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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sialic acid metabolism by viridans streptococci

Byers, Helen Louise January 1998 (has links)
No description available.
2

Comparative analysis of fermentative yeasts during spontaneous fermentation of grapes from different management systems

Bagheri, Bahareh 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The microorganisms associated with grape berry surface can be influenced by numerous factors such as agronomic parameters. Hence, the focus of this study was comparison between three agronomic farming systems to evaluate their impact on yeast diversity. In addition, the dynamics of the yeast population throughout wine alcoholic fermentation were monitored. Three vineyards (conventional, biodynamic and integrated) were chosen and the experiment was carried out during the 2012 and 2013 vintages. A total of 600 yeast isolates including Saccharomyces and non-Saccharomyces were obtained from grape must and during different stages of fermentation including beginning, middle and end of alcoholic fermentation, from all three vineyards. Yeast species diversity in grape must and their population dynamics were evaluated by cultivating the yeasts in nutrient media and using “Polymerase Chain Reaction and sequence analysis of the ITS1-5.8S rRNA-ITS2 region. Eight, four and one species were detected from biodynamic, conventional and integrated must in 2012 vintage whereas, 2013 vintage displayed a higher diversity and 12, 11 and 9 different species were identified from biodynamic, conventional and integrated vineyard, respectively. Aureobasidium pullulans was the most frequent isolate in all three vineyards whereas Saccharomyces cerevisiae was below detection level in grape must and was only isolated in low frequencies in biodynamic must (3% of the total population) in both vintages. In general, the overlap of common yeast isolates (e.g. M. pulcherrima and H. uvarum) was observed in the musts obtained from different vineyards although unique minor species could be isolated and clearly demonstrated the distinction between the three vineyards. Moreover, biodynamic must displayed a higher degree of diversity in both 2012 and 2013 compared to the conventional and integrated vineyards. The beginning of all spontaneous fermentations was dominated by non-Saccharomyces yeast species (e.g. H. uvarum, C. zemplinina), as the fermentation proceeded, the population of non-Saccharomyces species were gradually decreased and strongly fermentative yeast S. cerevisiae dominated and completed the fermentations. The dynamics of S. cerevisiae strains was also evaluated during different stages of fermentation (beginning, middle and end), using interdelta PCR methods. A high diversity (10-18 strains per fermentation) and the sequential substitution of S. cerevisiae strains were observed throughout spontaneous fermentations. In addition, integrated vineyard displayed the highest S. cerevisiae strains compared to biodynamic and conventional vineyard. / AFRIKAANSE OPSOMMING: Die mikro-organismes wat met die oppervlak van druiwe bessies geassosieer word kan deur veskeie agronomiese faktore beїnvloed word. Gevolglik was die focus van die studie om ‘n vergelyking tussen die impak van drie verksillende boerdery sisteme op die invloed op gis diversiteit te bepaal. Die dinamiek van gis populasies tydens alkoholiese fermentasie is bykomstig bestudeer. Drie verskillende wingerde (konvesioneel, biodinamies en geïntegreerd) is gebruik vir die studie tydens die 2012 en 2013 oesjare. In total is 600 gis isolate, insluitend Saccharomyces en nie-Saccharomyces giste, verky van druiwe mos tydens verkillende fases van die fermentasie proses (begin, middle en einde) vir al drie wingerde. Die diversiteit en populasie dinamika van gis spesies in die druiwe mos is geëvalueer deur die giste in verskillendde media op te groei en ook deur die gebruik van die “polymerase ketting reaksie” (PKR) en DNS volgorde bepaling van die ITS1-5.8S rRNA-ITS2 gebied. Tydens die 2012 oesjaar is agt, vier en een afsonderlike spesies geїsoleer, in vergelyking met die 12, 11 en 9 verskillende spesies wat tydens 2013 geidentifiseer is is uit die biodinamiese, konsensionele en geïntegreerde onderskeidelik. Aureobasidium pullulans is teen die hoogste frekwensie geїsoleer in al drie wingerde, terwyl Saccharomyces cerevisiae onder die deteksie limiet was in druiwe mos en ook slegs in lae getalle in die biodinamiese mos (3% van die totale populasie) in beide oesjare. Oor die algemeen is ‘n oorvleuling tussen verwante spesies (bv. M. pulcherrima en H. uvarum) waargeneem en die mos vanaf verskillende wingerde, terwyl meer geringe spesies deurgans geїsoleer kon word en duidelik ‘n verkill tussen die drie wingerde uitgewys het. Druiwe mos uit die biodinamiese wingerd het verder ‘n hoёr graad van diversiteit en beide 2012 en 2013 vertoon as beide die konvesnionele en geïntegreerde wingerde. Die begin van alle spontane fermentasies was gedomineer deur die populasie van nie-Saccharomyces gis spesies (bv. H. uvarum, C. zemplinina), wat geleidelik afgeneem het met die verloop van die fermentasie. Die populasie van die sterk fermentatiewe, S. cerevisiae, het toegeneem tydens fermentasie en die fermentasie afgehanel as dominante gis. Die dinamika van S. cerevisiae rasse is ook geëvalueer tydens die verskillende fases van fermentasie (begin, middle en einde) deur gebruik te maak van interdelta PKR metodes. ‘n Hoё diversiteit (10-18 rasse per fermentasie) en die opeenvolgende verplasing van S. cerevisiae rasse was waargeneem deur die verloop van spontane fermentasies. Daarbenewens het die geïntegreerde wingerd die grootste getal S. cerevisiae rasse in vergelyking met die biodinamiese en konvensionele wingerde opgelewer.
3

