This study explored the use of a biosecure, static composting structure to inactivate MAP. In Experiment #1, it was concluded that composting is unlikely to achieve temperatures necessary to inactivate MAP associated with cattle mortalities and that M. smegamatis is an unlikely surrogate for MAP. This study also used the same system to explore changes in the microbial community in mortality compost after exposure to thermophilic temperatures. As high-throughput sequencing technologies advance, it is possible to characterize microbial communities in environments with a high degree of resolution. In Experiment #2, as members of Clostridia were present at temperatures > 55°C, it appears that anaerobic conditions existed within regions of the compost. Extreme temperatures and non-homogeneous high moisture conditions resulted in spatial distribution of temperature in a biosecure, static composting system, which failed to meet conditions necessary for complete composting and pathogen reduction.

This study explored the use of a biosecure, static composting structure to inactivate MAP. In Experiment #1, it was concluded that composting is unlikely to achieve temperatures necessary to inactivate MAP associated with cattle mortalities and that M. smegamatis is an unlikely surrogate for MAP. This study also used the same system to explore changes in the microbial community in mortality compost after exposure to thermophilic temperatures. As high-throughput sequencing technologies advance, it is possible to characterize microbial communities in environments with a high degree of resolution. In Experiment #2, as members of Clostridia were present at temperatures > 55°C, it appears that anaerobic conditions existed within regions of the compost. Extreme temperatures and non-homogeneous high moisture conditions resulted in spatial distribution of temperature in a biosecure, static composting system, which failed to meet conditions necessary for complete composting and pathogen reduction.

The seasonal distribution of keratinophilic fungi bas been studied in the soils surrounding an outdoor swimming pool and in soils of summer pens of hedgehogs. The species isolated were conidial and cleistocarpic Arthroderma uncinatum, Trichohyton terrestre, Chrysosorium keratinophilum, Microsporum cookei and Microsporum gypseum. A correlation between some species and. The numbers of hedgehogs in the pens was seen, due to the influence of keratin provided by the quills and scales of the hedgehogs. No such relationship was seen at the swimming pool, although conidial A. uncinatum was seen to decrease when the swimming pool was open to the public in the summer. However, this appears to be the normal seasonal occurrence since a similar pattern of distribution in soils collected from outside the swimming pool was seen. The effects of the addition of fungicides to soil upon the isolation of keratinophilic fungi have been studied, using the hair-baiting technique. The general pattern showed an initial fall in percentage colonisation of baits followed by a fairly rapid recovery to give greater colonisation of greasy baits compared with controls, and a return to the same or less than the control on degreased wool. This contrasts with the normal observation that the majority of keratinophilic fungi grow better on degreased than greasy wool. A study of the keratinophilic flora of soils of different pH values and from coastal regions has been made as ground work for the experimental section. The new intake of students living in halls of residence at Nottingham University was studied in relation to tinea pedis over an academic year. The initial level in October 1972 was 9% by May 1973 it had increased to 24% but returned to 11% in October 1973. In addition to any seasonal influence, there seemed to be a correlation between the sports played by the students and the incidence of tinea pedis. The showers in halls of residence and the University sports centre were thought to be the main points of cross transfer of the infection. In the experimental section, the effects of pH, temperature, fungicides and sea water upon certain keratinophilic fungi have been examined in vitro. Aspects of the nutrition of C. keratinophllum, A. uncinatum and T. terrestre were studied and the most suitable combinations of carbon and nitrogen sources for optimal growth were determined. A study of the competitive saprophytic ability of several dermatophytes was made using various techniques. By use of the fluorescent antibody technique, it was found that A. uncinatum was a good competitive saprophyte in the presence of keratin and can thus be regarded as a true soil inhabitant. Finally, the mating structures of Arthroderma benhamiae, A. tuberculatum, A. uncinatum, Nannizzia cajetani, N. gypsea and N. incurvata were studied using the scanning electron microscope.

