Using glycerol from biodiesel production as a fuel in a microbial fuel cell (MFC) will generate electricity and valuable by-products from what is currently considered waste. This research aims to screen E. coli (W3110, TG1, DH5, BL21), P. freudenreichii (subspecies freudenreichii and shermanii), and mixed cultures enriched from compost (AR1, AR2, AR3) as anodic biocatalysts in a glycerol-oxidizing MFC. Anaerobic fermentation experiments were performed to determine the oxidative capacity of each catalyst towards glycerol. Using an optimized medium for each strain, the highest anaerobic glycerol conversion from each group was achieved by E. coli W3110 (4.1 g/L), P. freudenreichii ssp. shermanii (10 g/L), and AR2 (20 g/L). These cultures were then tested in an MFC system. All three catalysts exhibited exoelectrogenicity. The highest power density was achieved using P. freudenreichii ssp. shermanii (14.9 mW m-2), followed by AR2 (11.7 mW m-2), and finally E. coli W3110 (9.8 mW m-2).

Biodiesel has shown great promise to supplement the fossil diesel since it is a renewable energy resource and is environmentally friendly. However, the major obstacle to biodiesel large scale commercialization is the high production cost; so converting glycerol, the by-product of a biodiesel process, into value-added products is an efficient way to promote biodiesel production. 1,2-propanediol (1,2PD), also known as propylene glycol, is an important commodity chemical used for many applications such as polyester resins, liquid detergents and anti-freeze. It can be produced via dehydration of glycerol into acetol followed by hydrogenation of acetol into 1,2PD using a bi-functional catalyst. Currently high pressure gaseous hydrogen added for hydrogenation causes safety issues as well as additional costs of hydrogen purchasing, transportation and storage. Therefore, the utilization of the in situ hydrogen produced by steam reforming of a hydrogen carrier could be a novel route for this process. In this work, processes of glycerol hydrogenolysis to produce 1,2PD have been developed using different hydrogen sources, i.e. molecular hydrogen and in situ hydrogen produced by steam reforming. Three different preparation methods were attempted to prepare a Cu/ZnO/Al2O3 catalyst in a glycerol hydrogenolysis process, which were oxalate gel-coprecipitation, Na2CO3 coprecipitation and impregnation. The catalyst prepared by oxalate gel-coprecipitation showed the highest activity for production of 1,2PD. It was also found that the addition of alumina did not only improve the activity but also enhanced the stability of the Cu/ZnO catalyst as shown by the catalyst recycling experiments. The morphological and chemical properties of the catalysts were characterized via XRD, NH3 TPD, TGA and TEM. Compared with other preparation methods, the Cu/ZnO/Al2O3 catalyst prepared by oxalate gel-coprecipitation exhibited a well-mixed form for all the metals as suggested by the XRD and TGA results; the particle size of the Cu/ZnO/Al2O3 catalyst was smaller as shown in the XRD and TEM results, and also based on NH3 TPD analysis the Cu/ZnO/Al2O3 catalyst showed stronger acidic sites. When Ni was loaded onto the Cu/ZnO/Al2O3 catalyst by oxalate gel-coprecipitation, it was found that the activity for acetol hydrogenation was improved but the overall glycerol hydrogenolysis reaction was slower. This was mainly due to the reduced amount of strong acidic sites caused by the addition of Ni as observed from the NH3 TPD results. 