Microbial community biotechnology applications have the potential to create carbon neutral sources of bioproducts and bioenergy that could displace similar fossil fuel-based technologies. Microbial communities are preferable to pure cultures because they can use complex substrates to produce a range of products, and they benefit from mutualistic and synergistic interactions that can increase overall process efficiency. Additionally, processes using microbial communities can be run under non-sterile conditions, thereby lowering production costs. There are a number of challenges; however, that must be resolved before successful implementation of these communities at an industrial scale, and in bioreactor cultures in particular. One of the biggest challenges is our inability to predict the outcome of perturbations on reactor community membership and function. Few longitudinal studies of membership and function in response to disturbances have been conducted on these communities, and none of the longitudinal studies have used integrated 'omics techniques. This study examines bioreactor community membership and function in response to perturbations. Bioreactors seeded with cellulose-degrading rumen culture were perturbed by dilution and spatial disruption, altered retention rates, and pulses of acid. These were applied in a cumulative fashion over the study duration, and community composition and function was determined in response to these different perturbations.
The first chapter provides an overview of the broader relevance of this research and introduces the main goals of the research project. The second chapter is a review of the roles that microbial communities play in biotechnology and how emerging techniques and technologies can improve microbial processes. The third chapter examines the effect of a spatial disturbance on reactor membership and function in mother and daughter reactors. The fourth chapter provides an examination of an acid pulse perturbation on the daughter reactor and its effects on community structure and function using integrated 'omics. The fifth chapter examines the effects of a retention time change followed by a second pulse of acid on the daughter reactor community's structure and function, also using integrated 'omics. The sixth chapter discusses the broader conclusions that can be drawn from this research as well as potential future research directions.
|Advisor:||Ahring, Birgitte K.|
|Commitee:||Abu-Lail, Nehal I., Callister, Stephen J., Wilkins, Michael J.|
|School:||Washington State University|
|School Location:||United States -- Washington|
|Source:||DAI-B 76/07(E), Dissertation Abstracts International|
|Subjects:||Microbiology, Biochemistry, Chemical engineering|
|Keywords:||454 pyrosequencing, Anaerobic digestion, Biotechnology, Meta-metabolomics, Metaproteomics, Microbial consortia|
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