Construction of two ureolytic model organisms for the study of microbially induced calcium carbonate precipitation

Living building materials (LBMs) were engineered using photosynthetic cyanobacteria and an inert sand-gelatin scaffold. Microorganisms biomineralized LBMs with calcium carbonate, which imparted higher fracture toughness compared with no-cell controls. The microorganisms maintained relatively high viability in LBMs as long as sufficient humidity conditions were provided. The microorganisms were capable of on-demand exponential regeneration in response to temperature and humidity switches. Looking forward, LBMs represent a new class of structural materials that can be engineered to exhibit multiple biological functionalities.

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“…For example, microorganisms could potentially sense-and respond to-toxic chemicals or reveal structural damage with fluorescence. [40][41][42]…”

Section: Discussionmentioning

confidence: 99%

Biomineralization and Successive Regeneration of Engineered Living Building Materials

Heveran

Williams

Qiu

et al. 2020

Matter

156

130

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“…Biomass (fluorescence) and mineral deposit (reflectance) signals were obtained simultaneously. This approach is similar to an imaging method described previously (52). In experiments involving calcein staining, residual calcein was rinsed from the flow cell and biofilm before imaging by flowthrough of deionized (DI) water for 15 min.…”

Section: Methodsmentioning

confidence: 99%

Spatial Patterns of Carbonate Biomineralization in Biofilms

Chopp

Russin

et al. 2015

Appl Environ Microbiol

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dMicrobially catalyzed precipitation of carbonate minerals is an important process in diverse biological, geological, and engineered systems. However, the processes that regulate carbonate biomineralization and their impacts on biofilms are largely unexplored, mainly because of the inability of current methods to directly observe biomineralization within biofilms. Here, we present a method for in situ, real-time imaging of biomineralization in biofilms and use it to show that Pseudomonas aeruginosa biofilms produce morphologically distinct carbonate deposits that substantially modify biofilm structures. The patterns of carbonate biomineralization produced in situ were substantially different from those caused by accumulation of particles produced by abiotic precipitation. Contrary to the common expectation that mineral precipitation should occur at the biofilm surface, we found that biomineralization started at the base of the biofilm. The carbonate deposits grew over time, detaching biofilm-resident cells and deforming the biofilm morphology. These findings indicate that biomineralization is a general regulator of biofilm architecture and properties. Microbially induced carbonate precipitation represents an essential pathway for sequestration of large amounts of carbon in ancient and modern environments (1-5). Rock records reveal that Precambrian stromatolites formed as a consequence of trapping, binding, and precipitation of calcium carbonate by the growth and metabolism of microorganisms (2-4). Modern carbonate microbialites are found in a wide range of environments, including freshwater, oceans, hypersaline lakes, and soils (6, 7). Clinically, prolonged bacterial infection of indwelling urinary catheters leads to the formation of mineralized biofilms that can occlude the catheter lumen and cause serious complications (8-10). Some persistent infections of the lungs, particularly those associated with the genetic disorder primary ciliary dyskinesia, involve precipitation of calcium-rich stones or coatings (11)(12)(13)(14). In engineered systems, microbially induced scale formation decreases the performance of a wide variety of processes, including membrane separations in water treatment and heat exchange efficiency in cooling towers (15, 16). More recently, calcium carbonate biomineralization has also been explored as a novel biotechnology for the purpose of bioremediation and stabilization of porous structures, including soils, sediments, and construction materials (17-21).The microorganisms involved in carbonate biomineralization cover nearly all classes, including bacteria, algae, and fungi (22-27). It has been reported that more than 200 soil bacteria, including Pseudomonas spp., Bacillus subtilis, and Azotobacter spp., are capable of inducing calcium carbonate precipitation (5). Diverse microbial metabolisms, such as photosynthesis, sulfate reduction, and urea hydrolysis, can induce carbonate precipitation by significantly changing the saturation state of calcium carbonate (28,29). Microbial respiration p...

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“…12) biofilms were grown in 10 cm long, size 14 silicon tubes (Masterflex, Cole-Parmer, IL, USA) with influent urea concentrations ranging from 0.011 to 0.221 mol/l (0.63 to 13.3 g/l) at room temperature (approximately 20 °C). E. coli MJK2 possesses a pJN105 plasmid that has been modified to contain the urease operon from E. coli DH5α(pURE14.8) and also carries a mutant chromosomal gfp (green fluorescent protein gene).…”

Section: Methodsmentioning

confidence: 99%

“…First-order ( n =1, linear) and zero-order ( n =0, constant rate) relationships have been used previously to describe microbial ureolysis 7,12,23,24 so they were also included in the regression analysis.…”

Section: Methodsmentioning

confidence: 99%

Estimation of a biofilm-specific reaction rate: kinetics of bacterial urea hydrolysis in a biofilm

Connolly

Jackson

Rothman

et al. 2015

npj Biofilms Microbiomes

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Background/Objectives:Biofilms and specifically urea-hydrolysing biofilms are of interest to the medical community (for example, urinary tract infections), scientists and engineers (for example, microbially induced carbonate precipitation). To appropriately model these systems, biofilm-specific reaction rates are required. A simple method for determining biofilm-specific reaction rates is described and applied to a urea-hydrolysing biofilm.Methods:Biofilms were grown in small silicon tubes and influent and effluent urea concentrations were determined. Immediately after sampling, the tubes were thin sectioned to estimate the biofilm thickness profile along the length of the tube. Urea concentration and biofilm thickness data were used to construct an inverse model for the estimation of the urea hydrolysis rate.Results/Conclusions:It was found that urea hydrolysis in Escherichia coli MJK2 biofilms is well approximated by first-order kinetics between urea concentrations of 0.003 and 0.221 mol/l (0.186 and 13.3 g/l). The first-order rate coefficient (k1) was estimated to be 23.2±6.2 h−1. It was also determined that advection dominated the experimental system rather than diffusion, and that urea hydrolysis within the biofilms was not limited by diffusive transport. Beyond the specific urea-hydrolysing biofilm discussed in this work, the method has the potential for wide application in cases where biofilm-specific rates must be determined.

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Construction of two ureolytic model organisms for the study of microbially induced calcium carbonate precipitation

Cited by 40 publications

References 52 publications

Biomineralization and Successive Regeneration of Engineered Living Building Materials

Biomineralization and Successive Regeneration of Engineered Living Building Materials

Spatial Patterns of Carbonate Biomineralization in Biofilms

Estimation of a biofilm-specific reaction rate: kinetics of bacterial urea hydrolysis in a biofilm

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