FA Degradation Research Articles

Effects of ‘bask in sunlight and dewed at night’ on the formation of fermented flavor in shrimp paste after maturation

The purpose of the study was to illustrate the roles of three primary indexes, namely sunlight, ventilation and stirring, in the ‘bask in sunlight and dewed at night’ technique on the quality of shrimp paste, through a laboratory-scale design. The results showed that changes in the post-ripening fermentation conditions, especially sunlight, was instrumental in the physicochemical properties of the shrimp paste. E-nose and SPME-GC–MS were employed to assess the volatile flavor of post-ripening fermentation. A total of 29 key volatile aroma components played a crucial role in the development of post-ripening flavor in shrimp paste with or without sunlight. Lipidomic analysis revealed that sunlight promoted the oxidative degradation of FA, resulting in the production of a diverse range of flavor compounds that imparted the unique aroma of shrimp paste. The findings of this study will establish a theoretical basic for better control of the post-ripening fermentation of traditional shrimp paste.

Carboxypeptidase G and pterin deaminase metabolic pathways degrade folic acid in Variovorax sp. F1

BackgroundFolic acid (FA) is a synthetic vitamin (B9) and the oxidized form of a metabolic cofactor that is essential for life. Although the biosynthetic mechanisms of FA are established, its environmental degradation mechanism has not been fully elucidated. The present study aimed to identify bacteria in soil that degrade FA and the mechanisms involved.ResultsWe isolated the soil bacterium Variovorax sp. F1 from sampled weed rhizospheres in a grassland and investigated its FA degradation mechanism. Cultured Variovorax sp. F1 rapidly degraded FA to pteroic acid (PA), indicating that FA hydrolysis to PA and glutamate. We cloned the carboxypeptidase G (CPG) gene and found widely distributed paralogs within the Variovorax genus. Recombinant CPG preferred FA and deaminofolic acid as substrates, indicating its involvement in FA degradation by Variovorax. Prolonged culture of Variovorax sp. F1 resulted in decreased rates of deaminofolic acid (DFA) and deaminopteroic acid (DPA) accumulation. This indicated that the deamination reaction also comprised a route of FA degradation. We also identified an F1 gene that was orthologous to the pterin deaminase gene (Arad3529) of Agrobacterium radiobacter. The encoded protein deaminated FA and PA to DFA and DPA, which was consistent with the deamination activity of FA and PA in bacterial cell-free extracts.ConclusionWe discovered that the two enzymes required for FA degradation pathways in isolates of Variovorax sp. F1 comprise CPG and pterin deaminase, and that DFA and PA are intermediates in the generation of DPA.

Photocatalytic oxidation degradation of inhibitory fatty acids for aged Chlorella vulgaris cultivation medium recycling.

The medium used for Chlorella vulgaris cultivation exerted obvious inhibitory effects on the growth of C. vulgaris after several culture-harvest cycles. The accumulated fatty acids secreted by C. vulgaris during their growth process were expected to be the cell inhibition components. In this work, the ultraviolet-driven photocatalytic oxidation technique was applied for the degradation of microalgae cell growth inhibition components in the aged cultivation medium, and the reaction parameters were optimized. The results indicated that the photocatalytic oxidation processes using 0.5g/L [Formula: see text] NPs as the catalyst under the aeration condition showed as high as 74.61 ± 4.60% FA degradation efficiency after 20min illumination, and the contents of -COOH, [Formula: see text] (α) and -COO-R functional groups in the aged C. vulgaris medium were significantly reduced. In addition, the modification of the photocatalyst further improved the ability of the degradation of FA. When the modified [Formula: see text]/AC and [Formula: see text]/Ag catalysts were applied, the FA degradation rates reached as high as 92.46 ± 0.37% and 93.91 ± 1.37%, respectively. In the recycled medium treated with [Formula: see text]/AC, the cell density in the stable phase reached 96.33 ± 1.83% of that in the fresh medium as the control. In summary, the photocatalytic oxidation with the modified [Formula: see text]/AC catalyst was proposed as the efficient strategy to realize the recycling of the aged C. vulgaris cultivation medium via the degradation of the FA as the cell growth inhibitors.