Efeitos da inclusão de teores crescentes de prebióticos nas dietas de cães adultos sobre parâmetros digestivos, fermentação fecal, microbiota e imunidade / Effects of the inclusion of increasing levels of prebiotics in adult dogs on the digestive parameters, fecal fermentation, microbiota and immunity

Santos, Karine de Melo 18 August 2017 (has links)
No intuito de promover a saúde e reduzir o risco de doenças, a nutrição de animais de companhia tem evoluído de forma semelhante à humana, na busca por alimentos funcionais. Neste sentido, as Saccharomyces cerevisiea são leveduras com potencial prebiótico, pois podem estimular a produção de substâncias com propriedades imunoestimulatórias e aumentar a capacidade de prevenir a colonização de bactérias patogênicas no trato gastrintestinal. Porém, a composição e processo de produção podem influenciar na sua capacidade de atuação. Este estudo objetivou avaliar os efeitos da inclusão de teores crescentes de leveduras com metabólitos ativos (LMA) dietéticos na digestibilidade aparente dos nutrientes, microbiota e produtos da fermentação fecal e parâmetros imunológicos de cães adultos. Foram utilizados 18 cães adultos hígidos, machos e fêmeas, peso corporal médio de 15,8±7,37kg, distribuídos em delineamento inteiramente casualizado constituído de três tratamentos experimentais, denominados: DC (dieta controle), LMA 0,3 (dieta controle com 0,3% de leveduras com metabólitos ativos) e LMA 0,6 (dieta controle com 0,6% de leveduras com metabólitos ativos). As médias dos resultados obtidos foram comparadas pelo teste de Tukey (p<0,05) no SAS. Pôde-se verificar que a inclusão do aditivo alterou a digestibilidade aparente da fibra bruta, da proteína bruta, extrativos não nitrogenados e energia metabolizável (p<0,05). Os produtos de fermentação não foram afetados pelo aumento da inclusão do prebiótico (P>0,05). O índice de fagocitose foi maior nas dietas LMA 0,3 e LMA 0,6 (P<0,05). Nas dosagens de LMA 0,3 e 0,6 as concentrações fecais de Prevotela, Allobaculum, Fusobacterium reduziram e Clostridium aumentaram (p<0,05). Collinsela aumentou em LMA 0,6 (p<0,05). Blautia apresentou tendência de aumento em LMA 0,3 e 0,6 e Lactobacillus em LMA 0,3 (p<0,10). De acordo com os teores de inclusão e os parâmetros avaliados neste estudo, o aditivo pode apresentar possível efeito na imunidade inata e inespecífica e promover modestas alterações na microbiota fecal de cães adultos saudáveis. / In order to promote health and reduce the risk of diseases, pet nutrition has evolved in a similar way to human, in the search for functional foods. In this sense, Saccharomyces cerevisiaa are yeasts with high prebiotic capacity, since they stimulate the production of substances with immunostimulatory properties and increase the capacity to prevent the colonization of pathogenic bacteria in the gastrointestinal tract. However, its composition and production process determine the ability to act, based on the substrate and medium in which it was nourished. The objective of this study was to evaluate the effects of increasing levels of yeast with active metabolites (YAM), based on the fermentation of specific substrates, on the apparent digestibility of dietary nutrients, fecal fermentation products, microbiota, and immunological parameters of adult dogs. Eighteen adult healthy male and female dogs with a mean body weight of 15.8 ± 7.37 kg were distributed in a completely randomized design consisting of three experimental treatments: CD (control diet), YAM 0.3 (control diet with 0.3% of yeasts with active metabolites) and YAM 0.6 (control diet with 0.6% of yeasts with active metabolites). The mean of the obtained results were compared by the Tukey test (p<0,05) in the SAS. It can be verified that the inclusion of the additive altered the apparent digestibility of crude fiber, crude protein, nitrogen free extract and metabolizable energy (p<0.05). Regarding the fermentation products, they were not affected by the prebiotic (P>0.05). The phagocytosis index was higher in the diets YAM 0.3 and YAM 0.6 (P<0.05). At the dosages of YAM 0.3 and 0.6, fecal concentrations of Prevotela, Allobaculum, Fusobacterium reduced and Clostridium increased (p<0.05). Collinsela increased with LMA 0.6 (p<0.05). Blautia tended to increase with YAM 0.3 and 0.6 and Lactobacillus with YAM 0.3 (p<0.10). According to the inclusion levels and the parameters evaluated in this study, the additive may present a possible effect on innate and nonspecific immunity and promote modest changes in the fecal microbiota of healthy adult dogs.
4

