Search Results (42)

This review examines the role of sulfate-reducing bacteria in the anaerobic degradation of hydrocarbons in marine sediments, where they contribute to the mineralization of organic matter under anoxic conditions. The metabolic diversity of these microorganisms is described, including their ability to degrade various classes of hydrocarbons such as short-chain (C₂–C₅), medium-chain (C₆–C₁₂), and long-chain (C₁₃–C₂₀₊) alkanes, alkenes, and aromatic compounds like naphthalene and phenanthrene. The primary mechanisms involved in the initial activation of these hydrocarbons—fumarate addition and carboxylation—are discussed, along with key enzymes, including alkylsuccinate synthase and benzylsuccinate synthase. Syntrophic interactions are also considered, particularly in which archaea initiate the oxidation of short-chain alkanes (e.g., ethane and butane), with sulfate-reducing bacteria serving as terminal electron acceptors via sulfate reduction. The potential application of these anaerobic processes in bioremediation strategies for oil-contaminated marine sediments is discussed. This microbially mediated degradation may offer a complementary approach to aerobic methods, particularly in oxygen-limited environments. Understanding the activity of sulfate-reducing bacteria activity is relevant to several areas: the development of remediation techniques for anoxic zones, the assessment of methane emissions from marine sediments, the management of microbiologically influenced corrosion, and potential biotechnological applications. Current research directions include the study of syntrophic microbial consortia and the exploration of bioelectrochemical systems. Full article

In this paper, the antifungal activity of medium-chain fatty acids with 8 to 11 carbon atoms in their chemical structures, medium-chain fatty acid lactones, and a partially fluorinated medium-chain fatty acid was determined. As the length of the alkyl chain increased in medium-chain fatty acids with 8 to 11 carbon atoms, the MIC and MFC became smaller, with increased antifungal activity (octanoic acid, 225 µg/mL(MIC), 450 µg/mL (MFC); nonanoic acid, 225 µg/mL (MIC), 450 µg/mL (MFC); decanoic acid, 112.5 µg/mL (MIC), 225 µg/mL (MFC); undecanoic acid, 112.5 µg/mL (MIC), 225 µg/mL (MFC)), whereas the antifungal activity of γ-undecalactone, in which the carboxyl group of the medium-chain fatty acid with 11 carbon atoms was converted to a five-membered lactone ring, also had antifungal activity (γ-undecalactone, 112.5 µg/mL (MIC), 225 µg/mL (MFC)). The antifungal activity of the partially fluorinated fatty acid with 11 carbon atoms and δ-undecalactone was not observed and their MICs were not evaluated in this study. The equation derived through multiple regression analysis revealed that the polarizability value was significantly related to the MICs or MFCs of fatty acids containing 8 to 11 carbon atoms and γ-undecalactone (R² = 0.78, p < 0.05). C. albicans cultured at 37 °C with γ-undecalactone at the MIC formed hyphae or biofilms, which were observed using scanning electron microscopy in this study. Dead C. albicans were observed when cultured at 37 °C with γ-undecalactone at the MFC, indicating that in order to demonstrate complete killing, C. albicans must be killed at or above the MFC of γ-undecalactone when cultured at 37 °C. γ-undecalactone exhibited no hemolytic activity at the MFC, similar to negative controls. Our results show that γ-undecalactone has an antifungal effect against C. albicans over the MFC, without hemodialysis as the observed cytotoxicity. Full article

Kargı Tulum cheese differs from other Tulum cheeses with its unique production and ripening method. No systematic study has yet explored the change in the volatile compounds and fatty acids during the ripening process of Kargı Tulum cheese. The objective of this study was to monitor the change in the fatty acids and volatile compounds of Kargı Tulum cheese at different time points during the production and ripening stages. Fatty acid profile, lipid quality parameters and volatile compound profiles were determined. A principal component analysis (PCA) was performed to determine how the volatile profiles differed across production and ripening stages. During the ripening, short- and medium-chain fatty acids (FAs) increased with notably high levels of butyric acid. Lipid quality parameters, including total saturated FAs (SFAs), atherogenicity index (AI), and thrombogenicity index (TI), remained unchanged throughout ripening. A total of 62 volatile compounds (VOC) were detected. Esters and ketones were the most abundant groups in fresh curds, while carboxylic acids became the dominant group by the end of the ripening process. The total concentration of most VOC increased over time. Butyric acid, hexanoic acid, ethyl hexanoate and acetic acid were the dominant compounds contributing the flavor of the Kargı Tulum cheese. This study presents data on what flavor compounds form and how they change during ripening and can be useful for comparative purposes in future studies on ripened raw milk cheeses. Full article