Polyhydroxy Ester Stabilized Perovskite for Low Noise and Large Linear Dynamic Range of Self-Powered Photodetectors.

Solution-processed perovskites as emerging semiconductors have achieved unprecedented milestones in sensor optoelectric devices. Stability along with the device noise issues are the major obstacle for photodetectors to compete with the traditional devices. Here, we demonstrated that l-ascorbic acid (l-AA) as a polyhydroxy ester can coordinate with the amino group of formamidine cations (FA+) through multiple hydrogen bond interactions to stabilize the perovskite, which protect the FA+ ions from nucleophile attack and effectively suppress the degradation of FA+ ions, improving the perovskite stability and suppressing the device noise to below 0.3 pA Hz-1/2 with a large linear dynamic range of 239 dB. The dual functions of l-AA enable the perovskite photodetector to have a high detectivity of 1012 Jones. The self-powered device works with no energy consumption and maintains an undegraded performance over 1200 h of inspection at ambient conditions, which is promising for infrastructure construction, signal sensing, and real-time information delivery.

Aerobic degradation of 4-fluoroaniline and 2,4-difluoroaniline: performance and microbial community in response to the inocula.

In this study, a distinct inoculum was investigated as an isolated variable within sequencing batch reactors via a comparison of the 4-fluoroaniline (4-FA) or 2,4-difluoroaniline (2,4-DFA) removal amounts. The inocula were derived from a treatment plant for treating pharmaceutical wastewater plus a small amount of municipal sewage (PMS), a treatment plant for treating fluoridated hydrocarbon wastewater (FHS), and a treatment plant for treating the comprehensive wastewater in an industrial park (CIS). There were slight differences among the degradation patterns of the 4-FA for the three inocula, whether during the enrichment period or the high concentration shock period. In contrast, it was observed that the degradation efficiency of 2,4-DFA initially varied with the inocula. The FHS-derived inoculum was determined to be optimal, exhibiting the earliest degradation reaction only after an acclimation of 7 days had the highest degradation rate constant of 0.519h-1, and had the fastest recovery time of three weeks after high concentration shock. Additionally, compared with the PMS-derived inoculum, the CIS-derived inoculum exhibited an earlier degradation reaction within three weeks, and a higher microbial diversity, but a lower shock resistance and degradation rate constant of 0.257h-1. High-throughput sequencing demonstrated that each final consortium was different in composition, and the microbial consortia developed well on the inoculum and substrate. In comparison of the similarity among the three 2,4-DFA enrichment cultures, the higher similarity (63.9-70.0%) among three final consortia enriching with 4-FA was observed. The results indicated that the inoculum played an important role in the degradation of FAs and the microbial bacterial communities of final consortia, and the effect extent might well depend on the fluorinated level of FAs.

Flexible and Reusable Ag Coated TiO2 Nanotube Arrays for Highly Sensitive SERS Detection of Formaldehyde.

Quantitative analysis of formaldehyde (HCHO, FA), especially at low levels, in various environmental media is of great importance for assessing related environmental and human health risks. A highly efficient and convenient FA detection method based on surface-enhanced Raman spectroscopy (SERS) technology has been developed. This SERS-based method employs a reusable and soft silver-coated TiO2 nanotube array (TNA) material, such as an SERS substrate, which can be used as both a sensing platform and a degradation platform. The Ag-coated TNA exhibits superior detection sensitivity with high reproducibility and stability compared with other SERS substrates. The detection of FA is achieved using the well-known redox reaction of FA with 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) at room temperature. The limit of detection (LOD) for FA is 1.21 × 10−7 M. In addition, the stable catalytic performance of the array allows the degradation and cleaning of the AHMT-FA products adsorbed on the array surface under ultraviolet irradiation, making this material recyclable. This SERS platform displays a real-time monitoring platform that combines the detection and degradation of FA.

