Search Results (45)

This study explored the potential of chitosan (CH)/bacterial cellulose (BC) complexes (0.5% w/v) as novel emulsifiers to stabilize oil-in-water (o/w) Pickering emulsions (20% v/v sunflower oil), with a focus on their gel-like behavior. Emulsions were prepared using CH combined with BNC derived via H₂SO₄ (BNC1) or H₂SO₄-HCl (BNC2) hydrolysis. Increasing BNC content improved stability by reducing phase separation and enhancing viscosity, while CH contributed interfacial activity and electrostatic stabilization. CH/BNC1_25:75 emulsions showed the highest stability, maintaining an emulsion stability index (ESI) of up to 100% after 3 days, with minimal change in droplet size (R_h ~8.5–8.8 μm) and a positive ζ-potential (15.1–29.8 mV), as confirmed by dynamic/electrophoretic light scattering. pH adjustment to 4 and 10 had little effect on their ESI, while ionic strength studies showed that 0.1 M NaCl caused only a slight increase in droplet size combined with the highest ζ-potential (−35.2 mV). Higher salt concentrations led to coalescence and disruption of their gel-like structure. Rheological analysis of CH/BNC1_25:75 emulsions revealed shear-thinning behavior and dominant elastic properties (G′ > G″), indicating a soft gel network. Incorporating sunflower-seed protein isolates into CH/BNC1 (25:75) emulsions led to coacervate formation (three-layer system), characterized by a decrease in droplet size and an increase in ζ-potential (up to 32.8 mV) over 7 days. These findings highlight CH/BNC complexes as sustainable stabilizers for food-grade Pickering emulsions, supporting the development of biopolymer-based emulsifiers aligned with bioeconomy principles. Full article

Ecological restoration has increasingly been employed to reverse land degradation and increase carbon (C) sink, especially in ecologically fragile karst areas. Microbial necromass carbon (MNC) constitutes a critical pool within soil organic carbon (SOC), contributing substantially to long-term C sequestration through mineral stabilization. However, its distribution patterns across soil profiles and grassland restoration stages in karst areas remain unclear. To address this knowledge gap, the contents of bacterial necromass C (BNC), fungal necromass C (FNC), and their contributions to SOC were estimated based on glucosamine and muramic acid contents across the soil profile (0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm, and 80–100 cm) for four subalpine restoration stages (grazing enclosure for 5, 11, 17, and 25 years) in the karst region. Our findings demonstrated that both soil depth and grassland restoration stages effectively influenced the BNC and FNC contents. On average, the soil BNC, FNC, and total MNC at the depth of 80–100 cm reduced by 70.50%, 59.70%, and 62.18% compared with in topsoil (0–20 cm), respectively. However, the FNC/BNC ratio gradually increased with the increase in soil depth, which was 43.15% higher at 80–100 cm soil depth than in topsoil, suggesting that the accumulation efficiency of FNC was higher compared to BNC in the deep soil. The BNC, FNC, and MNC were positively correlated with the grassland restoration stage, while FNC/BNC ratio had a negative relationship with the restoration stage (R² = 0.45, p < 0.001). FNC contributed significantly more to SOC (28.6–36.4%) compared to BNC (7.7–9.9%) at all soil depths, indicating that soil fungal necromass has an essential effect on SOC sequestration. The results of the random forest model and distance-based redundancy analysis identified that pH, soil water content, and dissolved organic carbon were the three most essential predictors for the contribution of MNC to SOC. Our study highlights the importance of microbial necromass to SOC accumulation, providing significant scientific implications for the C pool management during the restoration of degraded grasslands in karst regions. Full article

In this study, cellulose nanocrystals (CNCs) were successfully isolated through the acid hydrolysis of freeze-dried and oven-dried bacterial nanocellulose (BNC) recovered from the floating pellicle generated during Kombucha tea production. The influence of the BNC drying method and its concentration on the yield and main characteristics of the CNCs obtained were studied. Additionally, selected CNC suspensions at various pH levels were subjected to freeze-drying and oven-drying, followed by an assessment of their dispersibility in water after undergoing different mechanical treatments. Results demonstrate the potential of utilizing byproducts from the expanding Kombucha industry as an alternative cellulose source for CNC production. Furthermore, the drying method applied to the BNC and its initial concentration in the hydrolysis medium were found to significantly impact the properties of the resulting CNCs, which exhibited diverse size distributions and Z-potential values. Finally, the redispersion studies highlighted the beneficial effect of drying CNCs from neutral and alkaline dispersions, as well as the requirement of ultrasound treatments to achieve the proper dispersion of dehydrated CNC powders. Full article