2wt% Pd supported on a Cu/MgO/Al2O3 catalyst was used in this process. Higher reaction rate and higher 1,2PD selectivity could be obtained compared with a Cu/ZnO/Al2O3 catalyst. However, a significant deactivation was observed when the spent catalyst was used. The catalyst deactivation was mainly due to catalyst sintering during the reaction resulting in a larger particle size as suggested by XRD results. The activation energies for the glycerol hydrogenolysis reaction using Cu/ZnO/Al2O3 and Pd supported on Cu/MgO/Al2O3 catalysts have been calculated. The activation energy was calculated to be 69.39kJ/mole using a Cu/ZnO/Al2O3 catalyst and 113.62kJ/mol using a Pd supported on Cu/MgO/Al2O3 catalyst. It is suggested that the reaction was chemically kinetically controlled using both catalysts and the reaction using the Pd supported on Cu/MgO/Al2O3 catalyst was more temperature dependent. It was found that the 1,2PD selectivity was strongly dependent on hydrogen pressure. The low 1,2PD selectivity at lower hydrogen pressure was due to the formation of by-products caused by side reactions with acetol. The kinetic data of acetol hydrogenation suggested that the acetol hydrogenation step was significantly faster than the overall reaction and hence the glycerol dehydration step was the rate-determining-step. In the glycerol hydrogenolysis process using in situ hydrogen, the activities of the Cu/ZnO/Al2O3 catalysts prepared by different methods were determined and the experimental results show that the catalyst prepared by oxalate gel-coprecipitation has the best catalytic activity for glycerol conversion and 1,2PD selectivity. With Ni loaded onto a Cu/ZnO/Al2O3 catalyst, the 1,2PD selectivity was improved and the glycerol conversion was lower. It might be because Ni could improve the steam reforming activity to produce more hydrogen, but due to the reduced strong acidic sites based on the NH3 TPD results glycerol conversion was decreased. Cu/MgO/Al2O3 catalysts prepared by oxalate gel-coprecipitation were used in this process and the activity was found to be higher, i.e. higher glycerol conversion and 1,2PD selectivity, compared with the Cu/ZnO/Al2O3 catalyst due to a higher amount of acidic sites based on the NH3 TPD results; the Cu/Mg/Al composition was optimized. When Ni was added into a Cu/MgO/Al2O3 catalyst, it was found that with only 1mole% Ni loaded, the glycerol conversion was lower than that without Ni loaded and the 1,2PD selectivity was slightly improved; when the Ni loading was increased to 5mole%, the catalyst was almost completely inactive, since when 5mole% Ni was loaded, the acidic sites were almost completely eliminated as observed from the NH3 TPD results. When Pd was added onto a Cu/MgO/Al2O3 catalyst the 1,2PD selectivity was significantly improved. When Pd was loaded, more surface hydrogen atoms were provided as observed from the H2 TPD results. Cu/ZnO/Al2O3 and Cu/MgO/Al2O3 catalysts have been recycled and reused to investigate the stability of the catalysts. All the catalysts were deactivated after they were recycled and reused, since it was apparent that catalyst sintering occurred during the reaction resulting in a larger particle size based on the XRD results. The deactivation of the spent catalyst was also possibly due to the formation of carbonate when the metals were contacted with CO2 which was formed via steam reforming.

Using glycerol from biodiesel production as a fuel in a microbial fuel cell (MFC) will generate electricity and valuable by-products from what is currently considered waste. This research aims to screen E. coli (W3110, TG1, DH5, BL21), P. freudenreichii (subspecies freudenreichii and shermanii), and mixed cultures enriched from compost (AR1, AR2, AR3) as anodic biocatalysts in a glycerol-oxidizing MFC. Anaerobic fermentation experiments were performed to determine the oxidative capacity of each catalyst towards glycerol. Using an optimized medium for each strain, the highest anaerobic glycerol conversion from each group was achieved by E. coli W3110 (4.1 g/L), P. freudenreichii ssp. shermanii (10 g/L), and AR2 (20 g/L). These cultures were then tested in an MFC system. All three catalysts exhibited exoelectrogenicity. The highest power density was achieved using P. freudenreichii ssp. shermanii (14.9 mW m-2), followed by AR2 (11.7 mW m-2), and finally E. coli W3110 (9.8 mW m-2).

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.