Medium-chain aliphatic compounds bearing oxygen-containing functional groups—such as alcohols, ketones, or carboxylic acids—have attracted increasing attention due to their potential as bioactive agents in pest management. These compounds have demonstrated diverse biocidal properties, including insecticidal, antimicrobial, fungicidal, and nematicidal activities. In this study, the nematicidal potency of three structurally related C9 aliphatic ketones—2-nonanone, 3-nonanone, and 5-nonanone—was evaluated against Bursaphelenchus xylophilus, the pinewood nematode (PWN). These isomeric ketones differ in the position of the carbonyl group, providing a useful model for examining structure–activity relationships (SAR) among positional isomers. The direct-contact bioassays, performed at 1 mg/mL, revealed that 2-nonanone exhibited the highest nematicidal activity, causing 92.3 ± 1.2% mortality on the PWN, followed by 3-nonanone at 80.1 ± 0.8%, while 5-nonanone showed significantly lower activity at 17.1 ± 0.5%. The results suggest a strong dependency of bioactivity on the position of the carbonyl group along the carbon chain. The increasing efficacy from 5- to 2-nonanone suggests that proximity of the carbonyl group to the terminal end may enhance activity, for example, by enhancing membrane interaction or disrupting nematode metabolic processes. These findings underscore the importance of molecule structure analysis in designing effective nematicidal agents and support further investigation into terminally positioned oxygenated medium-carbon chain aliphatic compounds as potential leads. This work highlights that subtle structural differences within homologous series can significantly influence bioactivity and provides a foundation for developing targeted, biodegradable nematicides derived from simple aliphatic frameworks. Full article

In this study, canola oil was used as a natural enriched source of C18 fatty acids and coconut oil as a natural enriched source of C12 fatty acids. The study synthesized five potassium carboxylate (RCOO⁻K⁺) liquid soaps via saponification of coconut–canola oil blends (100:0, 75:25, 50:50, 25:75, 0:100) using a novel in situ dissolution method with controlled KOH addition to prevent solid paste formation. The water demand required to dissolve RCOO⁻K⁺ and mitigate soap crystallization was determined, increasing from 1.76 to 5.18 g H₂O/g oil as canola oil content rose, with soap concentration decreasing from 55.1% (100:0) to 18.5% (0:100). Reaction kinetics revealed faster KOH depletion in coconut oil-rich blends (100:0, 75:25, 50:50; 2 h) compared to canola oil-rich blends (25:75, 0:100; 8 h). Key soap properties, including foam stability, detergency, wettability, viscosity, and thermal behavior, were assessed. The 50:50 blend exhibited the highest foam stability due to the synergistic effects of medium-chain saturated (e.g., laurates) and long-chain unsaturated (e.g., oleates) RCOO⁻K⁺. The short, saturated chains promoted rapid foam formation, while the longer, unsaturated chains enhanced foam film stability. RCOO⁻K⁺ detergency on hair tresses with artificial sebum ranged from 16.9% to 29.7% and was relatively higher compared to sodium lauryl sulfate, sodium laureth sulfate, cocamidopropyl betaine, and sodium cocoyl glutamate (6.1–13.2%) but lower compared to sodium isethionates (34.2%). RCOO⁻K⁺ wettability on cotton textiles improved with higher coconut oil content. RCOO⁻K⁺ contact angles on artificial sebum surface (6.1–13.7°) demonstrated excellent wettability, effectively penetrating and emulsifying hydrophobic residues. Viscosity ranged from 13–45 mPa·s with Newtonian Flow-type behavior. No crystals were observed in the soaps when cooled in the range of 60 to −30 °C. These results demonstrate RCOO⁻K⁺ soaps as tunable, sustainable liquid soaps with performance optimized by adjusting the oil blend ratios. Full article

