Search Results (135)

Simultaneous conversion of syngas and sugars is a promising approach to overcome limitations of syngas fermentation. Clostridium autoethanogenum LAbrini, obtained by adaptive laboratory evolution, is known to show improved autotrophic process performance. Under purely autotrophic conditions, C. autoethanogenum LAbrini exhibits substantially faster growth and biomass formation compared to the wild-type in fully controlled, stirred-tank bioreactors with a continuous gas supply. In mixotrophic processes, the pre-culture strategy has a significant impact on the growth and metabolic activity of C. autoethanogenum LAbrini. C. autoethanogenum LAbrini can metabolize sugars (D-fructose, D-xylose, or L-arabinose) and CO simultaneously. All mixotrophic batch processes showed increased growth and product formation compared to the autotrophic process. The mixotrophic batch process with D-fructose enabled superior production of alcohols (10.7 g L⁻¹ ethanol and 3.2 g L⁻¹ D-2,3-butanediol) with a heterotrophic pre-culture. Using an autotrophic pre-culture and L-arabinose resulted in a total alcohol formation of more than 13 g L⁻¹. The formation of meso-2,3-butanediol (>0.50 g L⁻¹) occurred exclusively under mixotrophic conditions. Thus, C. autoethanogenum LAbrini, clearly representing notable improvements over the wild-type strain in mixotrophic batch processes, offers a good basis for further strain improvements to shift the product range even further towards more reduced products. Full article

Oxidative stress contributes to brain aging processes and is implicated in related functional decline. Developing strategies to mitigate oxidative stress is therefore of significant interest. In this study, a neutral polysaccharide (GBPN) was isolated from ginseng berry. Structural analysis revealed that GBPN (molecular weight 1.52 × 10⁴ Da) is primarily composed of glucose (53.18%), arabinose (24.3%), and galactose (16.75%). Glucose exists in the forms of →4)-Glcp-(1→ (32.95%), →6)-Glcp-(1→ (13.81%), and →4,6)-Glcp-(1→ (3.70%), while arabinose exists as →1)-Araf (9.73%), →1)-Arap (5.82%), →2)-Arap-(1→ (0.66%), →5)-Araf-(1→ (7.62%), and →3,5)-Araf-(1→ (1.69%) forms, while galactose exists in the forms of →1)-Galp (3.58%), →3)-Galp-(1→ (1.59%), and →3,6)-Galp-(1→ (12.67%). GBPN adopts a triple-helix conformation and exhibits a curled lamellar appearance. Functionally, GBPN exhibited strong 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl radical scavenging activity, and iron ion chelation capacity. It can activate the antioxidant system in D-galactose-induced aging-like mice, and simultaneously enhance their learning and memory abilities. Mechanistic analysis revealed that these effects are associated with the kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 pathway. These findings suggest that ginseng berry polysaccharides like GBPN hold promise as potential agents for alleviating oxidative stress and cognitive deficits in aging-related contexts. Full article

In recent years, the number of diabetes patients worldwide has been increasing daily, and more than 700 million people are in a prediabetic state. Fructus arctii exhibits notable anti-diabetic activity, but its active components remain unclear. In this study, a polysaccharide (FAP-W) was extracted and characterized using UV, FTIR, HPLC, NMR, AFM, the Congo red test, and SEM. FAP-W has a molecular weight of 1.99 × 10⁴ Da and mainly consists of α-d-glucopyranosyl-(1→2)-[β-d-fructofuranosyl-(1→2)]₁₀-β-d-furanofructosyl units. Monosaccharide analysis revealed mannose, glucose, galactose, and arabinose in a 3.4:23.59:21.27:47.7 ratio. In insulin-resistant HepG2 cells, FAP-W significantly increased glucose consumption, enhanced glycogen content, and elevated HK and PK activities. It also decreased TG, MDA, and ROS levels while improving SOD activity. These results suggest that FAP-W ameliorates insulin resistance, regulates glucose–lipid metabolism, and alleviates oxidative stress, indicating its potential as a functional food or therapeutic candidate for diabetes. Full article