The present study investigated the capability of Schizochytrium limacinum SR21 to utilize various industrial or agricultural by-products for the production of lipids. The substrates analyzed were used restaurant oil (yellow grease) and animal fat (white grease) derived crude glycerol from biodiesel production, and sweet sorghum juice. Crude glycerol is the primary by-product from biodiesel production - 0.66 lb is generated for each gallon of biodiesel produced. The crude glycerol can be purified and used in food, chemical, drug, and other industries. Purification however, is an expensive and complicated process therefore other economical uses of crude glycerol must be identified such as the one described in this study - fermentation of crude glycerol via S. limacinum SR21 to produce lipids which then serve as biodiesel feedstocks. Sweet sorghum juice is harvested from the sweet sorghum plant, a C4 plant possessing high photosynthetic efficiency and high sugar yield including glucose, sucrose, and fructose. The juice is typically used for white sugar production, but may be a good substitution for common substrates used in lipid production via S. limacinum SR21. S. limacinum SR21 is a fast growing microalga capable of accumulating large quantities of lipids, which have applications in human health products, biodiesel, and animal feed. In separate batch studies, S. limacinum SR21 was grown on each substrate and monitored. On crude glycerol derived from yellow grease, 25 and 35 g/l were the optimal doses for untreated and treated crude glycerol, respectively. Biomass dry weights of 8.3 and 11.3 g/l were attained for these doses, respectively. The highest crude lipid content of all doses, 73.3%, was with 35 g/l treated crude glycerol. Crude glycerol derived from animal fats also provided similar results to these. S. limacinum SR21 grown on sweet sorghum juice furnished similar biomass density and lipid content. The optimum does of 50% juice produced a biomass dry weight of 9.4 g/l and 73.4% lipid content. While biomass dry weight was lower than that grown on glucose (10.9 g/l), lipid content was higher than typical values (50%). Of the three sugars, only glucose was utilized for growth. The remaining medium may still be used for white sugar production since fructose and sucrose were not consumed. Both crude glycerol and sweet sorghum juice caused substrate inhibition at high doses, and presence of methanol in crude glycerol presented an additional prohibitory effect on cell growth. Major fatty acids were nearly identical among the lipids produced from different substrates. This research shows that at certain concentrations of both crude glycerol and sweet sorghum juice can be utilized by S. limacinum SR21 to yield substantial quantities of lipids. Based upon the results revealed from the batch stage studies, large scale lipid production from industrial or agricultural by-products could be a reality in the near future. This production process will: 1) eliminate excessive crude glycerol from the market, 2) produce high-value lipids in an environmentally friendly, economical, and sustainable way, and 3) provide lipid feedstocks for various industrial applications.

Made available in DSpace on 2014-06-11T19:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-12Bitstream added on 2014-06-13T18:09:34Z : No. of bitstreams: 1 aizemberg_r_me_arafcf.pdf: 685654 bytes, checksum: d058342c2d66649275266dc34dcb968d (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / A levedura Pichia pastoris vem sendo largamente utilizada como um eficiente sistema de expressão para a produção de proteínas heterólogas, pois é um sistema seguro, fácil e mais barato que sistemas de expressão de outros eucariotos. Neste trabalho, a enzima de interesse é a glicerol quinase (GK), que cataliza a transferência do fosfato terminal do ATP para o glicerol originando glicerol-3-fosfato e ADP. Esta reação pode ser utilizada na determinação da concentração de glicerol, subproduto da fermentação alcoólica. A leitura do consumo de glicerol é realizada pela determinação espectrofotométrica do NADH gerado na reação de oxido-redução catalizada pela enzima glicerol-3-fosfato desidrogenase. Este estudo de indução foi realizado em diferentes condições de crescimento da levedura Pichia pastoris. Os resultados mostraram a seleção do melhor clone da levedura Pichia pastoris para a expressão extracelular da enzima glicerol quinase, e a determinação das melhores condições do meio de