The growing demand for sustainable lubricant solutions is driving the exploration of bio-based materials that deliver comparable performance to conventional, primarily fossil-based lubricant chemistries. This study focuses on squalane as a sustainable base oil, which can be derived from different renewable sources. A total of two squalane products were evaluated for thermal-oxidative stability and benchmarked against a polyalphaolefin, PAO 4, of the same total carbon number. Oils artificially altered in a closed reactor were sampled and subjected to conventional lubricant analyses, including infrared spectroscopy, to determine the changes due to autoxidation over time. For in-depth information, direct-infusion high-resolution mass spectrometry and gas chromatography coupled with triple quadrupole mass spectrometry were employed to identify degradation products from thermo-oxidative stress. The results revealed substantial variability in the stability of squalane products, suggesting that differences in raw materials and production processes have a major impact on their performance, including rheological properties. The degradation products of polyalphaolefin and squalane, identified through detailed mass spectrometry, were analyzed to understand their impact on conventional physicochemical properties. While polyalphaolefin predominantly generated carboxylic acids with short to medium chain lengths as degradation products, squalane oxidation produced carboxylic acids with medium to long chain lengths as well as several alcohols and ketones. Despite these differences, squalane demonstrates its potential as a non-fossil hydrocarbon base oil, as squalane products matched and even exceeded PAO 4 stability. Full article

As a promising polymer for the production of biomaterials and drug delivery systems, poly(lactic acid) (PLA) is characterized by its relative hydrophobicity, as well as its chemical and biological inertness. Here, we aimed to improve the biological properties of PLA-based materials via the covalent attachment of a hydrophilic biocompatible glycopolymer, namely poly(2-deoxy-N-methacrylamido-D-glucose) (PMAG) on their surface. PMAG is a water-soluble polymer that contains glucose units in its side chains, which are responsible for good biocompatibility and the ability to attach bioactive molecules. In the developed protocol, PMAG was synthesized by controlled radical polymerization in the presence of a reversible addition–fragmentation chain transfer (RAFT) agent, followed by the conversion of glycopolymer terminal dithiobenzoate functionality into a primary amino group (PMAG-NH₂). PLA-based films served as model aliphatic polyester materials for developing the surface biofunctionalization protocol. According to that, PMAG-NH₂ covalent immobilization was carried out after alkali treatment, allowing the generation of the surface-located carboxyl groups and their activation. The developed modification method provided a one-point attachment of hydrophilic PMAG to the hydrophobic PLA surface. PMAG samples, which differed by the degree of polymerization, and the variation of polymer concentration in the reaction medium were applied to investigate the modification efficacy and grafting density. The developed single-point polymer grafting approach provided the efficient functionalization with a grafting density in the range of 5–23 nmol/cm². The neat and modified polymer films were characterized by a number of methods, namely atomic force microscopy, thermogravimetric analysis, ellipsometry, and contact angle measurements. In addition, an ArgGlyAsp-containing peptide (RGD peptide) was conjugated to the PMAG macromolecules grafted on the surface of PLA films. It was shown that both surface modification with PMAG and with PMAG-RGD peptide enhanced the adhesion and growth of mesenchymal stem cells as compared to a neat PLA surface. Full article

Infections are a common post-operative ailment for patients who have received a dental implant or device and can be attributed to biofilm formation in tissue or on the implant. Many current solutions for oral hygiene have side effects and affect the natural oral microbiome. 2-heptylcyclopropane-1-carboxylic acid (2CP) is a medium-chain fatty acid and synthetic diffusible signaling factor that can prevent and disperse biofilm. The purpose of this work was to evaluate an immersion strategy for coating hydroxyapatite (HAp) with 2CP to prevent biofilm attachment on and around natural teeth and dental implants. The release profile of 2CP-loaded and 2CP+oral rinse-loaded HAp coupons (n = 6) was assessed by a 3-day exposure to phosphate buffered saline (PBS). Antimicrobial properties against Porphyromonas gingivalis and cytocompatibility of 2CP-loaded HAp coupons (n = 4) were also assessed alone and in combination with 0.12% chlorhexidine gluconate oral rinse. The majority of 2CP is released by 12 h. 2CP, oral rinse, and 2CP+oral rinse significantly reduced P. gingivalis viability, though direct contact assay demonstrates a significant reduction in Saos-2 viability for oral rinse and 2CP+oral rinse coupons. Immersion or rinsing hydroxyapatite with 2CP could inhibit biofilm-associated dental infections and prevent further complications including caries, gingivitis, and peri-implantitis. Full article