Polymyxin antibiotics are often the last line of defense against multidrug-resistant Gram-negative pathogens. A key resistance mechanism involves the addition of 4-amino-4-deoxy-L-arabinose (L-Ara4N) to lipid A, mediated by the bifunctional enzyme ArnA. However, the evolutionary rationale and structural basis for ArnA’s domain fusion, hexameric assembly, and catalytic coordination remain mechanistically unresolved. Here, we integrate evolutionary genomics, high-resolution cryo-electron microscopy (cryo-EM), and computational protein design to provide a comprehensive mechanistic analysis of ArnA. Our evolutionary analysis reveals that the dehydrogenase (DH) and formyltransferase (TF) domains evolved independently and were selectively fused in Gammaproteobacteria, suggesting an adaptive advantage. A 2.89 Å cryo-EM structure of apo-ArnA resolves the flexible interdomain linker and reveals a DH-driven hexameric architecture essential for enzymatic activity. 3D variability analysis captures intrinsic conformational dynamics, indicating a molecular switch that may coordinate sequential catalysis and substrate channeling. Structure-based peptide inhibitors targeting the hexamerization and predicted ArnA–ArnB interaction interfaces were computationally designed, offering a novel strategy for disrupting L-Ara4N biosynthesis. These findings illuminate a previously uncharacterized structural mechanism of antimicrobial resistance and lay the groundwork for therapeutic intervention. Full article

Fresh coconut meat polysaccharides (FCMPs) are high-value natural active polysaccharides with both medicinal and edible uses, but their structural characteristics and potential biological activities have not been well studied. In this work, FFCMP was separated and purified by sequential application of water extraction and alcohol precipitation methods, the Sevag method, DEAE-52 cellulose column chromatography, and Sephadex G-100 gel column chromatography, yielding four components (FCMP 1-FCMP 4). High-performance liquid chromatography (HPLC) was used to determine their molecular weights as 343,016.9, 2279.4, 1363.2, and 2228.9 Da, respectively. Structural characterization and monosaccharide analysis revealed that the FCMP series primarily consists of mannose, glucose, galactose, arabinose, and rhamnose. Methylation experiments and nuclear magnetic resonance (NMR) indicated that FCMP 1 exhibits a complex topological structure with a β-1→4 main chain, β-1→6 branches, and an α-L-rhamnose terminal; FCMP 2 is a heteropolysaccharide with a β-(1→3)-mannan main chain containing β-(1→6)-galactose branches; the main chain of FCMP 3 consists of β-D-mannose and β-D -galactose, with side chains containing α-L-rhamnose and terminal α-L-arabinose and β-D-mannose; and FCMP 4 has a main chain primarily composed of glucose and mannose linked via 1→4 bonds, with some C6 positions exhibiting 1→6 branch structures. Molecular docking predictions suggest that the FCMP series of polysaccharides possess immunomodulatory, anti-inflammatory, and edema-treating properties, providing a theoretical basis for their application in pharmacology and food science research. Full article

Background: Epilepsy is a high-burden neurological disorder worldwide, and several sedative drugs are used as therapy. Topiramate is among the more recent drugs shown to be effective in some patients, although its benefits are limited. Two carbohydrate derivatives, FB1 (from D-fructose) and AB1 (from D-arabinose), as well as phenylboronic acid, were recently reported as sedative and safe agents in mice. Their sedative properties and structural similarity to topiramate suggest potential antiseizure activity. Objective: The objective of this study was to evaluate the antiseizure potential of FB1 and AB1. Methods: Boron-containing compounds were administered to mice with seizures induced by pentylenetetrazol (a GABA-A receptor antagonist), 4-aminopyridine (a non-selective K⁺ channel blocker), or pilocarpine (a muscarinic agonist) to assess efficacy across models and explore potential mechanisms of action. Neuronal and glial toxicity was evaluated both in vitro and in vivo. Results: AB1 reduced seizure activity after intraperitoneal administration, whereas FB1 did not exhibit anticonvulsant effects, although it modified motor performance and limited neuronal loss. The effect of AB1 was comparable to that of topiramate across all three seizure models. Docking studies suggested that these compounds can interact with GABA-A (chloride), NMDA (glutamate), calcium, and potassium channels. Toxicity assays indicated that the concentrations required to affect neurons or glial cells were ≥300 µM, supporting the safety of these compounds. Conclusions: This preliminary evaluation demonstrates the antiseizure potential of AB1. Further experimental studies are needed to clearly establish its mechanism(s) of action. Full article

