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Brigmon, Robin L.

Publications and source records attributed to Brigmon, Robin L..

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Utilization of lasso peptides for biodegradation of polycyclic aromatic hydrocarbons

Abstract Many microbial genes involved in degrading recalcitrant environmental contaminants such as polycyclic aromatic hydrocarbons (PAHs) have been identified and characterized. However, all molecular mechanisms required for PAH utilization have not yet been elucidated. In this work, we demonstrate the proposed involvement of lasso peptides in the utilization of the PAH phenanthrene in Sphingomonas BPH. Transpositional mutagenesis of Sphingomonas BPH with the miniTn5 transposon yielded 3 phenanthrene utilization deficient mutants, #257, #1778, and #1782. In mutant #1782, Tn5 had inserted into the large subunit of the naph/bph dioxygenase gene. In mutant #1778, Tn5 had inserted into the B2 protease gene of a lasso peptide cluster. This finding is the first report on the role of lasso peptides in PAH utilization. Our studies also demonstrate that interruption of the lasso peptide cluster resulted in a significant increase in the amount of biosurfactant produced in the presence of glucose when compared to the wild‐type strain. Collectively, these results suggest that the mechanisms Sphingomonas BPH utilizes to degrade phenanthrene are far more complex than previously understood and that the #1778 mutant may be a good candidate for bioremediation when glucose is applied as an amendment due to its higher biosurfactant production.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Foamed glass ceramics—an upcycled scaffold for microbial biofilm development

Glass, a near infinitely recyclable material, can be upcycled to create new products such as foamed glass ceramics, which are essentially a synthetic pumice-like material. This material has been demonstrated to sustain preserved biofilms which have application in various fields based on the deployability of the product and the preserved microbes. Foamed glass ceramics have increased surface area compared to typical soda-lime glass cullet. This material has been explored for variety of applications including the growth, storage and transport of biofilms and microbial colonies which can be preserved and deployed later. Here, we demonstrate the ability for microbial cultures including BioTiger™, Escherichia coli K-12, Bacillus thuringiensis, and two environmental eukaryotic cells to colonize the upcycled glass products, undergo preservation, and regrow after 84 days of storage. The growth of preserved samples is correlated to the time spent incubating prior to preservation. These results demonstrate the applicability of this novel glass-biofilm combination in which various preserved microorganisms are able to be rapidly grown after storage on an upcycled glass product.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Bioremediation of heavy oily sludge: a microcosms study

Oily sludge is a residue from the petroleum industry composed of a mixture of sand, water, metals, and high content of hydrocarbons (HCs). The heavy oily sludge used in this study originated from Colombian crude oil with high density and low American Petroleum Institute (API) gravity. The residual waste from heavy oil processing was subject to thermal and centrifugal extraction, resulting in heavy oily sludge with very high density and viscosity. Biodegradation of the total petroleum hydrocarbons (TPH) was tested in microcosms using several bioremediation approaches, including: biostimulation with bulking agents and nutrients, the surfactant Tween 80, and bioaugmentation. Select HC degrading bacteria were isolated based on their ability to grow and produce clear zones on different HCs. Degradation of TPH in the microcosms was monitored gravimetrically and with gas chromatography (GC). The TPH removal in all treatments ranged between 2 and 67%, regardless of the addition of microbial consortiums, amendments, or surfactants within the tested parameters. The results of this study demonstrated that bioremediation of heavy oily sludge presents greater challenges to achieve regulatory requirements. Additional physicochemical treatments analysis to remediate this recalcitrant material may be required to achieve a desirable degradation rate.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

LDRD-2022-00108: Biomining Rare Earth Elements

Rare earth elements (REEs) are crucial to many high-tech devices and maintaining a competitive modern economy, thus they are of critical and strategic importance. Currently, mining approaches include rock grinding, strong acid or base extraction, separation, and concentration. The objective of this project was to develop cost-effective, environmentally friendly technologies for bioextracting REEs from mined materials.