A large amount of cattle manure is generated in the US every year, creating challenges for ecosystem sustainability while offering opportunities for value-added products through biorefinery. While methods like land application, composting, and anaerobic digestion are well established for treating cattle manure, advanced biorefinery technologies are needed to enhance the utilization of cattle manure or its digestate. Based on the composition of cattle manure, this review discusses technologies for the biorefinery of cattle manure or its digestate, including the recovery of fiber and protein, and the production of platform chemicals, such as volatile fatty acids, lactic acid, medium-chain carboxylic acids, ethanol, single-cell protein, and lipids. Additionally, this review discusses process integration for simultaneously producing multiple value-added products from cattle manure using various biorefinery technologies. By offering insights into different approaches, this review aims to support the development of integrated biorefinery processes, thereby improving the economic and environmental sustainability of cattle manure management. Full article

The pH- and thermo-responsive behavior of polymeric hydrogels $\left({\mathrm{M}}_{\mathrm{C}}-\mathrm{c}\mathrm{o}-{\mathrm{M}}_{\mathrm{A}}\right)$ have been studied in detail using dynamic light scattering $\left(\mathrm{D}\mathrm{L}\mathrm{S}\right)$, scanning electron microscopy$\left(\mathrm{S}\mathrm{E}\mathrm{M}\right)$, nuclear magnetic resonance (¹H NMR) and rheology to evaluate the conformational changes, swelling–shrinkage, stability, the ability to flow and the diffusion process of nanoparticles at several temperatures. Furthermore, polymeric systems functionalized with acrylic acid $\left({\mathrm{M}}_{\mathrm{C}}\right)$ and acrylamide $\left({\mathrm{M}}_{\mathrm{A}}\right)$ were subjected to a titration process with a calcium chloride $\left({\mathrm{C}\mathrm{a}\mathrm{C}\mathrm{l}}_2\right)$ solution to analyze its effect on the average particle diameter$\left({\mathrm{D}}_{\mathrm{z}}\right)$, polymer structure and the intra- and intermolecular interactions in order to provide a responsive polymer network that can be used as a possible nanocarrier for drug delivery with several benefits. The results confirmed that the structural changes in the sensitive hydrogels are highly dependent on the corresponding critical solution temperature $\left(\mathrm{C}\mathrm{S}\mathrm{T}\right)$ of the carboxylic (–COOH) and amide (–CONH₂) functional groups and the influence of calcium ions $\left({\mathrm{C}\mathrm{a}}^{2+}\right)$ on the formation or breaking of hydrogen bonds, as well as the decrease in electrostatic repulsions generated between the polymer chains contributing to a particle agglomeration phenomenon. The temperature leads to a re-arrangement of the polymer chains, affecting the viscoelastic properties of the hydrogels. In addition, the diffusion coefficients $\left(D\right)$ of nanoparticles were evaluated, showing a closeness among with the morphology, shape, size and temperature, resulting in slower diffusions for larger particles size and, conversely, the diffusion in the medium increasing as the polymer size is reduced. Therefore, the hydrogels exhibited a remarkable response to pH and temperature variations in the environment. During this research, the functionality and behavior of the polymeric nanoparticles were observed under different analysis conditions, which revealed notable structural changes and further demonstrated the nanoparticles promising high potential for drug delivery applications. Hence, these results have sparked significant interest in various scientific, industrial and technological fields. Full article

The quinoline ring is found in many biologically active natural alkaloids and is still being highly exploited by researchers due to its numerous potential applications in fields ranging from pharmacology to material science. During our synthetic attempts for new quinoline-4-carboxylic acids, using an extended version of the Doebner reaction, a new puzzling compound emerged when para-iodine aniline was reacted with salicylaldehyde and pyruvic acid in acetic acid as a reaction medium. The chemical structure of this new compound was established based on the information obtained from 1D and 2D NMR experiments (¹H-, ¹³C-, and ¹⁵N-NMR), corroborated with MS spectrometry and IR spectroscopy. The photophysical properties (UV–vis and fluorescence) were also investigated. The proposed structure contains as the main elements a 1,4-dioxane-2,5-dione core symmetrically substituted with a propylidene chain that has attached to it a salicylaldehyde fragment and a pyrrole-2-one ring containing two 4-iodophenyl fragments. The isolation of this compound, reported here for the first time, is direct evidence that unexpected compounds can emerge from “classical” synthetic pathways when the right components are combined. Full article

