Formation of ethane and propane via abiotic reductive conversion of acetic acid in hydrothermal sediments

A mechanistic understanding of formation pathways of low-molecular-weight hydrocarbons is relevant for disciplines such as atmospheric chemistry, geology, and astrobiology. The patterns of stable carbon isotopic compositions (δ13C) of hydrocarbons are commonly used to distinguish biological, thermogenic, and abiotic sources. Here, we report unusual isotope patterns of nonmethane hydrocarbons in hydrothermally heated sediments of the Guaymas Basin; these nonmethane hydrocarbons are notably 13C-enriched relative to sedimentary organic matter and display an isotope pattern that is reversed relative to thermogenic hydrocarbons (i.e., δ13C ethane > δ13C propane > δ13C n-butane > δ13C n-pentane). We hypothesized that this pattern results from abiotic reductive conversion of volatile fatty acids, which were isotopically enriched due to prior equilibration of their carboxyl carbon with dissolved inorganic carbon. This hypothesis was tested by hydrous pyrolysis experiments with isotopically labeled substrates at 350 °C and 400 bar that demonstrated 1) the exchange of carboxyl carbon of C2 to C5 volatile fatty acids with 13C-bicarbonate and 2) the incorporation of 13C from 13C-2–acetic acid into ethane and propane. Collectively, our results reveal an abiotic formation pathway for nonmethane hydrocarbons, which may be sufficiently active in organic-rich, geothermally heated sediments and petroleum systems to affect isotopic compositions of nonmethane hydrocarbons.

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Pilot Study of the Effects of Polyphenols from Chestnut Involucre on Methane Production, Volatile Fatty Acids, and Ammonia Concentration during In Vitro Rumen Fermentation

Animals ◽

10.3390/ani11010108 ◽

2021 ◽

Vol 11 (1) ◽

pp. 108

Author(s):

Yichong Wang ◽

Sijiong Yu ◽

Yang Li ◽

Shuang Zhang ◽

Xiaolong Qi ◽

...

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Propionic Acid ◽

Acid Content ◽

Volatile Fatty Acids ◽

Rumen Fermentation ◽

Gas Production ◽

Quadratic Response ◽

In Vitro Rumen Fermentation

Nutritional strategies can be employed to mitigate greenhouse emissions from ruminants. This article investigates the effects of polyphenols extracted from the involucres of Castanea mollissima Blume (PICB) on in vitro rumen fermentation. Three healthy Angus bulls (350 ± 50 kg), with permanent rumen fistula, were used as the donors of rumen fluids. A basic diet was supplemented with five doses of PICB (0%–0.5% dry matter (DM)), replicated thrice for each dose. Volatile fatty acids (VFAs), ammonia nitrogen concentration (NH3-N), and methane (CH4) yield were measured after 24 h of in vitro fermentation, and gas production was monitored for 96 h. The trial was carried out over three runs. The results showed that the addition of PICB significantly reduced NH3-N (p < 0.05) compared to control. The 0.1%–0.4% PICB significantly decreased acetic acid content (p < 0.05). Addition of 0.2% and 0.3% PICB significantly increased the propionic acid content (p < 0.05) and reduced the acetic acid/propionic acid ratio, CH4 content, and yield (p < 0.05). A highly significant quadratic response was shown, with increasing PICB levels for all the parameters abovementioned (p < 0.01). The increases in PICB concentration resulted in a highly significant linear and quadratic response by 96-h dynamic fermentation parameters (p < 0.01). Our results indicate that 0.2% PICB had the best effect on in-vitro rumen fermentation efficiency and reduced greenhouse gas production.

