale et modélisation." Toulouse, INPT, 2001. http://www.theses.fr/2001INPT036G.
Full textAbstract:
Les travaux présentés ici contribuent à une meilleure maîtrise du procédé de fabrication de la bière. Ils protent plus spécifiquement sur l'étape de brassage. Au prix d'un effort expérimental important, les connaissances sur les réactions d'hydrolyse de l'amidon et des Beta-glucanes en cuve matière ont pu être étendues et approfondies. Cette connaissance a été capitalisée dans un modèle stoechio-cinétique dont l'exploitation permet de contrôler la composition finale du moût et d'augmenter la productivité. La réalisation d'essais sur une installation pilote de 1001 du TEPRAL (brasseries Kronenbourg) a permis de proposer une nouvelle approche de l'activité ensymatique. Les schémas réactionnels pour l'hydrolyse de l'amidon et de Beta-glucanes par catalyse enzymatique ont été établis par l'analyse qualitative des résultats. Ces schémas prennent en compte les transformations physiques (gélatinisation de l'amidon, solubilisation des Béta-glucanes) et chimiques des substrats (production de sucres et de résidus de Béta-glucanes). L'exploitation quantitative des essais a ensuite permis d'établir un modèle cinétique complet pour l'hydrolyse de l'amidon. A partir des caractéristiques des malts utilisés et selon les conditions opératoires appliquées, il prédit l'évolution au cours du brassage des activités en x-amylase et beta-amylase, et des concentrations en dextrine, sucres fermentescibles et amidon gélatinisé. L'optimisation de la politique de température est réalisée à l'aide du modèles. Dans un premier temps, la productivité maximale pour atteindre une quantité fixée de dextrines est recherchée. Par la suite, pour intégrer les contraintes vis à vis des Beta-glucanes et des protéines, seul le palier de saccharification est optimisé. Grâce aux outils de calcul proposés, le gain en productivité est conséquent at la maîtrise du taux de dextrines dans le moût final est assurée.
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Bull, Joseph. "The application of hydrolytic enzymes for biotransformations of natural products in non-aqueous reaction conditions." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/76873.
Full textAbstract:
Flavonoids are naturally occurring compounds that are consumed regularly in the diet. The property of flavonoids, which they are most commonly known for, is their antioxidant activity. Other potential pharmaceutical applications of flavonoids can be related to their enzyme inhibition, anti-allergic, anti-inflammatory, anti-microbial and anti-cancer properties. Lipases have been used effectively in the production of flavonoid ester derivatives that have shown both increased antioxidant and antimicrobial activity. Enzymatic esterifications of flavonoids are performed in organic solvents that increase substrate solubility of complex organic molecules. For the esterification of compounds in non-aqueous reaction conditions, vinyl esters are often preferred as substrates compared to carboxylic acids (which can be involved in reversible reactions, due to the formation of the by-product, water). In this study a group of vinyl esters of tert-butoxycarbonylated amino acid derivatives were synthesized to study alongside a range of commercially available vinyl esters. The synthesis of ester derivatives of naringin using a range of hydrolytic enzymes has been studied. A range of small to medium sized commercially available vinyl esters (C2- C10), as well as amino acid vinyl esters were selected for the biotransformations. For the esterification of naringin, small-scale reactions were carried out for 72 hrs and the reaction mixtures were analysed by HPLC. Lipases from the species Pseudomonas stutzeri, Candida antarctica and Alcaligenes spp. performed more than 80% conversion of naringin with some of the selected acylating agents. Reactions carried out with P. stutzeri lipase were scaled up to isolate the product of the biotransformation. None of the screened enzymes were successful in the acylation of naringin with the amino acid vinyl esters. Assays were carried out to compare the antioxidant activity of naringin and the synthesized derivatives. Two of the acyl derivatives showed a greater antioxidant activity in the reduction of Cu2+, compared to naringin. Aminoglycosides are antibiotics that have anti-bacterial properties. As well as their anti-bacterial properties some have been employed for their ability to suppress stop codons, which is a useful property in reducing symptoms of some hereditary disorders. In the present work attempts were made to derivatise an aminoglycoside by acylating it with the amino acid vinyl esters, using hydrolytic enzymes. Despite screening with various proteases in different solvents, the acylation of amikacin was not succesful during this investigation.
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Teixeira, Stefanie Helena. "Catalyzed hydrolysis of PLA twines in composting conditions." Master's thesis, 2019. https://hdl.handle.net/10216/119302.
Full text
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Teixeira, Stefanie Helena. "Catalyzed hydrolysis of PLA twines in composting conditions." Dissertação, 2019. https://hdl.handle.net/10216/119302.
Full text
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Huang, Chiung-Dai, and 黃瓊代. "Component Analysis and Investigation of Hydrolysis Conditions for Chodatella sp." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/s7a843.
Full textAbstract:
碩士大仁科技大學
食品科技研究所
104
Microalgae products have been widely used in food, medicines, biomass energy and environmental purposes. In this study, the nutritional compositions, active ingredients and anti-oxidative abilities of microalgae - Chodatella sp. were analyzed, hydrolysis conditions were investigated. Finally, the chodatella sp. hydrolysate was compared with commercial products, such as chicken or clam extracts. The nutritional composition of chodatella sp. contains high amounts of proteins and total dietary fiber, at 35.26% and 42.77%, respectively. The highest mineral content was magnesium at 1225.7 mg/100g. The contents of branch chain amino acids, leucine, valine and isoleucine, and semi-essential amino acids, arginine, were 1443.6, 784.2, 565.4 and 2526.8mg/100g, respectively. The highest concentration of non-essential amino acids was alanine, at 2394.6 mg/100g. The content of non-protein amino acids, γ-aminobutyric acid, was 598.0 mg/100g, accounting for 3.11% of total hydrolytic amino acids. The highest fatty acid compositions were two essential fatty acids, linoleic and linolenic acids, which accounted for 41.34 and 10.24% of fatty acids, respectively; dietary fiber from chodatella sp. was mostly non-soluble dietary fiber. It showed that chodatella sp. could be a low-calorie, protein-rich and nutrient-rich food source. After treated under high heat and pressure to destroy cell-wall structures, the chodatella sp. solutions (algae-water ratio 1:20) were hydrolyzed for an hour with 5% Cellulase AP3 at 30ºC and pH 4.0, and then hydrolyzed with the 3 enzymes – Alcalase, Neutrase and Protease N “Amano” for 48 hours. Analysis of the chodatella sp. hydrolysates showed that concentrations of chlorella growth factors (CGA), total pholyphenols, soluble proteins and peptides after hydrolysis with 5 or 10% Alcalase for 36-48 hours were higher than those treated with the other two enzymes. Comparing the chodatella sp. hydrolysate of 5% Alcalase for 36 hours with commercial chicken essence, clam extracts, plain chicken essence and vegetarian peptide drinks, the chodatella sp. hydrolysate is the only one containing CGA. Soluble protein content, peptides, polyphenols and scavenging effect on DPPH free radicals of chodatella sp. hydrolysate were all higher than 3 commercial clam extract products. In the future, the concentration of beneficial ingredients in the hydrolysate may be increased by increasing the amount of chodatella sp. used, in order to enhance market competitiveness over products such as chicken essence or vegetarian peptide drinks.