The oxidation study of fuchsine acid dye by HP2W15Mo3Co2.5O62, 20H2O/H2O2: Temperature effect, kinetic and thermodynamic study

Abstract This study examines the oxidation kinetics of fuchsine acid by HP2W15Mo3Co2.5O62. 20H2O/H2O2c system. Firstly, the effect of temperature was investigated. Oxidation increases gradually with the increase in temperature. In addition, the kinetic study showed a proportional relationship between temperature increase and the FA degradation rate. The activation energy of the process was estimated as 25.4059 KJ mol−1. Thus, the HP2W15Mo3Co2.5O62, 20H2O/H2O2 system operates with a low energy barrier. Moreover, the thermodynamic study was realized by determining Gibbs energy, enthalpy variation and entropy variation. The results indicate that the oxidation process is spontaneous and exothermic in nature.

Derepression of bkd by the FadR loss dictates elevated production of BCFAs and isoleucine starvation

In many γ-proteobacteria, FadR is recognized as a global transcriptional regulator: in addition to being the most prominent regulator for FA biosynthesis and degradation, the protein also mediates expression of many genes in diverse biological processes. In Shewanella oneidensis, a bacterium renowned for its respiratory versatility, FadR directly controls only a few genes. However, the FadR loss substantially increases BCFA contents and impairs growth. In this study, we showed that FadR is required to activate a number of important FA biosynthesis genes, including fabA, fabB, and fabH1. Although most of these genes are controlled by FadR in a direct manner, they are not critically responsible for the phenotypes resulting from the FadR depletion. Subsequent investigations identified BKD encoded by the bkd operon as the critical factor for enhanced BCFA production. In the absence of FadR, the bkd operon is derepressed, resulting in elevated conversion of 3MOP to 3-methylbutanoyl-CoA, one of the direct substrates for BCFA synthesis. We further showed that the growth defect of the fadR mutant is due to BCAA shortage, a scenario also attributable to excessive BKD: 3MOP, the common substrate for both BCFA and BCAA, is disproportionately used for BCFA synthesis, leading to reduced production of BCAA. Collectively, our findings reveal that the S. oneidensis FadR regulon is surely larger than previously proposed and a new mechanism by which FadR impacts bacterial physiology.

Degradation of trans-ferulic acid in aqueous solution by a water falling film DBD reactor: Degradation performance, response surface methodology, reactive species analysis and toxicity evaluation

In this study, a water falling film dielectric barrier discharge (DBD) reactor was used to degrade trans-ferulic acid (FA) in water. The results show that 98.4% of FA was degraded by 10 min treatment with the discharge voltage of 19 kV. The reactor displayed an excellent energy efficiency, which could reach to 13.4 g/kWh for FA degradation. Degradation characteristics of the water falling film DBD for FA was studied by single factor experiments and response surface methodology. The optimal operating condition and a quadratic polynomial equation for predicting FA degradation efficiency were obtained by the response surface model. The reactive species analysis unveils that the peroxone reaction between H2O2 and O3 generated by DBD could promote the formation of OH, causing a synergistic effect for FA degradation. Hydrated electron (eaq−) converted into H in FA solution. In the present reaction system, H preferred to react with FA rather than merge with OH, and H showed a well ability to degrade FA. FA solution toxicity was weakened after DBD treatment.

Synergistic degradation of trans-ferulic acid by water falling film DBD plasma coupled with cobalt oxyhydroxide: Performance and mechanisms

In this study, trans-ferulic acid (FA) was degraded by water falling film dielectric barrier discharge (DBD) plasma coupled with CoOOH catalyst. The results reveal that CoOOH improved the degradation of FA by DBD plasma through an apparent catalytic effect. 98.2% of FA was degraded in 10 min by DBD + CoOOH (0.5 g/L dosage) system at 11.2 kV applied voltage, which was 23.8% higher than that in a sole DBD system; the corresponding energy yield (G50) was increased by 186% and the synergistic intensity for FA degradation reached up to 2.76. The evolution of reactive species reveals that the synergistic effect of DBD plasma and CoOOH catalyst can be attributed to the catalytic conversion of O3 and H2O2 into ·OH on the active sites of CoOOH surface. The results of Lewis acid sites, X-ray photoelectron spectroscopy and Raman spectroscopy suggest that the abundant oxygen vacancies and Lewis acid sites, which are offered by the lattice OH groups in CoOOH, serve as the catalytic active sites of CoOOH. According to the detected byproducts by liquid chromatograph/mass spectrometer, a possible FA degradation pathway was also tentatively proposed.

