Search NASA⌕ Search

SEARCH · Search NASA

Results for “caproic acid”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Wetlands harbor lactic acid-driven chain elongators

Wetlands are globally significant carbon storage hotspots. Recent research has suggested that microbially derived metabolites may contribute to soil organic matter formation. Identifying pathways driving the formation of such metabolites is critical to understand the global impact of wetland carbon cycling. Here, we evaluate the presence of chain-elongating organisms converting two to three carbon compounds (i.e., lactic and acetic acid) to medium-chain carboxylic acids (MCCA; i.e., six-carbon caproic acid) in wetland soils. We demonstrate the enrichment of a lactic acid-driven chain-elongating community from wetland soils producing a mixture of butyric and caproic acid. The enriched community was dominated by Clostridiaceae, Ruminococcaceae, and Lachnospiraceae, three families with known chain elongators. Amplicon sequencing identified three Ruminococcaceae and one Clostridiaceae zero-radius OTU (zOTU) that were (i) present in the soil, (ii) enriched over 1% relative abundance in the bioreactor, and (iii) were closely related to known chain elongators. Moreover, close relatives of the three Ruminococcaceae zOTU were also observed in several other wetland microbiomes. From this observation, we conclude that close relatives of known chain elongators, potentially capable of lactic acid-driven MCCA production themselves, are present in wetland soils. This observation may have implications for our understanding of carbon cycling and storage in wetland ecosystems.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2016

The Origin of Amino Acids in Lunar Regolith Samples

We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.

lunar regolith↗
NASA NTRS2021

Low Total Abundances and a Predominance of n-ω-Amino Acids in Enstatite Chondrites: Implications for Thermal Stability of Amino Acids in the Inner Solar System

Investigating the organic contents of enstatite chondrite meteorites may offer insights into both early inner solar system and early Earth chemistry. Enstatite chondrite meteorites have highly reduced and anhydrous compositions, and their bulk isotopic compositions closely resemble terrestrial values, suggesting that their parent body asteroids accreted within the inner protoplanetary disk and were a primary contributor during Earth’s late accretion (Javoy et al., 1995; Piani et al., 2020). Here, we present the first report of amino acids in enstatite chondrite meteorite samples. Three EH3 meteorites were analyzed (Dominion Range 14021, Larkman Nunatak 12001, and Larkman Nunatak 06252). The acid-hydrolyzed water extracts of the meteorites contained low abundances (1.5 – 215.9 pmol/g) of n-ω-amino acids (glycine, β-alanine, γ-amino-n-butyric acid (γ-ABA), δ-amino-n-valeric acid (δ-AVA), and ε-amino-n-caproic acid (ε-ACA)), but amino acids were not present above detection limits in the non-hydrolyzed samples. The low amino acid abundances and the predominance of n-ω-amino acids resembles amino acid distributions previously observed for thermally altered chondrites. These results suggest that the parent body asteroid was not conducive to the synthesis and/or preservation of α-amino acids, or free amino acids in general, and that EH3 chondrite-like material may not have been a primary contributor of diverse or abundant free amino acids to the early Earth.

Danielle N Simkus↗
NASA NTRS2021

Low total abundances and a predominance of n-ω-amino acids in enstatite chondrites: Implications for thermal stability of amino acids in the inner solar system

Investigating the organic contents of enstatite chondrite meteorites may offer insights into both early inner solar system and early Earth chemistry. Enstatite chondrite meteorites have highly reduced and anhydrous compositions, and their bulk isotopic compositions closely resemble terrestrial values, suggesting that their parent body asteroids accreted within the inner protoplanetary disk and were a primary contributor during Earth’s late accretion (Javoy, 1995; Piani et al., 2020). Here, we present the first report of amino acids in enstatite chondrite meteorite samples. Three EH3 meteorites were analyzed (Dominion Range [DOM] 14021, Larkman Nunatak [LAR] 12001, and Larkman Nunatak 06252). The acid-hydrolyzed water extracts of the meteorites contained low abundances (1.5–215.9 pmol per g) of n-ω-amino acids (glycine, β-alanine, γ-amino-n-butyric acid [γ- ABA], δ-amino-n-valeric acid [δ-AVA], and ϵ-amino-n-caproic acid [ϵ-ACA]), but amino acids were not present above detection limits in the nonhydrolyzed samples. The low amino acid abundances and the predominance of n-ω-amino acids resemble amino acid distributions previously observed for thermally altered chondrites. These results suggest that the parent body asteroid was not conducive to the synthesis and/or preservation of α-amino acids, or free amino acids in general, and that EH3 chondrite-like material may not have been a primary contributor of diverse or abundant free amino acids to the early Earth.

Danielle N. Simkus↗
NASA NTRS2009

Cometary Glycine Detected in Samples Returned by Stardust

Our previous analysis of cometary samples returned to Earth by NASA's Stardust spacecraft showed several amines and amino acids, but the or igin of these compounds could not be firmly established. Here, we pre sent the stable carbon isotopic ratios of glycine and E-amino-n-caproic acid (EACA), the two most abundant amino acids identified in Stardu st-returned foil samples measured by gas chromatography-mass spectrom etry coupled with isotope ratio mass spectrometry. The Delta C-13 value for glycine of +29 +/- ? 6%: strongly suggests an extraterrestrial origin For glycine, while the Delta C-13 value for EACA of -25 +/-2 % indicates terrestrial contamination by Nylon-6 during curation. This represents the first detection of a cometary amino acid.

Elsila, Jamie E.↗
NASA NTRS1977

Formation of fatty acids in photochemical conversions of saturated hydrocarbons

Abiogenic synthesis of fatty acids was studied in photochemical conversions of saturated hydrocarbons. It was shown that, in a hydrocarbon water CaCO3 suspension, the action of 254 nm UV rays caused the formation of fatty acids with a maximum number of carbon atoms in the chain not exceeding that in the initial hydrocarbon. Synthesis of acetic, propionic, butyric, valeric, caproic, enanthic and caprylic (in the case of octane) acids occurs in heptane water CaCO3 and octane water CaCO3 systems.

Telegina, T. A.↗