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Tsai, Hui-Ru, and 蔡慧如. "Investigation of Hydrolysis Conditions for Purple Flesh Sweet Potato Beverage." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60120656044304948945.
Full textAbstract:
碩士大仁科技大學
食品科技研究所
98
Sweet potato is ranked as the sixth major staple food in the world and characterized by its high nutritional values. Due to its higher vitamin, mineral and protein contents than the common vegetables, sweet potato was the major dietary food source for the poor populace in the food-shortage Japanese Occupation Period and the early years after the end of the World War Two. The overall size of Taiwan’s beverage market is approximately 50 billion New Taiwan dollars a year. Characterized by the unique tastes, diversified selections, and convenience, the beverages have become part of our daily life. The purple flesh sweet potato contains abundant anthocyanins and total polyphenols and exhibits multiple health maintenance functions. Therefore, this study is planning to investigate the hydrolytic conditions of the purple flesh sweet potato (PFSP) and develop it into a functional and health-oriented beverage for increasing the sweet potato’s added values. When the pH of the 2.5% steamed and freeze-dry purple flesh sweet potato (SFPSW) was adjusted by the baking soda or citric acid, the optimal hydrolytic conditions obtained with the Response Surface Methodology (RSM) for the α-amylase were pH 6.3, hydrolytic temperature at 60℃, and 30 minute hydrolytic duration. The hydrolytic ratio could reach 59.31%. However, the optimal hydrolytic conditions for the glucoamylase were pH 5.5, hydrolytic temperature at 50 ℃, and hydrolytic duration for 66.8 minutes. The hydrolytic ratio could reach as high as 93.86 %. When the 2.5% SFPSW underwent hydrolysis by the α-amylase and glucoamylase, the hydrolysis ratio was 93.52 %, which did not differ significantly from the single application of the glucoamylase. The hydrolysis ratio of using the alcalase and neutrase enzymes to hydrolyze the proteins of PFSP was significantly higher than the use of the papain and bromelain. Due to the fact that the hydrolysis conditions for the alcalase were relatively more basic and disadvantageous for the stability of anthocyanins in PFSP, the neutrase was therefore selected as the protein hydrolysis enzyme for the PFSP. The analysis of RSM showed the most optimal hydrolysis conditions for the neutrase were pH 6.0, hydrolytic temperature at 50 ℃, and hydrolytic duration for 70 minutes. The hydrolysis ratio was 59.45%. If simplifying the hydrolysis conditions by changing the hydrolysis pH of neutrase’s to be as the same as that for the glucoamylase (pH 5.5), the hydrolysis ratio could also reach 57.18%. When the SFPSW solution was hydrolyzed in sequence by the glucoamylase and neutrase for 70 minutes under the conditions of pH 5.5 and hydrolytic temperature at 50 ℃, the sugar and protein hydrolysis ratio of 91.38% and 69.53%,respectively. To conclude, the 7.5% SFPSW solution was hydrolyzed in sequence by the glucoamylase and neutrase for 70 minutes at the water temperature below 50 ℃ after modifying the pH value to 5.5. The sweet potato juice, which was acquired after the centrifuge process, was flavored with 20% pineapple juice, 10% sugarcane juice and 0.25% lemon juice, and added with 0.5% Gellan for increasing the stability. Thus the preparation of purple sweet potato beverage was completed.
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Wang, Chi Wen, and 王祈文. "The influence of dilute acid pretreatment conditions to enzymatic hydrolysis and structural." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/38981148905462597509.
Full textAbstract:
碩士明新科技大學
化學工程研究所
97
Under the double impact of global warming and crude oil shortage, the exploration of clean and sustainable resources has become one of the most important issues in many countries. Biomass is a renewable and sustainable resource that can be produced from agricultural feedstocks. However, some biomasses such as starch and sugar are also an imoportant food sources for mankind and livestocks. Utilization of these biomasses may be detrimental to food supply. Therefore, the use of non-ediable biomasses such as lignocellulosic materials as a liquid fuel source is inevitable. Because the structure of lignocellulose is relatively rigid, pretreatments will be helpful to release more sugar from lignocellulose in the following enzyme hydrolysis stage. In this study, dilute-acid hydrolysis was adopted to pretreat rice straw before it was further hydrolyzed by enzymes. The influences of three parameters, including concentration of sulfuric acid, reaction temperature and reaction time, to the extend of decomposition of rice straw, and composition and structure of rice straw are discussed. It was found that a more severe condition released more xylose in acidic hydrolysis. However, byproducts were produced when the operation condition got too severe. The formation of byproducts not only reduced the sugar released in acidic hydrolysis, but also resulted in the low converiosn in enzymatic hydrolysis. Among the acidic hydrolysis conditions investigated in this research, the preatment of rice straw with 1.8% of sulfuric acid at 180℃ for 20 minutes released the most aboundant sugars in a two stage acidic-enzymatic hydrolysis, with 16.68 g of xylose/100g of dry rice straw released, and 24.18 g of glucose/100g of dry rice straw released in acidic hydrolysis and enzymatic hydrolysis, respectively.
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Yeh, Wan-Chi, and 葉宛綺. "The Optimal Hydrolysis Conditions for the Conversion of Waste Biomass to Bioethanol." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/16615147633170321249.
Full textAbstract:
碩士弘光科技大學
環境工程研究所
99
With the shortage of traditional fossil fuels and global climate change worsening, the development of sustainable and renewable energy is highly emphasized by the industry, government and academia of many countries. Among the renewable energy, the conversion of lignocellulose into bioethanol is believed to have the most potential. Due to the hydrolysis of lignocellulosic materials into reducing saccharides is the bottleneck of producing bioethanol, it is important to clarify the influences of different operating parameters on the hydrolysis efficiency of lignocellulosic materials. Our laboratory has studied the microwave hydrolysis and fermentation of various lignocellulosic materials. In this study, all of the previous experimental conditions and results (132 data) are evaluated by the Principal Component Analysis (PCA) to find the major influences. Then the orthogonal array of Taguchi method and response surface method are applied to optimize the experimental conditions and parameters for the microwave hydrolysis of lignocellulose. The results of Principal Component Analysis show that there are three major components influence the microwave hydrolysis of waste biomass. The first major component is hydrolysis efficiency and reducing sugar. The second major component is microwave temperature. Different microwave temperatures provide different microwave energy for the destruction of cellulose. The third major component is the type and concentration of acid reagent. Different chemical reagents have different reaction ability and affinity with the celluloses. The results of Taguchi orthogonal array shows that the optimum hydrolysis efficiency and conditions are 106.67%, Goosegrass as substrate, with 5% H2SO4, and microwave 110℃ for 30 min. With the response surface method, the optimal parameters are narrowed down. The optimum hydrolysis conditions are Goosegrass, with 2.77% H2SO4 and microwave 117℃ for 37 min. At such conditions, the hydrolysis efficiency and reducing sugar were 118.25% and 18.62 g/L, respectively. The byproducts of lignocellulose hydrolysis are also analyzed and the concentrations are furfural 0.06 g/L, HMF 0.05 g/L, levulinic acid 2.79 g/L and formic acid 0.09 g/L. The hydrolysate at optimal hydrolysis conditions are further fermented with different yeasts. The fermentation temperature is 30℃ and pH is 5.0. The results show the hexose yeast, Saccharomyces cerevisiae, can produce the maximum ethanol concentration 2114.34 mg/L and ethanol yield 95 mg/g. The fermentation efficiency is 80.22%.
