Xiangan Li

Xiangan Li, 1st Year
Program: Chemical Engineering
Advisor: Michael Henson
Education: MS, Carnegie Mellon, Chemical Engineering, 2013
B.S., Environmental Engineering, Fachhochschule Luebeck, 2012
B.S., Chemical Engineering, East China University of Science and Technology, 2012

Research Summary

Modeling of Synthesis gas fermentation with genome-scale metabolic reconstruction in bubble column reactor

An overarching problem in applied biotechnology is the development of microbial technologies for the conversion of raw materials into higher value biochemicals. Microbial fermentation is a promising route to convert synthesis gas (syngas; mainly comprised of H2 and CO) and carbon rich waste gas streams to renewable liquid fuels and chemicals. The most commonly studied syngas fermenting bacterium is Clostridium ljungdahlii, which produces acetate and ethanol as its primary metabolic byproducts. On a commercial scale, bubble column bioreactors are typically utilized due to their high average mass transfer driving forces and longer gas-liquid contact times.

The goal of my project is to develop and validate high fidelity models of syngas bubble column reactors to enable in silico cellular and process engineering. This highly interdisciplinary project requires collaboration with microbiologists, synthetic biologists, multiphase modelers, computational scientists, process engineers and industrial practitioners. Building upon a first generation model developed by a 5th year Ph.D. student in our group, my current work is focused on accounting for the complex effects of non-ideal gas phase hydrodynamics on C. ljungdahlii metabolism. This work will allow the effects of the syngas flow rate and gas bubble size entering the reactor on cellular growth and byproduct secretion rates to be accurately predicted. We are collaborating with computational scientists at MIT and engineers at LanzaTech, the world leader in syngas fermentation technology, to develop and solve these multiphase metabolic models.