The present study investigated that chitosan production of Rhizopus oryzae NRRL 1526 and Aspergillus niger ATCC 16404. Fungal chitosans were characterized by scanning electron microscopy (SEM)‐energy dispersive X‐ray analysis, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter and deacetylation degrees of fungal chitosans were determined. The percentage yield of Ro‐chitosan and An‐chitosan were determined as 18.6% and 12.5%, respectively. According to percentage of chitosan yield and the results of the characterization studies, chitosan that obtained from Rhizopus oryzae NRRL 1526 was selected for subsequent studies. Cytotoxicity of chitosan obtained from Rhizopus oryzae NRRL 1526 was determined by MTT assay on human dermal fibroblast cell line. Acording to results of the cytotoxicity test fungal chitosan was nontoxic on cells. The high cell viability was observed 375 μg/mL concentration at 24th, 48th h periods and at the 187.5 μg/ml 72nd h periods on cells. The fungal chitosan obtained from Rhizopus oryzae NRRL 1526 was used to fabrication of electrospun nanofibers. Fungal chitosan based polymer solutions were prepared by adding different substances and different electrostatic spinning parameters were used to obtain most suitable nanofiber structure. Characterization studies of nanofibers were carried out by SEM, FTIR and X‐ray diffraction. The most suitable nanofiber structure was determined as F4 formula. The nanofiber structure was evaluated to be thin, bead‐free, uniform, flexible and easily remove from surface and taking the shape of the area. After the characterization analysis of fungal chitosan it was determined that the chitosan, which obtained from Rhizopus oryzae NRRL 1526 is actually chitosan polymer and this polymer is usable for pharmaceutical areas and biotechnological applications. The electrospun nanofiber that blends fungal chitosan and PCL polymers were fabricated successfully and that it can be used as fabrication wound dressing models.Research Highlights: Extraction of chitosan from Rhizopus oryzae NRRL 1526 and Aspergillus niger ATCC 16404 and characterization scanning electron microscopy‐energy dispersive X‐ray analysis, Fourier transform infrared spectroscopy, differential scanning calorimeter. Fabrication and characterization of the fungal chitosan/PCL electrospun nanofibers.

Hydrogels in active wound care products are 3D polymeric scaffolds that provide the desired moisture balance in the wound area with their high water retention capacity. Thanks to their biocompatible properties, flexible and porous structures, and high hydrophilic properties, they have frequently been preferred in the repair and regeneration of cells and tissues and the controlled release of bioactive substances to the target area. In this study, hydrogel structures were developed for the first time with levan produced by Halomonas elongata 153B halophilic bacteria. Extracts from Plantago lanceolata L., commonly known as a wound herb, which has medicinal importance for cell regeneration, ensuring tissue integrity in a short time and reducing infections in the wound area, were obtained and extract-loaded liposome structures were formed for controlled release into the wound area. The wound healing efficacy of the composite material developed by loading herbal liposomes into levan-based hydrogel structures was evaluated in an in vitro wound model. Thus, a natural, biocompatible, biodegradable, and functional wound care product containing herbal liposomes suitable for both clinical applications and point-of-care use has been developed. The developed bioactive hydrogels are a promising therapeutic approach for the healing of acute wounds. Graphical [ ]

Eighty-seven bacteria isolates were screened for the presence of the levansucrase encoding gene and those possessing the gene were used in gene expression studies and the production of levan. Based on both screening methods, isolate P19-1 was determined as the producer bacterium with the highest amounts of levan. Whole genome sequencing was done to characterize the isolate and determine its genomic potential. Both its 16 S rRNA and genome were closest to Chromohalobacter salexigens. The levansucrase gene and genes suggesting a versatile carbohydrate and nitrogen metabolism were annotated. A secondary metabolism suggestive of a possible new role in promoting plant growth in hypersaline environments was revealed. The chemical structure analysis of the produced polymer was confirmed by comparison with commercial pure Erwinia herbicola levan. Also, C. salexigens levan showed high biocompatibility. Overall, this is a practical molecular approach that will help researchers to effectively screen microbes with levan production potential.

The oral delivery of polyphenolic compounds such as rosmarinic acid (Ros) is limited by poor gastrointestinal stability and early release, resulting in low bioaccessibility. Herein, carboxymethylated guar gum (cmGG)-based nanoparticles were developed as a pH-responsive colloidal delivery system to enhance Ros stability, prevent early release, and improve intestinal bioaccessibility. In this context, pH-responsiveness refers to pH-dependent modulation of degradation, and stabilization along the gastrointestinal tract, rather than an abrupt pH-triggered burst release. Guar gum was chemically modified to different degrees of carboxymethylation to enhance its colloidal stability under gastrointestinal conditions, reduce polymer degradation, and enable a more controlled release of the phenolic compound Ros. Comparative evaluation of cmGG systems with varying degrees of carboxymethylation revealed that nanoparticles prepared from highly substituted cmGG exhibited superior colloidal stability and acid resistance, contributing to effective protection of Ros under gastric conditions. Ros-loaded guar gum nanoparticles effectively suppressed release at acidic pH while enabling controlled and sustained release at intestinal pH. Simulated gastrointestinal digestion studies demonstrated that Ros-loaded carboxymethylated guar gum nanoparticles significantly enhanced the gastrointestinal stability and bioaccessibility of Ros compared with non-carboxymethylated guar gum nanoparticles. Overall, these findings indicate that the degree of carboxymethylation is a critical design parameter for tuning colloidal behavior and release performance under the varying pH conditions encountered throughout the gastrointestinal tract in guar gum-based nanoparticle systems.