The conversion of CO2 into valuable feedstocks, such as high energy sugars would create paradigm shifting technologies for applications on earth and for interplanetary exploration. Microbes and microbe consortia may be one way to accomplish this conversion. Approximately 70% of the Earth’s microorganisms live in the dark marine biosphere (DMB). The DMB, which covers more than two-thirds of the Earth, is known as the most isolated region of the Earth’s largest CO2 sink. Despite its role in reducing CO2 and its vast majority of microorganisms, only about 5% of the sea floor has been explored. Due to the limited knowledge of the DMB and its microorganisms it, it is one of the best resources in discovering new dark carbon fixation pathways and carbon fixing microorganisms. We will explore how some DMB microorganisms may use urea as a nitrogen source for fixing carbonate. To start, microbes found in sediment extracted from the sea floor of the Gulf of Mexico were grown, in 96-wellplates, under varying concentrations of HCO3-, urea, and acetate. The growth of the microbes was monitored using OD600 readings with a plate reader. Consortia which appeared to show growth were transferred to 10mL of the successful media and continued to be monitored. Growth was confirmed by using IR spectroscopy and successfully isolating DNA from the consortia. Following confirmed growth, one successful consortia, grown with a media containing 10mM HCO3-, 10mM urea, and 1mM acetate under anaerobic conditions with a pH of 7.6 and a temperature of 4˚C was followed, using iron chromatography, in a 72-day experiment to determine how the levels of HCO3-, urea, and acetate changed with time and the success of carbonate fixation within the consortia. Individual microbes from the consortia and their DNA are also to be isolated.
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Wendel, Nina M., "Isolating and Manipulating Microorganisms using Ureolysis for Creating Extraterrestrial Microbial Biotechnology Systems" (2021). Honors Theses. 340.