Performance of an air membrane bioreactor for methanol removal under steady and transient state conditions
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Biological sulfate reduction (BSR) represents a promising strategy for bioremediation of sulfate-rich waste streams, yet the impact of metabolic interactions on performance is largely unexplored. Here, genome-resolved metagenomics was used to characterize 17 microbial communities in reactors treating synthetic sulfate-contaminated solutions. Reactors were supplemented with lactate or acetate and a small amount of fermentable substrate. Of the 163 genomes representing all the abundant bacteria, 130 encode 321 NiFe and FeFe hydrogenases and all genomes of the 22 sulfate-reducing microorganisms (SRM) encode genes for H 2 uptake. We observed lactate oxidation solely in the first packed bed reactor zone, with propionate and acetate oxidation in the middle and predominantly acetate oxidation in the effluent zone. The energetics of these reactions are very different, yet sulfate reduction kinetics were unaffected by the type of electron donor available. We hypothesize that the comparable rates, despite the typically slow growth of SRM on acetate, are a result of the consumption of H 2 generated by fermentation. This is supported by the sustained performance of a predominantly acetate-supplemented stirred tank reactor dominated by diverse fermentative bacteria encoding FeFe hydrogenase genes and SRM capable of acetate and hydrogen consumption and CO 2 assimilation. Thus, addition of fermentable substrates to stimulate syntrophic relationships may improve the performance of BSR reactors supplemented with inexpensive acetate.
Abstract Laboratory‐based studies on microbial Fe(II) oxidation are commonly performed for 5–10 days in small volumes with high substrate concentrations, resulting in geochemical gradients and volumetric effects caused by sampling. We used a chemostat to enable uninterrupted supply of medium and investigated autotrophic nitrate‐reducing Fe(II)‐oxidizing culture KS for 24 days. We analysed Fe‐ and N‐speciation, cell‐mineral associations, and the identity of minerals. Results were compared to batch systems (50 and 700 mL—static/shaken). The Fe(II) oxidation rate was highest in the chemostat with 7.57 mM Fe(II) d −1 , while the extent of oxidation was similar to the other experimental setups (average oxidation of 92% of all Fe(II)). Short‐range ordered Fe(III) phases, presumably ferrihydrite, precipitated and later goethite was detected in the chemostat. The 1 mM solid phase Fe(II) remained in the chemostat, up to 15 μM of reactive nitrite was measured, and 42% of visualized cells were partially or completely mineral‐encrusted, likely caused by abiotic oxidation of Fe(II) by nitrite. Despite (partial) encrustation, cells were still viable. Our results show that even with similar oxidation rates as in batch cultures, cultivating Fe(II)‐oxidizing microorganisms under continuous conditions reveals the importance of reactive nitrogen intermediates on Fe(II) oxidation, mineral formation and cell–mineral interactions.
3D printable reactor base provides all of the mixing innovations needed to make excellent mixing reactors at any scale
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Microbial-driven solubilization of lignocellulosic material is a natural mechanism that is exploited in anaerobic digesters (ADs) to produce biogas and other valuable bioproducts. Glycoside hydrolases (GHs) are the main enzymes that bacterial and archaeal populations use to break down complex polysaccharides in these reactors. Methodologies for rapidly screening the physical presence and types of GHs can provide information about their functional activities as well as the taxonomical diversity within AD systems but are largely unavailable. Targeted proteomic methods could potentially be used to provide snapshots of the GHs expressed by microbial consortia in ADs, giving valuable insights into the functional lignocellulolytic degradation diversity of a community. Such observations would be essential to evaluate the hydrolytic performance of a reactor or potential issues with it.
LANL received three types of simulated wastewater (oil-contaminated soil within a water matrix; commercial laundry; cheese production), which were treated with a corresponding biological agent (enzyme and/or microbial blend) provided by the company. Experiments were set up according to their instruction within an automated bioreactor/fermenter and monitored over time. Aliquots were obtained for total organic carbon (TOC), flow cytometry, Biological Oxygen Demand, Chemical Oxygen Demand.
