PhD Thesis Proposal: Michael Balch

Wednesday, December 20, 2017, 1:00–3:00pm

Jackson Conference Room, Cummings Hall

“Cotreatment of lignocellulose to enhance solubilization in lieu of thermochemical pretreatment”


Liquid biofuel is likely to be essential in a sustainable energy future due to its high energy density. Lignocellulose is the most promising feedstock for liquid biofuel production due to its prevalence and low cost. However, the economics of current conversion technologies are hindered by factors including the cost of thermochemical pretreatment, a step needed to achieve good yields.

In this thesis, the concept of milling during lignocellulosic fermentation, cotreatment, is investigated as an alternative to thermochemical pretreatment as a means of enhancing biological solubilization of lignocellulose. The first chapter investigates the impact of milling on soluble substrate fermentation by Clostridium thermocellum and yeast, and documents solubilization for fermentation of senescent switchgrass with and without ball milling. The next chapter looks at the impact of ball milling on soluble substrate fermentation by other model organisms. The third chapter expands further on work described in the first chapter by looking at the effect of cotreatment on different lignocellulosic feedstocks, focusing on substrates of industrial and scientific interest. Finally, the thesis is concluded by exploring new reactor configurations which test the impact of reduced milling time on solubilization performance.

This work finds that cotreatment can be as effective as conventional thermochemical pretreatment at improving solubilization of various lignocellulosic feedstocks, and does not much inhibit the fermentation of a variety of organisms. This success is an important first step in improving the economics of lignocellulosic biofuel conversion.

Thesis Committee

For more information, contact Daryl Laware at