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Levitt, David Benjamin 1980. "The optimal use of enhanced oil recovery polymers under hostile conditions." 2009. http://hdl.handle.net/2152/18417.
Full textAbstract:
The purpose of this work is to frame the main issues one must face in the design of a mobility control process using polyacrylamide and related acrylic polymers under hostile conditions. Proper preliminary lab evaluation techniques, chemical degradation and related calcium tolerance issues, thermal degradation, and economic optimization based upon injectivity are discussed. Emphasis is placed on stability under alkaline conditions, the use of sodium dithionite to prevent thermal degradation, and the beneficial use of in-situ hydrolysis to increase injectivity. Filtration properties are a focus of screening experiments, and though it often takes several days to achieve acceptable filter ratios in the lab, experience from two field observations indicate that even high molecular weight polymers have filtration ratios on the order of 1.2 or less before they are injected, so preparation procedures that do not result in this may not yield results that scale to the field. Chemical stability issues with acrylamide polymers are addressed in two parts, the first describing the kinetics of hydrolysis under neutral and alkaline conditions and the second estimating the calcium tolerance of aged polymers using industrial and lab produced analogues. Under alkaline conditions, hydrolysis is very rapid, even at low temperatures. Though aged copolymers of acrylamide (AM) and 2-acrylamide 2-methyl propane sulfonate (AMPS) exhibit similar calcium tolerances to similarly aged polyacrylamide (PAM), viscosity loss is much higher for the latter as this limit is approached. Thermal, or "oxidative" degradation, is examined using Pourbaix diagrams for iron to understand the commonly reported relationships between pH, Eh, and stability. The beneficial effects of sodium carbonate and sodium dithionite on polymer solutions as well as some inconsistencies in the literature point towards a catalytic role played by ppb level amounts of iron in oxidative degradation mechanisms. It is put forward that addition of sodium dithionite is a conservative approach to all acrylic-backboned polymer floods, and practical issues related to this are discussed. A simple analytical model is developed to take a brief look at economic optimization of polymer viscosity, and this is used to demonstrate the benefits of in-situ hydrolysis in alkaline or high-temperature floods.text
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Pan, Chuan-Yi, and 潘泉亦. "Effects of Co-B catalysts synthesis conditions on sodium borohydride hydrolysis reactors design." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/02431300131127318413.
Full textAbstract:
碩士淡江大學
化學工程與材料工程學系博士班
101
The objective of this work is to study the effect of various Co-B catalyst synthesis conditions on the catalyst surface morphology and kinetic parameters. The Co/B catalyst was synthesized on IR-120/TP-207 resin surface by using ion exchange and chemical reduction method using NaBH4 as a reduction agent. The reduction conditions which were investigated here were: reduction temperature, NaBH4 concentration, pH value, NaBH4 adding flow rate and different types of resins. The result shows reduction temperature gives the most dramatic effect on surface morphology which is caused by competing reactions of reduction and hydrolysis. Low reduction temperature resulted in a slower Co/B reduction rate and made the catalyst surface denser with a branched structure. This created more surface area than higher reduction temperatures. Low reduction temperature catalyst had the better performance on NaBH4 hydrolysis reaction for hydrogen generation rate. The optimal reduction temperature of the Co-B/IR-120 is 25 oC. The L-H model was used to regress kinetic parameters from the experiment data. The frequency factor, activation energy and adsorption constant are 1.17x109 mol/g-min, 70.65 kJ/mol, and 6.8 L/mol at 40oC, respectively. Finally, the TP-207 resin was used instead of IR-120. After scanning for all catalyst synthesis conditions, the Co-B/TP-207 had the higher catalyst loading, faster hydrogen generation rate and more durability than Co-B/IR-120. A mathematical model was built to design the NaBH4 hydrolysis reactor for hydrogen generation. The operating variables of the system are: reaction temperature and NaBH4 inlet concentration, inlet flowrate. From sensitivity analysis, the dominant variable of the hydrogen generation system is NaBH4 inlet flowrate. The I-4 catalyst shows the better operability at 80oC than other Co-B/IR-120 catalyst.
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Moura, Maria Eduarda Nogueira. "Bioactive potential of Mytilus galloprovincialis hydrolysates: effect of hydrolysis conditions and sample processing." Master's thesis, 2021. http://hdl.handle.net/10773/30856.
Full textAbstract:
This internship allowed integration in the ValorMar project, aimed at improving
aquaculture industries while also providing health benefits to humans.
Aquaculture generates great amounts of waste and by-products, which
constitutes an economic, health and environmental problem. These by-products
are known to possess nutritional and bioactive potential, worthy of exploration
for the manufacture of novel functional foods, that can exert specific beneficial
effects on human health and wellbeing.
Therefore, the goal of the present work was to explore the bioactive potential of
the Mediterranean mussel (Mytilus galloprovincialis), a common European
aquaculture shellfish product, that generates high amounts of waste, through
enzymatic hydrolysis, to extract potentially bioactive compounds that can later
be applied in the creation of new functional foods.
Mussel meat homogenates were subjected to hydrolysis with Alcalase® and
Protamex®, at pH 7.5, temperature of 60 °C, with different enzyme
concentrations (0, 1, 2 and 3%), substrate amounts (25 and 50 g) and duration
(1 and 2h). Resultant hydrolysates were further processed through lyophilization
or Amicon® ultrafiltration. Pre-thermal-treatment, hydrolysis and hydrolysates
processing conditions were evaluated to understand which would lead to the
production of bioactive peptides.
Hydrolysates were tested for their antioxidant ability, through 2,2-diphenyl-1-
picrylhydrazyl (DPPH) radical scavenging method, antimicrobial activity, by disk
and well diffusion techniques, and for antihypertensive ability by their capacity in
inhibiting angiotensin-converting enzyme (iACE).
Produced hydrolysates revealed that multiple enzyme hydrolysis produces
higher bioactive potential. DPPH scavenging ability increased with substrate and
revealed lower activity with the >3 kDa fraction, unlike iACE potential, which
increased with the ultrafiltered fraction. In general, boiled mussel hydrolysates
showed high antihypertensive potential. However, no antimicrobial effect was
observed from samples obtained in the tested conditions.
