No description available.

The work presented in this thesis describes the occurrence and properties of two multicopper oxidases derived from lichens. Despite numerous data on laccases and tyrosinases in fungi and flowering plants, this is the first report of the occurrence of these enzymes in lichenized ascomycetes. Extracellular laccase and tyrosinase activity was measured in 50 species of lichens from different taxonomic groupings and contrasting habitats. Out of 27 species tested from suborder Peltigerineae, all displayed laccase and tyrosinase activity that correlated to each other, while activity was absent in species tested from other lichen groups. Identification of the enzymes as laccases and tyrosinases was confirmed by the ability of lichen thalli or leachates to readily metabolize substrates such as 2,2’-azino(bis-3-ethylbenzthiazoline-6-sulfonate) (ABTS), syringaldazine and o-tolidine in case of laccase and L-dihydroxyphenylalanine (L-DOPA), Ltyrosine and epinephrine in case of tyrosinase in the absence of hydrogen peroxide. The activities of both enzymes were highly sensitive to cyanide and azide, and tyrosinase activity was sensitive to hexylresorcinol. Laccase activity had typical pH and temperature optima and an absorption spectrum with a peak at 614 nm. Tyrosinases could be activated by sodium dodecyl sulphate (SDS) and had typical tyrosinase molecular masses of approx. 60 kDa. The diversity of laccase isoforms in 20 lichen species from suborder Peltigerineae was investigated. The molecular masses of the active forms of most laccases varied between 135 and 190 kDa, although some lichens within the family Peltigeraceae had laccases with higher masses, typically varying from 200 to over 350 kDa. Most species contained one oligomeric laccase isoform. Desiccation and wounding stimulated laccase activity, while only wounding stimulated tyrosinase activity. The ability of laccases to decolorize dye is a classic attribute of laccases, and one with biotechnological potential. The ability of eight lichen species to decolourize different types of dyes was therefore tested. Interestingly, results showed that not only species belonging to suborder Peltigerineae but also species from other lichen group effectively decolourised dyes after 48 h suggesting that other oxidases appear to have ability to decolorize. Hopefully, our work could contribute to the better knowledge and application of lichen multicopper oxidases. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

ABSTRACT UTILIZATION OF SCYTALIDIUM THERMOPHILUM PHENOL OXIDASE IN BIOORGANIC SYNTHESES Kaptan, Yelda M.S., Department of Biotechnology Supervisor: Prof. Dr. Z&uuml / mr&uuml / t B. &Ouml / gel Co-supervisor: Prof Dr. Ufuk Bakir September 2004, 90 pages In this study, the ultimate aim was to utilize phenol oxidases of Scytalidium thermophilum in bioorganic syntheses. For this purpose, studies were conducted towards enhancing the production of phenol oxidases by Scytalidium thermophilum, developing a suitable method for laccase activity assays, analyzing the effects of organic solvents on phenol oxidase activity and analysis of the biotransformation of a number of organic substrates by phenol oxidases of Scytalidium thermophilum. In order to enhance the production of phenol oxidases, induction experiments were carried out with gallic acid, syringaldazine and chlorogenic acid. Gallic acid was found as the most effective inducer for phenol oxidase production. Inductive effect of edible mushroom Agaricus bisporus was also assayed, however, the phenolic compounds released by mushroom did not represent any induction for phenol oxidase activity of Scytalidium thermophilum. Different substrates were tested and catechol was determined as the most suitable substrate rather than syringaldazine and ABTS. Molar extinction coefficient (e) of catechol was calculated as 3450 M-1 cm-1 and 3700 M-1 cm-1 by using &ldquo / substrate blank&rdquo / and &ldquo / enzyme blank&rdquo / respectively at 420 nm. Kinetic parameters, Km and Vmax for the enzymatic reactions in which catechol was used as substrate were calculated as 52.03 mM and 0.253 U/ml respectively from Lineweaver-Burk plot and as 41.25 mM and 0.2055 U/ml from Hanes-Woolf plot. Effect of some organic solvents on phenol oxidases of Scytalidium thermophilum was assayed and DMSO was found as an appropriate solvent for the organic substrates. Phenol oxidase containing culture supernatant could oxidize benzoin, hydrobenzoin and benzoyl benzoin.

Thesis (M. Eng.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 95-101.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisors: Keith P. Johnston and William J. Koros. Vita. Includes bibliographical references.

Universiẗat, Diss., 2002--Stuttgart.