Sunflower (Helianthus annuus L.) is a cross-pollinated species that relies on pollinators, attracted by itsnectar composition. Nectar consists primarily of sugars (up to 70%), with sucrose, glucose, and fructose being dominant, while minor components such as mannose, arabinose, xylose, and sugar alcohols (e.g., mannitol and inositol) occur in lower concentrations and vary with biotic and abiotic factors. This study developed a robust high-performance liquid chromatography method with refractive index detection (HPLC-RID) for the simultaneous quantification of eight sugars (D-ribose, xylose, arabinose, fructose, mannose, glucose, sucrose, and maltose) and two sugar alcohols (mannitol, meso-inositol) in wild sunflower nectar. A Box–Behnken design (BBD), coupled with response surface methodology (RSM), was used to systematically optimize column temperature (20–23 °C), acetonitrile concentration (80–85%), and flow rate (0.7–1 mL/min), while achieving baseline separation of critical sugar pairs, including the previously co-eluting glucose/mannitol and glucose/mannose. Satisfactory resolution (Rs > 1 for all analytes) was achieved under optimized separation conditions comprising a column temperature of 20 °C, 82.5% acetonitrile, and a flow rate of 0.766 mL/min. The RSM efficiently evaluated factor interactions to maximize chromatographic performance, resulting in an optimized protocol that provides a cost-effective and environmentally friendly alternative to conventional sugar analysis methods. Method validation confirmed satisfactory linearity across relevant concentration ranges (50–500 mg/L for most sugars; 50–5500 mg/L for fructose and glucose), with correlation coefficients (R) between 0.985 and 0.999. The limits of detection (LOD) and quantification (LOQ) for the analyzed sugars and sugar alcohols ranged from 4.04 to 19.46 mg/L and from 13.46 to 194.61 mg/L, respectively. Glucose exhibited the highest sensitivity showing LOD of 4.04 and LOQ of 13.46 mg/L, whereas mannose was identified as the least sensitive analyte, with LOD of 19.46 mg/L and LOQ of 194.61 mg/L. The described method represents a reliable tool for sugar and sugar alcohol analysis in sunflower nectar and can be extended to other plant and food matrices with suitable sample preparation. Full article

The gut microbiota plays a significant role in metabolic diseases such as obesity. We extracted and purified a new type of pectin polysaccharide (mango peel pectin, MPP) from mango (Mangifera indica L.) peel. The structural analysis results reveal that MPP has a molecular weight (Mw) of 6.76 × 10⁵ Da and the mass fractions of the main components were galacturonic acid (21.36%), glucose (8.85%), and arabinose (5.97%). The results of methylation and NMR analyses reveal that the backbone of MPP consisted of →6)-α-D-GalpAOMe-(1→ and →4)-β-D-Glcp-(1→ linkages. Based on the above structural analysis, we further explored the therapeutic effect of MPP on high-fat diet-induced obese mice. The results demonstrate that MPP significantly suppressed body weight and dyslipidemia, reduced liver damage and lipid accumulation, attenuated changes in adipocyte hypertrophy, and improved glucose homeostasis and insulin resistance, with fasting blood glucose (FBG) levels decreasing by more than 12.8%. Furthermore, the modulatory impact of MPP on gut microbiota composition was investigated. MPP treatment significantly enhanced the levels of short-chain fatty acids (SCFAs) by decreasing the amount of Bacillota and reducing the Bacillota/Bacteroidota ratio, especially with an increase in the total SCFA content of over 64%. Meanwhile, MPP treatment encouraged beneficial bacteria to grow (e.g., Bacteroidota, Akkermansia, and Nanasyncoccus), altered the gut microbiome profiles in mice, and decreased the abundance of harmful bacteria (e.g., Paralachnospira, Coproplasma, Pseudoflavonifractor, Parabacteroides, Acetatifactor, and Phocaeicola). Overall, the findings demonstrate for the first time that MPP treats obesity by alleviating dyslipidemia, improving insulin resistance, and regulating gut microbiota to improve the intestinal environment. Full article