Further studies should be done, widening hydrolysis and purification conditions,
testing for different bioactive potential, to gather more knowledge on this species
potential as a source of bioactive compounds. Further assays are required to
assess hydrolysates stability in food matrices and during digestion, and their
effect on target sites.Este estágio permitiu a integração no projeto ValorMar, que visa melhorar indústrias de aquacultura e ao mesmo tempo fornecer benefícios de saúde ao homem. A aquacultura gera grandes quantidades de desperdício e subprodutos, o que constitui um problema económico, de saúde e ambiental. Estes subprodutos são conhecidos por possuírem potencial nutritivo e bioativo, merecedores de exploração para o fabrico de novos alimentos funcionais que possam exercer efeitos benéficos específicos na saúde e bem-estar humano. Deste modo, o objetivo do presente trabalho foi explorar o potencial bioativo do mexilhão Mediterrâneo (Mytilus galloprovincialis), um produto comum na aquacultura europeia e que gera altas quantidades de desperdício, através de hidrólise enzimática, para extrair compostos potencialmente bioativos que possam ser posteriormente aplicados na criação de novos alimentos funcionais. Homogeneizados de carne de mexilhão foram hidrolisados com Alcalase® e Protamex®, a um pH 7.5, temperatura de 60 °C, com diferentes concentrações de enzima (0, 1, 2 e 3%), de quantidade de substrato (25 e 50 g) e de duração (1 e 2 h). Os hidrolisados resultantes foram posteriormente processados através de liofilização ou ultrafiltração por Amicon®. Condições de pré-tratamento termal, hidrólise e processamento de hidrolisados foram avaliadas para compreender quais levariam à produção de péptidos bioativos. Os hidrolisados foram testados quanto à sua capacidade antioxidante, através do método de eliminação do radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), atividade antimicrobiana, pelas técnicas de difusão em disco e por poço, e atividade anti-hipertensiva pela sua capacidade em inibir a enzima conversora de angiotensina (iACE). Os hidrolisados produzidos revelaram que hidrólise com múltiplas enzimas produz um maior potencial bioativo. A capacidade de eliminar o radical DPPH aumentou com o substrato e mostrou ser inferior com a fração >3 kDa, ao contrário do potencial iACE, que aumentou com a fração ultrafiltrada. Em geral, hidrolisados de mexilhão fervido mostraram um alto potencial anti-hipertensivo. No entanto, nenhum efeito antimicrobiano foi observado nas amostras obtidas nas condições testadas. Estudos posteriores deverão ser realizados, ampliando condições de hidrólise e purificação e testando variados potenciais bioativos, de modo a reunir mais informação acerca do potencial desta espécie como fonte de compostos bioativos. Mais ensaios são requeridos para avaliar a estabilidade dos hidrolisados na matriz do alimento e durante digestão, e o seu efeito nos locais alvos.
Mestrado em Microbiologia
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Yu-chain, Hsu, and 許佑銓. "Effects of Delignification Conditions and Surfactants on The Enzymatic Hydrolysis of Steam-Exploded Napiergrass." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/bgx6qb.
Full textAbstract:
碩士國立臺北科技大學
有機高分子研究所
100
Napiergrass (Pennisetum Purpureum) is regarded as apotential energy crop, the napiergrass via enzymatic hydrolysis, follow by fermentation can be converted to platform chemicals, such as ethanol, succinic acid, etc. The residual solids after steam explosion were subjected to alkaline hydrogen peroxide treatment before enzymatic hydrolysis. The effects of alkaline hydrogen peroxide residence time and hydrogen peroxide concentration on lignin removal and enzymatic saccharification was studied. When saccharides recovery are considered, a milder alkaline hydrogen peroxide condition should be used, The results indicate that the highest yield of saccharides was the hydrogen peroxide concentration is 2 %(wt/wt), Solid-liquid ratio is 1:20 and the residence time is 30 minute, the lignin removal and enzymatic saccharification were 71.76 % and 84.98 %. In addition, surfactants could incrase enzyme stability and enhance the yield of cellulose to fermentationable sugars. Therefore, we add different types and different concentration of surfactants in the process of enzymatic hydrolysis to explore the effect of surfactant in the Napiergrass hydrolysis. When the surfactant is Tween 80, and a dose of 4.5 g / L, glucose concentrations can be up to the highest.
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Wu, Ya-Jing, and 吳雅靜. "Optimization on the Conditions for the Hydrolysis and Probiotic Fermentation on Waste Coffee Grounds." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/65msbn.
Full textAbstract:
碩士國立高雄海洋科技大學
水產食品科學研究所
102
This study evaluated the acid, bile salts tolerances and antioxidant ability to optimize the hydrolysis and fermentation conditions of coffee grounds. The highest reducing sugars (33.14±1.64 mg/mL) calibrated by glucose was obtained after 6 hrs hydrolysis of cellulase (150 U/mL) at 37oC, 120 rpm, which is considered to be the optimal hydrolysis conditions. The carbohydrates were significantly released from coffee grounds after hydrolysis, compared to the non-hydrolyzed and commercial coffee extracts by analyzing with thin layer chromatography (TLC). The LAB counts increased from 5.98 to 8.52 log CFU/mL, while the pHs decreased from 4.63 to 3.77, after 24 hr fermentation by 0.05% Lactobacillus plantarum BCRC 10069 at 37oC. The reducing sugars decreased 19.08, 16.93 and 13.87 mg/mL, calibrated by glucose, mannose and arabinose, respectively. And trolox equivalent antioxidant capacity was 7.75 mM (relatively to trolox as standard), respectively. The pH 3 of acid tolerance for 3 hr, the LAB counts remained to 8.19±0.05 log CFU/mL. And the bile salt tolerance was 99.35%. According to the data obtained, coffee hydrolysates are with high potential in the production of functional prebiotics.
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Lin, Shou Pu, and 林守璞. "Tryptic hydrolysis of Ca-caseinate by immobilized bioreactor : optimum operating conditions and bioreactor design." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/30509360517638015245.
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Oyekola, Oluwaseun Oyekanmi. "The enzymology of sludge solubilisation under biosulphidogenic conditions : isolation, characterisation and partial purification of endoglucanases /." 2003. http://eprints.ru.ac.za/143/.
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Lee, Kuan-Wei, and 李冠緯. "Effect of Co-B catalysts synthesis conditions on hydrogen generation curves during NaBH4 hydrolysis reaction." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/66243271742117001470.
Full textAbstract:
碩士淡江大學
化學工程與材料工程學系碩士班
103
In this work, the ion exchange and chemical reduction method were used to synthesize Co-B catalyst. Catalyst loading, surface structure, surface area, metal composition, and crystal structure of Co-B catalyst were investigated in order to understand the connection between surface morphology/composition and the kinetic parameters of NaBH4 hydrolysis reaction. In the ion exchange step, the maximum Co ion exchange amount over TP-207 resin was operated at the synthesis condition: CoCl2 precursor, 3.93 pH, 25 oC ion exchange temperature. In the reduction step, types and concentrations of reduction agents, the concentration of dispersion agent, the reduction temperatures, and injection rates were investigated. The metal composition, surface area, and crystal structure were adjusted by the synthesis variable. The 40 and 80oC activities of Co-B catalyst were improved by adjusting the ratio of Co and B to 2, increasing surface area, and synthesing the certain Co-B crystal type. The results show that the 40 and 80 oC activity of Co-B catalyst was improved while different crystal structure was formation. The optimal result shows the best Co-B catalyst activity was located on following synthesis condition: 0.5 wt.% KBH4, 10 wt.% Ethylene glycol, 75 oC reduction temperature and 5 ml/min injection rate. After regressing kinetic parameters by using L-H model, the catalyst activity can be improved by decreasing KBH4 concentration, reduction temperature and injection rate; the tail of hydrogen generation curve can be improved by decreasing KBH4 concentration and injection rate.
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Peng, Xian-Hui, and 彭顯惠. "Screening of the Cellulase-Producing Bacteria and Optimizing the Conditions for the Hydrolysis of Chlorella by Cellulase." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/31684836201347975954.