cultura para a produção da enzima de interesse foram: concentração do meio de cultura BMMY (20 vezes), densidade inicial de célula (0,1 mg/mL), concentração de metanol na fase de indução (1%), natureza do tampão (fosfato de potássio), pH (6,0), suplementação de glicerol no meio BMMY (1%), peptona (marca Difco), sem adição de sulfato de amônio, caseína e glicina, uso do meio BMMY e liofilização do mesmo. Estudos de parâmetros cinéticos foram realizados e a atividade máxima da GK foi obtida em pH 9,8, a 50ºC e 2,5 μM de substrato, por metodologia clássica, além da presença de sulfato de magnésio e diluição da enzima de 30 vezes. A enzima apresentou alta estabilidade térmica ― a atividade foi completamente... / The yeast Pichia pastoris has been widely used as an efficient expression system for production of heterologous proteins because it is a safe, easy and cheaper than expression systems in other eukaryotes.In this studie, the enzyme of interest is glycerol kinase (GK), which catalizes the transfer of terminal phosphate from ATP to glycerol resulting glycerol-3-phosphate and ADP. This reaction can be used in determining the concentration of glycerol, a byproduct of fermentation. The reading of the consumption of glycerol is carried out by spectrophotometric determination of NADH generated in the redox reaction catalyzed by the enzyme glycerol-3-phosphate dehydrogenase. This study of induction was performed in different conditions of growth of the yeast Pichia pastoris. The results show that selecting the best clone of the yeast Pichia pastoris for the expression of extracellular enzyme glycerol kinase, and determining the best conditions of the culture medium for producing the enzyme of interest were: concentration of the culture medium BMMY (20 times), initial cell density (0.1 mg/mL), methanol concentration in the induction phase (1%), nature of buffer (potassium phosphate), pH (6.0), glycerol supplementation in BMMY medium (1%), peptone (Difco), without addition of ammonium sulfate, casein and glycine in BMMY and lyophilized medium. Studies of kinetic parameters were conducted and the GK maximum activity was obtained at pH 9.8 at 50°C and 2.5 μM substrate by conventional method, besides the presence of magnesium sulfate and diluting the enzyme 30 times. The enzyme showed high thermal stability - the activity was fully maintained up to 50°C for one hour - and at pH 7.0 for 7 days and kept under refrigeration, freeze-dried extract showed a decrease in enzymatic activity. Calculated by... (Complete abstract click electronic access below)

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Nos Ãltimos anos, um grande interesse na associaÃÃo de materiais magnÃticos e biolÃgicos tem sido relatado na literatura. A obtenÃÃo de novos compÃsitos constituÃdos de galactomanana (GM), nanopartÃculas magnÃticas (MNPs) de NiZn e glicerol (GL) foram produzidos em diferentes proporÃÃes com finalidade de potencializar as caracterÃsticas individuais de cada material para futuras aplicaÃÃes. Sendo assim, as propriedades estruturais, magnÃticas e dielÃtricas dos nanobiocompÃsitos foram investigadas por DifraÃÃo de Raios-X (DRX), Espectroscopia de AbsorÃÃo na RegiÃo de Infravermelho (FTIR), AnÃlise TÃrmica (TG), Calorimetria ExploratÃria Diferencial (DSC), Microscopia EletrÃnica de Varredura (MEV), Microscopia EletrÃnica de TransmissÃo (TEM), Medidas MagnÃticas e Medidas DielÃtricas. A estrutura de espinÃlio da ferrita de NiZn foi confirmada por DRX e TEM e a amostra GMGL apesar de ser um material amorfo apresentou em seus nanobiocompÃsitos picos caracteristicos da fase de NiZn. As bandas caracterÃsticas para as amostras foram confirmadas por FTIR. Estas por sua vez seguiram um perfil de degradaÃÃo de acordo com as quantidades de NiZn incorporados, confirmados nos termogramas de DSC. A caracterizaÃÃo por MEV foi importante para avaliaÃÃo da morfologia. Os resultados das medidas dielÃtricas apresentaram baixas perdas dielÃtricas e das medidas magnÃticas mostraram comportamento magnÃtico para todos os nanobiocompÃsitos. Portanto, os resultados da caracterizaÃÃo dos nanobiocompÃsitos foram satisfatÃrios para possÃveis aplicaÃÃes como biomaterias, dispositivos eletrÃnicos ou em Ãreas afins. / In recent years, a great interest in the association of magnetic and biological materials has been reported in the literature. New composite consisting of galactomannan (GM), magnetic nanoparticles (NPs) of NiZn and glycerol (GL) were produced in different proportions