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DUST-BORNE TRACE GASES AND ODORANTS The analysis of dust-borne trace gases requires their i-solation from the dust particles. Procedures for the isolation and characterization of trace gases and odorants in the dust from pig houses are given by SCHAEFER et al. (29), HAMMOND et al.(30) and TRAVIS and ELLIOTT (31). Alcoholic solvents were found to be effective for the extraction of volatile fatty ac ids and phenols from the dust of hen (32) and pig houses (33), (34). Today, gas chromatography is usually used for the sepa ration and identification of the trace gases. Table IV gives a literature review of compounds identified in the dust of pig houses. There are only very few reports on investigations on the dust from hen houses (32). Most of the odours coming from livestock production units are associated with the biological degradation of the animal wastes (35), the feed and the body odour of the animals (1). Volatile fatty acids and phenolic compounds were found to con tribute mostly to the strong, typical odour of animal houses by the help of sensory evaluations parallel to the chemical analysis (29),(30). Table V gives quantitative values of volatile fatty acids and phenolic/indolic compounds found in the aerosol phase and in settled dust of piggeries, respectively. The results from the aerosol phase coincide, particularly as far as acetic acid is concerned. For the investigations of the settled dust the coefficients of variation (CV) and the relative values (%) characterizing the percentage of the single compounds as part of the total amount are quoted. The values are corrected with the dry matter content of the dust. Main components are acetic acid and p-cresol, respectively. Table VI compares results from air, dust and slurry in vestigations on VFA and phenolic/indolic compounds in piggeries. Relative values are used. When comparing the results derived from investigations on dust, air or slurry it is necessary to use relative values because of the different dimensions, for experience shows that in spite of large quantitative differ ences between two samples within the group of carboxylic acids and within the group of phenolic/indolic compounds the propor tions of the components remain rather stable (36). In the group of VFA acetic acid is the main component in air, dust, and slurry followed by propionic and butyric acid. The other three acids amount to less than 25%. In the group of phenols/ indoles p-cresol is the main component in the four cited in vestigations. However, it seems that straw bedding can reduce the p-cresol content; in this case phenol is the main compo nent , i nstead (37 ). 4. EMISSION OF DUST-BORNE VFA AND PHENOLS/INDOLES FROM PIGGERIES The investigations of dust from piggeries show that both VFA and phenols/indoles are present in a considerable amount. However, compared to the air-borne emissions calculated on the base of the results of LOGTENBERG and STORK (38) less than the tenth part (1/10) of phenols/indoles and about the hundredth part (1/100) of VFA are emitted by the dust, only. Table VII compares the dust-borne and air-borne emissions of VFA and

Odour Prevention and Control of Organic Sludge and Livestock Farming ◽

10.1201/9781482286311-131 ◽

1986 ◽

pp. 337-337

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Volatile Fatty Acids ◽

Trace Gases ◽

Matter Content ◽

Biological Degradation ◽

Indolic Compounds ◽

Settled Dust ◽

Main Components ◽

Main Component

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POTENTIAL OF LIVESTOCK MANURE FOR COAL ACTIVATION

Jurnal Biologi Udayana ◽

10.24843/jbiounud.2017.vol21.i01.p06 ◽

2017 ◽

Vol 21 (1) ◽

pp. 26 ◽

Cited By ~ 1

Author(s):

EllIN HARlIA HARlIA ◽

MARlINA ET ◽

MASITA R ◽

RAHMAH KN

Keyword(s):

Carbon Dioxide ◽

Fatty Acids ◽

Acetic Acid ◽

Volatile Fatty Acids ◽

Coal Bed ◽

Coal Bed Methane ◽

Anaerobic Conditions ◽

Descriptive Approach ◽

Carbon Dioxide Co2 ◽

Reduction Of Co2

The natural methane formed by bacteria in anaerobic conditions is known as biogenic gas. Gas trapped in coal, formed through thermogenesis as well as biogenesisis known as coal-bed methane (CBM). The availability of organic material as decomposition of this material into methane is continuously required for the production of methane in the coal aquifer. The aim of this research was to investigate whether or not cattle feces bacteria were able to grow and produce methane in coal. Parameters measured were Volatile Fatty Acids (VFA) and the production of biogas, such as nitrogen, hydrogen, carbon dioxide, and methane. Explorative method was used and data obtained was analyzed by descriptive approach. The results showed that the bacteria found in the feces survived in the coal and produce biogas. On day 2 when the process was at the acidogenesis phase, it produced VFA with the largest component of acetic acid. Acetic acid would undergo decarboxylation and reduction of CO2 followed by reactions of H2and CO2 to produce methane (CH4) and carbon dioxide (CO2) as the final products. ,