Made available in DSpace on 2014-12-17T14:08:36Z (GMT). No. of bitstreams: 1 RodrigoCS.pdf: 3685250 bytes, checksum: 36c02ba21672c99c459225abadc4fe02 (MD5) Previous issue date: 2009-08-21 / Petr?leo Brasileiro SA - PETROBRAS / Produced water is the main effluent linked to the activity of extraction of oil and their caring management is necessary due to the large volume involved, to ensure to minimize the negative impacts of discharges of these waters in the environment. This study aimed to analyze the use of retorted shale, which is a reject from the pyrolysis of pirobituminous shale, as adsorbent for the removal of phenols in produced water. The material was characterized by different techniques (grain sized analysis, thermal analysis, BET, FRX, FT-IR, XRD and SEM), showing the heterogeneity in their composition, showing its potential for the removal of varied compounds, as well as the phenols and their derivatives. For the analysis of the efficiency of the oil shale for the adsorption process, assays of adsorption balance were carried through, and also kinetic studies and dynamics adsorption, in the ETE of the UTPF of Petrobras, in Guamar?-RN. The balance assays shown a bigger conformity with the model of Langmuir and the kinetic model more adjusted to describe the adsorption of phenols in retorted shale was of pseudo-second order. The retorted shale presented a low capacity of adsorption of phenols (1,3mg/g), when related to others conventional adsorbents, however it is enough to the removal of these composites in concentrations presented in the produced water of the UTPF of Guamar?. The assays of dynamics adsorption in field had shown that the concentration of phenol in the effluent was null until reaching its rupture (58 hours). The results showed the possibility of use of the reject for removal of phenols in the final operations of the treatment process, removing as well, satisfactorily, the color and turbidity of the produced water, with more than 90% of removal / A ?gua Produzida ? o principal efluente ligado ? atividade de extra??o de Petr?leo e seu gerenciamento cuidadoso ? necess?rio devido ao grande volume envolvido de forma a garantir a minimiza??o dos impactos negativos dos descartes destas ?guas no meio ambiente. Este estudo teve o objetivo de analisar a utiliza??o de xisto retortado, rejeito proveniente da pir?lise do xisto pirobetuminoso, como adsorvente para remo??o de fen?is em ?guas Produzidas. O material foi caracterizado por diferentes t?cnicas (an?lise granulom?trica, an?lise t?rmica, BET, FRX, FT-IR, DRX e MEV), mostrando a heterogeneidade em sua composi??o, comprovando seu potencial para remo??o de compostos variados, assim como para os fen?is e seus derivados. Para a an?lise da efici?ncia do xisto retortado para o processo de adsor??o, foram realizados ensaios de equil?brio de adsor??o, estudos cin?ticos e din?mica de adsor??o, na ETE da UTPF da Petrobras, em Guamar?-RN. Os ensaios de equil?brio mostraram uma maior conformidade com o modelo de Langmuir e o modelo cin?tico mais adequado para descrever a adsor??o dos fen?is em xisto retortado foi o de pseudo-segunda ordem. O xisto retortado apresentou uma capacidade de adsor??o de fen?is baixa (1,3mg/g), quando relacionada a de outros adsorventes convencionais, por?m suficiente para a remo??o desses compostos em concentra??es apresentadas na ?gua Produzida da UTPF de Guamar?. Os ensaios de din?mica de adsor??o em campo mostraram que a concentra??o de fen?is no efluente foi nula at? atingir sua ruptura (58 horas). Os resultados mostraram a possibilidade do uso do rejeito para remo??o de fen?is em opera??es finais do processo de tratamento, removendo tamb?m, de forma satisfat?ria, a cor e turbidez da ?gua produzida, com remo??o superior a 90%.

Neste trabalho, foram preparadas resinas contendo o grupo sulfônico a partir de copolímeros sintetizados à base de estireno e divinilbenzeno (Sty-DVB), utilizando a técnica de polimerização em suspensão aquosa via radical livre. Os copolímeros foram preparados com diferentes graus de porosidade designados como: poros menores, porosidade intermediária e poros grandes. Esses copolímeros foram caracterizados por FTIR, ASAP, densidade aparente, grau de inchamento, termogravimetria e microscopia eletrônica de varredura. Os copolímeros de Sty-DVB foram modificados quimicamente com sulfato de acetila para a obtenção de resinas sulfonadas. A modificação química dos copolímeros foi confirmada pelo aparecimento das bandas de absorção características no infravermelho do grupo sulfônico, pela capacidade de troca iônica introduzida por esse grupo funcional (aproximadamente 5 mmol/g) e pela modificação das características térmicas. As resinas sulfonadas foram impregnadas com metais de Ni ou Co para a obtenção de materiais magnéticos. Os compósitos obtidos foram caracterizados por microscopia eletrônica de varredura, sendo possível visualizar as partículas metálicas sobre a superfície da matriz polimérica. O comportamento magnético desses materiais foi investigado, sendo observado um pequeno campo coercivo, que é característico de materiais magnéticos moles. Os materiais sintetizados foram avaliados na remoção de fenol de soluções aquosas. A remoção de fenol foi mais efetiva quando os compósitos de Ni foram empregados. / In this work, resins containing the sulfonic group were prepared from synthesized copolymer beads based on styrene and divinylbenzene (Sty-DVB) by suspension polymerization. These crosslinked copolymers were prepared with different porosities, namely small, intermediate and large porosity. These copolymers were characterized by infra-red spectrometry (FTIR), bulk density, specific area, swelling degree , termogravimetry (TG/DTG) and scanning electron microscopy (SEM). The synthesized copolymers were modified with acetyl sulphate aiming to obtain sulphonated resins. The chemical modification of the copolymers as confirmed by the displaying of the characteristc bands of sulfonic groups in the infrared spectra, by the ionic exchange capacity given by this functional group (around 5 mmol/g) and by the changes of thermal profiles. Ni or Co particles were anchored on the sulphonated copolymer matrix aiming to obtaining different magnetic materials. These composites were characterized by scanning electron micrscopy (SEM), permiting the observation of particles on the resin surfaces. The magnetic behavior of the composites was investigated. They presented behavior of soft materials due to their low coercive field. These composites were evaluated on the phenol removal from the aqueous solutions. The phenol removal was more efficient from materials containing Ni particles.