with the purpose of enhancing the individual characteristics of each material for future applications. Thus, the structural, magnetic and dielectric properties of nanobiocomposites were investigated by Absorption Spectroscopy in the Region of Infrared (FTIR), X-Ray Diffraction (XRD), Thermal Analysis (TG), Differential Scanning Calorimetry (DSC), Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Magnetic Measurements and Dielectric Measurements. The structure of spinel NiZn ferrite was confirmed by XRD and TEM. Sample GMGL despite being an amorphous material presented in their nanobiocomposites characteristic peaks of phase NiZn. The characteristic bands in the samples were confirmed by FTIR. These in turn followed a degradation profile in accordance with the amounts of NiZn incorporated, which was confirmed in the DSC thermograms. The characterization by SEM was important to assess the morphology. The results of dielectric measurements showed low dielectric loss and magnetic measurements showed magnetic behavior for all nanobiocomposites. Therefore, the results of the characterization of nanobiocomposites were satisfactory for potential applications as biomaterials, electronic devices or related areas.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Os biossurfactantes formam molÃculas anfipÃticas, que possuem em sua estrutura quÃmica segmentos hidrofÃbicos e hidrofÃlicos, espacialmente separados que auxiliam a formaÃÃo de emulsÃes e disponibilizam compostos à cÃlula microbiana. Em funÃÃo dessas caracterÃsticas, os emulsificantes reduzem a tensÃo superficial na interface das fases imiscÃveis, permitindo, portanto, que elas se misturem, formando a emulsÃo. Com isso, este trabalho foi dividido em seis etapas: a primeira tendo como objetivo avaliar a produÃÃo de biossurfactante a partir da glicerina, proveniente da produÃÃo do biodiesel de soja, pela cepa comercial de Bacillus subtilis ATCC 6633, possÃvel produtora de biossurfactante que foi selecionada devido a sua habilidade em sintetizar biossurfactantes a partir de diferentes fontes de carbono; a segunda, resolveu-se avaliar o potencial de produÃÃo de surfactina por cepas de Bacillus sp. nÃo patogÃnicas isoladas da EstaÃÃo de Tratamento de Efluentes da Universidade Federal do CearÃ, com propÃsito de avaliar o maior potencial de produÃÃo do biossurfactante; a terceira, avaliar e otimizar experimentalmente a produÃÃo de biossurfactante em mesa agitadora, utilizando a cepa selecionada durante o screening; a quarta, produÃÃo do biossurfactante utilizando biorreator de 4 L; a quinta, caracterizar o biossurfactante produzido, determinando os grupos funcionais, os estudos de conformaÃÃo e estrutura dos compostos; a sexta, estudar o poder de emulsificaÃÃo do biossurfactante atravÃs da construÃÃo de diagramas de fases para uma posterior aplicaÃÃo do emulsificante. Inicialmente, foi analisada uma cepa produtora de biossurfactante de Bacillus subtilis (ATCC 6633), cultivada em meio de cultura contendo glicerina, um resÃduo da indÃstria do biodiesel, como fonte de carbono e energia, a fim de avaliar a viabilidade desta matÃria-prima na sÃntese de biossurfactante. Uma concentraÃÃo mÃxima de surfactina de 158,14 mg.L-1 foi obtida. Posteriormente, um screening com sete cepas isoladas de Bacillus sp. foi realizado quanto ao crescimento e produÃÃo de biossurfactante a partir da glicerina. Apenas duas cepas (LAMI005 e LAMI009) foram selecionadas atravÃs de dois mÃtodos indiretos, quanto a reduÃÃo da tensÃo superficial e a capacidade de emulsionar trÃs fontes hidrofÃbicas (querosene, Ãleo de soja e n-hexadecano). Foi avaliada a cinÃtica de crescimento e a produÃÃo de biossurfactante para as cepas selecionadas e o melhor resultado em frascos de Erlenmeyer foi realizado com Bacillus subtilis LAMI005, com concentraÃÃo de surfactina de 441,06 mg.L-1 e tensÃo superficial que manteve-se numa faixa estÃvel de 28,8  0,05 mN.m-1 com uma concentraÃÃo micelar crÃtica (CMC) de 19,8 mg.L-1. Posteriormente, ensaios foram realizados em biorreator de 4L, porÃm nÃo se atingiu a concentraÃÃo de surfactina produzida em mesa agitadora, devido, provavelmente, a condiÃÃes de aeraÃÃo, que nÃo foi monitorada quando os ensaios foram realizados em frascos agitados. A surfactina produzida em biorreator foi submetida a anÃlises de espectroscopia vibracional no infravermelho com transformada de Fourier (FTIR), atravÃs destes espectros foi confirmado que o biossurfactante produzido tinha caracterÃsticas similares a