Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Biohydrogen”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1977

Biohydrogenation and availability of linoleic acid in lactating cows.

Linoleic acid biohydrogenation, absorption and availability for maintenance and milk production in dairy cows fed high grain (60--85% of dry matter) diets were quantitatively estimated by isotope dilution, using two methods of dosing. [1-14C]Linoleic acid-labeled chylomicra and very low density lipoproteins (VLDL) were obtained from lymph of a calf fed [1-14C]linoleic acid and fitted with a thoracic duct-venous shunt. Labeled chylomicra were injected intravenously into two cows: a Jersey (trial 1), and a Holstein (trial 2). Labeled VLDL was injected intravenously into a Holstein cow (trial 3). In trials 4 and 5 the [1-14C]linoleic acid was placed into the omasal canal of two rumen-fistulated Holstein cows. Linoleic acid biohydrogenation (%), absorption (g/day), and availability above requirements for milk production (mg/kg body wt 3/4) were: 68.1 +/- 2.28, 52.1 +/- 2.92, and 244 +/- 19.4 (mean +/- SE), respectively. The biohydrogenation data indicate that both methods of dosing the cows were equally dependable. The estimates of linoleic acid biohydrogenation are consistent with limited data previously reported, indicating that the isotope dilution technique used is a reliable method to estimate linoleic acid absorption in lactating cows. Linoleic acid available to the lactating cow above milk production requirements was more than double the requirement of weanling female rats, when compared on the basis of metabolis body size.

Animal Feed↗
PubMed1991

Synthesis and biohydrogenation of fatty acids by ruminal microorganisms in vitro.

Ruminal degradation, synthesis, and biohydrogenation of fatty acids were examined in vitro. Diets were incubated with ruminal contents, and changes of fatty acids were measured. Two fat supplements, a calcium soap and an animal-vegetable blend, were included in diets at various levels. Addition to diets of acetate and isoacids (collective term for certain short-chain acids) also were tested for effects on fatty acid synthesis. Overall, 6.6 mg of fatty acids/g of fat-free diet were synthesized during 24-h incubation regardless of supplementations. Fatty acids synthesized in greatest amounts were odd-numbered or branched chains, whereas chains of 16 and 18 carbons changed little, and chains shorter than 14 carbons decreased. Degradation of [1-14C]palmitic acid was negligible, as determined by recovery of the label in CO2 (.03%) and acetate (1.09%) after 4-h incubation with rumen contents. Biohydrogenation of fatty acids averaged 47% in diets containing calcium soap and 71% with animal-vegetable blend. Synthesis and biohydrogenation were similar to those measured previously in vivo, showing that in vitro measurements reliably predicted metabolism of fatty acids in vivo.

Animal Feed↗
PubMed2026

Exploring biohydrogen producing potential of Arctic ice and water through metagenomics and dark fermentation kinetics.

Cryospheric ecosystems in the high Arctic harbor largely unexplored microbiomes with significant biotechnological potential. The present study evaluates the biohydrogen production capabilities of the indigenous microbiome of Ny-Ålesund, Svalbard, using glacial ice and surface water samples. Dark fermentation batch assays were performed at 4 °C and 20 °C with 2-bromoethanesulfonate (BES), a methanogenic inhibitor, to track the succession of metabolic and taxonomic diversity. Metagenomic and functional analyses revealed that under 20 °C and BES conditions, psychrotolerant microbial communities maximize biohydrogen production to 85% of the total biogas produced, with an acetate-dominant fermentation pathway, as inferred from volatile fatty acid (VFA) analysis. This evolves into a highly coordinated system utilizing a coupled Rnf-nitrogenase route alongside Formate Hydrogenlyase and [FeFe]-hydrogenase pathways. Kinetic modelling using the Modified Gompertz equation, along with Q10 temperature-sensitivity indices, demonstrated a very high latent catalytic potential in these cold-adapted microbiomes. This study indicates that Arctic microbiomes are highly elastic thermodynamically and could serve as highly efficient, manipulatable biocatalysts for the environmental recovery of bioenergy through engineered low-temperature systems.

Fermentation↗
PubMed1972

Quantitative aspects of fatty acid biohydrogenation, absorption and transfer into milk fat in the lactating goat, with special reference to the cis- and trans-isomers of octadecenoate and linoleate.

