Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Biological Engineering

Committee Chair(s)

Charles D. Miller


Charles D. Miller


Ronald C. Sims


Randolph V. Lewis


Polyhydroxyalkanoates (PHAs) are a type of biologically-produced plastic known for their biocompatibility and biodegradability. They have the potential to replace petroleum-based plastics as an environmentally-friendly alternative. This is beneficial because the release of plastics into environments such as the ocean and the buildup of plastics in landfills are major concerns facing society today. Currently, however, PHAs are significantly more expensive than their petroleum-based counterparts. This is largely due to the cost of carbon sources and of extracting the bioplastics from bacteria. The goal of these studies was to examine replacing traditional carbon sources used in PHA production like sugar and oils with sustainable carbon sources and to improve extraction procedures by inducing secretion of PHAs in bacteria.

A few sustainable carbon sources were examined for use in PHA production. First, studies focused on the conversion of food waste into PHAs were reviewed. It was shown that utilizing food wastes as carbon sources may be a viable approach to producing PHAs. A second carbon source examined was methanol. A novel isolate of Methylobacterium that demonstrated the ability to produce PHAs from methanol was identified. A system of secreting PHAs that was constructed using synthetic biological engineering approach was introduced to this isolate. This secretion system was not shown to improve extraction of PHAs in Methylobacterium in its current form.