Date of Award


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Departmental Honors


Biological and Irrigation Engineering


The purpose of this project was to characterize the potential of various strains of purple non-sulfur bacteria for the production of fixed nitrogen fertilizers for the manned Mars missions. Six strains of Rhodopseudomonas palustris (CGA009, CGA010, TIE-1, NifA*, and PB23) were all investigated. Through initial growth trial experiments, R. palustris NifA* and PB23 were selected for their engineered nitrogen fixation and rapid growth respectively. Growth curves and ammonium concentrations were collected over time in pilot scale batch photobioreactors (200 mL). Biomass production was then scaled up to benchtop photobioreactors (1.5 L). Fourteen liters of both NifA* and PB23 were then grown at scale. Cells were harvested via centrifugation, and nitrogen degradation was characterized using both volatile ammonia and soluble nitrogen arrays. While PB23 was found to grow more rapidly at small scale, NifA* performed better in scale up. Further studies will quantify rates of nitrogen degradation using the arrays developed in this study.



Faculty Mentor

Ronald Sims