Full textAbstract:
碩士國立臺灣海洋大學
食品科學系
94
A cellulase-producing bacterium, could form a clear zone on carboxy methyl cellulose (CMC) agar plates and designated as C-6, was isolated from soil and identified to be a Cellulomonas sp.. The optimal conditions for its growth were pH 6.8 in nutrient broth with 1.0 % carboxy methyl cellulose (CMC) at temperature of 30 oC and 150 rpm of shaking speed. The maximal cellulase activity was obtained after 96 hr incubation at 30 oC. In order to hydrolyze the cell wall of Chlorella, 10 % and 20 % extracellular enzyme solution hydrolyzed 10 % and 20 % Chlorella water were tested. Higher chlorophyll and protein contents, and lower residual dry weight were observed after the hydrolysis with 10 % extracellular fluid hydrolyzed 20 % Chlorella water. Although the cellulase activity lost gradually during 2 hr hydrolysis at 50 oC, breaking of Chlorella cell walls and release of chlorophyll were clearly observed after 30 min hydrolysis. According to the microscopic observation and measurement of chlorophyll content, obvious lysis of cell walls was obtained after 60 min hydrolysis. In order to increase Chlorella nutritive value, the extracellular fluid was determined protease activity and this property can hydrolyze protein from breaking of Chlorella. After, the peptide contents raised gradually and the free amino acid contents also raised during 3 hr hydrolysis.
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Notturno, Melissa Hagstrom. "Lipase-catalyzed hydrolysis of olive oil an in vitro method that mimics conditions in the human duodenum /." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32841349.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1994.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 134-146).
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Yu, Hui-Chuan, and 游慧娟. "Investigation of different enzymes, ultrasonic treatments, and hydrolysis conditions on the antioxidant properties of porcine liver protein hydrolysates." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/69602188411705469717.
Full textAbstract:
博士國立中興大學
動物科學系所
105
Porcine liver, a by-product of pig slaughtering, is rich in proteins and various nutrients. However, it is rarely used in Taiwan. Enzymatic hydrolysis is used to recover and improve the nutritional and functional properties of proteins from fish and animal byproducts to yield functional components. Ultrasonic has been used to improve protein hydrolysis and modify enzyme activities. Therefore, the objective of this study was to evaluate the effects of different enzymes, ultrasonic treatments, and hydrolysis conditions on the enzymatic hydrolysis of porcine liver for the production of hydrolysates and further characterization of their antioxidant activities. In the experiment 1, the antioxidant activity of porcine liver protein hydrolysates (PLPH) prepared by using Alcalase®, papain, pepsin, or Monascus purpureus microbial suspension (APLH, PaPLH, PePLH, and MPLH, respectively) after various hydrolysis time (3, 6, and 12 h) was evaluated. The results exhibited that the highest yield and peptide content were obtained from APLH, whereas the degree of hydrolysis (DH) of PaPLH was higher than the others. MPLH had the highest 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power, whereas APLH and PaPLH had higher ferrous ion-chelating ability than did MPLH. The molecular weights of all the hydrolysates were <10 kDa. The PaPLH exhibited the highest contents of total amino acids and hydrophobic amino acids. Fifteen antioxidant fractions obtained from MPLH contained one or more of the following amino acids in their sequences: Tyr, Trp, Ala, Pro, Met, Lys, Asp, Cys, Val, Leu, and His. Even though the hydrolysate hydrolyzed by Monascus purpureus microbial suspension exhibited the highest DPPH free radical scavenging activity and reducing power, it had the lowest yield and DH. Therefore, Alcalase® which exhibited the highest yield, peptide content and ferrous ion-chelating ability has been selected to hydrolyze porcine liver proteins in the next experiment. In the experiment 2, ultrasonic was applied on the enzymatic hydrolysis in order to improve the antioxidant activity of the porcine liver hydrolysate. The effect of the ultrasonic pretreatment (0, 15, 30, 45, and 60 s) on the antioxidant activity of PLPH employing Alcalase® was evaluated. The results exhibited the DH and peptide contents of the PLPHs increased as the time of ultrasonication increased. The hydrolysate pretreated with ultrasonication for 60 s exhibited the highest DH and peptide contents. The hydrolysate pretreated with ultrasonication for 45 s exhibited the highest ferrous ion chelating ability and reducing power. The hydrolysate pretreated with ultrasonication for 30 s exhibited the highest DPPH radical scavenging activity and the higher inhibitory activity in the linoleic acid autoxidation system. The molecular weight of the peptides in the hydrolysates was less than 6.2 kDa. In the experiment 3, by using response surface methodology (RSM), the effect of various hydrolysis parameters (E/S ratio, pH, and temperature) on the ultrasonic-assisted enzymatic hydrolysis of PLPH was evaluated. The results exhibited that E/S ratio, pH, and temperature significantly affected the antioxidant activity of the hydrolysate (P < 0.01). The optimal conditions for producing PLPH with the highest scavenging activity by using RSM were as follows: E/S ratio, 1.4% (v/w); temperature, 55.5°C; and initial pH, 10.15. Under these conditions, the degree of hydrolysis, DPPH free radical scavenging activity, ferrous ion chelating ability, and reducing power of PLPHs were 24.12%, 79%, 98.18%, and 0.601, respectively. The molecular weight of PLPH produced under these optimal conditions was less than 5,400 Da and contained 45.7% hydrophobic amino acids. In conclusion, favorable antioxidant hydrolysates from porcine liver enzymatic hydrolysis, which have a potential application for retarding lipid oxidation in food products, can be obtained by using Monascus purpureus microbial suspension, applying of ultrasonic treatment as well as selecting of the optimal hydrolysis conditions.
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Mei-Hong, Jhuang, and 莊美虹. "Isolation conditions of feruloylated oligosaccharides from rice bran by using hydrochloric acid,phosphoric acid hydrolysis and antioxidant activity." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/43319381578404372444.
Full textAbstract:
碩士國立澎湖科技大學
食品科學研究所
102
This study was to investigate the isolation conditions of feruloylated oligosaccharides from rice bran by using hydrochloric acid, phosphoric acid hydrolysis and the antioxidant activity of feruloylated oligosaccharides. First, tested the range of hygrolyzed rice bran and reaction time the following were: Hydrochloric acid (HCl) concentration- 0.05, 0.1, 0.2, 0.3M; reaction time- 30, 60, 90 minute.Phosphoric acid (H3PO4) concentration- 0.25, 0.5, 1M; reaction time- 60, 90, 120 minute. The result of conditions scope were calculated by regression equation, then obtained a defferential analysis of the optimal conditions for acid hydrolysis and validation tests. The result showed that the optimal conditions of hydrolysis rice bran for hydrochloric acid, phosphoric acid were: Hydrochloric acid (HCl) concentration- 0.144M; reaction time- 62 minute. Phosphoric acid (H3PO4) concentration- 0.64M; reaction time- 72 minute. Furthermore, after hydrolysis rice bran by the optimal conditions of hydrochloric acid and phosphoric acid. The feruloylated oligosaccharides of rice bran was separated and purified from the extract. In the activity of Trolox equivalent antioxidant that the sample of feruloylated oligosaccharides from rice bran by using HCl hydrolysis without neutralization. Concentration of the sample were diluted to 100, 200, 300 μg / ml. The result were 7.2, 11.6, 44.5 trolox eq. μg / g. Activity for the sample of feruloylated oligosaccharides from rice bran by using HCl hydrolysis with neutralization were 3.5, 6.9, 22.4 trolox eq. μg / g. Then, activity of Trolox equivalent antioxidant that the sample of feruloylated oligosaccharides from rice bran by using H3PO4 hydrolysis without neutralization. Concentration of the sample were diluted to 100, 200, 300 μg / ml. The result were 6.7, 12.2, 33.7 trolox eq. μg / g. Activity for the sample of feruloylated oligosaccharides from rice bran by using H3PO4 hydrolysis with neutralization were 5.4, 9.6, 23.9 trolox eq. μg / g. Both of the sample by using hydrochloric acid, phosphoric acid hydrolysis that have activity of Trolox equivalent antioxidant, but the sample without neutralization were higher than the sample with neutralization. The situation might due to the sample after neutralization cause by ion of feruloylated oligosaccharides were dissociation, thereby affecting the antioxidant activity. X The result that ferulic acid connected oligosahharides with higher antioxidant activity.
