Scholarly Work - Center for Biofilm Engineering
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Item Subsurface hydrocarbon degradation strategies in low- and high-sulfate coal seam communities identified with activity-based metagenomics(Springer Science and Business Media LLC, 2022-02) Schweitzer, Hannah D.; Smith, Heidi J.; Barnhart, Elliott P.; McKay, Luke J.; Gerlach, Robin; Cunningham, Alfred B.; Malmstrom, Rex R.; Goudeau, Danielle; Fields, Matthew W.Environmentally relevant metagenomes and BONCAT-FACS derived translationally active metagenomes from Powder River Basin coal seams were investigated to elucidate potential genes and functional groups involved in hydrocarbon degradation to methane in coal seams with high- and low-sulfate levels. An advanced subsurface environmental sampler allowed the establishment of coal-associated microbial communities under in situ conditions for metagenomic analyses from environmental and translationally active populations. Metagenomic sequencing demonstrated that biosurfactants, aerobic dioxygenases, and anaerobic phenol degradation pathways were present in active populations across the sampled coal seams. In particular, results suggested the importance of anaerobic degradation pathways under high-sulfate conditions with an emphasis on fumarate addition. Under low-sulfate conditions, a mixture of both aerobic and anaerobic pathways was observed but with a predominance of aerobic dioxygenases. The putative low-molecular-weight biosurfactant, lichysein, appeared to play a more important role compared to rhamnolipids. The methods used in this study—subsurface environmental samplers in combination with metagenomic sequencing of both total and translationally active metagenomes—offer a deeper and environmentally relevant perspective on community genetic potential from coal seams poised at different redox conditions broadening the understanding of degradation strategies for subsurface carbon.Item In Situ Enhancement and Isotopic Labeling of Biogenic Coalbed Methane(American Chemical Society, 2022-02) Barnhart, Elliott P.; Ruppert, Leslie; Hiebert, Randy; Smith, Heidi J.; Schweitzer, Hannah D.; Clark, Arthur C.; Weeks, Edwin P.; Orem, William H.; Varonka, Matthew S.; Platt, George; Shelton, Jenna L.; Davis, Katherine J.; Hyatt, Robert J.; McIntosh, Jennifer C.; Ashley, Kilian; Ono, Shuhei; Martini, Anna M.; Hackley, Keith C.; Gerlach, Robin; Spangler, Lee; Phillips, Adrienne J.; Barry, Mark; Cunningham, Alfred B.; Fields, Matthew W.Subsurface microbial (biogenic) methane production is an important part of the global carbon cycle that has resulted in natural gas accumulations in many coal beds worldwide. Laboratory studies suggest that complex carbon-containing nutrients (e.g., yeast or algae extract) can stimulate methane production, yet the effectiveness of these nutrients within coal beds is unknown. Here, we use downhole monitoring methods in combination with deuterated water (D2O) and a 200-liter injection of 0.1% yeast extract (YE) to stimulate and isotopically label newly generated methane. A total dissolved gas pressure sensor enabled real time gas measurements (641 days preinjection and for 478 days postinjection). Downhole samples, collected with subsurface environmental samplers, indicate that methane increased 132% above preinjection levels based on isotopic labeling from D2O, 108% based on pressure readings, and 183% based on methane measurements 266 days postinjection. Demonstrating that YE enhances biogenic coalbed methane production in situ using multiple novel measurement methods has immediate implications for other field-scale biogenic methane investigations, including in situ methods to detect and track microbial activities related to the methanogenic turnover of recalcitrant carbon in the subsurface.Item Addressing wellbore integrity and thief zone permeability using microbially-induced calcium carbonate precipitation (MICP): A field demonstration(Elsevier BV, 2020-02) Kirkland, Catherine M.; Thane, Abby; Hiebert, Randy; Hyatt, Robert; Kirksey, Jim; Cunningham, Alfred B.; Gerlach, Robin; Spangler, Lee; Philips, Adrienne J.Microbially-induced calcium carbonate precipitation (MICP) is an emerging biotechnology for wellbore integrity applications including sealing defects in wellbore cement and