surfactina padrÃo da Sigma. O comportamento dos diagramas de fases demonstrou o potencial de emulsificaÃÃo do biossurfactante produzido nestes experimentos, que à bastante positivo em relaÃÃo à possibilidade de aplicaÃÃes do biossurfactante analisado em diversos setores industriais. / Biosurfactants are amphipathic molecules, which possess in their chemical structure hydrophobic and hydrophilic segments, separated spatially, that favor the formation of emulsions and improve the availability of compounds to microbial cell. Given these characteristics, emulsifiers reduce surface tension at the interface of immiscible phases, thereby allowing them to blend in, forming an emulsion. Thus, this study was divided into six stages: the first stage aimed at studying the biosurfactant producers using glycerol, a co-product of biodiesel production from soybean oil, the commercial strain of Bacillus subtilis ATCC 6633, a known biosurfactant-producing was selected due their ability to synthesize biosurfactants from different carbon sources; the second stage aimed at studying the potential of Bacillus sp. strains, isolated from the tank of chlorination, at the Wastewater Treatment Plant on the âCampus do Piciâ (WWTP-PICI), at the Federal University of CearÃ, in producing biosurfactants; the third step was to experimentally evaluate and optimize the production of biosurfactant in shaker, using the strains selected during the screening; the fourth step was the process by using a 4 L batch bioreactor; the fifth step was to characterize the biosurfactant produced by determining the functional groups through studies of conformation and structure of compounds; and the sixth, to study the emulsifying power of the biosurfactant produced by the construction of phase diagrams for a subsequent application of the surfactant. Initially, a biosurfactant-producing strain of Bacillus subtilis (ATCC 6633) was cultived in a culture medium containing glycerin, a residue of the biodiesel industry, as carbon and energy source, in order to evaluate the viability of this raw material in the synthesis of biosurfactants. A maximum concentration of surfactin of 158.14 mg. L-1 was achieved. Next, a screening with seven strains of Bacillus sp. was performed aiming to study growth and biosurfactant production from glycerin. Only two strains (LAMI005 and LAMI009) were selected through two indirect methods, surface tension reduction and the ability to emulsify three hydrophobic sources (kerosene, soybean oil and n-hexadecane). Kinetics of growth and biosurfactant production was evaluated for the selected strains and best results in Erlenmeyer flasks was achieved with Bacillus subtilis LAMI005, 441.06 mg.L-1 of surfactin concentration and the surface tension remained stable in the range of 28.8  0.05 mN.m-1 with a critical micelle concentration (CMC) of 19.8 mg.L-1. Later, tests were conducted in 4L bioreactor, but the concentration of surfactin obtained during grothw in shaker flasks were not achieved probably due to different aeration condition. The surfactin produced in bioreactor was subjected to analysis of the vibrational spectroscopy of Fourier transform infrared (FTIR), the spectra confirmed that the biosurfactant produced had similar characteristics to a standard of surfactin from Sigma. The behavior of phase diagrams showed the potential of the biosurfactant produced for emulsification, which is very encouraging regarding the possibility of biosurfactant applications in many industrial sectors.

Using glycerol from biodiesel production as a fuel in a microbial fuel cell (MFC) will generate electricity and valuable by-products from what is currently considered waste. This research aims to screen E. coli (W3110, TG1, DH5, BL21), P. freudenreichii (subspecies freudenreichii and shermanii), and mixed cultures enriched from compost (AR1, AR2, AR3) as anodic biocatalysts in a glycerol-oxidizing MFC. Anaerobic fermentation experiments were performed to determine the oxidative capacity of each catalyst towards glycerol. Using an optimized medium for each strain, the highest anaerobic glycerol conversion from each group was achieved by E. coli W3110 (4.1 g/L), P. freudenreichii ssp. shermanii (10 g/L), and AR2 (20 g/L). These cultures were then tested in an MFC system. All three catalysts exhibited exoelectrogenicity. The highest power density was achieved using P. freudenreichii ssp. shermanii (14.9 mW m-2), followed by AR2 (11.7 mW m-2), and finally E. coli W3110 (9.8 mW m-2).