Nanochitosan (NCH) has previously been shown to possess antifungal activity against Colletotrichum species (C. chrysophilum, C. siamense, and C. fructicola) isolated from infected Mangifera indica leaves and fruit. However, the molecular response of this phytopathogenic fungus to NCH is still unclear. The objective of this work was to study the gene expression profiles of NCH-treated/untreated Colletotrichum species to gain insight into their molecular responses using RNA sequencing (RNA-seq). Samples for RNA-seq were obtained from the mycelia of each Colletotrichum species, which were either left untreated (control) or treated with NCH (2 mg/mL). The transcriptomes from C. chrysophilum, C. siamense, and C. fructicola were obtained by sequencing with the MGISEQ-2000 platform. The results revealed a differential expression of a total of 1787 (C. chrysophilum), 362 (C. siamense), and 3156 (C. fructicola) genes isolated from leaves, and 3976 (C. fructicola) genes isolated from fruit. Functional annotations showed that DEGs associated with the fungal infection process and the NCH response mechanism were mainly involved in cell wall modifications and oxidative stress responses. Our findings suggest that NCH acts by altering the fungal cell wall’s integrity and mitigating oxidative stress. These findings were similar in the three Colletotrichum species, suggesting a conserved mechanism. Further studies are required to support this assumption.
The symbiotic culture of bacteria and yeast (SCOBY) is a cellulose-rich biofilm generated during kombucha fermentation and represents an underutilized by-product with considerable biotechnological potential. This study aimed to produce and characterize nanocellulose from SCOBY through acid (BNCA) and enzymatic (BNCE) hydrolysis and evaluate its performance as a Pickering emulsion stabilizer. The materials were characterized by dynamic light scattering (DLS), zeta potential, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), contact angle measurements, and interfacial tension. Acid hydrolysis yielded nanocellulose with a high crystallinity index (CrI ≈ 89.4%), a relatively narrow particle size distribution, and a zeta potential of −46.4 mV, indicating good electrostatic colloidal stability. These properties were associated with favorable interfacial characteristics and an emulsification index (EI) of 100%. The enzymatic hydrolysis produced a cellulose with lower crystallinity, broader particle size distributions, and zeta potential values ranging from −10.2 to −30.9 mV, indicating reduced colloidal stability. Nevertheless, BNCE exhibited amphiphilic behavior and successfully stabilized oil-in-water Pickering emulsions, particularly after 24 h of hydrolysis (EI ≈ 96%). Contact angle measurements confirmed the hydrophilic character of both materials (water contact angles < 30°), supporting their potential for oil-in-water emulsification. Thermogravimetric analysis revealed that acid-hydrolyzed nanocellulose degraded at lower temperatures, potentially due to surface sulfate groups, whereas enzymatically hydrolyzed nanocellulose exhibited greater thermal stability. Overall, SCOBY-derived nanocellulose is a promising bio-based Pickering stabilizer. Although acid hydrolysis yielded materials with superior physicochemical properties, enzymatic hydrolysis offers an environmentally friendly alternative, warranting further optimization for sustainable food applications.
Essential oil-loaded bio-based capsules have emerged as promising candidates for sustainable antimicrobial textiles; however, the relationships between processing conditions, capsule architecture, textile fixation, and functional performance remain poorly understood. In this study, chitosan and alginate–chitosan capsules encapsulating clove essential oil (CEO) were comparatively engineered to investigate the process–structure–performance relationships governing antifungal cotton functionalization. Two encapsulation strategies based on emulsion-assisted alkaline gelation and ionic gelation were optimized using Taguchi L18 experimental designs and response optimization to identify suitable processing conditions and target capsule characteristics. For the chitosan system, the selected formulation consisted of 0.5% chitosan, 5% acrylic acid, 1% Tween 80, 7% CEO, 1% NaOH, and a 2× dilution ratio, yielding a predicted capsule size of 259.539 nm and an intensity of 81.3945% with an overall desirability of 0.677991. For the alginate–chitosan system, the selected formulation contained 1% alginate, 0.5% chitosan, 7% CEO, 2% Tween 80, and a 30× dilution ratio, resulting in a predicted capsule size of 382.753 nm and an intensity of 93.0053% with a desirability of 0.736852. Particle-size analysis showed predominantly nanometric populations, with a bimodal distribution centered at approximately 230 nm for chitosan capsules and a trimodal distribution with a predominant population around 360 nm for alginate–chitosan capsules. The optimized capsule suspensions were applied to cotton fabrics using citric acid-assisted thermal treatment. ATR–FTIR analysis revealed spectral changes consistent with interactions between the capsule components, citric acid, and cellulose, while the treated fabrics exhibited improved retention after washing. Both encapsulated systems retained antifungal activity against Candida albicans, although the inhibition zones were lower than those obtained with free CEO, consistent with modified CEO accessibility and diffusion. Overall, the results establish a process–structure–performance framework linking formulation and processing conditions to capsule architecture, textile fixation, and antifungal functionality, providing a basis for the rational design of durable bio-based functional textiles.
Low redox potential (Eh) leads to low bioavailability and utilization efficiency of several nutrients, including selenium (Se), in paddy soil. Applying oxidants with a slow-release function to maintain soil Eh at a sufficiently high level during the key nutrient stage is beneficial to plant-nutrient accumulation. A multi-component coating material consisting of alginate, chitosan, nano-silicon dioxide, carboxymethyl cellulose, and selenate was used to embed urea peroxide to prepare a slow-release fertilizer of oxidative substances in this study. The effects of the components on oxidative substance release and mechanical properties were investigated, and their contribution to altering soil Eh and Se speciation was verified by paddy soil assay. The formula containing 20~25 mg g−1 alginate, 15 mg g−1 chitosan, 30 mg g−1 silicon dioxide nanoparticle, 10 mg g−1 carboxymethyl cellulose, 0.1 mg g−1 sodium selenate, and 150 mg g−1 urea peroxide performed the best among treatments. It had satisfactory mechanical properties and an elevated Eh with an amplitude of over 100 mV for at least 40 d compared to the soil with a single Se treatment, and increased the contents and proportions of soluble, exchangeable, and a part of iron/manganese-binding Se, especially the hexavalent one, in soil. Notably, selenate not only supplied Se but also contributed to structure reinforcement. The findings provided a slow-release carrier for soil nutrient management, but it still needs to be improved for more coordinated release of Se and oxidative substances.