Efeito da concentração de glicose e da alcalinidade na produção de hidrogênio em reator anaeróbio de leito fluidificado / Effect of glucose concentration and alkalinity in the hydrogen production in anaerobic fluidized bed

Amorim, Eduardo Lucena Cavalcante de 12 November 2009 (has links)
O objetivo deste estudo foi avaliar o efeito da adição de alcalinidade, da concentração da glicose e da taxa de carregamento orgânico na produção de hidrogênio e ácidos orgânicos em reator anaeróbio de leito fluidificado (RALF), contendo argila expandida (2,8 - 3,35 mm) como material suporte para adesão microbiana. Foram utilizados oito reatores idênticos, sendo quatro deles operados sem adição de alcalinidade, e com concentração de glicose de 2000, 4000, 10000 e 25000 mg/L, respectivamente. Outros quatro reatores operados com adição de alcalinidade, e com as mesmas concentrações de glicose cada um. Os reatores foram inoculados com lodo anaeróbio pré-tratado termicamente, operado com tempo de detenção hidráulica (TDH) decrescente de 8 h a 1 h à temperatura controlada de 30°C. Foi constatada produção volumétrica de hidrogênio máxima de 1,58 L/h.L, para o reator operado com 10000 mg/L de glicose com adição de alcalinidade (R10CA) e um rendimento máximo de 2,52 mol \'H IND.2\'/mol glicose, para o reator operado com 4000 mg/L de glicose com adição de alcalinidade (R4CA). O biogás produzido foi composto de \'H IND.2\' e \'CO IND.2\'. Em ambos os reatores, o conteúdo de hidrogênio aumentou com a redução do TDH de 8 h para 1 h, alcançando valor máximo de 77%, para o reator operado com 4000 mg/L sem adição de alcalinidade (R4SA). Os reatores operados com altas concentrações de glicose produção de hidrogênio, o qual predominou o ácido acético e butírico. Neste mesmo reator, o rendimento da produção de hidrogênio foi superior aos outros reatores. As análises de clonagem e sequenciamento do consórcio bacteriano revelaram semelhanças com Clostridium, Klebsiella, Enterobacter e bactérias não cultivadas. / This study evaluated the effect alkalinity addition, glucose concentration and organic loading rate in the hydrogen production and organic acids in an anaerobic fluidized bed reactor (AFBR), containing expanded clay (2.8 - 3,35 mm) as support material for microbial adhesion. We used eight identical reactors, four of them operated without the addition of alkalinity, and concentration of glucose in 2000, 4000, 10000 and 25000 mg/L, respectively. Another four reactors operated with the addition of alkalinity, and with the same concentrations of glucose each. The reactors were operated with hydraulic retention times (HRT) ranging from 8 h at 1 h, and temperature of 30°C. It has been found for hydrogen production rate maximum 1.58 L/h.L for the reactor operated with 10000 mg/L glucose with the addition of alkalinity (R10CA) and a maximum yield of 2.52 mol \'H IND.2\'/mol glucose to the reactor operated with 4000 mg/L glucose with the addition of alkalinity (R4CA). The biogas produced was composed of \'H IND.2\' and \'CO IND.2\'. In both reactors, the hydrogen content increased with the reduction of HRT of 8 h at 1 h, reaching a maximum of 77% for the reactor operated from 4000 mg/L without added alkalinity (R4SA). The reactors operated with high glucose concentrations (10000 mg/L and 25000 mg/L) had higher proportions of solvents such as soluble metabolites. There was a linear correlation between the hydrogen production rate and organic loading rate in all reactors. The yield, the hydrogen production rate and distribution of soluble metabolites in both reactors, were influenced by the glucose concentration. The reactor operated with 4000 mg/L and addition of alkalinity, presented the most favorable distribution of soluble metabolites to hydrogen production, which was predominant acetic and butyric acid. In the same reactor, the hydrogen yield was higher than other reactors. The cloning and sequencing analysis bacterial consortium revealed the presence of Clostridium, Klebsiella, Enterobacter and uncultivated bacteria.
5