1. Surgically prepared lactating goats were used to obtain quantitative information on the biohydrogenation and absorption of dietary fat, and on the mammary uptake and transfer into milk fat of the complex mixture of cis- and trans-isomers of octadecenoate that arise during ruminal biohydrogenation. 2. About 90% of dietary linolenate, linoleate and oleate was hydrogenated in the rumen, and the availability to the animals of the essential fatty acid, linoleate, represented only 0.5-1.5% of the total dietary energy. 3. The intra-ruminal administration of (14)C-labelled linolenate and linoleate showed that these acids were not absorbed from the rumen, in agreement with previous work. 4. No selectivity was observed in the metabolism of the geometrical and positional isomers of octadecenoate: their rates of absorption from the small intestine, transfer into lymph, uptake by the mammary gland and appearance in milk fat were similar. 5. The desaturase activity of intestinal epithelium was demonstrated by the appearance in lymph of [1-(14)C]oleate after the addition of [1-(14)C]stearate to the small intestine.

Animals↗
PubMed1992

Ruminal biohydrogenation of linoleoyl methionine and calcium linoleate in sheep.

Four ruminally and duodenally cannulated Hampshire wethers were used in a 4 x 4 Latin square experiment to determine whether linoleoyl methionine and calcium linoleate would increase duodenal flow of unsaturated fatty acids (C18:2 + cis C18:1). All animals received the same basal diet plus a treatment enclosed in gelatin capsules that were placed directly in the rumen. Of the four experimental treatments, one was a control (empty capsules) and three were 5 g of fatty acid equivalent as either free linoleic acid, calcium linoleate, or linoleoyl methionine. Linoleoyl methionine had the lowest ruminal disappearance of C18:2 + cis C18:1. Ruminal loss of unsaturated fatty acids from each supplement exclusive of feed unsaturated fatty acids was 69.8, 92.9, and 94.6% for linoleoyl methionine, free linoleic acid, and calcium linoleate, respectively. Duodenal flow of methionine also was higher for linoleoyl methionine than for control, free linoleic acid, or calcium linoleate (2.5, 1.7, 2.0, and 2.5 g/d, respectively). Plasma linoleic acid was higher for linoleoyl methionine than for control or free linoleic acid but was not different from calcium linoleate (22.0, 17.8, 18.9, and 20.2% of total fatty acids, respectively). Plasma methionine levels were not different among treatments. Intestinal disappearance of unsaturated fatty acids did not differ among treatments. Linoleoyl methionine resisted ruminal biohydrogenation and was digested normally in the intestine. Calcium linoleate did not escape biohydrogenation by ruminal bacteria.

Absorption↗
PubMed1991

Ruminal synthesis, biohydrogenation, and digestibility of fatty acids by dairy cows.

Ruminal synthesis and biohydrogenation of fatty acids in dairy cows were determined by sampling duodenal digesta through T-cannulas. Fatty acid digestibility in the total tract also was measured. Five diets (concentrate:alfalfa hay:alfalfa haylage:corn silage, 2:1:1:1, DM) in a 5 x 5 Latin square contained either no added fat; 3 or 6% added calcium soap; or 3 or 6% animal-vegetable blend fat. Seventy percent of dietary fatty acids were recovered at the duodenum, and 106 g/d were synthesized in the rumen regardless of diets. Fatty acids synthesized in greatest amounts were odd or branched chains, whereas more than 90% of the fatty acids shorter than 14 carbons disappeared. Fatty acids in calcium soap were biohydrogenated 57% and in animal-vegetable blend 87%. Fatty acids in calcium soap were more digestible (80.0 vs. 75.7%) than those in the blended fat due to greater unsaturation in the small intestine. Ruminal microorganisms selectively synthesized fatty acids.

Animal Feed↗
PubMed1966

The biohydrogenation of alpha-linolenic acid and oleic acid by rumen micro-organisms.

1. alpha-[U-(14)C]Linolenic acid was incubated with the rumen contents of sheep and the metabolic products were characterized by thin-layer chromatography, gas-liquid chromatography and absorption spectroscopy in the ultraviolet and infrared. 2. A tentative scheme for the biohydrogenation route to stearic acid is presented. The main pathway is through diconjugated cis-cis-cis-octadecatrienoic acid, non-conjugated trans-cis (cis-trans)-octadecadienoic acid and trans-octadecenoic acid, but other pathways are apparent. 3. Washed rumen micro-organisms possessed only a limited capacity to hydrogenate alpha-linolenic acid and oleic acid but the rate was greatly stimulated by a factor(s) present in the supernatant rumen liquor. 4. Pure cultures of Clostridium perfringens, Streptococcus faecalis, Escherichia coli and a coliform organism isolated from sheep faeces possessed negligible ability to hydrogenate unsaturated fatty acids compared with a mixed population of rumen micro-organisms. Butyrivibrio fibrisolvens slowly converted linoleic acid into octadecenoic acid.

Animals↗
PubMed1976

Effects of treatment of whole fat soybeans or soy flour with formaldehyde to protect the polyunsaturated fatty acids from biohydrogenation in the rumen.

