Engineering Bacterial Surfaces For CO2 Capture

Undergraduate #379
Discipline: Technology and Engineering
Subcategory: Nanoscience

Efrain C. Cuellar - Chabot College
Co-Author(s): Jenny Cappuccio, Humboldt State University, CA Behzad Rad and Caroline Ajo-Franklin, Lawrence Berkeley National Laboratory, CA

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Carbon dioxide, one of the four important greenhouse gases, warms the Earth’s surface by re-radiating energy. Although this warming fosters life, global warming and acidification are two anthropogenic factors caused by overproduction of carbon dioxide emission since the industrial revolution. Because of this serious environmental concern, many institutions are interested in developing novel climate intervention technologies such as biosequestration, greenhouse gas remediation, and mineral trapping strategies. To trap CO2 gas in the deep surface as a mineral, research groups have focused on certain microorganisms that have shown promise to induce CaCO3 formation from CO2. As an additional means to develop novel sequestration methods, our group is engineering the surface of aquatic dimorphic bacterium Caulobacter vibrioides to tune mineralization of CaCO3 from atmospheric carbon dioxide. The engineered surfaces of these bacterial strains show increased rates of CaCO3 mineralization. A critical step though for engineering bacteria is to understand the behavior of these bacterial surfaces binding to Ca2+. We developed an assay to measure Ca2+ binding by bacteria using a fluorescent dye to measure Ca2+ in solution. We then measured the binding of Ca2+ between engineered and wild-type strains of Caulobacter vibrioides. These experiments show that negatively charged surfaces of engineered C. vibrioides strains may bind Ca2+ better than the surfaces of wild type strains. This supports that engineering bacterial surfaces may influence mineralization of CaCO3 from atmospheric carbon dioxide.

Funder Acknowledgement(s): This work was fully supported by The Molecular Foundry, an affiliated Lawrence Berkeley National Laboratory site.

Faculty Advisor: Caroline Ajo-Franklin, cajo-franklin@lbl.gov