It takes a village: channeling fatty acid metabolism and triacylglycerol formation via protein interactomes

Diet, hormones, gene transcription, and posttranslational modifications control the hepatic metabolism of FAs; metabolic dysregulation causes chronic diseases, including cardiovascular disease, and warrants exploration into the mechanisms directing FA and triacylglycerol (TAG) synthesis and degradation. Long-chain FA metabolism begins by formation of an acyl-CoA by a member of the acyl-CoA synthetase (ACSL) family. Subsequently, TAG synthesis begins with acyl-CoA esterification to glycerol-3-phosphate by a member of the glycerol-3-phosphate acyltransferase (GPAT) family. Our studies of the isoforms ACSL1 and GPAT1 strongly suggest that these proteins are members of larger protein assemblies (interactomes). ACSL1 targeted to the ER interacts with peroxisomal, lipid droplet, and tethering proteins, uncovering a dynamic role for ACSL1 in organelle and lipid droplet interactions. On the outer mitochondrial membrane (OMM), PPARα upregulates ACSL1, which interacts with proteins believed to tether lipid droplets to the OMM. In contrast, GPAT1 is upregulated nutritionally by carbohydrate and insulin in a coordinated sequence of enzyme reactions, from saturated FA formation via de novo lipogenesis to FA esterification by GPAT1 and entry into the TAG biosynthesis pathway. We propose that involved enzymes form a dynamic protein interactome that facilitates esterification and that other lipid-metabolizing pathways will exist in similar physiologically regulated interactomes.

Evaluation of trans-ferulic acid degradation by dielectric barrier discharge plasma combined with ozone in wastewater with different water quality conditions

In this study, dielectric barrier discharge plasma and ozone (O3) were combined to synergistically degrade trans-ferulic acid (FA), and the effect of water quality on FA degradation was studied. The results showed that 96.9% of FA was degraded after 40 min treatment by the plasma/O3 process. FA degradation efficiency increased with the pH values. The presence of suspended solid and humic acid inhibited FA degradation. FA degradation efficiency increased as the water temperature increased to 30 °C. However, the further increase in water temperature was adverse for FA degradation. Effects of common inorganic ions on FA degradation were also investigated. The addition of Cl− inhibited the FA degradation, while had both negative and positive influences on FA degradation. and did not have significant effect on FA degradation. Fe3+ and Cu2+ benefited FA degradation through the Fenton-like and catalytic ozonation reactions.

Synergistic degradation of trans-ferulic acid in aqueous solution by dielectric barrier discharge plasma combined with ozone.

Trans-ferulic acid (FA), extensively used in pharmaceutical and olive oil industries, causes huge risks to ecological environment due to its biotoxicity and phytotoxicity, leading to the difficulty of biochemical processes in treating FA wastewater. In this study, synergistic degradation of FA via dielectric barrier discharge (DBD) plasma and O3 (plasma-ozone) was studied. The results showed that FA degradation efficiency reached 96.9% after a 40-min treatment by plasma-ozone process, and the energy efficiency of FA degradation was increased by 62.5 and 24.5% compared to single DBD plasma and ozonation treatment. Moreover, FA degradation rate constant in plasma-ozone process was 41% higher compared with the sum of single DBD plasma and ozonation, indicating a significant synergistic effect. Radical diagnosis experiments reveal that a profound increase of ·OH yield through peroxone (H2O2/O3) and UV/O3 pathways is the important mechanism of synergistic degradation of FA in plasma-ozone process, while eaq- played little role in FA degradation. A degradation pathway of FA by plasma-ozone was also proposed according to the detected intermediates from EEM and LC-MS. This work revealed that plasma-ozone process is an alternative process for FA treatment, and the findings are helpful for understanding FA degradation characteristics and synergistic mechanisms in plasma-ozone process.

