Analysis of Terrestrial Deep Subsurface Simulated Environment and Native Microorganisms Interacting with Oxidative Hydrothermal Dissolution Processed Corn Cob

Author

Tia Zimmerman, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2024

Degree Name

Master of Science

Department

Molecular Biology Microbiology and Biochemistry

First Advisor

Hamilton-Brehm, Scott

Abstract

An increase in atmospheric carbon dioxide (CO2) concentrations has been observed, with values ~40% higher than those seen in the last 800,000 years. This increase in atmospheric CO2 has been linked to anthropogenic emissions due to burning of fossil fuels, and is considered a major driving factor of the contemporary climate change. Development and implementation of carbon dioxide removal (CDR) methods is imperative to the mitigation and reversal of climate change and its effects. Carbon fixing organisms, such as plants, are able to remove CO2 from the atmosphere and store it as biomass. A novel CDR method known as indirect air capture (iDAC) proposes to make use of a technology known as Oxidative Hydrothermal Dissolution (OHD) to break down biomass into low molecular weight water soluble molecules. With the iDAC method, the OHD processed biomass would by injected into a deep subsurface geological reservoir for long term sequestration of the carbon. The deep subsurface is not a sterile environment, but rather its own ecosystem populated with a diverse phylogenetic array of microorganisms. OHD-processed biomass injected into the deep subsurface would certainly come into contact with these communities, and introduce to them new compounds and chemical characteristics. In this study, an OHD-processed corn cob solution was injected into a simulated deep subsurface environment containing deep subsurface microorganisms in order to observe outcomes of interaction and to provide data that can be extrapolated for scale-up and in situ iDAC method studies. The results of this study showed that during the interaction between the OHD-processed corn cob and subsurface native and non-native microorganisms there was a shift in the microbial community but no loss of biodiversity. Additionally, over the course of the study, production of CO2 was observed. Further studies are recommended to amend the OHD-processed corn cob solution by basification to expectedly mitigate the production of CO2.