Made available in DSpace on 2016-06-02T19:56:56Z (GMT). No. of bitstreams: 1 DissLTS.pdf: 9020125 bytes, checksum: e5e1b73c065d46b9f7bb52f9113ba1dd (MD5) Previous issue date: 2005-03-24 / Universidade Federal de Minas Gerais / This work had as objective studies of the biofilms formation in polymerics particles used as material supports in anaerobic fluidized-bed reactors. Three polymerics supports were tested: polystyrene, PET and PVC, which suffered appropriate acid treatment, in way to provide them superficial characteristics as rugosity, porosity and favorable electric charge, with the purpose of favoring the microbial adhesion. The reactors were inoculated with sludge originating from reactor UASB that treated swine slaughterhouse residue, adapted to the degradation of the phenol by 150 days. The volume of the reactors was of 770cm3, and they operated with ascendant speed of 1,3 times of the flow rate of the minimum fluidization. The phenol concentration varied from 100 to 400mg/L in the feeding of each system, presenting results of removal of phenol of 97%, 98% and 97,5% and removal of DQO of 84%, 88,5% and 87%, respectively for the reactors with polystyrene, PET and PVC, which operated with time of detention hydraulic relative the height of the bed, corresponding to the reactional volume of the reactors (TDHr) of 22 h, 10,6 h and 20,4 h, respectively. The quantification of extracellular polymeric showed better results for the particles of PVC that it presented 0,2 mgCarbohydrate/gParticle and 0,06 mgProteyn/gParticle. However, deformations in those particles harming the acting of the reactor, defining as better support the particles of PET, and in this reactor the percentage of phenol removal was larger for a smaller TDHr. / Este trabalho teve como objetivo estudar da formação de biofilmes em partículas poliméricas usadas como meio suporte em reatores anaeróbios de leito fluidizado. Foram testados 3 suportes poliméricos: poliestireno, PET e PVC, os quais sofreram tratamento ácido adequado, de modo a proporcionar-lhes características superficiais como rugosidade, porosidade e carga elétrica favorável, com a finalidade de favorecer a adesão microbiana. Os reatores foram inoculados com lodo proveniente de reator UASB que tratava resíduo de suinocultura, adaptado à degradação do fenol por 150 dias. O volume dos reatores era de 770cm3, e operaram com velocidade ascensional igual a 1,3 vezes da vazão de mínima fluidização. A concentração de fenol variou de 100 a 400mg/L na alimentação de cada sistema, apresentando resultados de remoção de fenol de 97%, 98% e 97,5% e remoção de DQO de 84%, 88,5% e 87%, respectivamente para os reatores com poliestireno, PET e PVC, os quais operaram com tempo de detenção hidráulico relativo a altura do leito, correspondente ao volume reacional dos reatores (TDHr) de 22 h, 10,6 h e 20,4h, respectivamente. A quantificação de polímeros extracelulares mostrou melhores resultados para as partículas de PVC que apresentou 0,2 mgCarboidrato/gPartícula e 0,06 mgProteina/gPartícula. No entanto, deformações nessas partículas prejudicaram o desempenho do reator, definindo como melhor suporte as partículas de PET, sendo que neste reator a porcentagem de remoção de fenol foi maior para um menor TDHr.

abstract: With the aid of metabolic pathways engineering, microbes are finding increased use as biocatalysts to convert renewable biomass resources into fine chemicals, pharmaceuticals and other valuable compounds. These alternative, bio-based production routes offer distinct advantages over traditional synthesis methods, including lower energy requirements, rendering them as more "green" and "eco-friendly". <italic>Escherichia coli</italic> has recently been engineered to produce the aromatic chemicals (S)-styrene oxide and phenol directly from renewable glucose. Several factors, however, limit the viability of this approach, including low titers caused by product inhibition and/or low metabolic flux through the engineered pathways. This thesis focuses on addressing these concerns using magnetic mesoporous carbon powders as adsorbents for continuous, in-situ product removal as a means to alleviate such limitations. Using process engineering as a means to troubleshoot metabolic pathways by continuously removing products, increased yields are achieved from both pathways. By performing case studies in product toxicity and reaction equilibrium it was concluded that each step of a metabolic pathway can be optimized by the strategic use of in-situ adsorption as a process engineering tool. / Dissertation/Thesis / Masters Thesis Chemical Engineering 2014