Naturally occurring microbial communities from high-salt and/or high-temperature environments were collected from sites across the United States and Puerto Rico and screened for their efficacy in the MixAlco biofuel production platform. The MixAlco process, based on the carboxylate platform, is a sustainable and economically viable platform for converting lignocellulosic biomass to biofuels. Using a mixed culture of anaerobic organisms, lignocellulosic biomass is fermented into carboxylic acids, which are neutralized to their corresponding carboxylate salts. These salts can then be converted into a wide variety of chemical products and fuels (alcohols, gasoline, diesel, jet fuel). The central hypothesis is that microbial communities from relatively extreme environments, having evolved to withstand selection pressures similar to the conditions in the carboxylate platform, will exhibit high rates of biomass conversion. A total of 559 soil communities was screened as inocula in established laboratory-scale fermentations. We used pyrotag sequencing of 16S rRNA genes to characterize the bacterial components of the best-performing microbial communities. The best performing communities converted up to 3 times more biomass to acids than a standard marine community inoculum. The community analyses have allowed us to determine the extent to which the same functional types are favored during fermentation, at both laboratory and demonstration plant scales. In all cases, we observed a shift from the more diverse sediment community to post-fermentation communities with relatively low diversity dominated by organisms in the phylum Firmicutes, specifically Bacilli and Clostridia classes. Despite the fact that the inoculum sources were both geographically and ecologically diverse, all of the post-fermentation communities were more similar to each other in community structure than to the corresponding original inoculum community. In addition, studies of the sediments used as inocula revealed that environmental parameters, such as pH and water content, were significantly correlated with bacterial community composition. The wealth of data provided by current sequencing technologies allowed us to question whether communities with high process performances tend to achieve that performance with similar community structures.

Antarctica provides some of the most extreme environments on earth. Low temperatures, low water availability and nutrient deficiency are contributing factors to the limited colonisation of Antarctic biotopes, particularly in the continental Dry Valleys. The survival of microorganisms in this harsh continent provides the basis for the significance of this study. This study aimed to explore microbial phylotypic diversity across a 500 m altitudinal transect in the Miers Dry Valley, Ross Desert, East Antarctica. The study also attempted to infer from phylogenetic data, the possible presence of indicative phenotypes which might contribute to a functional microbial community.

<p>Soil communities are regarded as among the most complex and diverse assemblages of microorganisms with estimated bacterial numbers in the order of 10â?¹ cells.gâ?»&sup1 / . Studies on extreme soils however, have reported lower cell densities, supporting the perception that the so-called extreme environments exhibit low species diversity. To assess the extent of microbial diversity within an extreme environment, the mineral soils of the Dry Valleys, Ross Dependency, Eastern Antarctica were investigated using 16S rDNA analysis.</p>

Soil microbial communities can be characterized by community structure and function (community composition) across a spectrum of spatial scales, and variation in soil microbial composition has been associated with a number of environmental gradients. This study investigates the structure and function of soil microbial communities under mature, undisturbed forested sites across a range of regional climates in British Columbia and Alberta, and also examines the variation in community composition within sites. Phospholipid fatty acid analysis was used to investigate the structure of soil microbial communities and total soil microbial biomass at each site. Extra-cellular enzyme assays established the functional potential of the soil microbial community at each site. Multivariate analysis of the data showed that the soil microbial communities under different forest types did significantly separate along the regional climate gradient by both community structure and function, despite high local variation in the communities. Soil moisture content and soil organic matter concentration consistently exhibited the strongest relationship with microbial community characteristics, although the functional and structural responses to the external drivers were different. Microbial community function and structure also changed with soil depth but not with time of sampling. Microbial community function was related to the regional annual average precipitation gradient. Most of the locations exhibited unique microbial community functional profiles in their soil layers; however the enzyme activities in the samples from the driest (Ponderosa Pine) and wettest (Mountain Hemlock) locations were notably different from each other and from those of the other locations, especially in the organic layers. The moist maritime-influenced Coastal Western Hemlock (CWH) forest exhibited microbial community structural characteristics which were unique from those of the other forest locations. The higher abundance of bacteria relative to fungi in the CWH forest soils may be related to the significantly higher available nitrogen concentrations at this site.

No description available.

Thesis (M. S. - Soil and Water Science)--University of Arizona, 1992. / Includes bibliographical references (leaves 95-105).

Thesis (M. Ag. Sc.)--University of Adelaide, Department of Soil Science, Waite Agricultural Research Institute, 1992. / Includes bibliographical references.