Investigation of Complete Groundwater Denitrification Utilizing an Environmentally Relevant Bacterial Co-culture

Uve Strautmanis, Heidi Smith, Sara Altenburg, and Matthew Fields, The Center for Biofilm Engineering and The Department of Microbiology and Immunology Montana State University, Bozeman MT, 59717

Primary motivations for studying the subsurface are to expand what is known about Earth’s microbial diversity and the subsurface microorganisms under low nutrient conditions that significantly impact C, S, N, P and mineral cycles. One such biogeochemical cycle of importance to groundwater systems is microbial denitrification, the reduction of nitrate (NO3-) from organic and inorganic sources back to atmospheric nitrogen (N2). However, little is known about the extent of microbially-mediated denitrification in groundwater environments. The key to harnessing microbial potential is to find the optimal set of parameters that promotes enhanced rates of denitrification, which is what this work aims to accomplish. In anaerobic environments, oxygen is not readily available for respiration, therefore microbes must use alternative electron acceptors such as NO3- to respire, reducing NO3-  to N2. To investigate the environmental parameters that influence denitrification this work uses a co-culture of Rhodanobacter sp. R12 and Acidovorax sp. 3H11 that when grown together, can complete full biotic denitrification. Batch experiments mimicking field conditions were run using the Rhodanobacter sp. R12 and Acidovorax sp. 3H11 co-culture under varying pH values (5 and 7), dissolved oxygen concentrations (anaerobic, 2mg/L, and 5mg/L), carbon sources, and amino acids. Samples were analyzed for growth performance, nitrate reduction, and single cell analysis including the integration of stable isotope probing with Raman Microspectroscopy and the identification of individual microbial cells and fluorescent in-situ hybridization (FISH). This will quantitatively track the abundance of individual organisms across treatments. Higher rates of denitrification are expected to occur when the organisms are grown together and in anaerobic conditions at a pH of 7. 

Additional Abstract Information

Presenter: Uve Strautmanis

Institution: Montana State University Bozeman

Type: Poster

Subject: Biology

Status: Approved

Time and Location

Session: Poster 2
Date/Time: Mon 3:00pm-4:00pm
Session Number: 2627