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Enhanced lipid production by Yarrowia lipolytica cultured with synthetic and waste-derived high-content volatile fatty acids under alkaline conditions

Biotechnology for Biofuels ◽

10.1186/s13068-019-1645-y ◽

2020 ◽

Vol 13 (1) ◽

Cited By ~ 7

Author(s):

Ruiling Gao ◽

Zifu Li ◽

Xiaoqin Zhou ◽

Wenjun Bao ◽

Shikun Cheng ◽

...

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Propionic Acid ◽

Yarrowia Lipolytica ◽

Butyric Acid ◽

Lipid Content ◽

Volatile Fatty Acids ◽

Lipid Production ◽

Initial Ph ◽

Alkaline Conditions

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.

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Studies on the production of volatile fatty acids from grass by rumen liquor in an artificial rumen: II. The volatile fatty acid production from dried grass

The Journal of Agricultural Science ◽

10.1017/s0021859600036157 ◽

1957 ◽

Vol 49 (2) ◽

pp. 171-179 ◽

Cited By ~ 4

Author(s):

A. John ◽

G. Barnett ◽

R. L. Reid

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Propionic Acid ◽

Metabolic Pathways ◽

Volatile Fatty Acid ◽

Volatile Fatty Acids ◽

Water Soluble ◽

Fatty Acid Production ◽

Growing Seasons ◽

Titration Curves

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.

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Impact of Alkaline Pretreatment to Enhance Volatile Fatty Acids (VFAs) Production from Rice Husk

Biochemistry Research International ◽

10.1155/2019/8489747 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Qian Fang ◽

Sinmin Ji ◽

Dingwu Huang ◽

Zhouyue Huang ◽

Zilong Huang ◽

...

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Propionic Acid ◽

Butyric Acid ◽

Rice Husk ◽

Volatile Fatty Acids ◽

Alkaline Pretreatment ◽

Rice Husks ◽

Acid Fermentation ◽

Study Results

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.

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Metabolism of propane-1:2-diol infused into the rumen of sheep

British Journal Of Nutrition ◽

10.1079/bjn19720125 ◽

1972 ◽

Vol 27 (3) ◽

pp. 553-560 ◽

Cited By ~ 21

Author(s):

J. L. Clapperton ◽

J. W. Czerkawski

Keyword(s):

Carbon Dioxide ◽

Fatty Acids ◽

Acetic Acid ◽

Lactic Acid ◽

Polyethylene Glycol ◽

Energy Metabolism ◽

Heat Production ◽

Volatile Fatty Acids ◽

Carbon Dioxide Production ◽

Total Volatile

1. Propane-1:2-diol (loog/d) was infused through a cannula into the rumen of sheep receiving a ration of hay and dried grass. The concentration of volatile fatty acids, propanediol, lactic acid and of added polyethylene glycol, and the pH of the rumen contents were measured. The energy metabolism of the sheep was also determined.2. Most of the propanediol disappeared from the rumen within 4 h of its infusion. The infusion of propanediol resulted in a 10% decrease in the concentration of total volatile acids; the concentration of acetic acid decreased by about 30%, that of propionic acid increased by up to 60% and there was no change in the concentration of butyric acid.3. The methane production of the sheep decreased by about 9% after the infusion of propanediol and there were increases in the oxgyen consumption, carbon dioxide production and heat production of the animals; each of these increases was equivalent to about 40% of the theoretical value for the complete metabolism of 100 g propanediol.4. It is concluded that, when propanediol is introduced into the rumen, a proportion is metabolized in the rumen and a large proportion is absorbed directly. Our thanks are due to Dr J. H. Moore for helpful discussions, to Mr D. R. Paterson, Mr J. R. McDill and Mr C. E. Park for looking after the animals and to Miss K. M. Graham, Miss A. T. McKay and Mrs C. E. Ramage for performing the analyses.

