Center for Biofilm Engineering (CBE)
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/9334
At the Center for Biofilm Engineering (CBE), multidisciplinary research teams develop beneficial uses for microbial biofilms and find solutions to industrially relevant biofilm problems. The CBE was established at Montana State University, Bozeman, in 1990 as a National Science Foundation Engineering Research Center. As part of the MSU College of Engineering, the CBE gives students a chance to get a head start on their careers by working on research teams led by world-recognized leaders in the biofilm field.
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Item Potential use of fungal-bacterial co-cultures for the removal of organic pollutants(Informa UK Limited, 2021-07) Espinosa-Ortiz, Erika J.; Rene, Eldon R.; Gerlach, RobinFungi and bacteria coexist in a wide variety of natural and artificial environments which can lead to their association and interaction – ranging from antagonism to cooperation – that can affect the survival, colonization, spatial distribution and stress resistance of the interacting partners. The use of polymicrobial cultivation approaches has facilitated a more thorough understanding of microbial dynamics in mixed microbial communities, such as those composed of fungi and bacteria, and their influence on ecosystem functions. Mixed (multi-domain) microbial communities exhibit unique associations and interactions that could result in more efficient systems for the degradation and removal of organic pollutants. Several previous studies have reported enhanced biodegradation of certain pollutants when using combined fungal-bacterial treatments compared to pure cultures or communities of either fungi or bacteria (single domain systems). This article reviews: (i) the mechanisms of pollutant degradation that can occur in fungal-bacterial systems (e.g.: co-degradation, production of secondary metabolites, enhancement of degradative enzyme production, and transport of bacteria by fungal mycelia); (ii) case studies using fungal-bacterial co-cultures for the removal of various organic pollutants (synthetic dyes, polycyclic aromatic hydrocarbons, pesticides, and other trace or volatile organic compounds) in different environmental matrices (e.g. water, gas/vapors, soil); (iii) the key aspects of engineering artificial fungal-bacterial co-cultures, and (iv) the current challenges and future perspectives of using fungal-bacterial co-cultures for environmental remediation.Item Struvite Stone Formation by Ureolytic Biofilms(2019) Espinosa-Ortiz, Erika J.; Gerlach, RobinThis chapter describes the role ureolytic biofilms (communities of microbes attached to surfaces) play in struvite stone formation in the urinary tract. The formation of struvite stones (MgNH4PO4·6H2O), commonly known as infection stones, is associated with urinary tract infections, particularly, with ureolytic microorganisms. Establishment of ureolytic biofilms in the urinary tract can result in increased microbial resistance to medical treatment and development of the necessary urine conditions to promote struvite (or other mineral) precipitation possibly leading to stone formation. Ureolytic microorganisms produce urease, an enzyme that breaks down urea (CO(NH2)2) generating ammonium (NH4+) and alkalizing urine, which changes urine chemistry to potentially promote struvite and other mineral precipitation. This chapter describes the series of steps involved in biofilm development and struvite precipitation leading to stone formation. Furthermore, this chapter presents an overview of controlled laboratory experiments and computer simulations currently used in different disciplines to study microbe-fluid-mineral interactions. We conclude that an interdisciplinary approach including the disciplines of engineering, mathematics, chemistry, microbiology and medicine will provide a more comprehensive understanding of the process of stone formation in the urinary tract and will ultimately allow for the development of improved management and prevention strategies for infection stones.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 Current insights into the mechanisms and management of infection stones(2018-11) Espinosa-Ortiz, Erika J.; Eisner, Brian H.; Lange, Dirk; Gerlach, RobinInfection stones are complex aggregates of crystals amalgamated in an organic matrix that are strictly associated with urinary tract infections. The management of patients who form infection stones is challenging owing to the complexity of the calculi and high recurrence rates. The formation of infection stones is a multifactorial process that can be driven by urine chemistry, the urine microenvironment, the presence of modulator substances in urine, associations with bacteria, and the development of biofilms. Despite decades of investigation, the mechanisms of infection stone formation are still poorly understood. A mechanistic understanding of the formation and growth of infection stones — including the role of organics in the stone matrix, microorganisms, and biofilms in stone formation and their effect on stone characteristics — and the medical implications of these insights might be crucial for the development of improved treatments. Tools and approaches used in various disciplines (for example, engineering, chemistry, mineralogy, and microbiology) can be applied to further understand the microorganism–mineral interactions that lead to infection stone formation. Thus, the use of integrated multidisciplinary approaches is imperative to improve the diagnosis, prevention, and treatment of infection stones.Item Selenate removal in biofilm systems: effect of nitrate and sulfate on selenium removal efficiency, biofilm structure and microbial community(2018-08) Tan, Lea Chua; Espinosa-Ortiz, Erika J.; Nancharaiah, Yarlagadda V.; van Hullebusch, Eric D.; Gerlach, Robin; Lens, Piet N. L.BACKGROUND Selenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se‐laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3‐) and sulfate (SO42‐), can influence selenate (SeO42‐) reduction and impact the efficiency of biological treatment systems. RESULTS SeO42‐ removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3‐ and SO42‐ using drip flow reactors operated continuously for 10 days at pH 7.0 and 30 °C. The highest total Se (∼60%) and SeO42‐ (∼80%) removal efficiencies were observed when the artificial wastewater contained SO42‐. A maximum amount of 68 μmol Se cm‐2 was recovered from the biofilm matrix in SO42‐ + SeO42‐ exposed biofilms and biofilm mass was 2.7‐fold increased for biofilms grown in the presence of SO42‐. When SeO42‐ was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3‐ or SO42‐, biofilms were thicker (> 0.6 mm), less compact and exhibited gas pockets. CONCLUSION The presence of SO42‐ had a beneficial effect on biofilm growth and the SeO42‐ removal efficiency, while the presence of NO3‐ did not have a significant effect on SeO42‐ removal by the biofilms.Item Effect of selenite on the morphology and respiratory activity of Phanerochaete chrysosporium biofilms(2016-06) Espinosa-Ortiz, Erika J.; Pechaud, Yoan; Lauchnor, Ellen G.; Eldon, Rene R.; Gerlach, Robin; Peyton, Brent M.; van Hullebusch, Eric D.; Lens, Piet N. L.The temporal and spatial effects of selenite (SeO32-) on the physical properties and respiratory activity of Phanerochaete chrysosporium biofilms, grown in flow-cell reactors, were investigated using oxygen microsensors and confocal laser scanning microscopy (CLSM) imaging. Exposure of the biofilm to a SeO32- load of 1.67 mg Se L-1 h-1 (10 mg Se L-1 influent concentration), for 24 h, resulted in a 20% reduction of the O2 flux, followed by a ~10% decrease in the glucose consumption rate. Long-term exposure (4 days) to SeO32- influenced the architecture of the biofilm by creating a more compact and dense hyphal arrangement resulting in a decrease of biofilm thickness compared to fungal biofilms grown without SeO32-. To the best of our knowledge, this is the first time that the effect of SeO32- on the aerobic respiratory activity on fungal biofilms is described.