ORCID
https://orcid.org/0000-0002-0664-307X
Date of Award
12-17-2024
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Purple non-sulfur bacteria (PNSB) are a taxonomically diverse group of gram-negative bacteria representing some of Earth’s most metabolically versatile life, with many genera capable of switching between the four major metabolic modes – chemoheterotrophy, chemoautotrophy, photoheterotrophy, and photoautotrophy. Today, we exploit this diversity to explore fundamental questions about microbial metabolism. At the same time, many researchers are eager to use PNSB as tools for biotechnological innovations. Yet there exists a gap between fundamental biology and applied science. Part of the challenge is that we rely on a handful of model organisms – namely, members of the genera Rhodopseudomonas and Rhodobacter – for understanding the breadth and depth of PNSB physiology. By branching out into understudied, less conventional microbes, we can gain valuable insights into PNSB metabolism in new physiological and genetic contexts. In that vein, this dissertation seeks to leverage the untapped metabolic versatility in the Rhodomicrobium genus – specifically, R. vannielii and R. udaipurense – for bioplastic production. In Chapter 1, I provide an overview of PNSB, with an emphasis on their metabolic versatility and the utility in exploring understudied microbes. In Chapter 2, I evaluate newly acquired Rhodomicrobium spp. genomes to understand these species’ metabolic capabilities. I follow up in Chapter 3 by exploring their ability to synthesize the bioplastic polyhydroxyalkanoate, then compare their performance to the model PNSB Rhodopseudomonas palustris TIE-1. In Chapter 4, I tackle the bioproduction bottleneck of electron transfer using these microbes’ unique abilities as electrotrophs and phototrophic iron oxidizers. The dissertation concludes with a discussion of microbial metabolism, bioenergetics, and the ramifications for bioproduction in Chapter 5. This work establishes the Rhodomicrobium genus as a valuable tool for studying PNSB metabolisms. It also provides important lessons regarding fundamental PNSB physiology and provides guidance for future bioproduction studies.
Language
English (en)
Chair and Committee
Arpita Bose
Committee Members
Arpita Bose; Gemma Reguera; Haluk Beyenal; Hani Zaher; Joshua Blodgett
Recommended Citation
Conners, Eric Michael, "Sustainable Plastics from Plastic metabolisms: Leveraging Purple Non-sulfur Bacteria for Polyhydroxyalkanoate Synthesis" (2024). Arts & Sciences Electronic Theses and Dissertations. 3366.
https://openscholarship.wustl.edu/art_sci_etds/3366