Objectives: Deoxynivalenol (DON) is a ubiquitous mycotoxin detected in the environment and foodstuffs. DON exposure can lead to chronic intestinal inflammation. Therefore, intervention strategy needs to be established to prevent the intestinal inflammation caused by DON. Methods: The structure of Mesona chinensis Benth polysaccharide-3 (MCP-3), a major component isolated and purified from crude MCP, was analyzed using spectroscopic and chromatographic methods. In vitro assays were conducted on the potential antioxidant bioactivities of MCP-3 and its ameliorative effects on deoxynivalenol-induced oxidative stress in intestinal epithelial cells. Results: Saline-eluted MCP-3 was identified as an acidic heterogeneous polysaccharide with an average molecular weight of 16.014 kDa. Its major monosaccharide components were glucose (20.19%), galactose (11.82%), rhamnose (17.23%), galacturonic acid (29.72%), arabinose (7.11%), xylose (8.09%), mannose (2.79%), and glucuronic acid (3.04%). The main backbone of MCP-3 was composed of the following sequence: →4)-α-D-GalpA-6-(1→4)-α-GalpA-(1→4)-α-D-GalpA-6-(1→2)-α-L-Rhap-(1→4)-α-D-GalpA-6-(1→2,4)-α-L-Rhap-(1→. MCP-3 showed strong antioxidant ability in in vitro assays. It effectively prevented redox imbalance induced by the mycotoxin deoxynivalenol in intestinal epithelial cell models based on Caco-2 and NCM460 cells. MCP-3 significantly increased (p < 0.05) the activities of superoxide dismutase, glutathione peroxidase, and catalase, and significantly decreased (p < 0.05) the levels of malondialdehyde and reactive oxygen species, thereby improving redox homeostasis. Conclusions: MCP-3 has potential as a natural antioxidant for use in functional food and nutraceutical industries to help regulate intestinal oxidative stress caused by mycotoxin DON. Full article

One of the world’s most sustainable solutions is to replace fossil-based polymers with biopolymers. The production of xanthan gum can be optimized using various renewable and cost-effective raw materials, which is a key focus in industrial biotechnology. Xanthan gum is a bioengineered thickening, stabilizing, and emulsifying agent. It has unique properties for use in many industries (food, biotechnology, petrochemicals, agricultural, cosmetics, wastewater treatment) and medical applications. It is tasteless, environmentally safe, non-toxic, and biodegradable. The biotechnological production of xanthan gum depends on several factors: bacterial strain development, culture medium preparation, carbon sources, fermentation parameters and modes, pH, temperature, recovery, purification, and quality control regulations. Bio-innovative strategies have been developed to optimize the production of xanthan gum. A variety of carbon and nitrogen sources, as well as alternative renewable sources, have been used in the production of xanthan gum. The aim of the present study was to optimize the xanthan gum yield using Xanthomonas campestris bacteria and different carbon (D-glucose, D-sorbitol, lactose, sucrose, D-mannitol, D-fructose, erythritol, coconut palm sugar, L-arabinose, unrefined cane sugar), various nitrogen (bacterial peptone, casein peptone, L-glutamic acid, L-arginine, L-methionine, L-tryptophan, malt extract, meat extract, L-phenylalanine, soy peptone) and alternative carbon (orange peels, tangerine peels, lemon peels, avocado peels, melon peels, apple peels, cellulose, xylose, xylitol) sources. The xanthan gum samples were analyzed using antioxidant methods. Our study showed that using L-glutamic acid as the carbon source for 72 h of bacterial fermentation of Xanthomonas campestris resulted in the highest xanthan gum yield: 32.34 g/L. However, using renewable resources, we achieved a very high concentration of xanthan gum in just 24 h of fermentation. According to the reducing power and DPPH methods, the highest antioxidant activities were measured for xanthan gum whose biosynthesis was based on renewable resources. Xanthan gum structures have been verified by FT-IR and ¹H NMR analysis. The sustainable biotechnology study has the advantage of increasing the sustainable production of xanthan gum by using renewable alternative resources compared to other production processes. Xanthan gum continues to be a valuable biopolymer with a wide range of industrial applications while promoting environmentally friendly production practices. Full article