Qualidade pós-colheita de colmos de cana armazenados e seus reflexos na produção de cachaça / Quality of post-harvest stored cane stalks and its effects on the production of cachaça

Oliveira Filho, José Humberto de 19 November 2015 (has links)
O armazenamento dos colmos de cana pode comprometer a manutenção do seu estado fisiológico, refletindo em consideráveis alterações na qualidade do caldo. Esta pesquisa teve como objetivos, avaliar as características tecnológicas e microbiológicas do caldo de cana colhida e armazenada, assim como seus reflexos na condução dos processos fermentativos e formação dos compostos químicos da cachaça. Após colheita da cana-de-açúcar, os colmos foram armazenados a temperatura ambiente (20 - 32°C) por períodos de 0, 24, 48, 72 e 96 horas, sendo o mosto preparado após extração do caldo. As fermentações foram conduzidas em processo batelada com reciclo de células, durante cinco ciclos fermentativos. O monitoramento da fermentação foi realizado através da quantificação de micro-organismos em atividade no processo e no fermento reciclado. Ao término das fermentações, foram analisadas as características tecnológicas dos vinhos, os quais foram destilados em alambique de cobre para quantificação dos compostos secundários (ácido acético, aldeído, álcoois superiores, ésteres e furfural) e contaminantes (álcool metílico, cobre e carbamato de etila) da cachaça. O armazenamento dos colmos de cana por períodos superiores a 48 horas causou significantes perdas na qualidade do caldo, reduzindo o conteúdo de sacarose, pureza e açúcares redutores totais, aumentando os níveis de acidez total, açúcares redutores e bactérias láticas. Os colmos de cana armazenados por 72 e 96 horas, afetou a condução do processo fermentativo, ocasionando decréscimo na viabilidade de células e brotos de leveduras, e elevação nas concentrações de bactérias láticas e leveduras não-Saccharomyces no fermento reciclado. As características tecnológicas dos vinhos também foram comprometidas com a utilização de colmos armazenados. Os níveis de acidez volátil, acetato de etila, acetaldeído, álcool metílico, cobre e carbamato de etila das cachaças apresentaram-se dentro do estabelecido pela Legislação Brasileira, enquanto o conteúdo de álcoois superiores e furfural foram superiores em destilados de cana colhida e armazenada. As concentrações de acetato de etila e carbamato de etila permaneceram elevadas ao final do 5º ciclo para destilados de colmos armazenados por períodos superiores a 48 horas, porém não excederam os limites especificados na Legislação. / The cane stalks storage can compromise the maintenance of their physiological state, resulting in considerable changes in the quality of the juice. This research aimed to evaluate the sugarcane juice technological and microbiological characteristics when harvested and stored, as well its reflexes in the cachaça fermentative processes and secondary compounds guiding processes. After harvested, the sugarcane stalks were stored at environmental temperature (20 - 32°C) at 0, 24, 48, 72, and 96 hours, preparing the must just before the juice extraction. Fermentations were carried out through the batch process, using five fermentative cycles. Monitoring the fermentation was carried out by quantifying microorganisms active in the process and recycled yeast. At the end of fermentation, the technological characteristics of the wines were analyzed, which was distilled in copper still for quantification of secondary compounds (acetic acid, aldehyde, higher alcohols, esters and furfural) and contaminants (methyl alcohol, copper and ethyl carbamate) of cachaça. The cane stalks storage for periods exceeding 48 hours caused significant losses in the juice technological quality, reducing the sucrose content, purity and total reducing sugars, increasing the acidity levels, reducing sugars and lactic acid bacteria. The cane stalks stored for 72 and 96 hours, influencing negatively the fermentative process; presenting decreasing in the viability of the yeast cells and shoots, as well an elevation in the lactic bacteria and non-Saccharomyces yeasts concentration in the recycled yeast. The technical characteristics of the wines were also compromised with the use of stalks stored. The volatile acidity levels, ethyl acetate, acetaldehyde, methanol, copper, and ethyl carbamate in the cachaças were within the ones established by the Brazilian law, while the superior alcohols and furfural content were high in the sugarcane distillated after harvested and stored. The concentrations of ethyl acetate and ethyl carbamate remained high at the end of the 5th cycle to cane spirits stored for longer than 48 hours, but did not exceed the limits specified in legislation.
6