modifying the permeability of rock formations. The goal of this field demonstration was to characterize a failed waterflood injection well and provide proof of principle that MICP can reduce permeability in the presence of oil using conventional oilfield fluid delivery methods. We compared well logs performed at the time the well was drilled with ultrasonic logs, sonic cement evaluation, and temperature logs conducted after the well failed. Analysis of these logs suggested that, rather than entering the target waterflood formation, injectate was traveling through defects in the well cement to a higher permeability sandstone layer above the target formation. Sporosarcina pasteurii cultures and urea-calcium media were delivered 2290 ft (698 m) below ground surface using a 3.75 gal (14.2 L) slickline dump bailer to promote mineralization in the undesired flow paths. By Day 6 and after 25 inoculum and 49 calcium media injections, the injectivity [gpm/psi] had decreased by approximately 70%. This demonstration shows that 1) common well logs can be used to identify scenarios where MICP can be employed to reduce system permeability, remediate leakage pathways, and improve waterflood efficiency, and 2) MICP can occur in the presence of hydrocarbons.Item A Numerical Model for Enzymatically Induced Calcium Carbonate Precipitation(MDPI, 2020-06) Hommel, Johannes; Akyel, Arda; Frieling, Zachary; Phillips, Adrienne J.; Gerlach, Robin; Cunningham, Alfred B.; Class, HolgerEnzymatically induced calcium carbonate precipitation (EICP) is an emerging engineered mineralization method similar to others such as microbially induced calcium carbonate precipitation (MICP). EICP is advantageous compared to MICP as the enzyme is still active at conditions where microbes, e.g., Sporosarcina pasteurii, commonly used for MICP, cannot grow. Especially, EICP expands the applicability of ureolysis-induced calcium carbonate mineral precipitation to higher temperatures, enabling its use in leakage mitigation deeper in the subsurface than previously thought to be possible with MICP. A new conceptual and numerical model for EICP is presented. The model was calibrated and validated using quasi-1D column experiments designed to provide the necessary data for model calibration and can now be used to assess the potential of EICP applications for leakage mitigation and other subsurface modifications.Item Kinetics of Calcite Precipitation by Ureolytic Bacteria under Aerobic and Anaerobic Conditions(2019-05) Mitchell, Andrew C.; Espinosa-Ortiz, Erika J.; Parks, Stacy L.; Phillips, Adrienne J.; Cunningham, Alfred B.; Gerlach, RobinThe kinetics of urea hydrolysis (ureolysis) and induced calcium carbonate (CaCO3) precipitation for engineering use in the subsurface was investigated under aerobic conditions using Sporosarcina pasteurii (ATCC strain 11859) as well as Bacillus sphaericus strains 21776 and 21787. All bacterial strains showed ureolytic activity inducing CaCO3 precipitation aerobically. Rate constants not normalized to biomass demonstrated slightly higher-rate coefficients for both ureolysis (kurea) and CaCO3 precipitation (kprecip) for B. sphaericus 21776 (kurea=0.10±0.03 h−1, kprecip=0.60±0.34 h−1) compared to S. pasteurii (kurea=0.07±0.02 h−1, kprecip=0.25±0.02 h−1), though these differences were not statistically significantly different. B. sphaericus 21787 showed little ureolytic activity but was still capable of inducing some CaCO3 precipitation. Cell growth appeared to be inhibited during the period of CaCO3 precipitation. Transmission electron microscopy (TEM) images suggest this is due to the encasement of cells and was reflected in lower kurea values observed in the presence of dissolved Ca. However, biomass regrowth could be observed after CaCO3 precipitation ceased, which suggests that ureolysis-induced CaCO3 precipitation is not necessarily lethal for the entire population. The kinetics of ureolysis and CaCO3 precipitation with S. pasteurii was further analyzed under anaerobic conditions. Rate coefficients obtained in anaerobic environments were comparable to those under aerobic conditions; however, no cell growth was observed under anaerobic conditions with NO−3, SO2−4 or Fe3+ as potential terminal electron acceptors. These data suggest that the initial rates of ureolysis