Revealing the three dimensional architecture of focal adhesion components to explain Ca2 +-mediated turnover of focal adhesions

BackgroundFocal adhesions (FAs) are large, dynamic protein complexes located close to the plasma membrane, which serve as the mechanical linkages and a biochemical signaling hub of cells. The coordinated and dynamic regulation of focal adhesion is required for cell migration. Degradation, or turnover, of FAs is a major event at the trailing edge of a migratory cell, and is mediated by Ca2+/calpain-dependent proteolysis and disassembly. Here, we investigated how Ca2+ influx induces cascades of FA turnover in living cells. MethodsImages obtained with a total internal reflection fluorescence microscope (TIRFM) showed that Ca2+ ions induce different processes in the FA molecules focal adhesion kinase (FAK), paxillin, vinculin, and talin. Three mutated calpain-resistant FA molecules, FAK-V744G, paxillin-S95G, and talin-L432G, were used to clarify the role of each FA molecule in FA turnover. ResultsVinculin was resistant to degradation and was not significantly affected by the presence of mutated calpain-resistant FA molecules. In contrast, talin was more sensitive to calpain-mediated turnover than the other molecules. Three-dimensional (3D) fluorescence imaging and immunoblotting demonstrated that outer FA molecules were more sensitive to calpain-mediated proteolysis than internal FA molecules. Furthermore, cell contraction is not involved in degradation of FA. ConclusionsThese results suggest that Ca2+-mediated degradation of FAs was mediated by both proteolysis and disassembly. The 3D architecture of FAs is related to the different dynamics of FA molecule degradation during Ca2+-mediated FA turnover. General significanceThis study will help us to clearly understand the underlying mechanism of focal adhesion turnover by Ca2+.

Decreased Fatty Acid <i>β</i>-Oxidation Is the Main Cause of Fatty Liver Induced by Polyunsaturated Fatty Acid Deficiency in Mice

Insufficient intake of polyunsaturated fatty acids (PUFA) causes fatty liver. The mechanism responsible is primarily related to increased lipogenesis and decreased FA degradation based on rodent studies. However, these studies were limited by the fact that the typical PUFA-deficient diets contained insufficient amounts of long-chain FA, the PUFA-containing diets were primarily composed of n-3 PUFA-enriched oil, and the intake of PUFA was excessive compared with the physiological requirement. To address these issues, mice were fed a PUFA-deficient diet containing long-chain FA at a standard fed level and then were orally fed a n-3/n-6-balanced PUFA-containing oil [PUFA (+)] or a PUFA-deficient oil [PUFA (-)] at physiological relevant levels (0.1 mL/mouse/2d). We compared these groups and examined whether fatty liver in PUFA deficiency was attributable to both the effects of increased lipogenesis and decreased FA catabolism. Compared with the PUFA (+) group, the PUFA (-) group showed increases in liver triglyceride and serum FA content. Hepatic gene expression of several mitochondrial β-oxidation enzymes, the serum 3-hydroxybutyrate level, and DNA-binding ability of peroxisome proliferator-activated receptor α (PPARα) were increased in the PUFA (+) group, whereas these adaptive responses were significantly attenuated in the PUFA (-) group. The hepatic expression of typical lipogenesis genes did not differ between the groups. Therefore, fatty liver in PUFA deficiency is attributable to suppression of the FA-degrading system probably from decreased PPARα adaptive responsiveness, and PUFA may be an essential factor for PPARα functioning. This finding is helpful for managing clinical situations having a risk of PUFA deficiency.

Malassezia spp. beyond The Mycobiota

Malassezia species are part of the normal mycobiota of skin of animals and humans but they can cause skin and blood stream infections as well. These yeasts are all lipid dependent explained by the absence of fatty acid synthase genes in their genome. At the same time, metabolic reconstruction revealed differences in the metabolism of fungal steroids and degradation of CoA-activated long-chain FAs, arachidonic acid, and butanoate metabolism between Malassezia yeasts. In addition, differences in the assimilation of palmitic acid were predicted. Indeed, M. furfur was able to metabolize palmitic acid but M. globosa, M. sympodialis, M. pachydermatis, and an atypical variant of M. furfur were not able to do so. Tools to genetically modify Malassezia have become available recently, which will speed up the process to decipher mechanisms underlying growth and pathogenicity of these yeasts. Here, we will provide an overview about the genus Malassezia and make an assessments to the new insights in this yeast.