A influência da matéria-prima e diferentes cepas de levedura no rendimento fermentativo de um processo de obtenção de etanol / The influence of the raw material and different yeast strains on the fermentative yield of a process of obtaining ethanol

Tognete, Milena Heloisa Pozenatto Bicudo [UNESP] 17 February 2017 (has links)
Submitted by MILENA HELOISA POZENATTO BICUDO TOGNETE null (mibicudo28@gmail.com) on 2017-03-28T20:38:07Z No. of bitstreams: 1 Dissertacao versao final.pdf: 1702848 bytes, checksum: c8c7d8d8e47d1bf45f97875ac83a2798 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-30T17:07:32Z (GMT) No. of bitstreams: 1 tognete_mhpb_me_sjrp.pdf: 1702848 bytes, checksum: c8c7d8d8e47d1bf45f97875ac83a2798 (MD5) / Made available in DSpace on 2017-03-30T17:07:32Z (GMT). No. of bitstreams: 1 tognete_mhpb_me_sjrp.pdf: 1702848 bytes, checksum: c8c7d8d8e47d1bf45f97875ac83a2798 (MD5) Previous issue date: 2017-02-17 / Este estudo tem como objetivo avaliar a matéria-prima e sua influência isolada no desempenho do rendimento fermentativo de uma linhagem padrão da levedura CAT-1 testada em 31 meios de cultivos provenientes do processo de fermentação alcoólica da Usina Virgolino de Oliveira – Unidade Catanduva. Os meios foram amostrados e compostos a cada quinzena durante toda as safras 2012 e 2013. O trabalho também tem como finalidade identificar a dinâmica populacional das leveduras do mesmo processo fermentativo, através da diferenciação das linhagens por cariotipagem. As cepas isoladas foram testadas em um meio de cultivo padrão para obtenção das características tecnológicas industriais através da metodologia da Capacidade Fermentativa. Os experimentos de fermentação foram realizados nos laboratórios da Usina Virgolino de Oliveira - Unidade Catanduva em escala reduzida sempre acompanhados de um ensaio padrão utilizando meio de cultivo sintético. O primeiro ponto de estudo consistiu na caracterização da matéria-prima, mosto, e sua capacidade isolada de perturbar o Rendimento Fermentativo. Enquanto que no segundo, onde onze diferentes cepas de levedura foram identificadas ao longo das duas safras, testadas em um mesmo meio de cultivo padrão para obtenção de parâmetros industriais tecnológicos como rendimento em produto (Yp/s), rendimento em célula (Yx/s), Velocidade de consumo do substrato (Vcs), Produtividade (PROD) e Conversão (CONV) e estudada a influência no Rendimento Fermentativo. O terceiro ponto de estudo foi a comparação entre os rendimentos fermentativos obtidos experimentalmente e os rendimentos fermentativos industriais da Planta. O impacto da presença das cepas com maior rendimento em etanol foi estudado em relação aos valores de rendimento fermentativo industrial. Os resultados mostraram diferenças de desempenho da Cepa Padrão na maioria das quinzenas testadas, o que significa que há variação da matéria-prima ao longo da safra e entre as safras capazes de afetar rendimento fermentativo. Diferenças de rendimento também foram observadas entre as onze cepas nativas testadas, porém com oscilações menores e menos consideráveis do que com a matéria-prima. Os resultados obtidos em escala reduzida com base nos balanços de massa se apresentaram valores semelhantes em relação aos números de referência o que sugere que a metodologia usada para avaliar a capacidade fermentativa das cepas e a qualidade da matéria-prima foi adequada. Apesar da forte influência dos fatores estudados, não foi possível afirmar, através destes experimentos, qual deles teve papel determinante no impacto do Rendimento Fermentativo. Isso sugere que outros fatores não estudados neste trabalho estão diretamente relacionados que são capazes de influenciar o Rendimento Fermentativo. / The purpose of this study is to evaluate the sucrose mash and its influence isolated on the performance of the Fermentative Yeld of a standard strain from CAT-1 yeast tested in 31 different culture medium formulation from the Virgolino de Oliveira Plant – Catanduva Unit alcoholic fermentation process. The culture medium formulation were sampled and composed every fortnight during the whole 2012 and 2013 harvest. The work also has as purpose to evaluate the yeasts population dynamics of the same fermentative process, through the differentiation of the strains by karyotyping. The isolated strains were tested in a standard culture medium to obtain the industrial technological characteristics through the Fermentative Capacity methodology. Fermentation experiments were carried out in mill’s laboratories on a reduced scale always accompanied by a standard assay using synthetic culture medium formulation. The first point of study consisted in the characterization of the raw material, sucrose mash, and its isolated capacity to disturb Fermentative Yield. In the second, eleven different strains of yeast identified during the two harvests, they were tested in the same culture medium to obtain industrial technological parameters as Yield in product (Yp/s), Yield in cell (Yx/s), Substrate consumption velocity (Vcs), Productivity (PROD) and Conversion (CONV) and studied their influence on the Fermentative Yield. The third point of study was the comparison between the fermentative yields obtained experimentally and the industrial fermentative yields of the Plant. The impact of the presence of strains with higher Yp/s was studied in relation to industrial fermentation yield values. The results showed differences in performance of the Standard Strain in most of the fortnight tested, which means that there is variation of the raw material during the harvest and between the crops capable of affecting fermentative yield. There were also Yeld difference observed among the eleven native strains tested, but with smaller and less considerable oscillations than with the raw material. The results obtained on a reduced scale based on the mass balances were within the range expected in relation to the reference values, which suggests that the methodology used to evaluate the fermentative capacity of the strains and the quality of the raw material was adequate. Despite the strong influence of the studied factors, it was not possible to prove, through these experiments, which one had a determinant role in the Fermentative Yield impact. This suggests that other factors not studied in this work are directly related that are able to influence Fermentative Yield.
7