and ureolysis-induced CaCO3 precipitation are not significantly affected by the absence of oxygen but that long-term ureolytic activity might require the addition of suitable electron acceptors. Variations in the ureolytic capabilities and associated rates of CaCO3 precipitation between strains must be fully considered in subsurface engineering strategies that utilize microbial amendments.Item Changes in microbial communities and associated water and gas geochemistry across a sulfate gradient in coal beds: Powder River Basin, USA(2019-01) Schweitzer, Hannah D.; Ritter, Daniel J.; McIntosh, Jennifer C.; Barnhart, Elliott P.; Cunningham, Alfred B.; Vinson, David S.; Orem, William; Fields, Matthew W.Competition between microbial sulfate reduction and methanogenesis drives cycling of fossil carbon and generation of CH4 in sedimentary basins. However, little is understood about the fundamental relationship between subsurface aqueous geochemistry and microbiology that drives these processes. Here we relate elemental and isotopic geochemistry of coal-associated water and gas to the microbial community composition from wells in two different coal beds across CH4 and SO42− gradients (Powder River Basin, Montana, USA). Areas with high CH4 concentrations generally have higher alkalinity and δ13C-DIC values, little to no SO42−, and greater conversion of coal-biodegradable organics to CH4 (based on δ13C-CH4 and δ13C-CO2 values). Wells with SO42− concentrations from 2 to 10 mM had bacterial populations dominated by several different sulfate-reducing bacteria and archaea that were mostly novel and unclassified. In contrast, in wells with SO42− concentrations <1 mM, the sequences were dominated by presumptive syntrophic bacteria as well as archaeal Methanosarcinales and Methanomicrobiales. The presence of sequences indicative of these bacteria in low SO42− methanogenic wells may suggest a syntrophic role in coal biodegradation and/or the generation of methanogenic substrates from intermediate organic compounds. Archaeal sequences were observed in all sampled zones, with an enrichment of sequences indicative of methanogens in low SO42− zones and unclassified sequences in high SO42− zones. However, sequences indicative of Methanomassiliicoccales were enriched in intermediate SO42− zones and suggest tolerance to SO42− and/or alternative metabolisms in the presence of SO42−. Moreover, sequences indicative of methylotrophic methanogens were more prevalent in an intermediate SO42− and CH4 well and results suggest an important role for methylotrophic methanogens in critical zone transitions. The presented results demonstrate in situ changes in bacterial and archaeal population distributions along a SO42− gradient associated with recalcitrant, organic carbon that is biodegraded and converted to CO2 and/or CH4.Item Field-scale modeling of microbially induced calcite precipitation(2018-11) Cunningham, Alfred B.; Class, Holger; Ebigbo, Anozie; Gerlach, Robin; Phillips, Adrienne J.; Hommel, JohannesThe biogeochemical process known as microbially induced calcite precipitation (MICP) is being investigated for engineering and material science applications. To model MICP process behavior in porous media, computational simulators must couple flow, transport, and relevant biogeochemical reactions. Changes in media porosity and permeability due to biomass growth and calcite precipitation, as well as their effects on one another must be considered. A comprehensive Darcy-scale model has been developed by Ebigbo et al. (Water Resour. Res. 48(7), W07519, 2012) and Hommel et al. (Water Resour. Res. 51, 3695–3715, 2015) and validated at different scales of observation using laboratory experimental systems at the Center for Biofilm Engineering (CBE), Montana State University (MSU). This investigation clearly demonstrates that a close synergy between laboratory experimentation at different scales and corresponding simulation model development is necessary to advance MICP application to the field scale. Ultimately, model predictions of MICP sealing of a fractured sandstone formation, located 340.8 m below ground surface, were made and compared with corresponding field observations. Modeling MICP at the field scale poses special challenges, including choosing a reasonable model-domain