caproic acid
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Author(s):  
Gu Shiyan ◽  
Zhang Wenyi ◽  
Xing Huige ◽  
Wang Ruji ◽  
Sun Jiyang ◽  
...  

Abstract The fermentation system with high solid materials for food waste (FW) is uneven in nutrition and easy to produce volatile acid accumulation, which causes the reaction system to acidify and affects the normal operation of fermentation. This study evaluated the effect of the co-substrate percentages (FW:CB = 9:1, FW:CB = 8:2, FW:CB = 7:3) and the initial total solid contents (12%, 15%, 18%) on the co-fermentation acidification performance of FW and cardboard waste (CB). The maximum methane production was obtained when mono-fermenting FW had high solids contents(1.4 L/kg). The methane production increased and then decreased with the increasing percentages of CB. Under the conditions of FW:CB = 8:2, the maximum methane production could reach 3.4 L/kg. The lower methane production (1.8 ∼ 2.5 L/kg) with high percentages of CB (FW:CB = 7:3) was translated into higher yields of caproic acid (up to 26%), which indicated lower percentages of CB had a stabilization effect due to the higher buffering capacities in co-fermentation. As a result, this study demonstrated new possibilities for using CB percentages to control the production of high added-value biogas in dry co-fermentation of FW.


2021 ◽  
Author(s):  
Yaxue He ◽  
Chiara Cassarini ◽  
Piet N. L. Lens

Abstract An anaerobic granular sludge was enriched to utilize H2/CO2 in a continuous gas-fed up-flow anaerobic sludge reactor by applying operating conditions expected to produce acetic acid, butyric acid and ethanol. Three stages of fermentation were found: Stage I with acetic acid accumulation with the highest concentration of 35 mM along with a pH decrease from initial 6 to 4.5. In Stage II, H2/CO2 was replaced by 100% H2 to induce solventogenesis, whereas butyric acid was produced with the highest concentration of 2.5 mM. At Stage III with 10 μM tungsten (W) addition, iso-valeric acid, valeric acid and caproic acid were produced at pH 4.5 -5.0. In the batch tests inoculated with the enriched sludge taken from the bioreactor (day 70), however, methane production occurred at pH 6. Exogenous 15 mM acetate addition enhanced both the H2 and CO2 consumption rate compared to exogenous 10, 30 and 45 mM acetate by the enriched sludge. Exogenous acetate failed to be converted to ethanol using H2 as electron donor by the enriched acetogens.


2021 ◽  

Abstract Aroma components of wines play an important role in the sensory quality of wines. In our paper we investigate the effect of commercially available yeast nutrients under different fermentation parameters. Caproic acid, caprylic acid, capric acid, and different fatty acid esters were used as markers of the alcoholic fermentation process. The optimal temperature for the fermentation of different white wines was at 15–16 °C, in the case of examined wines lower concentrations of fatty acids and fatty acid esters were found at this temperature. At 25–26 °C fermentation temperature very high concentrations of fatty acids and fatty acid esters were detected. Applying different nitrogen-containing wine additives we managed to achieve better aroma profiles for white wines even using musts of lower quality.


2021 ◽  
Vol 8 ◽  
Author(s):  
Francine Ngaffo Mekontso ◽  
Wenhui Duan ◽  
El Hadji Malick Cisse ◽  
Tianye Chen ◽  
Xiangbin Xu

Chilling injury is a physiological disorder affecting the quality of carambola fruit. In the present study, the effect of exogenous γ-aminobutyric acid (GABA) on CI development in carambola fruit during storage at 4°C for 15 days was investigated. The results showed that 2.5-mM GABA reduced CI index, maintained pericarp lightness, and decreased the electrolyte leakage (EL) and malondialdehyde content (MDA) while increased the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activities. Endogenous GABA content was significantly higher in the treated fruit than in the control fruit during the whole storage. Besides, the treatment promoted the accumulation of proline and ascorbic acid (AsA) under chilling stress. Compared to the control, GABA-treated fruit exhibited a higher activity of phenylalanine ammonia-lyase (PAL) and total phenolic compounds, and a lower activity of polyphenol oxidase (PPO). In addition, the Safranin O/fast green staining revealed via microscopic images that the GABA treatment reduced the cell walls degradation of carambola fruit. Moreover, the results displayed a lower activity of phospholipase D (PLD) and lipoxygenase (LOX) enzymes, which coincided with a higher content of oleic acid (C18:1), linoleic acid (C18:2n6), and α-linolenic acid (C18:3n3) after 15 days of treatment, leading to the maintenance of the integrity and prevention of the membrane of the rapid softening of carambola fruit. The findings of the present work showed particularly new insights into the crosstalk between GABA and fatty acids. GABA might preserve the pericarp of carambola fruit by increasing the content of the unsaturated fatty acid (UFA) γ-linolenic acid and reducing the saturated fatty acid (SFA) such as caproic acid (C6:0), caprylic acid (C8:0), myristic acid (C14:0), and palmitic acid (C16:0) progressively. GABA can be used as an appropriate postharvest technology for improving the quality of carambola fruit during low-temperature storage.


