Jones Seminar: Single-Carbon Feedstocks for Sustainable Bioprocess Engineering

Benjamin Woolston, Post-Doctoral Associate, MIT

Friday, March 30, 2018, 3:30–4:30pm

Rm. 100 (Spanos Auditorium), Cummings Hall

Single-carbon (C1) substrates, such as methane, methanol, formate, and synthesis gas are attractive feedstocks for biochemical processes, as they are widely available, can be produced renewably, and do not compete with food supply. However, their use in industrial bioprocesses remains limited, primarily because microbes that utilize these substrates are poorly characterized biochemically, and limited tools exist for their genetic modification. This leaves the metabolic engineer with a choice: to develop genetic tools to enable engineering in the desired host, or to import the relevant catabolic pathway into a more tractable organism, such as Escherichia coli. In this seminar, I will explore the merits and challenges of both options, using examples from my work on developing strains for the conversion of synthesis gas and methanol into chemicals and fuels.

Clostridium ljungdahlii is an acetogen that grows autotrophically on synthesis gas (CO, H2, and CO2) using the Wood-Ljungdahl pathway, and is a promising candidate for renewable biofuel and biochemical production from gasified biomass or waste industrial gases. In the first section of the talk, I will describe the metabolic engineering of this microbe to produce 3-hydroxybutyrate, a platform molecule used for the production of vitamins, antibiotics, and flavor compounds. I will focus on the development of a CRISPR-interference (CRISPRi) system for the inducible knockdown of competing pathway genes, insights into the complexity of acetogen metabolism, and on new strategies to overcome thermodynamic limitations on product yield.

To explore the alternative approach of importing a single-carbon catabolic pathway into a tractable host, in the second section of the talk I will discuss engineering E. coli to metabolize methanol, a plentiful C1 feedstock with a well-defined catabolic pathway. I will describe a systematic approach based on quantitative metabolomics, isotopic tracer experiments, and small-molecule inhibitors that was used to establish and eliminate the main bottlenecks in the engineered pathway, and ongoing work using evolutionary approaches to further improve pathway flux.

About the Speaker

Ben is a post-doctoral associate in Greg Stephanopoulos’ lab at MIT. His research interests are in developing tools to better understand and control cellular energy metabolism. Originally from the United Kingdom, Ben has been living in the US since 2001. He attended Pennsylvania State University, where he attained his BSc with honors in chemical engineering, and minors in chemistry and biochemistry & molecular biology. While at Penn State, Ben conducted undergraduate research with Wayne Curtis on a DARPA-funded project to engineer mushrooms for heterologous protein expression for vaccine production, winning the AIChE National Student Paper Competition in 2010. As a PhD student at MIT, Ben worked in the lab of Greg Stephanopoulos, where his thesis focused on the use of single-carbon feedstocks in bioprocess engineering. Outside the lab, he is an inaugural Fellow of the MIT Chemical Engineering Communication Lab, where he works with students and post-docs across the department to aid them in improving their scientific communication skills. In his free time, Ben enjoys competitive cycling, triathlon, and tennis, and has been heavily involved with the MIT Cycling Team and Triathlon Team.

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