Numerous investigators have confirmed the early work of H. W. Conn (1889a), (1889b), (1903), and Conn and Esten (1904) in regard to the effects of cold storage upon bacteria in milk. In general, these workers have agreed that 40-50 F (4.4-10 C) is the maximum temperature for the storage of milk; they recognized, however, the fact that bacterial growth does occur not only at refrigeration temperatures but at and near the freezing point.

No description available.

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Made available in DSpace on 2015-03-26T13:51:59Z (GMT). No. of bitstreams: 1 texto completo.pdf: 775105 bytes, checksum: a65f62092072dba5b21d0daf4645e166 (MD5) Previous issue date: 2013-12-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The effectiveness of spray dried surfactin, produced from a culture of Bacillus subtilis 4914 strain, was evaluated in microcosms containing sandy clay loam soil (SCL) or clayey soil (CLA) contaminated with petroleum. The highest respiratory rates in the microcosms additioned of petroleum demonstrated that oil was utilized as carbon source for microbiota in the microcosms of both soils. Maltodextrin, utilized as a drying adjuvants in the preparation of spray dried surfactin, was also utilized as a source of carbon and energy. The means of accumulated CO2 during the decline phase of the respiration rate shared by all microcosms of a same soil type, ranged from 47,6 to 137,7 μmol g-1 for SCL soil and from 37,5 to 98,5 μmol g-1 for CLA soil. The removal of TPH ranged from 19,6 to 38,4 % and from 62,6 to 73,2 % for the SCL and CLA soils, respectively. Surfactin in its two forms (in liquid solution and dried) influenced positively the degradation of the TPH in the SCL and CLA soils and in late phase of bioremediation. Maltodextrin did not interfere in the degradation of TPH. The lowest values of residual TPH in microcosms assembled with CLA soil were attributed to the highest microbial activity and biomass. The microbial community dynamics was studied by T-RFLP multiplex analysis of the groups Bacteria, Fungi e Archaea. The results demonstrated the occurrence of negative impact of oil on the microbial communities of all microcosms of both soil types, in the beginning of incubation period, and recovery of the community structure in subsequent times. The fungal community showed highest values of Shannon-Weaver index (H ), Simpson index (D) and Richness (S), followed by the Bacteria. In conclusion, spray dried surfactin favors the biodegradation of petroleum hydrocarbons in soils. / A efetividade da surfactina desidratada em spray dryer, produzida a partir do cultivo do isolado Bacillus subtilis LBBMA 4914, foi avaliada em microcosmos contendo amostras de solos franco-argilo-arenoso (FAA) ou argiloso (ARG) contaminados com petróleo. As taxas respiratórias mais elevadas nos microcosmos adicionados de petróleo demonstraram que o petróleo foi utilizado como fonte de carbono pelas microbiotas nos microcosmos de ambos os tipos de solo. A maltodextrina, utilizada como adjuvante de secagem na preparação da surfactina desidratada por spray dryer, foi também utilizada como fonte de carbono e energia. As médias dos valores de CO2 acumulado durante a fase de declínio das taxas respiratórias compartilhada por todos os microcosmos em um mesmo tipo de solo variaram entre 47,6 a 137,7 μmol g-1 (microcosmos com o solo FAA) e 37,5 a 98,5 μmol g-1 (microcosmos com solo ARG). A remoção dos HTPs variou entre 19,6 a 38,4 % (solo FAA) e 62,6 a 73,2 % (solo ARG). A surfactina em suas duas formas (solução e desidratada) influenciou positivamente a degradação dos HTPs nos solos FAA e ARG e em fase tardia da biorremediação. A maltodextrina não interferiu na degradação dos HTPs. Os menores valores de HTPs residuais em microcosmos montados com o solo ARG foram atribuídos às maiores atividade e biomassa microbianas. A dinâmica das comunidades microbianas foi estudada pela análise de T-RFLP multiplex dos grupos de Bacteria, Fungi e Archaea. Os resultados demonstraram a ocorrência de impacto negativo do petróleo nas comunidades microbianas de todos os microcosmos em ambos os tipos de solo, no início do período de incubação, e recuperação da estrutura das comunidades nos tempos subsequentes. A comunidade de fungos apresentou valores mais elevados dos índices de Shannon-Weaver (H ), Simpson (D) e Riqueza (S), seguida pela de Bacteria. Conclui-se que surfactina desidratada por spray-drying favorece a biodegradação de hidrocarbonetos de petróleo em solos.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-03-26T11:47:22Z No. of bitstreams: 2 Dissertação - Douglas Siqueira Freitas - 2014.pdf: 1490936 bytes, checksum: 760aec6ca100ccf3d644ceaf93ade6ff (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-03-27T10:44:02Z (GMT) No. of bitstreams: 2 Dissertação - Douglas Siqueira Freitas - 2014.pdf: 1490936 bytes, checksum: 760aec6ca100ccf3d644ceaf93ade6ff (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-27T10:44:02Z (GMT). No. of bitstreams: 2 Dissertação - Douglas Siqueira Freitas - 2014.pdf: 1490936 bytes, checksum: 760aec6ca100ccf3d644ceaf93ade6ff (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-07-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The conservation of native and cultivated soils quality in the Cerrado region, seen by a microbiological point of view, has been discussed with both ecological as productive focus. In this work, the quality of native Cerrado was contrasted with that present in no-tillage system (soybean/sorghum), crop-livestock system (soy/pasture), cultivated coffee, eucalyptus forest and not managed grassland, to form the object of study. Since it is laborious to assess all the physical and chemical parameters that surround the quality of soil and, as the community of fungi and bacteria receive direct influence of these factors, the microbiological study can answer questions about the quality of a native or cultivated system. For this study 10 composite samples were collected within each cropping system on a transect shape, lying 20 meters from each other. The microbial community was evaluated for its density from the quantification of microbial biomass carbon, total carbon, microbial biomass nitrogen and total nitrogen. Once is known that the quantitative assessment would not be enough to express the behavior of microbial community, an analysis of the metabolic potential based on degrading capacity of substrates, enzyme assay and basal soil respiration tests were applied. Quantitative data showed that areas of pasture and no-tillage had similar microbial biomass of the soil under native Cerrado (control) but differ significantly in the degradative capacity of substrates and enzyme activity, showing that crops impress selection under microbiota in these areas. / A conservação da qualidade de solos nativos e cultivados na região do Cerrado, vista do ponto de vista microbiológico, tem sido discutida tanto com foco ecológico quanto produtivo. Neste trabalho, a biota do solo sob Cerrado nativo foi contrastada com aquela presente nos sistemas de cultivo plantio direto (soja/sorgo), integração lavoura-pecuária (soja/braquiária), café, floresta de eucalipto cultivada e pastagem não manejada, formando o objeto de estudo. Posto que é laborioso levantar todos os parâmetros físicos e químicos que circundam a qualidade de um solo e como a comunidade de fungos e bactérias sofre influência direta destes fatores, o estudo microbiológico, exclusivamente, pode responder sobre a qualidade de um sistema nativo ou cultivado. Para este estudo foram coletadas 10 amostras compostas dentro de cada sistema de cultivo em forma de transecto, distando 20 metros entre si. A comunidade microbiológica foi avaliada quanto a sua densidade a partir da quantificação do carbono da biomassa microbiana, do carbono total, do nitrogênio da biomassa e do nitrogênio total. Sabendo que a avaliação quantitativa não seria suficiente para expressar o comportamento da comunidade microbiana, a análise do potencial metabólico baseada nos testes de capacidade degradativa de substratos, teste enzimático e respiração basal do solo, foram aplicadas. Os dados quantitativos mostraram que as áreas de pastagem e plantio direto apresentam uma biomassa microbiana semelhante ao solo sob Cerrado nativo (controle) porém divergem significativamente na capacidade degradativa dos substratos e na atividade enzimática, mostrando que o cultivo imprimiu seleção sobre a microbiota nestas áreas.