Author(s):  
Mengde Wu ◽  
Guangci Li ◽  
Mohong Lu ◽  
Mingshi Li ◽  
Xuebing Li ◽  
...  

Abstract The aim of this study is to achieve the hydro-liquefaction of asphaltene for the production of liquid fuel. The oil soluble molybdenum catalysts, molybdenum dialkyl dithiophosphate, and nickel carboxylate precursor with different carbon chains, were synthesized. The catalysts were characterized by ICP-OES, TEM and XPS. Their catalytic performance for the hydro-liquefaction of asphaltene to liquid fuels was investigated in a slurry bed reactor by using decalin as hydrogen donor and dispersant. The results show that the bimetal catalytic system composed of molybdenum dialkyl dithiophosphate and caproic acid nickel produces more MoS2 and NiS x active species. The metal contents of which accounts for 81.8 and 81.0 wt% of the total amount of Mo and Ni, respectively, and thus exhibits the best catalytic performance among the catalysts studied. The liquid yield of the asphaltene hydrogenation over the bimetal catalyst is 84.6 wt%, which is much higher than that over other catalysts, and the coke content is only 8.6 wt% under the conditions of 1000 μg/g of total metal addition, 1:1 Mo/Ni metal mass ratio and 1:1 asphaltene/naphthalene mass ratio. The content of saturated and aromatic components in the liquid products of asphaltene hydrogenation of the bimetal catalyst system is 78.9 wt%, which is a high-quality liquid fuel component.


2021 ◽  
Author(s):  
Shunchang Pu ◽  
Cuie Shi ◽  
Yu Zhang ◽  
Ning Lu ◽  
Shoubao Yan

Abstract Background Few studies to date have sought to characterize the spatial profiles of pit mud microbial communities in fermentation cellars from Chinese strong-flavour liquor distilleries. This study was thus designed to evaluate these eukaryotic communities in pit mud samples via a multidimensional DGGE approach and by assessing associated sample physicochemical properties. Results Penicillium fuscoglaucum, Penicillium glandicola, Aotearoamyces nothofagi, Malassezia restricta, Penicillium lanosocoeruleum, Penicillium crustosum, and Aspergillus tonophilus were detected only in pit mud from the upper cellar wall, while Alternaria alstroemeriae, Trichosporon insectorum, Fusarium equiseti, Calonectria pseudoreteaudii, Penicillium clavigerum, Penicillium compactum, Ascochyta phacae, Metarhizium frigidum, Alternaria burnsii, Fusarium nurragi, and Didymella keratinophila were present only in the middle cellar wall layer. Alternaria zantedeschiae and Ilyonectria cyclaminicola were only present in pit mud samples from the lower cellar wall, while Leptobacillium leptobactrum, Calonectria queenslandica, Aspergillus appendiculatus, and Candida pseudolambica were only detected in pit mud from the cellar bottom. Moisture, pH, PO43−, acetic acid, humus, K+, Mg2+, Ca2+, acetic acid, butyric acid, and caproic acid levels in these different pit mud positions exhibited a rising incremental pattern from the upper wall layer to the bottom layer, whereas lactic acid levels were significantly lower in the bottom pit mud layer relative to other layers. Conclusions A clear relationship between fungal community structure and physicochemical variables in different spatial pit mud samples, especially moisture, pH, and NH4+-N were identified as the three most significant factors associated with fungal community through a redundancy analysis.


Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 990
Author(s):  
Ko Sakauchi ◽  
Wataru Taira ◽  
Joji M. Otaki

The biological consequences of the Fukushima nuclear accident have been intensively studied using the pale grass blue butterfly Zizeeria maha and its host plant, the creeping wood sorrel Oxalis corniculata. Here, we performed metabolomic analyses of Oxalis leaves from Okinawa to examine the plant metabolites that were upregulated or downregulated in response to low-dose radiation exposure from Fukushima’s contaminated soil. The cumulative dose of radiation to the plants was 5.7 mGy (34 μGy/h for 7 days). The GC-MS analysis revealed a systematic tendency of downregulation among the metabolites, some of which were annotated as caproic acid, nonanoic acid, azelaic acid, and oleic acid. Others were annotated as fructose, glucose, and citric acid, involved in the carbohydrate metabolic pathways. Notably, the peak annotated as lauric acid was upregulated. In contrast, the LC-MS analysis detected many upregulated metabolites, some of which were annotated as either antioxidants or stress-related chemicals involved in defense pathways. Among them, only three metabolite peaks had a single annotation, one of which was alfuzosin, an antagonist of the α1-adrenergic receptor. We conclude that this Oxalis plant responded metabolically to low-dose radiation exposure from Fukushima’s contaminated soil, which may mediate the ecological “field effects” of the developmental deterioration of butterflies in Fukushima.


Author(s):  
Lucía Guadamuro ◽  
M. Andrea Azcárate-Peril ◽  
Rafael Tojo ◽  
Baltasar Mayo ◽  
Susana Delgado

Isoflavones are metabolized by components of the gut microbiota and can also modulate their composition and/or activity. This study aimed to analyze the modifications of the fecal microbial populations and their metabolites in menopausal women under dietary treatment with soy isoflavones for one month. Based on the level of urinary equol, the women had been stratified previously as equol-producers (n = 3) or as equol non-producers (n = 5). The composition of the fecal microbiota was assessed by high-throughput sequencing of 16S rRNA gene amplicons and the changes in fatty acid excretion in feces were analyzed by gas chromatography. A greater proportion of sequence reads of the genus Slackia was detected after isoflavone supplementation. Sequences of members of the family Lachnospiraceae and the genus Pseudoflavonifractor were significantly increased in samples from equol-producing women. Multivariable analysis showed that, after isoflavone treatment, the fecal microbial communities of equol producers were more like each other. Isoflavone supplementation increased the production of caproic acid, suggesting differential microbial activity, leading to a high fecal excretion of this compound. However, differences between equol producers and non-producers were not scored. These results may contribute to characterizing the modulating effect of isoflavones on the gut microbiota, which could lead to unravelling of their beneficial health effects.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lingxiong Chai ◽  
Qun Luo ◽  
Kedan Cai ◽  
Kaiyue Wang ◽  
Binbin Xu

Abstract Background IgA nephropathy(IgAN)) is the common pathological type of glomerular diseases. The role of gut microbiota in mediating “gut-IgA nephropathy” has not received sufficient attention in the previous studies. The purpose of this study was to investigate the changes of fecal short-chain fatty acids(SCFAs), a metabolite of the intestinal microbiota, in patients with IgAN and its correlation with intestinal flora and clinical indicators, and to further investigate the role of the gut-renal axis in IgAN. Methods There were 29 patients with IgAN and 29 normal control subjects recruited from January 2018 to May 2018. The fresh feces were collected. The fecal SCFAs were measured by gas chromatography/mass spectrometry and gut microbiota was analysed by16S rDNA sequences, followed by estimation of α- and β-diversity. Correlation analysis was performed using the spearman’s correlation test between SCFAs and gut microbiota. Results The levels of acetic acid, propionic acid, butyric acid, isobutyric acid and caproic acid in the IgAN patients were significantly reduced compared with control group(P < 0.05). Butyric acid(r=-0.336, P = 0.010) and isobutyric acid(r=-0.298, P = 0.022) were negatively correlated with urea acid; butyric acid(r=-0.316, P = 0.016) was negatively correlated with urea nitrogen; caproic acid(r=-0.415,P = 0.025) showed negative correlation with 24-h urine protein level.Exemplified by the results of α-diversity and β-diversity, the intestinal flora of IgAN patients was significantly different from that of the control group. Acetic acid was positively associated with c_Clostridia(r = 0.357, P = 0.008), o_Clostridiales(r = 0.357, P = 0.008) and g_Eubacterium_coprostanoligenes_group(r = 0.283, P = 0.036). Butyric acid was positively associated with g_Alistipes (r = 0.278, P = 0.040). The relative abundance of those were significantly decreased in IgAN group compared to control group. Conclusions The levels of fecal SCFAs in the IgAN patients were reduced, and correlated with clinical parameters and gut microbiota, which may be involved in the pathogenesis of IgAN, and this finding may provide a new therapeutic approach.


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