Wild fruits are distributed worldwide, but are consumed mainly in developing countries, where they are an important part of the diet. Still, in many other countries, they are consumed only locally. Blackthorn (Prunus spinosa L.) is an underutilized species rich in fibres and phenolic compounds, making it suitable as a potential functional food for supporting human health. Cold (Cw) and hot (Hw) water-extracted (poly)phenolic polysaccharide–protein complexes, differing in carbohydrate, phenolic and protein contents, were isolated from blackthorn fruits and characterized. The complexes exhibited molecular weights of 235,200 g/mol (Cw) and 218,400 g/mol (Hw), and were rich in pectic polymers containing galacturonic acid, arabinose, galactose and rhamnose, indicating a dominance of homogalacturonan (HG) [→4)-α-D-GalA(1→4)-α-D-GalA(1→]n and a low content of RGI [→2)-α-L-Rha(1→4)-α-D-GalA(1→2)-α-L-Rha(1→]n sequences associated with arabinan or arabinogalactan. Minor content of glucan, probably starch-derived, was also solubilized. Pectic polysaccharides were highly esterified and partly acetylated. Pharmacological testing was performed in male Dunkin–Hartley guinea pigs, a model with human-like airway reflexes. Both complexes affected airway defense mechanisms. Particularly, Hw significantly suppressed citric acid-induced cough, similar to codeine, and reduced bronchoconstriction comparably to salbutamol in a dose-dependent manner. These findings support further exploration of Hw as a natural antitussive and bronchodilatory agent. Full article

As global milk production continues to rise, the disposal of expired milk contributes to environmental pollution and valuable resource wastage. This study presents the development of a novel L-arabinose isomerase, designated BmAIase12, and its application in the enzymatic recycling of expired milk. BmAIase12 exhibited a specific activity of 10.7 U/mg and showed optimal performance at 50 °C and pH 7.0. Furthermore, it exhibited higher activity than most other L-arabinose isomerases. It converted D-galactose into D-tagatose with a high conversion ratio of 53.3% after 48 h at 50 °C. The conversion efficiency of expired milk to D-tagatose was recorded at 40.62%, resulting in a maximum tagatose yield of 1.625 g/L. This was accomplished through the incorporation of β-galactosidase (120 U/mL) and Saccharomyces cerevisiae (30 mg/mL) to hydrolyze lactose and metabolize glucose, followed by the addition of 3 U/mL of BmAIase12. Ultimately, following purification, the purity of tagatose was determined to be 98%, and the final yield was 29.8%. These results suggest that BmAIase12 may serve as a promising enzyme for D-tagatose production due to its high conversion yield. Full article

The electrocatalytic reduction of O₂ via two-electron reaction (2e-ORR) to H₂O₂ represents a promising alternative to the current anthraquinone process, since it is advantageous in the sustainable and decentralized production of H₂O₂. Herein, we report the development of oxygen and nitrogen-rich few-layered graphene-like materials (ms-dcda) by the one-step carbonization of biomass-sourced monosaccharides (D-glucose, D-fructose, D-galactose, D-ribose, D-xylose, L-arabinose, and D-mannose) with the aid of dicyandiamide for electrochemical O₂ reduction to H₂O₂. The ms-dcda materials were porous and possessed wrinkled morphology typical of graphene nanosheets. In H₂O₂ production via 2e-ORR in an acidic electrolyte, these ms-dcda materials were all active and stable catalysts, among which glu-dcda derived from D-glucose and dicyandiamide displayed the lowest onset potential of 0.553 V and the highest selectivity of up to 91.6%. The catalyst was also highly stable in chronoamperometric tests. Selective chemical titration of the C–OH and C=O groups revealed that the latter is far more active and selective than the former in 2e-ORR. Moreover, a positive correlation between the contents of C=O and pyrrolic N and the H₂O₂ partial current suggests that the pyrrolic N group also contributes to 2e-ORR. This work affords a facile strategy for the sustainable fabrication of metal-free carbon-based catalysts efficient for H₂O₂ electrosynthesis. Full article