This study assesses the contribution of agricultural non-point source pollution, to poor water quality of the Vaal River within the Grootdraai dam catchment area. The study evaluates agricultural pollutants affecting the quality of water within the study area. The impact of agricultural non-point source pollution on the water quality of the Vaal River was evaluated by establishing a correlation between the quantity of polluted runoff reaching the River and the quantity of measured nitrates and phosphates in its waters. A questionnaire using random sampling was used to capture data from 15 commercial farmers 35 local residents and the Department of Water Affairs management. The results of the study show that agricultural nutrients are heavily impacting and compromising the water quality of the Grootdraai Dam. The mean concentrations of Nitrogen and Phosphorus were found to be well above the water quality guidelines there by promoting eutrophication. / Environmental Sciences / M. Sc. (Environmental Management)

This study assesses the contribution of agricultural non-point source pollution, to poor water quality of the Vaal River within the Grootdraai dam catchment area. The study evaluates agricultural pollutants affecting the quality of water within the study area. The impact of agricultural non-point source pollution on the water quality of the Vaal River was evaluated by establishing a correlation between the quantity of polluted runoff reaching the River and the quantity of measured nitrates and phosphates in its waters. A questionnaire using random sampling was used to capture data from 15 commercial farmers 35 local residents and the Department of Water Affairs management. The results of the study show that agricultural nutrients are heavily impacting and compromising the water quality of the Grootdraai Dam. The mean concentrations of Nitrogen and Phosphorus were found to be well above the water quality guidelines there by promoting eutrophication. / Environmental Sciences / M. Sc. (Environmental Management)