Given the growing interest in the functional properties of nanocellulosic forms, bacterial cellulose nanocrystals (BCNCs) have gained attention as sustainable, high-performance materials for diverse applications. Although recent research has addressed the use of agro-industrial waste for BCNCs production, limited attention has been given to residual crude glycerol, a widespread byproduct of the biodiesel industry. Therefore, this work aimed to synthesize and thoroughly characterize BCNCs from bacterial nanocellulose (BNC) obtained through the metabolism of crude glycerol via the novel bacterial strain Ancylobacter sp. STN1A. The influence of sulfuric acid (H₂SO₄) hydrolysis time on BCNCs´ morphology and physicochemical properties was evaluated. Severe hydrolysis conditions yielded shorter, narrower nanocrystals (0.91 μm × 40 nm; L/D = 22.8) with increased crystallinity (63%) and high colloidal stability (−40.17 ± 0.68 mV), as well as slightly reduced thermal stability. In contrast, milder conditions produced longer BCNCs (1.13 μm × 42 nm; L/D = 26.9) with similarly high zeta potential (−44.13 ± 0.73 mV), while maintaining the thermal and crystalline features of the starting BNC. These findings demonstrate the potential to tailor BCNCs´ properties through controlled hydrolysis and support the viability of producing versatile nanocellulosic materials from residual byproducts, contributing to both cost-effective production and environmental sustainability. Full article

This study develops a pH-responsive label by incorporating anthocyanin from Clitoria ternatea into a bacterial nanocellulose (BNC) film derived from acid whey fermentation. The labels were designed to display two distinct colors—pink and purple—by adjusting the pH of anthocyanin and were integrated into beef mince packaging to monitor quality changes over a 15-day storage period at 4 °C. Color variations were assessed using a chroma meter and visual inspection, with both label types exhibiting a shift to blue in response to a deterioration in freshness. Significant differences (p < 0.05) in total color difference (∆E) were observed across data collection days. The pink label showed an ∆E of 14.19 between day 0 and day 8, increasing to 27.39 by day 15. The purple label exhibited an ∆E of 12.94 by day 8 and 27.86 by day 15. A Total Volatile Basic Nitrogen (TVBN) analysis and microbial evaluations confirmed a degradation in the quality of the beef mince, with strong correlations between ∆E and ∆TVBN (r = 0.956 for pink, r = 0.993 for purple). Additionally, good correlations were recorded between label total color differences and coliform counts (r = 0.933 for pink, r = 0.875 for purple), as well as Total Plate Counts (TPCs) (r = 0.982 for pink, r = 0.950 for purple). These results highlight the potential of acid whey-derived nanocellulose films as real-time quality indicators for intelligent food packaging systems. Full article

ABA Insensitive 5 (ABI5) is a basic leucine zipper (bZIP) transcription factor (TF) that plays a critical role in seed dormancy and germination, particularly under stress conditions. This study identified ABI5 as an important candidate gene regulating seed germination under drought stress during early germination in rapeseed (Brassica napus L.) seeds through Genome-Wide Association Study (GWAS). Using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/CAS9) technology, ABI5 mutant plants were generated, showing higher germination rates and more developed root systems at 72 h. Transcriptomic analysis of wild-type (WT) and mutant seeds under water, 2μM of abscisic acid (ABA), and 10% PEG treatments after 0, 24, 48, and 72 h revealed complex changes in gene regulatory networks due to ABI5 mutation. Differential expression analysis showed that the number of downregulated differentially expressed genes (DEGs) in the mutant was significantly higher than upregulated DEGs at multiple time points and treatments, indicating a negative regulatory role for ABI5 in gene expression. Weighted Gene Co-Expression Network Analysis (WGCNA) revealed that genes related to ABA content, such as those in the glutathione metabolism pathway, were similarly downregulated in the ABI5 mutants. Key genes, including BnA03g0120550.1 (GST), BnA09g0366300.1 (GST), BnA10g0413960.1 (gshA), and BnC02g0518750.1 (GST), were identified as potential candidates in ABI5-regulated drought responses. Additionally, TFs involved in regulating the glutathione metabolism pathway were identified, providing insights into the collaboration of ABI5 with other TF. This comprehensive transcriptomic analysis of ABI5 mutant plants highlights how ABI5 affects gene expression in multiple pathways, impacting seed germination and drought resistance, offering a foundation for improving drought tolerance in rapeseed. Full article

