Tools for improving and understanding microbial performance in biorenewable applications

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Davis, Kirsten
Major Professor
Laura Jarboe
Committee Member
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Chemical and Biological Engineering

The function of the Department of Chemical and Biological Engineering has been to prepare students for the study and application of chemistry in industry. This focus has included preparation for employment in various industries as well as the development, design, and operation of equipment and processes within industry.Through the CBE Department, Iowa State University is nationally recognized for its initiatives in bioinformatics, biomaterials, bioproducts, metabolic/tissue engineering, multiphase computational fluid dynamics, advanced polymeric materials and nanostructured materials.

The Department of Chemical Engineering was founded in 1913 under the Department of Physics and Illuminating Engineering. From 1915 to 1931 it was jointly administered by the Divisions of Industrial Science and Engineering, and from 1931 onward it has been under the Division/College of Engineering. In 1928 it merged with Mining Engineering, and from 1973–1979 it merged with Nuclear Engineering. It became Chemical and Biological Engineering in 2005.

Dates of Existence
1913 - present

Historical Names

  • Department of Chemical Engineering (1913–1928)
  • Department of Chemical and Mining Engineering (1928–1957)
  • Department of Chemical Engineering (1957–1973, 1979–2005)
    • Department of Chemical and Biological Engineering (2005–present)

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The production of biorenewable fuels and chemicals is attractive because biomass is diverse, cheap, and abundant. Chemicals and fuels derived from renewable feedstocks can contribute to mitigation of climate change and improved rural economies. To compete with the petroleum industry, the biological processes involved in biorenewable fuel and chemical production need to be efficient. Here we engineer microorganisms and their environment for improved performance in biorenewable applications. In Chapters 1-4, we focus on lignin valorization. Lignin is a component of biomass that is underutilized, but abundant in renewable aromatics. We developed an emulsion formulation composed of Tween®20, Span®80, and a lignin-rich fraction of pyrolyzed biomass which enables P. putida KT2440 to grow in a lignin-rich fraction of pyrolytic bio-oil. This type of emulsion could be applied for microbial conversion of lignin-rich feedstocks to valuable products. To determine more about the specific compounds that are being utilized by the P. putida KT2440 and other lignin utilizing microorganisms, we developed a unique disk diffusion assay (Diffusive Inhibition with Substrate Consumption) which allowed for simultaneous quantification of inhibition and utilization. The DISC assay could be useful for quickly and easily screening lignin monomers or other monomers when little is known about their toxicity or microbial degradability. In Chapters 5, we focus on improving the robustness of biological membranes. Microorganism growth and production can be inhibited by both biomass feedstocks and the biorenewable products. One component of that inhibition is due to membrane damage. There is still little known about the biomolecular effects of alcohols which are attractive biorenewable chemicals. Here we utilized artificial biological membranes to characterize the membrane damage caused by alcohols. These experimental results are being used to inform an in silico model of a yeast plasma membrane which can be used to inform design strategies for more robust membranes. We observed increased fluidity and leakage in artificial phospholipid bilayers when treated with alcohols. Also, altering just 5% of the phospholipid head groups from phosphocholine to phosphoethanolamine somewhat improved the leakiness and fluidity. Therefore, small alterations in the phospholipid composition could be helpful in creating more robust membranes.

Thu Aug 01 00:00:00 UTC 2019