D-tagatose is a functional sweetener with glucose-regulating and prebiotic properties, but its bioproduction from D-galactose faces many limitations, particularly the high production costs. In particular, the current biosynthesis of D-tagatose suffers from thermal instability and the substrate selectivity issues of L-arabinose isomerase (L-AI) required to convert D-galactose into D-tagatose. In this study, recombinant Escherichia coli BW25113/pQE-80L-araA_F118M/F279I expressing double mutant L-AI was immobilized to enhance its stability and reusability. The optimal conditions for whole-cell catalysis were 60 °C, pH 6.5, 5 mM Mn²⁺, and 20 h, with a yield of 55.2 g/L of D-tagatose. Immobilization with 3% sodium alginate and 2% CaCl₂ retained 90% of the production efficiency displayed by free cells. Notably, the immobilized cells exhibited enhanced heat resistance (60–70 °C) and operational stability, retaining 76% activity after five cycles. The D-tagatose production was further increased to 129.43 g/L by increasing the substrate concentration to 250 g/L. Compared to free cells, immobilized cells retained 83.6% of the initial yield up to 10 batches. This study presents a cost-effective and sustainable method for the production of D-tagatose using optimized whole-cell catalysis through immobilization, which paves the way to solve industrial challenges such as thermal instability and low substrate efficiency. Full article

In the study presented herein, an aerobic, Gram-stain-positive, spore-forming bacterium, designated as WLY-B-L8^T, was isolated from a qu-starter (baobaoqu) cultivation facility used for the production of Wuliangye baijiu in Yibin city (Sichuan province, China). The strain comprised short, rod-shape cells of 1.2–1.9 μm in width and 1.7–4.8 μm in length, arranged singly or in pairs. The isolate was able to grow at temperatures of 20–42 °C (optimum growth at 40 °C), pH 5.0–10.0 (optimum growth at pH 8.0), and in the presence of 0–2% (w/v) NaCl (optimum growth with 1% NaCl). Ribose, xylose, arabinose, mannose, glucose, and galactose constituted the major cell-wall sugars. Moreover, meso-diaminopimelic acid (meso-DAP) constituted the diagnostic amino acid. The main polar lipids of WLY-B-L8^T included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), unidentified aminolipids (UAL 1–2), an unidentified aminophospholipid (UAPL), an unidentified aminoglycolipid (UAGL), and an unidentified lipid (UL). MK-7 was the predominant menaquinone and iso-C_15:0 (23.00%) was the major fatty acid. Comparisons of the 16S rRNA gene sequence indicated that WLY-B-L8^T was most closely related to Bacillus rhizoplanae JJ-63 DSM 12442^T (98.71%), Bacillus pseudomycoides DSM 12442^T (98.21%), and Bacillus cytotoxicus NVH 391–98^T (98.14%). The average nucleotide identity (ANI) values of strain WLY-B-L8^T and the three type strains mentioned above were 88.24%, 80.57%, and 78.70%. The average amino identity (AAI) values between them were 89.84%, 79.51%, and 80.41%. In addition, the digital DNA–DNA hybridization (dDDH) values between them were 36.70%, 26.10%, and 23.90%. The genomic DNA G+C content was 35.97%. Based on the evidence presented herein, WLY-B-L8^T (CICC 25210^T = JCM 36284^T) exhibits promise as the type strain of a novel species, designated as Bacillus multifaciens sp. nov., that can produce protease (119.38 ± 7.44 U/mL) and volatile flavor components when cultured on raw wheat, such as 2-pipendinone (21.95 ± 1.56 mg/L), phenylethyl alcohol (19.08 ± 0.82 mg/L), hydrocinnamic acid (18.60 ± 0.53 mg/L), and acetoin (7.58 ± 0.11 mg/L). Full article