Qualidade pós-colheita de colmos de cana armazenados e seus reflexos na produção de cachaça / Quality of post-harvest stored cane stalks and its effects on the production of cachaça

José Humberto de Oliveira Filho 19 November 2015 (has links)
O armazenamento dos colmos de cana pode comprometer a manutenção do seu estado fisiológico, refletindo em consideráveis alterações na qualidade do caldo. Esta pesquisa teve como objetivos, avaliar as características tecnológicas e microbiológicas do caldo de cana colhida e armazenada, assim como seus reflexos na condução dos processos fermentativos e formação dos compostos químicos da cachaça. Após colheita da cana-de-açúcar, os colmos foram armazenados a temperatura ambiente (20 - 32°C) por períodos de 0, 24, 48, 72 e 96 horas, sendo o mosto preparado após extração do caldo. As fermentações foram conduzidas em processo batelada com reciclo de células, durante cinco ciclos fermentativos. O monitoramento da fermentação foi realizado através da quantificação de micro-organismos em atividade no processo e no fermento reciclado. Ao término das fermentações, foram analisadas as características tecnológicas dos vinhos, os quais foram destilados em alambique de cobre para quantificação dos compostos secundários (ácido acético, aldeído, álcoois superiores, ésteres e furfural) e contaminantes (álcool metílico, cobre e carbamato de etila) da cachaça. O armazenamento dos colmos de cana por períodos superiores a 48 horas causou significantes perdas na qualidade do caldo, reduzindo o conteúdo de sacarose, pureza e açúcares redutores totais, aumentando os níveis de acidez total, açúcares redutores e bactérias láticas. Os colmos de cana armazenados por 72 e 96 horas, afetou a condução do processo fermentativo, ocasionando decréscimo na viabilidade de células e brotos de leveduras, e elevação nas concentrações de bactérias láticas e leveduras não-Saccharomyces no fermento reciclado. As características tecnológicas dos vinhos também foram comprometidas com a utilização de colmos armazenados. Os níveis de acidez volátil, acetato de etila, acetaldeído, álcool metílico, cobre e carbamato de etila das cachaças apresentaram-se dentro do estabelecido pela Legislação Brasileira, enquanto o conteúdo de álcoois superiores e furfural foram superiores em destilados de cana colhida e armazenada. As concentrações de acetato de etila e carbamato de etila permaneceram elevadas ao final do 5º ciclo para destilados de colmos armazenados por períodos superiores a 48 horas, porém não excederam os limites especificados na Legislação. / The cane stalks storage can compromise the maintenance of their physiological state, resulting in considerable changes in the quality of the juice. This research aimed to evaluate the sugarcane juice technological and microbiological characteristics when harvested and stored, as well its reflexes in the cachaça fermentative processes and secondary compounds guiding processes. After harvested, the sugarcane stalks were stored at environmental temperature (20 - 32°C) at 0, 24, 48, 72, and 96 hours, preparing the must just before the juice extraction. Fermentations were carried out through the batch process, using five fermentative cycles. Monitoring the fermentation was carried out by quantifying microorganisms active in the process and recycled yeast. At the end of fermentation, the technological characteristics of the wines were analyzed, which was distilled in copper still for quantification of secondary compounds (acetic acid, aldehyde, higher alcohols, esters and furfural) and contaminants (methyl alcohol, copper and ethyl carbamate) of cachaça. The cane stalks storage for periods exceeding 48 hours caused significant losses in the juice technological quality, reducing the sucrose content, purity and total reducing sugars, increasing the acidity levels, reducing sugars and lactic acid bacteria. The cane stalks stored for 72 and 96 hours, influencing negatively the fermentative process; presenting decreasing in the viability of the yeast cells and shoots, as well an elevation in the lactic bacteria and non-Saccharomyces yeasts concentration in the recycled yeast. The technical characteristics of the wines were also compromised with the use of stalks stored. The volatile acidity levels, ethyl acetate, acetaldehyde, methanol, copper, and ethyl carbamate in the cachaças were within the ones established by the Brazilian law, while the superior alcohols and furfural content were high in the sugarcane distillated after harvested and stored. The concentrations of ethyl acetate and ethyl carbamate remained high at the end of the 5th cycle to cane spirits stored for longer than 48 hours, but did not exceed the limits specified in legislation.
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Hydrogen (H2) Production and Membrane Fouling in Fermentative H2-producing Membrane Bioreactors

