Theses and Dissertations Collection

Polyhydroxyalkanoates (PHAs) are bacterially synthesized polymers that exhibit thermoplastic material properties when desiccated. PHA can be synthesized by mixed microbial consortia (MMC) cultured on volatile fatty acid (VFA)-rich wastewater. However, with an ultimate aim to achieve commercial PHA production using MMC and wastewater, much remains to be understood about critical metabolisms to maximize polymer production. This research aimed to characterize metabolomes within undefined mixed microbial consortia (MMC) to better understand what factors inhibit and/or enhance the efficient conversion of volatile fatty acids (VFAs) into polyhydroxyalkanoate (PHA). LC/MS-based targeted metabolomics methods were applied to uncover “feast” PHA metabolisms of MMC cultured on fermented dairy manure; “feast” metabolisms induced under aerobic dynamic feeding (ADF) remain poorly understood, with only limited molecular-level exploration. Preliminary metabolomic data helped illustrate potentially important biochemical pathways of PHA synthesis such as the glycolysis pathway, and describe correlated metabolites present in the MMC metabolome. Results enhance understanding of MMC cultured on real wastewaters, MMC metabolome dynamics when synthesizing PHAs, better describe the feast-famine response, and identify critical metabolites involved in PHA synthesis.