Metabolic engineering of E. coli top 10 for production of vanillin through FA catabolic pathway and bioprocess optimization using RSM

Metabolic engineering and construction of recombinant Escherichia coli strains carrying feruloyl-CoA synthetase and enoyl-CoA hydratase genes for the bioconversion of ferulic acid to vanillin offers an alternative way to produce vanillin. Isolation and designing of fcs and ech genes was carried out using computer assisted protocol and the designed vanillin biosynthetic gene cassette was cloned in pCCIBAC expression vector for introduction in E. coli top 10. Recombinant strain was implemented for the statistical optimization of process parameters influencing F A to vanillin biotransformation. CCD matrix constituted of process variables like FA concentration, time, temperature and biomass with intracellular, extracellular and total vanillin productions as responses. Production was scaled up and 68 mg/L of vanillin was recovered from 10 mg/L of FA using cell extracts from 1 mg biomass within 30 min. Kinetic activity of enzymes were characterized. From LCMS-ESI analysis a metabolic pathway of FA degradation and vanillin production was predicted.

ω-Azido fatty acids as probes to detect fatty acid biosynthesis, degradation, and modification

FAs play a central role in the metabolism of almost all known cellular life forms. Although GC-MS is regarded as a standard method for FA analysis, other methods, such as HPLC/MS, are nowadays widespread but are rarely applied to FA analysis. Here we present azido-FAs as probes that can be used to study FA biosynthesis (elongation, desaturation) or degradation (β-oxidation) upon their uptake, activation, and metabolic conversion. These azido-FAs are readily accessible by chemical synthesis and their metabolic products can be easily detected after click-chemistry based derivatization with high sensitivity by HPLC/MS, contributing a powerful tool to FA analysis, and hence, lipid analysis in general.

Efficient degradation of fulvic acids in water by catalytic ozonation with CeO2/AC

AbstractBACKGROUNDFulvic acids (FA), the main organic compounds in landfill leachate, are toxic and bio‐resistant organic compounds. Ozonation is effective in removing non‐biodegradable components and the addition of catalysts can improve the removal rates. The objective of this study is to prepare and improve CeO2/AC catalyst for catalytic ozonation of FA.RESULTSThe cerium precursor, calcination atmosphere and calcination temperature changed the percentage of Ce3+ on the surface, thus affecting the catalytic performance of CeO2/AC catalyst. A linear relationship was established between the correcting apparent rate constant of FA degradation (kapp/SBET) and the percentage of Ce3+ on the surface. The CeO2/AC with 5% of Ce loading and calcined under hydrogen atmosphere at 450 °C showed the highest catalytic activity, allowing a FA removal efficiency of 83%. The FA removal efficiency and ozone utilization efficiency were enhanced in O3/CeO2/AC compared with ozonation alone.CONCLUSIONCe3+ on the CeO2/AC surface is the active site for ozonation, indicating a feasible way to improve the catalytic performance of CeO2/AC. The O3/CeO2/AC process may be applied as a promising treatment method for landfill leachate. © 2013 Society of Chemical Industry

Trans-ferulic acid-based solid lipid nanoparticles and their antioxidant effect in rat brain microsomes

In this study, stearic acid- and stearyl ferulate-based solid lipid nanoparticles containing trans-ferulic acid (SLN-FA and SLN-SF-FA, respectively), were prepared and characterized for loading efficiency, size and shape. In addition, by using rat brain microsomes, we evaluated in vitro the antioxidant activity of these formulations against three well known initiators of lipid peroxidation, such as AAPH, NADPH/ADP-Fe3+ and SIN-1 which in turn generate the peroxyl and perferryl radicals as well as peroxynitrite, respectively. Commercially available FA and its ethyl ester (FAEE) were used as comparators. Both SLN-FA and SLN-SF-FA dose-dependently reduced lipid peroxidation induced by the three oxidants. Interestingly, SLN-SF-FA displayed greater efficacy (EC50) and potency (maximal activity) against AAPH- and NADPH/ADP-Fe3+-induced lipid peroxidation. Our results support the idea that this new formulations could facilitate the uptake of FA by the cells because of their lipophilic structure, thus increasing FA bioavailability. Furthermore, stearyl ferulate-based nanoparticles could prevent the degradation of FA entrapped on their structure, making FA almost entirely available to explicate its antioxidant power once released