Shen, Li Hong 31 August 2011 (has links)
This research examined the influence of organic loading rate (OLR) and biosolids type on the performance of fermentative H2-producing membrane bioreactors (HPMBRs) with respect to H2 production and membrane fouling. Five OLRs ranging from 4.0 to 30 g COD L-1 d-1 were examined in a lab-scale HPMBR. The system performance with both suspended and granulated biosolids was also investigated. The H2 yield from the suspended biosolids HPMBR was not significantly influenced by OLR at OLRs ≤ 13 g COD L-1 d-1, appeared to be maximized at an OLR of 22 g COD L-1 d-1, and then decreased as the OLR was increased further. An optimum OLR that maximizes H2 yield may be near the OLR that causes reactor overload with respect to substrate utilization. Under the same operating conditions, the H2 yield from a suspended HPMBR was significantly higher than that from a granulated HPMBR. A higher H2 consumption rate and a higher concentration of bound extracellular polymeric substances from the granulated HPMBR may contribute 5–48% and 25–67% of the H2 production difference between the two systems, respectively. The experimental results accompanied with microscopic examination of fouled membrane surfaces indicated that biosolids deposition and colloidal adhesion were the two dominant membrane fouling mechanisms in the HPMBRs. Membrane fouling was characterized by two distinct stages: an initial stage with a relatively higher fouling rate and a second stage with a lower fouling rate. Membrane fouling rates and resistances were influenced by the properties of biosolids and colloids in the mixed liquor. The fouling rates increased with increased biomass concentration, but decreased as colloids became more negatively charged. The irreversible and irremovable fouling resistance increased with increased concentration of colloids, while the removable fouling resistance had no relationship with biomass concentration. Biosolids granulation may benefit membrane performance due to a lower colloidal concentration produced. The single cake filtration model was proper to simulate membrane performance in the initial fouling stage. Both cake filtration and combined cake-standard models provided good fits for the second fouling stage, whereas future study is required to improve model predictability for membrane fouling in this stage.
9

Hydrogen (H2) Production and Membrane Fouling in Fermentative H2-producing Membrane Bioreactors

Shen, Li Hong 31 August 2011 (has links)
This research examined the influence of organic loading rate (OLR) and biosolids type on the performance of fermentative H2-producing membrane bioreactors (HPMBRs) with respect to H2 production and membrane fouling. Five OLRs ranging from 4.0 to 30 g COD L-1 d-1 were examined in a lab-scale HPMBR. The system performance with both suspended and granulated biosolids was also investigated. The H2 yield from the suspended biosolids HPMBR was not significantly influenced by OLR at OLRs ≤ 13 g COD L-1 d-1, appeared to be maximized at an OLR of 22 g COD L-1 d-1, and then decreased as the OLR was increased further. An optimum OLR that maximizes H2 yield may be near the OLR that causes reactor overload with respect to substrate utilization. Under the same operating conditions, the H2 yield from a suspended HPMBR was significantly higher than that from a granulated HPMBR. A higher H2 consumption rate and a higher concentration of bound extracellular polymeric substances from the granulated HPMBR may contribute 5–48% and 25–67% of the H2 production difference between the two systems, respectively. The experimental results accompanied with microscopic examination of fouled membrane surfaces indicated that biosolids deposition and colloidal adhesion were the two dominant membrane fouling mechanisms in the HPMBRs. Membrane fouling was characterized by two distinct stages: an initial stage with a relatively higher fouling rate and a second stage with a lower fouling rate. Membrane fouling rates and resistances were influenced by the properties of biosolids and colloids in the mixed liquor. The fouling rates increased with increased biomass concentration, but decreased as colloids became more negatively charged. The irreversible and irremovable fouling resistance increased with increased concentration of colloids, while the removable fouling resistance had no relationship with biomass concentration. Biosolids granulation may benefit membrane performance due to a lower colloidal concentration produced. The single cake filtration model was proper to simulate membrane performance in the initial fouling stage. Both cake filtration and combined cake-standard models provided good fits for the second fouling stage, whereas future study is required to improve model predictability for membrane fouling in this stage.
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Torta de maca?ba como aditivo em silagem de capim-elefante