Full-fat, ground soy flour (GSF) was treated with 37% formaldehyde (HCHO) and evaluated by in vitro and in vivo criteria to determine the protection afforded linoleic acid against ruminal biohydrogenation when the materials described above were fed as a protein supplement to rations for growing lambs. The supplements compared were soybean meal (SBM), uked for 2 hours. Organoleptic evaluations were conducted to determine if any flavor differences in meat from lambs fed these supplements could be detected. Excellent protection of linoleic acid, the major polyunsaturated fatty acid in soybeans, was noted both in vitro and in vivo. Rump, shoulder, kidney knob and omental fat depots of lambs fed the HCHO treated GSF ration had significantly more linoleic acid than lambs fed untreated GSF while lambs fed untreated GSF had significantly, more linoleic acid in their fat depots than lambs fed SBM. Linoleic acid content of intramuscular (loin) fat from lambs fed HCHO treated GSF was not significantly different from lambs fed untreated GSF, but lambs fed untreated GSF had significantly more loin linoleic acid than lambs fed SBM. No significant differences were noted in daily feed intake, feed efficiency or average daily gain for lambs fed growing-finishing rations containing any of the products tested as the protein supplement. A taste panel could not detect any differences in flavor of ground loin among any of the treatments.

Adipose Tissue↗
PubMed1976

Biohydrogenation of unsaturated fatty acids. Hydrogenation by cell-free preparations of Butyrivibrio fibrisolvens.

Hydrogenation of cis-9,trans-11-octadecadienoic acid to yield trans-11-octadecenoic acid by cell-free preparations of Butyrivibrio fibrisolvens has been obtained under strictly anaerobic conditions. Reduced methyl viologen, NADH, and an endogenous electron donor each can serve as a reductant. Inhibition studies and gel filtration patterns reveal the presence of at least two hydrogenation systems, one of which is coupled through a flavin, possibly FMN. Although the enzymes comprising the biohydrogenation pathway, the fatty acid reductases and linoleic acid isomerase, are part of the bacterial membrane, they do not appear to be constituted as a multienzyme complex.

Cell-Free System↗
PubMed1979

Biohydrogenation of unsaturated fatty acids. Presence of dithionite and an endogenous electron donor in Butyrivibrio fibrisolvens.

Two oxygen-consuming substances were isolated from cell-free extracts of the rumen anaerobe, Butyrivibrio fibrisolvens. The major fraction comprising 97% of the total activity was characterized as a three-component mixture of glucose, maltose, and dithionite. The minor activity fraction contained an electron donor for the reduction of cis-9,trans-11-octadecadienoate to trans-11-octadecenoate. After oxidation, the electron donor could be reduced by the dithionite, thereby accounting for the previously observed capacity of cell-free extracts of the bacterium to carry out the biohydrogenation of the conjugated dienoic fatty acid.

Dithionite↗
PubMed1979

[Biohydrogenation of erucic acid (22:1 n-9 cis) in an "artificial rumen". II) Effect of pH, potential hydrogen donors and type of anaerobiosis].

The possibility of dietary C18 unsaturated fatty acids double bonds biohydrogenation, which normally occurs in ruminants, has been investigated in the case of erucic acid (22:1 n-9 cis). The results have shown that, while oleic acid is always converted into hydrogenation intermediates and stearic acid, to various extent, erucic acid does not undergo hydrogenation process, unrelated to the incubation conditions applied. Data are discussed on the basis of the different structure of erucic and oleic acids.

Anaerobiosis↗
PubMed1978

Diet and sterol biohydrogenation in the rat: occurrence of epicoprostanol.

The fecal sterols from rats fed several types of semipurified or commercial diets were analyzed by a combination of thin layer and gas liquid chromatography. In rats fed semipurified diets with lard, sucrose, and casein, increasing proportions of lard (0, 8, 20, 65%) enhanced the fecal coprostanol/coprostanol + cholesterol ratio (from 0.50 to 0.85). This ratio was reduced by replacing lard with triolein or a mixture of calcium oleate and linoleate (1:1) and did not change when trierucin was substituted. No coprostanol formation was observed in rats fed a diet with tripalmitin or tristearin. The addition of sodium hyodeoxycholate (0.5%) or cholestyramine (2%) to the basal diet was without effect on the coprostanol/coprostanol + cholesterol ratio in the feces. The addition of sodium taurocholate (0.2, 0.75, and 4%) strongly reduced coprostanol formation, while a chronic bile duct ligation led to an enhancement. Cholesterol feeding (0.05, 0.2, and 0.5% in the diet) slightly increased (from 51 to 66%) coprostanol formation. Trace amounts of epicoprostanol were generally found in the feces. However, in some cases a very high proportion (up to 60%) of this sterol was observed. Possible relationships between the presence of epicoprostanol and the nature of the diet are discussed.

Animals↗