This study examines how nitrogen and phosphorus fertilization influence soil microbial necromass carbon (MNC) content of farmland on the Loess Plateau, central Gansu. Based on an extensive (6 years) experiment, a control (CK, no fertilization) and three treatment groups employing different fertilization methods, namely, nitrogen fertilization (N, 115 kg·ha⁻¹), phosphorus fertilization (P, 115 kg·ha⁻¹), and combined fertilization of nitrogen and phosphorus (NP, 115 kg·ha⁻¹ each), were set up in this research. The results show that, in the tillage soil layer (within a depth range of 0–20 cm), the application of nitrogen and/or phosphorous fertilizers can significantly reduce the ratio between glucosamine and muramic acid (GluN/MurA) (p < 0.05), with a reduction range of 12.70–35.29%. Phosphorus fertilization can also reduce the content of fungal necromass carbon (FNC) and MNC and their contributions to SOC (p < 0.05). In addition, phosphorus fertilization and combined fertilization of nitrogen and phosphorus can both increase the content of bacterial necromass carbon (BNC) and contribute to the content of SOC (p < 0.05). Primarily because of the reduced accumulation efficiency of FNC, the combined fertilization of nitrogen and phosphorus can significantly decrease the accumulation efficiency of MNC. In the non-tillage soil layer (within depth range of 20–40 cm), both nitrogen fertilization and the combined fertilization of nitrogen and phosphorus can increase the content of FNC and MNC in soils and their impacts on SOC (p < 0.05). The addition of nitrogen and/or phosphorus fertilizers does not alter the accumulation efficiency of soil MNC. Total phosphorus (TP), total nitrogen (TN), soil pH, nitrogen-to-carbon ratio of microbial biomass (MBN/MBC), leucine aminopeptidase (LAP), and β-glucosidase activities (BG) are the primary factors that affect changes in FNC, BNC, and MNC. In summary, phosphorus fertilization alone decreases soil MNC contribution to SOC and reduces carbon pool stability in the tillage layer. On the contrary, both nitrogen fertilization and the combined fertilization of nitrogen and phosphorus can increase the content of soil MNC in the non-tillage layer and its impact on SOC, thus improving the stability of SOC. Full article

Tillage, cover crops (CC) and nutrient amendments are regenerative agricultural practices (RAPs) which enhance desirable ecosystem services (DESs), including the beneficial nematode community structure (BNCS), soil organic matter (SOM), pH, and available nitrogen, and the Ferris et al. soil food web (SFW) model relates changes in the BNCS to biophysicochemical conditions generating DESs. However, the SFW model’s power to identify soil health conditions influencing DESs’ outcomes has been limited. We tested how tillage, winter rye CC, and 0, 112, or 224 kg N/ha from inorganic and compost sources affected the DESs after four years of corn production. The SOM and NO₃ was much greater in the no-till than the tilled soil, and the SOM in the 224 kg organic source, compared with the rest of the N rates, was significantly increased. The N recovery was not proportional to what was applied. The variable effects of the RAPs on the DESs suggest either changing or continuing treatments until suitable outcomes are achieved, all without knowing the source(s) of variability. The SFW model revealed primarily resource-limited and structured (Quadrant C) conditions, suggesting that (1) nutrient cycling needs biological activities and (2) the presence of a process-limiting factor may have contributed to the variable results. The impacts of the SFW model as a diagnostic tool are outlined. Full article

The escalating challenge of high-salinity organic wastewater has prompted the development of persulfate-based advanced oxidation processes (AOPs) for the effective degradation of pollutants. This study presents the synthesis and application of a carbon-doped hexagonal boron nitride (C-hBN) catalyst, which is designed to activate peroxymonosulfate (PMS) efficiently under high-salinity conditions. The C-hBN catalyst is prepared through a two-step process using dopamine as the carbon source, resulting in a uniform doping of carbon and the formation of B-N-C bonds. The catalyst exhibits a significantly enhanced specific surface area and superior catalytic performance towards phenol degradation, with a rate constant of 0.74 min⁻¹. Under high-salinity conditions, the C-hBN catalyst demonstrates robust resilience against common ions, maintaining high catalytic activity. The degradation process is primarily driven by a non-radical pathway, with singlet oxygen (¹O₂) identified as the key reactive species. This work provides valuable insights into the development of metal-free catalysts for environmental remediation and offers a promising strategy for the treatment of organic pollutants in high-salinity wastewater. Full article

