(433c) Termite-Inspired Electrochemical Processing of Lignocellulose to Chemicals and Fuels

Lignocellulosic biomass is the most abundantly available raw material on the planet and has great promise as a feedstock for the production of biofuels. Unfortunately, lignocellulose is difficult to break down by fermentation and other conventional approaches and man-made engineered systems have yet to truly harness the energy in wooden waste. Therefore, there is a significant need to find alternative pathways to convert this vital resource into next-generation energy carriers.

The most efficient known system to process lignocellulose to useful chemicals is the digestive track of termites [1-2]. The reason termites are able to efficiently break down these woody feedstocks is because of the diverse community of microbes inhabiting their hindguts, which includes protists, bacteria and archea. These microbes work symbiotically to decompose the lignocellulose, each performing a different role in the digestion process. They self-assemble into a complex community with specific structure and function, resulting in a radial and axial oxygen gradient.

The first objective of this work is to develop a microfluidic habitat that mimics the structure and function of the hindgut of a common lower termite, Reticulitermies flavipes [3]. The microfluidic habitat will serve as a well-controlled system to study how chemical and physical composition impact the function of the microbial community. Long-term we intend to use this information to scale up the production of biofuels from wooden materials.

The second objective of this work recognizes that the most common byproduct of the termite digestion is acetate. Though the global market for acetate/acetic acid is limited, in the future it may be widely available since acetate is a very common fermentation product. Therefore, our goal is to find an efficient catalytic pathway for the conversion of acetate to useful commodity chemicals, i.e. methanol.

This talk will highlight our group’s most recent progress towards both objectives as well as a general discussion of electrochemical pathways for fuels and commodity chemical production.

References

1. Brune, A., D. Emerson, and J.A. Breznak, The Termite Gut Microflora as an Oxygen Sink: Microelectrode Determination of Oxygen and pH Gradients in Guts of Lower and Higher Termites. Appl Environ Microbiol, 1995. 61, 2681-2687.

2. Brune, A., Termite Guts: The World's Smallest Bioreactors. Trends Biotechnol., 1998. 16, 16-21.

3. Kadilak, A. L., Liu, Y., Shrestha, S., Bernard, J. R., Mustain, W. E., and Shor, L. M., Selective Deposition of Chemically-bonded Gold Electrodes onto PDMS Microchannel Side Walls. J. Electroanal. Chem., 2014. 727, 141-147.