Date of Award

2018

Degree Type

Thesis

Degree Name

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

First Advisor

Geoffrey Bothun

Abstract

This work showcases the capabilities of a lipid bilayer based solvent for butanol extraction. Previous work in our group has shown that lipid bilayers have a high affinity for butanol extraction. Here, we show higher butanol partition coefficients than previously seen in other solvents. Our partition coefficients were found using a quantitative NMR method to allow for in situ measurements to be taken which resulted in higher partition coefficients than previously found by HPLC methods. Two lipids were used for these experiments in order to examine the effect that lipid bilayer phase has on the butanol partition coefficient and we see that a mixed phase bilayer (DPPC/DOPC) resulted in the highest butanol partition coefficient. Additionally, butanol’s effect on bilayer size was examined by dynamic light scattering. DPPC vesicles showed the largest change in size when butanol was added due to the smaller spaces in between lipid head groups in a DPPC bilayer.

Working in collaboration with Dr. Carmen Scholz’s group at the University of Alabama Huntsville, a continuous fermentation was developed that used glycerol as a feedstock for Clostridium pasteurianum. We also utilized our lipid bilayer solvent in an extractive fermentation of these continuous cultures. Our results showed an increase in butanol production and yield at lower dilution rates, which can also be attributed to the extraction of butanol from the system.

Available for download on Saturday, July 18, 2020

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