Reinforcing crack-damaged concrete structures with ultra-high-performance concrete (UHPC) proves to be more time-, labor-, and cost-efficient than demolishing and rebuilding under the dual-carbon strategy. In this study, the extended finite element method (XFEM) in ABAQUS was first employed to develop a numerical model of UHPC-reinforced single-notched concrete (U+SNC) beams, analyze their crack extension behavior, and obtain the parameters necessary for calculating fracture toughness. Subsequently, the fracture toughness and instability toughness of U+SNC were calculated using the improved double K fracture criterion. The effects of varying crack height ratios (a/h) of SNC, layer thicknesses (d) of UHPC reinforcement, and fiber contents in UHPC (V_SF) on the fracture properties of U+SNC beams were comprehensively investigated. The results indicate that (1) the UHPC reinforcement layer significantly enhances the load-carrying capacity and crack resistance of the U+SNC beams. Crack extension in the reinforced beams occurs more slowly than in the unreinforced beams; |(2) the fracture performance of the U+BNC beams increases exponentially with d. Considering both the reinforcement effect benefit and beam deadweight, the optimal cost-effective performance is achieved when d is 20 mm; (3) with constant d, increasing a/h favors the reinforcement effect of UHPC on the beams; (4) as V_SF increases, the crack extension stage in the U+BNC beam becomes more gradual, with higher toughness and flexural properties; therefore, the best mechanical properties are achieved at a V_SF of 3%. Full article

Starch-based pH-sensing films with bacterial nanocellulose (BNC) and red cabbage anthocyanins (RCA) as active components were investigated in this research. Their structural, physical, surface and colorimetric properties were analyzed, mainly as a function of BNC concentration. The aim of the research was to relate the changes in the intermolecular interactions between the components of the films (starch, anthocyanins and BNC) to the physical, surface and colorimetric properties that are important for the primary intended application of the produced films as pH indicators in smart packaging. The results showed that maize starch (MS) was more suitable as a matrix for the stabilization of anthocyanins compared to potato starch (PS). PS-based films showed a lower value of water contact angle than MS-based films, indicating stronger hydrophilicity. The swelling behavior results indicate that the concentrations of BNC in MS-based films (cca 10%) and the concentration of about 50% BNC in PS-based films are required if satisfactory properties of the indicator in terms of stability in a wet environment are to be achieved. The surface free energy results of PS-based films with BNC were between 62 and 68 mJ/m² and with BNC and RCA between 64 and 68 mJ/m²; for MS-based films, the value was about 65 mJ/m² for all samples with BNC and about 68 mJ/m² for all samples with BNC and RCA. The visual color changes after immersion in different buffer solutions (pH 2.0–10.5) showed a gradual transition from red/pink to purple, blue and green for the observed samples. Films immersed in different buffers showed lower values of 2 to 10 lightness points (CIE L*) for PS-based films and 10 to 30 lightness points for MS-based films after the addition of BNC. The results of this research can make an important contribution to defining the influence of intermolecular interactions and structural changes on the physical, surface and colorimetric properties of bio-based pH indicators used in smart packaging applications. Full article

Interest in bacterial nanocellulose (BNC) has grown due to its purity, mechanical properties, and biological compatibility. To address the need for alternative carbon sources in the industrial production of BNC, this study focuses on banana leaves, discarded during harvesting, as a valuable source. Banana midrib juice, rich in nutrients and reducing sugars, is identified as a potential carbon source. An optimal culture medium was designed using a simplex-centroid mixing design and evaluated in a 10 L bioreactor. Techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were used to characterize the structural, thermal, and morphological properties of BNC. Banana midrib juice exhibited specific properties, such as pH (5.64), reducing sugars (15.97 g/L), Trolox (45.07 µM), °Brix (4.00), and antioxidant activity (71% DPPH). The model achieved a 99.97% R-adjusted yield of 6.82 g BNC/L. Physicochemical analyses revealed distinctive attributes associated with BNC. This approach optimizes BNC production and emphasizes the banana midrib as a circular solution for BNC production, promoting sustainability in banana farming and contributing to the sustainable development goals. Full article