Silveira, Hugo Vin?cius Lelis 04 August 2017 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-08-07T17:20:56Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-10-05T19:15:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) / Made available in DSpace on 2018-10-05T19:15:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se com este trabalho avaliar os efeitos da adi??o de doses crescentes do subproduto torta de polpa de Acrocomia aculeata (maca?ba) sobre o valor nutritivo, caracter?sticas fermentativas, perdas do processo fermentativo e influ?ncia na estabilidade aer?bica de silagens de capim-elefante (Pennisetum purpureum Schum.). O delineamento experimental foi inteiramente casualizado com 4 repeti??es. Os tratamentos foram constitu?dos pela forrageira capim-elefante aditivada de seis doses de torta de polpa de coco de maca?ba com base na mat?ria natural (0, 6, 12, 18, 24, 30%). A planta forrageira passou por per?odo de 150 dias de amarmazenamento em silos experimentais de polietileno (PVC). Foi determinado o valor nutritivo, as caracter?sticas fementativas, as perdas e a estabilidade aer?bia.Verificou-se efeito linear crescente (P <0,05) das doses de TPCM sobre o teor m?dio de mat?ria seca (MS), extrato et?reo (EE), lignina, carboidratos n?o fibrosos (CNF) e digestibilidade in vitro da mat?ria seca (DIVMS) das silagens de capim-elefante, entretanto, os teores de fibra em detergente neutro (FDN), fibra em detergente neutro corrigida para cinzas e prote?na (FDNcp), fibra em detergente ?cido (FDA) e prote?na bruta (PB) foram reduzidos linearmente (P<0,05) ? medida que se elevou a adi??o de TPCM. A inclus?o de TPCM elevou linearmente (P<0,05) os valores de pH e reduziu os valores de nitrog?nio amoniacal (N-NH3) das silagens. Os valores de produ??o de efluentes na silagem decresceram linearmente (P<0,05) com a inclus?o do aditivo. Os valores de perda por gases apresentaram resposta quadr?tica (P<0,05) ? medida que se elevou a adi??o de TPCM nas silagens. A estabilidade aer?bica foi afetada nas silagens de capim-elefante, mostrando uma eleva??o na estabilidade a medida que se elevava a dose de inclus?o da TPCM. De forma geral a adi??o da TPCM melhora o valor nutritivo e os par?metros fermentativos da silagem de capim-elefante, sendo recomendado a inclus?o de 15 % desse aditivo. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of this work was to evaluate the effects of the addition of doses of Acrocomia aculeata pulp by-product (maca?ba) on nutritive value, fermentative characteristics, losses of fermentation and influence on aerobic stability of Elephant grass silages (Pennisetum Purpureum Schum.). The experimental design was completely randomized with 4 replicates. The treatments were constituted by Elephant grass forage with six leves of maca?ba coconut pulp cake (MCPC) based on natural matter (0, 6, 12, 18, 24, 30%). The silos were storage by 150 days in experimental polyethylene (PVC) silos. The nutritive value, fementative characteristics, losses and aerobic stability were determined. There was an increasing linear effect (P <0.05) of MCPC doses on the mean dry matter (DM), ether extract (EE), non-fibrous carbohydrates (NFC) and in vitro dry matter digestibility (IVDMD) of Elephant grass silages. However, neutral detergent fiber (NDF), neutral detergent fiber corrected for ash and protein (FDNcp) , acid detergent fiber (ADF), and crude protein (CP) were linearly reduced (P <0.05) as the addition of MCPC was increased. The inclusion of MCPC linearly increased (P <0.05) the pH values and reduced the ammoniacal nitrogen (N-NH3) values of the silages. The values of effluent production in the silage decreased linearly (P <0.05) with inclusion of the additive. The gas loss values presented a quadratic response (P <0.05) as the addition of MCPC to the silages increased. Aerobic stability was affected in Elephant grass silages, showing an increase in stability as the inclusion dose of MCPC was increased. In general, the addition of MCPC improves the nutritive value and fermentative parameters of Elephant grass silage. Recommended the inclusion of 15% of this additive.

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