Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)


Biological Engineering

Committee Chair(s)

Charles Miller (Committee Co-Chair), Ronald C. Sims (Committee Co-Chair)


Charles Miller


Ronald C. Sims


Randolph V. Lewis


H. Scott Hinton


Anthony F. Turhollow


The biotechnology revenues in the United States exceeded $100 billion in 2010 and the potential impact of synthetic biological engineering has been identified nationally as an emerging technology to further expand the national bioeconomy. Synthetic biological engineering approaches biology from an engineering perspective to make biology easier to engineer. The potential to engineer microorganisms for novel applications can have far-reaching implications and benefits for society. Some of the potential applications range from biosensors, biofuels, therapeutics, and biomaterials.

In this study two biomaterials were produced in genetically engineered Escherichia coli: polyhydroxybutyrates (PHBs) and spider silk. PHBs are bioplastics that have similar properties to petrochemical-derived plastics. Synthetic biological engineering can be used to optimize PHB extraction from E. coli by secretion of the PHB polymer outside of the cell.

Another biomaterial, spider silk, was also produced in E. coli. Spider silk is a unique material with high tensile strength and elasticity and thus could have a wide range of potential applications. Since spider silk is not naturally produced in microorganisms, the DNA sequences were optimized for increased production in E. coli.

In addition to optimization of bioproduct production in microorganisms using synthetic biology, another major cost is the carbon substrate. In this study wastewater microalgae were used as an alternative carbon substrate. Coupling synthetic biological engineering and sustainable engineering could potentially make production of bioproducts economically viable in the future.