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"Ab initio molecular dynamics study of the solvation effect on chlorine hydrolysis and its reverse reaction." 1999. http://library.cuhk.edu.hk/record=b5890057.
Full textAbstract:
Siu Chi-kit.Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.
Includes bibliographical references (leaves 48-52).
Abstracts in English and Chinese.
TITLE PAGE --- p.i
THESIS COMMITTEE --- p.ii
ABSTRACT (ENGLISH) --- p.iii
(CHINESE) --- p.iv
ACKNOWLEDGEMENTS --- p.v
TABLE OF CONTENTS --- p.vi
LIST OF TABLES --- p.viii
LIST OF FIGURES --- p.ix
Chapter CHAPTER 1 --- Introduction --- p.1
Chapter Section 1.1 --- Introduction --- p.1
Chapter Section 1.2 --- Reaction of Chlorine Hydrolysis and Its Reverse Reaction --- p.2
Chapter 1.2.1 --- Reaction in the Gas Phase --- p.2
Chapter 1.2.2 --- Reaction in Aqueous Solution --- p.4
Chapter 1.2.3 --- Reaction on Ice Surface --- p.5
Chapter Section 1.3 --- Computational Method --- p.6
Chapter Section 1.4 --- Study of Chemical Reaction by Constraint Molecular Dynamics --- p.8
Chapter 1.4.1 --- Constraint Molecular Dynamics --- p.8
Chapter 1.4.2 --- RATTLE Constraint Dynamics --- p.9
Chapter 1.4.3 --- Free Energy of Chemical Reaction --- p.10
Chapter 1.4.4 --- Radial Distribution Function --- p.11
Chapter CHAPTER 2 --- "Ab initio Molecular Dynamics Study of the Reaction Between HC1 and HOC1 in Gas Phase, in Aqueous Solution and on Ice Surface" --- p.12
Chapter Section 2.1 --- Structure of the Isolated Molecules --- p.13
Chapter Section 2.2 --- Chlorine Hydrolysis in Aqueous Solution --- p.17
Chapter 2.2.1 --- Model --- p.17
Chapter 2.2.2 --- Results and Discussion --- p.18
Chapter 2.2.3 --- Conclusion --- p.31
Chapter Section 2.3 --- Heterogeneous Reaction of HC1 and HOC1 on Ice Surface --- p.32
Chapter 2.3.1 --- Model --- p.32
Chapter 2.3.2 --- Results and Discussion --- p.36
Chapter 2.3.3 --- Conclusion --- p.45
Chapter Section 2.4 --- "Comparison of the Reaction between HC1 and HOC1 in Gas Phase, in Aqueous Solution and on Ice Surface" --- p.46
REFERENCES --- p.48
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Liu, Shu-Ying, and 劉淑櫻. "Distribution of cyanogens in mei fruit at different growth periods and the hydrolysis of cyanogens under simulated gastraintestinal tract conditions." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/51081019677694573862.
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Guo, Ya-Ting, and 郭雅婷. "Optimization on conditions for the hydrolysis of shrimp waste by protease and chitinase from Bacillus subtilis YJ1 and Development of probiotics fermented chitooligosaccharide beverages." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/02917216057794960159.
Full textAbstract:
碩士國立高雄海洋科技大學
水產食品科學研究所
97
To produce high protease and chitinase activities, extra addition of chitins and CMC to the medium was conducted on the cultivation of Bacillus subtilis YJ-1. When this strain was incubated in a complex medium containing 0.5% (w/v) commercial chitin at 37oC, 150 rpm for 3 days, the highest neutral (655.2 U/mL•min) and alkaline (638.2 U/mL•min) proteases activities were obtained. The chitinases activities were 438.04 U/mL•min and 4.22 U/mL•min measured by neocuproine and DMBA methods, respectively. The shrimp shell solution was subjected to the hydrolysis by the above crude selective enzymes at 50oC for 3-4 hr, the soluble proteins, peptides, total free amino acid and reducing sugar of shrimp hydrolysates increased significantly (p<0.05), compared with those before hydrolysis. This phenomenon suggested the degradation of proteins contained in shrimp shell solution occurred. This study also investigated the effects of glucose content and pH on the fermerntation by Lactobacillus acidophilus BCRC 17010, Bifidobacterium adolescentis BCRC 14608 or Lactobacillus casei BCRC 12272. It was found that addition of 2% glucose at neutra pH was benefit for the growth of Bifidobacterium adolescentis BCRC 14608 (10.68 log CFU/mL after 36 hr fermentation). This result indicated that the shrimp shell hydrolysates were a good medium for Bifidobacterium adolescentis BCRC 14608. The molecular mass of the degraded products by electrophoresis weas approximately 2.5 kDa and the degraded chitooligosaccharides were pentaacetylchitopentaose and N-acetylchitobiose to pentaacetylchitopentaose measured by TLC and HPLC, respectively. The antioxidation ability including trolox equivalent antioxidant capacity, reducing power and Fe2+ ion chelating ability of the hydrolysate were 4 mM, 1.5 nm and 80.42% respectively. These results suggested that the combination use of selective enzymes produced by B. subtilis YJ1 with B. adolescentis BCRC 14608 fermentation could process the shrimp shell into a fermented functional chitooligosaccharide beverages.
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Tao, Yuan Ching, and 袁景道. "The Studies on the Effect of Fermenter Production Conditions on Pseudomonas vesicularis MA103 Agarases and on the Application of algal Polysaccharides and Its Oligosaccharides via Agarases Hydrolysis." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/59625431032593577036.