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Recovery of volatile fatty acids (VFA) from complex waste effluents using membranes

Water Science & Technology ◽

10.2166/wst.2013.717 ◽

2013 ◽

Vol 69 (3) ◽

pp. 495-503 ◽

Cited By ~ 32

Author(s):

M.-P. Zacharof ◽

R. W. Lovitt

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Butyric Acid ◽

Volatile Fatty Acids ◽

Agricultural Waste ◽

Permeate Flux ◽

Anaerobic Digesters ◽

Waste Effluents

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.

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Nutritional status and intake regulation in sheep. V. Effects of intraruminal infusions of volatile fatty acids upon voluntary intake of roughage by sheep

Australian Journal of Agricultural Research ◽

10.1071/ar9660741 ◽

1966 ◽

Vol 17 (5) ◽

pp. 741 ◽

Cited By ~ 13

Author(s):

AR Egan

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Energy Balance ◽

Nutritional Status ◽

Propionic Acid ◽

Feed Intake ◽

Volatile Fatty Acids ◽

Voluntary Intake ◽

Induced Changes ◽

Intake Regulation

Results of experiments with infusions of volatile fatty acids into the rumen reveal that the induced changes in voluntary intake of roughages are not immediate, and vary in extent between animals. Single infusions resulted in subsequent depressions of feed intake, these being only partly related to the amount of energy of the infused volatile fatty acids. When longer-term infusions were made, acetic acid in small quantities depressed feed intake more than did propionic, and propionic acid modified the effect of acetic when the two were given together. Also recorded is an observation that animals receiving a casein-supplemented roughage diet reduced their feed intake when casein was infused per duodenum over 14-day periods. Results are discussed in relation to an hypothesis of an indirect mechanism attempting to maintain or restore the original energy balance, but showing considerable delay or inertia and imprecision when observed on a day to day basis.

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THE PRODUCTION OF ORGANIC ACIDS IN THE PIG: I. THE EFFECT OF DIET ON THE PROPORTIONS OF VOLATILE FATTY ACIDS IN PIG FECES

Canadian Journal of Animal Science ◽

10.4141/cjas62-008 ◽

1962 ◽

Vol 42 (1) ◽

pp. 55-62 ◽

Cited By ~ 14

Author(s):

D. W. Friend ◽

J. W. G. Nicholson ◽

H. M. Cunningham

Keyword(s):

Fatty Acids ◽

Acetic Acid ◽

Organic Acids ◽

Volatile Fatty Acids ◽

Statistical Significance ◽

Valeric Acid ◽

Crude Fiber ◽

The Difference ◽

Diet Level

Experiments were conducted to determine the effect of diet, level of feeding and age and/or weight on the proportions of volatile fatty acids (VFA) in the feces of pigs. Cellulose was added to the control ration fed in one experiment and dried whey or bran to that fed in another experiment. When the level of intake of the cellulose-supplemented ration was reduced, the digestibility of crude fiber in the ration increased. The proportion of fecal acetic acid also increased, but the difference observed did not reach statistical significance at P = 0.05. Differences in the proportion of acetic, butyric and valeric acid due to cellulose supplementation of the control ration were statistically significant (P < 0.05). The whey and the bran-supplemented rations gave statistically significant differences (P < 0.05 or P < 0.01) for the proportions of fecal valeric, propionic or acetic acid. The proportions of fecal VFA appeared to be relatively unaffected by the age and/or weight of pigs from weaning to market weight.

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