58 GEOSCIENCES↗
DOE OSTI2022

Bioremediation of copper in sediments from a constructed wetland ex situ with the novel bacterium Cupriavidus basilensis SRS

The H-02 constructed wetland was designed to remove metals (primarily copper and zinc) to treat building process water and storm water runoff from multiple sources associated with the Tritium Facility at the DOE-Savannah River Site, Aiken, SC. The concentration of Cu and Zn in the sediments has increased over the lifetime of the wetland and is a concern. A bioremediation option was investigated at the laboratory scale utilizing a newly isolated bacterium of the copper metabolizing genus Cupriavidus isolated from Tim’s Branch Creek, a second-order stream that eventually serves as a tributary to the Savannah River, contaminated with uranium and other metals including copper, nickel, and mercury. Cupriavidus basilensis SRS is a rod-shaped, gram-negative bacterium which has been shown to have predatory tendencies. The isolate displayed resistance to the antibiotics ofloxacin, tetracycline, ciprofloxacin, select fungi, as well as Cu 2+ and Zn 2+ . Subsequent ribosomal sequencing demonstrated a 100% confidence for placement in the genus Cupriavidus and a 99.014% match to the C. basilensis type strain. When H-02 wetland samples were inoculated with Cupriavidus basilensis SRS samples showed significant (p < 0.05) decrease in Cu 2+ concentrations and variability in Zn 2+ concentrations. Over the 72-h incubation there were no significant changes in the inoculate densities (10 6 –10 8 cells/ML) indicating Cupriavidus basilensis SRS resiliency in this environment. This research expands our understanding of the Cupriavidus genus and demonstrates the potential for Cupriavidus basilensis SRS to bioremediate sites impacted with heavy metals, most notably copper.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

The impact of tritium phytoremediation on plant health as measured by fluorescence

Phytoremediation, using plants for soil, sediment, or water contaminant clean-up, is an established technology dependent on plant health. Tritium (3H), a radioactive isotope of hydrogen that is generally found in the environment as tritiated water (HTO), is a low-level beta emitter with a half-life of 12.32 years. Chlorophyll fluorescence (CF) for monitoring risk assessment of tritium to plant health was conducted at the Tritium Irrigation Facility (TIF) located on the US Department of Energy's Savannah River Site (SRS) near Aiken, SC. Two fluorometers were evaluated in conjunction with phytoremediation at the 25 –acre TIF where tritiated groundwater is being spray–irrigated on a mixed coniferous/deciduous forested watershed as a means of reducing tritium release to a nearby stream that serves as a tributary to the Savannah River. Tritium activity in irrigated water averaged 104 + 42 pCi mL -1 during the 2003 project. Fluorescence parameters measured by the two fluorometers were well correlated with each other (p < 0.0001). Tritium in water respired from oak leaves ranged up to 1845.13 pCi ml -1 and 2138.22 pCi ml -1 in pine needles. Trees in both the test and control sites were approximately 15 years old. In this report we demonstrated that fluorescence parameters provide an effective way to estimate the impact of HTO on plant health in a noninvasive, extremely rapid, and cost-effective manner. In the current study applying fluorometry, plants within the TIF phytoremediation site exposed to the site tritiated water were not significantly impacted by the tritium phytoremediation based on CF parameters as compared to the control, a nascent non-irrigated site.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2021

Biomining Critical Elements and Metals

The US government has identified 17 critical elements, including most rare earth elements (REEs), and metals, which are used extensively in consumer electronics as well as military and national security hardware. We are developing techniques for biomining these elements, the process of using microorganisms to extract critical elements from water, ores, and mine waste to fill these needs. Bioextraction is focusing on: 1) building on our first-year successes of identifying microbes that generate exudates that enhance the extraction of multivalent cations, 2) evaluating available phosphate solubilizing microbes to dissolve apatite and monazite, and 3) and biosurfactant producing microbes. Bioaccumulation efforts involves testing microbes that: 1) naturally release complex exudates that contain organic chelating agents, and 2) naturally accumulate or hyperaccumulate (wt-% levels) metals. Results from year one includes proof of concept that biosurfactant producing microorganisms can release REEs from select ores and that release of REEs is increased by the addition of glucose. Molecular results for microorganism profiling proved a population shift after addition of microorganisms. The study will culminate in a proof-of-concept demonstration, manuscripts, and the data needed for scaledup biomining of REEs.

36 MATERIALS SCIENCE↗
NASA NTRS2001

Carbonate Biogenic Structures in Storrs Lake, Bahamas

Storr's Lake, an inland hypersaline lake on San Salvador Island, Bahamas, contains calcium carbonate-rich lithified mats of filamentous microorganisms, diatoms, associated photosynthetic and chemotrophic bacteria, and trapped sediment. In addition, 16S rRNA analysis indicates the presence of five sulfur-reducing genera of bacteria. These microbes are potential modern-day analogs to some ancient stromatolitic structures. The goals of this study are to identify unique compositional and biogenic features, possibly correlating some of these with some of the sulfate-reducing bacteria. Additional information is contained in the original extended abstract.

Byrne, Monica↗