Full textAbstract:
碩士國立海洋大學
食品科學系
89
Pseudomonas vesicularis MA103 is a marine bacterium, which has the ability to degrade agar. As P. vesicularis MA103 was incubated in MM-P broth, containing 0.15% agar, 0.1% yeast extract, 1.0 mM CaCl2, 1% b-glycerophosphate and 0.6% NaCl, at 26oC with shaking speed of 120 rpm, the cultured broth could reach 98.30 unit/mL agarase activity and pH value of 6.21 after 48 hr. P. vesicularis MA103 was cultivated in various incubation conditions as (1) 500 mL MM-P broth in a 1 L fermenter, (2) 3 L MM-P broth in a 5 L fermenter, or (3) 3 L MM-P broth with controlled pH value at 6.20 in a 5 L fermenter. While being cultivated in (1) 500 mL MM-P broth, strain MA103 performed 51.91 unit/mL agarase activity. As incubated in (3) 3 L MM-P broth, strain MA103 achieved a higher agarase activity, 101.20 unit/mL. Total carbohydrate contents of algal polysaccharides that extracts from Gracilaria, Porphyra dentata, and Monostroma nitidium with different methods are ranged from 23.34 to 49.25%. The highest content of sulfate (1.41%) was observed in the polysaccharides extracted from Porphyra dentata as treated with hot water. The highest content of 3, 6-anhydro- galactose (31.26%) was revealed on the polysaccharides extracted from Gracilaria as treated with enzymes or mixture. The highest yield 50.16% of polysaccharide extract was obtained when Porphyra dentata was treated with enzymes or mixture. Total sugar contents of oligosaccharide lysates derived from algal polysaccharides extracts following digested by P. vesicularis MA103 agarases at 26oC for 48 hr are ranged from 5.74 to 31.26%. Molecular weight of the oligosaccharide mixture, derived from eight algal polysaccharides extracts that digested by P. vesicularis MA103 agarases at 26oC for 48 hr, were determined by the gel permeation chromatography (with Sephadex G-10) are in the range of 292.0 - 1689.6 Da. In the experiment of emulsifying properties of algal polysaccharide extracts, as the concentration of algal polysaccharide was increased from 0.0 to 1.0% (w/v), the emulsifying activity of the reacting mixture was also increased. When 1.0% polysaccharide extract, derived from Porphyra dentata with hot water treatment, were added to the emulsifying mixture, the best performance of emulsifying activity and emulsion stability were measured as 100% and 90%, respectively. Porphyra oligosaccharide mixtures, which obtained from the porphyral polysaccharide extract with enzyme or hot water treatment followed by digested by P. vesicularis MA103 agarases, were added (2.0%) individually to the emulsifying reacting solution, and the resulting emulsifying activity was 52.63 and 56.25%, repectively. The emulsifying activity of the rest oligosaccharide mixtures were measured between 45.00 and 46.66%. As to the emulsion stability, various oligosaccharide lysates did not show significant differences, which are among 40.00 and 46.15%. After dehydration under 60oC for 8 hr, eight algal polysaccharides extracts showed the capability of film formation. The higher penetration force (796.96 g) was observed happened on the film made by the polysaccharide extract derived from Gracilaria that treated with enzymes. Among various oligosaccharide hydrolysates, film made by oligosaccharides derived from Gracilaria polysaccharide extract treated with enzyme and then digested by P. vesicularis MA103 agarases, showed a higher penetration force (288.66 g).
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(14010168), Mirta Golic. "The preparation of dienes and dienophiles containing nucleic acid bases." Thesis, 1999. https://figshare.com/articles/thesis/The_preparation_of_dienes_and_dienophiles_containing_nucleic_acid_bases/21397758.
Full textAbstract:
The work presented in this thesis deals initially with the synthesis of rigid polyalicyclic dienes and dienophiles with pyrimidine moieties inbuilt in a rigid fashion (building BLOCKS). This work has allowed the production of a new class of ribbon molecules with precisely defined size, shape and position of the pyrimidine ring. In the second stage of the project, an assessment of their ability to participate in cycloaddition reactions as pyrimidine building BLOCK* components was investigated.
2,4-Dimethoxy-1,3-diazaanthracene (I) has acted as the pyrimidine transfer reagent for preparing building BLOCKs. The Diels-Alder adducts IV and V (Scheme I), prepared by reaction of I with norbomadiene, are new pyrimidine dienophilic BLOCKs. Both I and 2,4-dichloro-1,3-diazaanthracene (II) were active in photochemical [4π+4π] cycloaddition reactions with cyclopentadiene to form a second class of building BLOCKs VII and VIII (Scheme I). In addition, the photodimerisation of I and II was studied and structures IX-XII assigned on the basis of spectral and X-ray method.
The 2,4-dichloro-photoadduct VIII is of particular importance for this work since it is easily hydrolysed (2M NaOH, 60 °C, overnight) to the corresponding uracil XIII In contrast, thermal adducts IV and V were very difficult to hydrolyse (NaOH fusion) to uracils XIV and XV (Figure I).
The availability of pyrimidine BLOCKs which contain a reactive π-bond, e.g. (IV, V, VII and VIII) has enabled us to employ 3,6-di(2'-pyridyl)-s-tetrazine (XVI) and ACE (Alkene plus Cyclobutene Epoxide) coupling methods to obtain precisely functionalised ribbon molecules in a direct, convergent synthetic strategy.
The synthesis of the bis-pyrimidines by coupling norbornene reagents using 3,6-di(2'-pyridyl)-s-tetrazine is illustrated in Scheme II. In the first step, s-tetrazine XVI was reacted with pyrimidine BLOCK V under basic conditions to generate the dihydropyridazine XVII. This diaza-1,3-diene was reacted with a further equivalent of V under high pressure conditions to yield the bis-pyrimidines XVIII and XIX, which were separated by radial chromatography. The same procedure was used to link pyrimiclines to other effectors by using alternative alkenes in the second step.
The ACE coupling protocol is illustrated by the reaction of alkene VIII with the dimethoxynaphthalene-containing epoxide XX (Scheme III). The reaction can be conducted under thermal or photochemical conditions and is considered to proceed via 1,3-dipolar intermediate formed by ring-opening of the epoxide C-C bond of XX (See Chapter 4).
Each class of coupled adduct could be hydrolysed to the corresponding uracil by using either acid (XXII) or base (XXIII) hydrolysis conditions, the choice depending on the structure of the molecule in question and its substituents.
The work presented in this thesis involves a deal of new work and has been instrumental in the development of the Lego®-based BLOCK assembly protocol for ribbon molecules construction.
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Tsai, Sheng Fen, and 蔡昇奮. "The study of Hydrolysis Optimal condition of N-2-(vinylbenzylamino)-ethyl-3-aminopropyltrimethoxysilane." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/22625466992855251437.
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碩士國立中正大學
化學工程研究所
92
The printed circuit board equipped in computers and various type of mechanism is made from single-face or double-face copper clad laminate, which includes the following types: (1) phenolic copper clad laminate made from paper substrate/ phenolic resin; (2) hard copper clad laminate made from glass cloth impregnated with epoxy resin and polyester resin. The glass cloth, which is used in the glass fiber epoxy copper clad laminate, adopts plain weave after being bound into glass yarn, and then use silane coupling agent to conduct surface treatment. The main purpose is to increase adhesion of glass cloth and epoxy interface. The surface of glass cloth impregnated with silane coupling agent will increase not only the interface adhesion with resin, but also the permeability of epoxy resin into glass yarn. In addition, it will increase laminate heat resistance, reduce moisture absorption rate, improve dimensional stability and stabilize the electronic characteristic of glass fiber. It is necessary to hydrolyze alkoxy groups into hydroxide groups before the silane coupling agent is coated on the surface of glass cloth. Then the hydroxide groups will form covalent bonds with the surface’s hydroxide groups. The hydrolysis reaction of silane coupling agent is influenced by the following factors: PH value, acid type, grade of stirring, concentration of silane coupling agent, type of silane coupling agent, aging time and etc. The hydrolysis of Dow Corning’s N-2-(vinylbenzylamino)- ethyl-3-aminopropyltrimethoxysilane(Z-6032) was studied using The Taguchi Method by setting up four factors and three levels. Nucleus magnetism resonance spectroscopic analysis (29Si-NMR-Spectroscopic analysis) was used to measure the relative quantity of D-structure and T-structure in first hydrolysis of Z-6032. After changing various factors and levels, the optimum conditions for the maximum relative quantity of D-structures in the first hydrolysis was figured out. The second hydrolysis solution was then coated on the glass fiber, and the micro-bond pulling out test was conducted to verify the change in bond strength due to the combination with epoxy resin micro drops.