Accurate and reliable quantification of organic acids with carboxylic acid functional groups in complex biological samples remains a major analytical challenge in clinical chemistry. Issues such as spontaneous decarboxylation during ionization, poor chromatographic resolution, and retention on a reverse-phase column hinder sensitivity, specificity, and reproducibility in multiple-reaction monitoring (MRM)-based LC–MS assays. We report a targeted metabolomics method using phenylenediamine derivatization for quantifying carboxylic acid-containing metabolites (CCMs). This method achieves accurate and sensitive quantification in various biological matrices, with recovery rates from 90% to 105% and CVs ≤ 10%. It shows linearity from 0.1 ng/mL to 10 µg/mL with linear regression coefficients of 0.99 and LODs as low as 0.01 ng/mL. The library included a wide variety of structurally variant CCMs such as amino acids/conjugates, short- to medium-chain organic acids, di/tri-carboxylic acids/conjugates, fatty acids, and some ring-containing CCMs. Comparing CCM profiles of pancreatic cancer cells to normal pancreatic cells identified potential biomarkers and their correlation with key metabolic pathways. This method enables sensitive, specific, and high-throughput quantification of CCMs from small samples, supporting a wide range of applications in basic, clinical, and translational research. Full article

Utilities of whey powder (WP) and whey protein concentrate 34% powder (WPC34) prepared as dairy-processing residues were evaluated using a green alga Chlamydomonas reinhardtii. Analysis of C. reinhardtii growth showed that the strain used WP and WPC34 as nitrogen sources. Its specific growth rate and maximum cell density in WP-containing medium were higher than those in WPC34-containing medium; growth with WPC34 was improved by adding KCl or K₂HPO₄, which content was decreased as a result of WPC34’s preparation from WP. Although the lipid contents in media containing dairy-processing residues were 2.72 ± 0.31 wt% and 2.62 ± 0.20 wt% with no significant difference, the composition ratio of fatty acid C14 with WPC34 was higher than that with WP and the composition ratio of the sum of fatty acid-C16 and -C18 with WPC34 tended to be lower than that with WP. Additionally, analyses of gene transcription showed that the transcription level of acetyl-CoA carboxylase biotin carboxyl carrier protein in WPC34-containing medium was lower than that in WP-containing medium, possibly affecting the ratios of the chain lengths of fatty acids. The transcription of genes involved in glycolysis and the TCA cycle was outstandingly lower in algae grown in WPC34-containing medium when compared to those cultivated in the presence of WP, resulting in differences in energy production for cell proliferation. Full article

To establish a circular economy, waste streams should be used as a resource to produce valuable products. Biodegradable plastic waste represents a potential feedstock to be microbially recycled via a carboxylate platform. Bioplastics such as polylactic acid food packaging waste (PLA-FPW) are theoretically suitable feedstocks for producing carboxylates. Once feasible, carboxylates such as acetate, n-butyrate, or n-caproate can be used for various applications like lubricants or building blocks for making new bioplastics. In this study, pieces of industrial compostable PLA-FPW material (at 30 or 60 g/L) were added to a watery medium with microbial growth nutrients. This broth was exposed to 70 °C for a pretreatment process to support the hydrolysis of PLA into lactic acid at a maximum rate of 3.0 g/L×d. After 21 days, the broths of the hydrolysis experiments were centrifugated and a part of the supernatant was extracted and prepared for anaerobic fermentation. The mixed microbial culture, originating from a food waste fermentation bioprocess, successfully fermented the hydrolyzed PLA into a spectrum of new C2-C6 multi-carbon carboxylates. n-butyrate was the major product for all fermentations and, on average, 6.5 g/L n-butyrate was obtained from 60 g/L PLA-FPW materials. The wide array of products were likely due to various microbial processes, including lactate conversion into acetate and propionate, as well as lactate-based chain elongation to produce medium-chain carboxylates. The fermentation process did not require pH control. Overall, we showed a proof-of-concept in using real bioplastic waste as feedstock to produce valuable C2-C6 carboxylates via microbial recycling. Full article

The main purpose of this article is to explore the mechanism of action of carbon-based materials in the anaerobic digestion (AD) production of medium-chain carboxylic acids (MCCA). Currently, there are various methods to increase production, but there is no review on how carbon-based materials improve MCCA. This paper first introduced the chain elongation (CE) technology, focusing on the factors affecting the production of MCCA by AD, such as pH, temperature, the ratio of electron donor (ED) to an electron acceptor (EA), substrate type, and other related factors. This article introduces the preparation and characteristics of carbon-based materials, as well as the effect and mechanism of adding carbon-based materials to AD acid production. Finally, the shortcomings of the current research were pointed out, and future research directions were prospected, aiming to provide a reference for improving the efficiency of AD of MCCA using carbon-based materials. Full article