size, initial and boundary conditions, and determining the initial distribution of porosity and permeability. In the presented study, model predictions of deposited calcite volume agree favorably with corresponding field observations of increased injection pressure during the MICP fracture sealing test in the field. Results indicate that the current status of our MICP model now allows its use for further subsurface engineering applications, including well-bore cement sealing and certain fracture-related applications in unconventional oil and gas production.Item Enhancing wellbore cement integrity with microbially induced calcite precipitation (MICP): A field scale demonstration(2018-12) Phillips, Adrienne J.; Troyer, E.; Hiebert, R.; Kirkland, Catherine M.; Gerlach, Robin; Cunningham, Alfred B.; Spangler, Lee H.; Kirksey, J.; Rowe, W.; Esposito, R.The presence of delaminations, apertures, fractures, voids and other unrestricted flow channels in the wellbore environment substantially reduces wellbore integrity. Compromised cement may cause a loss of zonal isolation leading to deleterious flow of fluids between zones or to the surface with multiple potential negative impacts including: loss of resource production, reduction of sweep efficiency in EOR operations, and regulatory non-compliance. One potential solution to enhance wellbore integrity is microbially induced calcite precipitation (MICP) to plug preferential flow pathways. MICP is promoted with micrometer-sized organisms and low viscosity (aqueous) solutions thereby facilitating fluid transport into small aperture, potentially tortuous leakage flow paths within the cement column. In this study, MICP treatment of compromised wellbore cement was demonstrated at a depth interval of 310.0–310.57 m (1017–1019 feet) below ground surface (bgs) using conventional oil field subsurface fluid delivery technologies (packer, tubing string, and a slickline deployed bailer). After 25 urea/calcium solution and 10 microbial (Sporosarcina pasteurii) suspension injections, injectivity was reduced from the initial 0.29 cubic meters per hour (m3/h) (1.28 gallons per minute (gpm)) to less than 0.011 m3/h (0.05 gpm). The flow rate was decreased while maintaining surface pumping pressure below a maximum pressure of 81.6 bar (1200 psi) to minimize the potential for fracturing a shale formation dominant in this interval. The pressure decay immediately after each injection ceased decreased after MICP treatment. Comparison of pre- and post-test cement evaluation logs revealed substantial deposition of precipitated solids along the original flow channel. This study suggests MICP is a promising tool for enhancing wellbore cement integrity.Item The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface(1999) Jordan, Ryan N.; Nichols, E. P.; Cunningham, Alfred B.Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.Item Mobilization of a broad host range plasmid from pseudomonas putida to an established biofilm of bacillus azotoformans part ii: modeling(1998-02) Beaudoin, D. L.; Bryers, James D.; Cunningham, Alfred B.; Peretti, Steven W.A strain of Pseudomonas putida that harbors plasmids RK2 and pDLB101 was exposed to a pure culture biofilm of Bacillus azotoformans grown in a rotating annular reactor. Transfer of the RK2 mobilizable pDLB101 plasmid to B. azotoformans was monitored over a 4-day period. Experimental results demonstrated that the broad host range, RSF1010 derivative pDLB101 was transferred to and expressed by B. azotoformans. In the companion article to this work, the rate of plasmid transfer was quantified as a function of the limiting nutrient, succinate, and as a function of the mechanism of transfer. A biofilm process simulation program (AQUASIM) was modified to analyze resultant experimental data. Although the AQUASIM package was not designed to simulate or predict genetic events in biofilms, modification of the rate process dynamics allowed successful modeling of plasmid transfer. For the narrow range of substrate concentrations used in these experiments, nutrient level had only a slight effect on the rate and extent of plasmid transfer in biofilms. However, further simulations using AQUASIM revealed that under nutrient poor conditions, the number of transconjugants appearing in the biofilm was limited.