The study of plant electrophysiology offers promising techniques to track plant health and stress in vivo for both agricultural and environmental monitoring applications. Use of superficial electrodes on the plant body to record surface potentials may provide new phenotyping insights. Bacterial nanocellulose (BNC) is a flexible, optically translucent, and water-vapor-permeable material with low manufacturing costs, making it an ideal substrate for non-invasive and non-destructive plant electrodes. This work presents BNC electrodes with screen-printed carbon (graphite) ink-based conductive traces and pads. It investigates the potential of these electrodes for plant surface electrophysiology measurements in comparison to commercially available standard wet gel and needle electrodes. The electrochemically active surface area and impedance of the BNC electrodes varied based on the annealing temperature and time over the ranges of 50 °C to 90 °C and 5 to 60 min, respectively. The water vapor transfer rate and optical transmittance of the BNC substrate were measured to estimate the level of occlusion caused by these surface electrodes on the plant tissue. The total reduction in chlorophyll content under the electrodes was measured after the electrodes were placed on maize leaves for up to 300 h, showing that the BNC caused only a 16% reduction. Maize leaf transpiration was reduced by only 20% under the BNC electrodes after 72 h compared to a 60% reduction under wet gel electrodes in 48 h. On three different model plants, BNC–carbon ink surface electrodes and standard invasive needle electrodes were shown to have a comparable signal quality, with a correlation coefficient of >0.9, when measuring surface biopotentials induced by acute environmental stressors. These are strong indications of the superior performance of the BNC substrate with screen-printed graphite ink as an electrode material for plant surface biopotential recordings. Full article

The ability of 2D hybrid structures formed by boron, nitrogen and carbon atoms (h-BNCs) to act as potential substrates for the surface-enhanced Raman spectroscopy (SERS) detection of dioxin-like pollutants is theoretically analyzed. The strong confinement and high tunability of the electromagnetic response of the carbon nanostructures embedded within the h-BNC sheets point out that these hybrid structures could be promising for applications in optical spectroscopies, such as SERS. In this work, two model dioxin-like pollutants, TCDD and TCDF, and a model h-BNC surface composed of a carbon nanodisk of ninety-six atoms surrounded by a string of borazine rings, BNC96, are used to simulate the adsorption complexes and the static and pre-resonance Raman spectra of the adsorbed molecules. A high affinity of BNC96 for these pollutants is reflected by the large interaction energies obtained for the most stable stacking complexes, with dispersion being the most important contribution to their stability. The strong vibrational coupling of some active modes of TCDF and, specially, of TCDD causes the static Raman spectra to show a ”pure” chemical enhancement of one order of magnitude. On the other hand, due to the strong electromagnetic response of BNC96, confined within the carbon nanodisk, the pre-resonance Raman spectra obtained for TCDD and TCDF display large enhancement factors of 10⁸ and 10⁷, respectively. Promisingly, laser excitation wavelengths commonly used in SERS experiments also induce significant Raman enhancements of around 10⁴ for the TCDD and TCDF signals. Both the strong confinement of the electromagnetic response within the carbon domains and the high modulation of the resonance wavelengths in the visible and/or UV region in h-BNCs should lead to a higher sensitivity than that of graphene and white graphene parent structures, thus overcoming one of the main disadvantages of using 2D substrates for SERS applications. Full article

This paper presents the results obtained from the chemical activation of bacterial nanocellulose (BCN) using fique juice as a culture medium. BNC activation (BNCA) was carried out with H₃PO₄ and KOH at activation temperatures between 500 °C to 800 °C. The materials obtained were characterized morphologically, physicochemically, superficially, and electrochemically, using scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), the physisorption of gases N₂ and CO₂ at 77 K and 273 K, respectively, cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The samples activated with H₃PO₄ presented specific surface areas (S_BET) around 780 m² g⁻¹, while those activated with KOH values presented specific surface areas between 680 and 893 m² g⁻¹. The XPS analysis showed that the P_XPS percentage on the surface after H₃PO₄ activation was 11 wt%. The energy storage capacitance values ranged between 97.5 F g⁻¹ and 220 F g⁻¹ by EIS in 1 M H₂SO₄. The samples with the best electrochemical performance were activated with KOH at 700 °C and 800 °C, mainly due to the high S_BET available and the accessibility of the microporosity. The capacitance of BNCAs was mainly improved by electrostatic effects due to the S_BET rather than that of pseudocapacitive ones due to the presence of phosphorus heteroatoms. Full article