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Shih-WeiChang and 張詩偉. "Studies on Effect and Optimizing Condition for Saccharum-Miscanthus Leaves Pretreatment via Acid Hydrolysis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/46817743500795866829.
Full textAbstract:
碩士國立成功大學
化學工程學系
102
The leaves of Saccharum-Miscanthus, which is a hybrid of sugarcane and miscanthus, provide a good biomaterial due to its high holocellulose contain and production. In the present study, dilute acid hydrolysis process is applied to hydrolyze cellulose and hemicellulose to produce reducing sugars such as glucose and xylose. After process optimization, we obtained that under the condition of 30oC, with the leaf size of 3-5mm soaked in 70wt.% H2SO4 solution for 1hr followed by 5wt.% H2SO4 solution hydrolysis under 121oC, 1.2atm for 1hr, the highest total reducing sugar yield was 0.487g reducing sugar/g raw-material-added. To cost down and make it economic viable, we developed a process that using two-stage pretreatment. In the developed process, Saccharum- Miscanthus leaves were first soaked in 30oC, 4wt.%NaOH solution for 6hr, then soaked in 70oC, 20wt.% H2SO4 for 1hr. The two-stage pretreated leaves could give total reducing sugar yield of 0.402g reducing sugar/g raw-material, followed by 5wt.% H2SO4 hydrolysis at 121oC for 1hr.
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Huang, Chih-Hao, and 黃致豪. "Sequential Diluted Acid and Enzymatic Hydrolysis of Spent Coffee Ground at High Solids Condition for Bioproductions." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/25619771736019945501.
Full textAbstract:
碩士國立雲林科技大學
化學工程與材料工程系
103
Spent coffee ground (SCG) has been indicated as a potential feedstock for bioproductions by many research reports. However， as a kind of lignocellulosic biomass， SCG also requires pretreatment and enzymatic hydrolysis to liberate the fermentable sugars from it. In this study， a bio-refinery concept was applied to fully utilize the SCG. The locally collected SCG was first extracted by hexane to obtain the coffee oil， and then the de-oiled biomass was subjected to dilute acid hydrolysis and enzymatic saccharification to generate fermentable sugars for microbial oil production. In order to have the optimal pretreatment condition， a response surface methodology was applied to investigate the effects of concentration of dilute sulfuric acid (2-6 % w/w) and reaction time (1- 2 hours) on the yield of fermentable sugar from enzymatic saccharification. The result indicated that the reducing sugar yield was around 0.55 g/g biomass at the optimal condition which was corresponding to ~90% conversion rate of biomass carbohydrate.
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Wu, Ling-Tsai, and 吳鈴彩. "Establishment of an optimal pasteurization condition of fresh milk by the peptide content from protein hydrolysis in vitro." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/41773484110993331486.
Full textAbstract:
碩士東海大學
畜產與生物科技學系
93
Milk is a highly nutritious food, and must be pasteurized to destroy all the pathogenic and microorganisms in order to extend shelf life. However, the different pasteurization conditions could induce physicochemical changes in milk. This study was intended to establish an optimal pasteurization condition of milk using response surface methodology by the peptide content from protein hydrolysis in vitro. The first factor temperature (X1) and the second factor holding time (X2) of response surface were located through preliminary study. Then X1 and X2 were used as the center point of central composite rotatable design in order to establish an optimal pasteurization condition of fresh milk. The physicochemical properties of fresh milk processed from the optimal pasteurization condition were then compared with market milk. Results suggested that temperature (X1) of 81℃ and holding time (X2) of 20 seconds, were used as center point for central composite rotatable design. Fresh milk pasteurized by 81℃ for 20 seconds had the highest peptide content. The alkaline phosphatase and lactoperoxidase activity tests were negative of fresh milk pasteurized by 81℃ for 20 seconds. The L*, b* value and titratable acidity of fresh milk pasteurized by 81℃ for 20 seconds were significantly lower (P<0.05) than market milk. In addition, pH value, available lysine content, undenatured whey protein content and peptide content were significantly (P<0.05) higher than market milk. The electrophoresis showed that fresh milk pasteurized by 81℃ for 20 seconds had more undenatured whey protein than market milk. The overall acceptability of fresh milk pasteurized by 81℃ for 20 seconds in sensory evaluation was among different market milk. Therefore, temperature of 81℃ and holding time of 20 seconds was the optimal pasteurization condition of fresh milk.
44
Akhurst, P., P. D. Rose, Chris G. Whiteley, and B. I. Pletsheke. "Accelerated sludge solubilisation under sulphate reducing conditions: the effect of hydrolytic enzymes on sludge floc size distribution and EPS composition." 2002. http://hdl.handle.net/10962/d1010430.
Full textAbstract:
Extracellular polymeric substances (EPS) are the construction materials for microbial aggregates such as biofilms, flocs and sludge, and greatly contribute to the structural integrity of sludge flocs in wastewater treatment processes. The loss of integrity of the sewage sludge floc is believed to be due to enhanced hydrolysis of important structural components such as lignin, protein and cellulose in the sludge floc matrix. The mechanism of enhanced sludge floc fracture, due to the action of enzymes hydrolysing these structural components, remains a key element in our understanding of how the floc integrity in systems utilising a sulphate reducing system is compromised. A range of relatively non-specific exogenous enzymes (ß-glucosidase, cellulase, proteases: trypsin, pronase E and chymotrypsin) were added to a sulphidogenic bioreactor- (containing both sulphate reducing bacteria (SRB) and a methanogenic bacterial system) and a (control) methanogenic bioreactor sample, and the effect of these enzymes on sludge floc size (diameter) distribution and EPS composition was investigated. Sludge samples from the bioreactors were examined under bright field and differential interference contrast light microscopy. Proteolytic and glucohydrolytic activity of the enzymes were monitored using standard enzyme assaying techniques, and Bradford, Somogyi-Nelson, and total carbohydrate assays were performed to establish the composition of the EPS (after extraction with 3% (v/v) glutaraldehyde and Sephacryl S-400 size exclusion chromatography). Sludge flocs present in the sulphidogenic environment of the sulphidogenic bioreactor were found to have smaller diameters than their counterparts present in the methanogenic bioreactor. The addition of hydrolytic (i.e. proteolytic and glycohydrolytic) enzymes resulted in an increased rate of matrix hydrolysis, leading to increased rates of floc fracture and deflocculation. The presence of ß-glucosidase, cellulase, and proteases naturally residing within the sludge floc was confirmed. We propose that the addition of commercially available enzymes may be prohibitively costly on a large scale, and that the activity of the enzymes naturally residing within the floc matrix be optimised or enhanced. As the bulk of the EPS was shown to be composed of mainly polysaccharides, we propose that by increasing the activity of the naturally occurring ß-glucosidases residing within the floc matrix, the process of deflocculation may be enhanced. As sulphide has been shown to increase the activity of this very important key enzyme, we propose that this is one of the contributing factors why sludge solubilisation is accelerated under sulphate reducing conditions.