This project focused on developing advanced optical coatings to improve solar energy utilization. The research aimed to create lanthanide-doped upconversion nanoparticles (UCNPs) capable of capturing unused near-infrared (NIR) light from the sun and converting it into visible light (blue and red photons) that can be used for photosynthesis. The primary goal was to identify, synthesize, and integrate highly efficient UCNPs into a transparent thin-film device. Through a comprehensive workflow involving computer simulations, high-throughput robotic synthesis, and detailed optical characterization, the project successfully developed a high-performance material. The key technical achievement was the creation of a core-shell UCNP (NaYF₄:20%Yb³⁺, 2%Er³⁺ coated with a 10 nm NaYF₄ shell) that demonstrated a quantum yield of 3.2% for converting 980 nm NIR light into visible light. Transparent thin films fabricated from these nanoparticles showed excellent optical properties, confirming their potential for practical applications. This research adds to the scientific understanding of energy transfer in lanthanide materials and demonstrates a technically effective method for creating efficient light-converting coatings. The primary benefit to the public lies in the potential for these coatings to enhance the efficiency of solar-driven processes, such as boosting the growth of algae in photobioreactors for biofuel production.
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A bio-reactor system wherein a tubular housing contains an internal circularly disposed set of blade members and a central tubular filter all mounted for rotation about a common horizontal axis and each having independent rotational support and rotational drive mechanisms. The housing, blade members and filter preferably are driven at a constant slow speed for placing a fluid culture medium with discrete microbeads and cell cultures in a discrete spatial suspension in the housing. Replacement fluid medium is symmetrically input and fluid medium is symmetrically output from the housing where the input and the output are part of a loop providing a constant or intermittent flow of fluid medium in a closed loop.
A bio-reactor system where cell growth microcarrier beads are suspended in a zero head space fluid medium by rotation about a horizontal axis and where the fluid is continuously oxygenated from a tubular membrane which rotates on a shaft together with rotation of the culture vessel. The oxygen is continuously throughput through the membrane and disbursed into the fluid medium along the length of the membrane.
The goal was to delineate mechanisms of genetic responses to angiogenic stimulation of human coronary arterial and dermal microvascular endothelial cells during exposure to microgravity. The NASA-designed rotating-wall vessel was used to create a three-dimensional culture environment with low shear-stress and microgravity simulating that in space. The primary specific aim was to determine whether simulated microgravity enhances endothelial cell growth and whether the growth enhancement is associated by augmented expression of Basic Fibroblast Growth Factor (BFGF) and c-fos, an immediate early gene and component of the transcription factor AP-1.
Novel methods and apparatus that employ the rapid heating characteristics of microwave irradiation to facilitate the aseptic transfer of nutrients, products, and other materials between microbially sensitive systems and the external environment are described. The microwave-sterilizable access port (MSAP) consists of a 600-W magnetron emitting at a frequency of 2.45 GHz, a sterilization chamber with inlet and outlet flow lines, and a specimen transfer interface. Energy is routed to the sterilization chamber via a coaxial transmission line where small quantities of water couple strongly with the incident radiation to produce a superheated vapor phase. The efficiency of energy transfer is enhanced through the use of microwave susceptors within the sterilization chamber. Mating surfaces are thermally sterilized through direct contact with the hot gas. Efficacy has been demonstrated using the thermophile Bacillus stearothermophilus.
The pathogenesis of HIV infection involves a complex interplay between both the infected and noninfected cells of human lymphoid tissue, the release of free viral particles, the de novo infection of cells, and the recirculatory trafficking of peripheral blood lymphocytes. To develop an in vitro model for studying these various aspects of HIV pathogenesis we have utilized blocks of surgically excised human tonsils and a rotating wall vessel (RWV) cell culture system. Here we show that (1) fragments of the surgically excised human lymphoid tissue remain viable and retain their gross cytoarchitecture for at least 3 weeks when cultured in the RWV system; (2) such lymphoid tissue gradually shows a loss of both T and B cells to the surrounding growth medium; however, this cellular migration is reversible as demonstrated by repopulation of the tissue by labeled cells from the growth medium; (3) this cellular migration may be partially or completely inhibited by embedding the blocks of lymphoid tissue in either a collagen or agarose gel matrix; these embedded tissue blocks retain most of the basic elements of a normal lymphoid cytoarchitecture; and (4) both embedded and nonembedded RWV-cultured blocks of human lymphoid tissue are capable of productive infection by HIV-1 of at least three various strains of different tropism and phenotype, as shown by an increase in both p24 antigen levels and free virus in the culture medium, and by the demonstration of HIV-1 RNA-positive cells inside the tissue identified by in situ hybridization. It is therefore reasonable to suggest that gel-embedded and nonembedded blocks of human lymphoid tissue, cocultured with a suspension of tonsillar lymphocytes in an RWV culture system, constitute a useful model for simulating normal lymphocyte recirculatory traffic and provide a new tool for testing the various aspects of HIV pathogenesis.