Biosynthesis and characterization of deuterated chitosan in filamentous fungus and yeast

Low molecular weight chitosan from Pleurotus ostreatus waste and its prebiotic potential

The booming mushroom industry envisages economic merits, and massive unutilized waste production (∼ 20 %) creates an opportunity for valorization. Chitosan, a bioactive polysaccharide, has drawn immense attention for its invaluable therapeutic potential. Thus, the present study was conducted to extract chitosan from mushroom waste (MCH) for its prebiotic potential. The structural characterization of MCH was carried out using NMR, FTIR, and XRD. The CP/MAS-13CNMR spectrum of MCH appeared at δ 57.67 (C2), 61.19 (C6), 75.39 (C3/C5), 83.53 (C4), 105.13 (C1), 23.69 (CH3), and 174.19 (C = O) ppm. The FTIR showed characteristic peaks at 3361 cm-1, 1582 cm-1, and 1262 cm-1 attributed to -NH stretching, amide II, and amide III bands of MCH. XRD interpretation of MCH exhibited a single strong reflection at 2θ =20.19, which may correspond to the "form-II" polymorph. The extracted MCH (∼ 47 kDa) exhibited varying degrees of deacetylation from 79 to 84 %. The prebiotic activity score of 0.73 to 0.82 was observed for MCH (1 %) when supplemented with probiotic strains (Lactobacillus casei, L. helveticus, L. plantarum, and L. rhamnosus). MCH enhanced the growth of Lactobacillus strains and SCFA's levels, particularly in L. rhamnosus. The MCH also inhibited the growth of pathogenic strains (MIC of 0.125 and 0.25 mg/mL against E. coli and S. aureus, respectively) and enhanced the adhesion efficiency of probiotics (3 to 8 % at 1 % MCH supplementation). L. rhamnosus efficiency was higher against pathogens in the presence of MCH, as indicated by anti-adhesion assays. These findings suggested that extracted polysaccharides from mushroom waste can be used as a prebiotic for ameliorating intestinal dysbiosis.

Advances in Small Angle Neutron Scattering on Polysaccharide Materials

Polysaccharide materials and biomaterials gain the focus of intense research owing to their great versatility in chemical structures and modification possibilities, as well as their biocompatibility, degradability, and sustainability features. This review focuses on the recent advances in the application of SANS on polysaccharide systems covering a broad range of materials such as nanoparticulate assemblies, hydrogels, nanocomposites, and plant-originating nanostructured systems. It motivates the use of SANS in its full potential by demonstrating the features of contrast variation and contrast matching methods and by reporting the methodologies for data analysis and interpretation. As these soft matter systems may be organized in multiple length scales depending on the interactions and chemical bonds between their components, SANS offers exceptional and unique opportunities for advanced characterization and optimization of new nanostructured polysaccharide materials.

Mixed organic and inorganic nitrogen sources enhance chitosan yield in novel isolates of Penicillium

Chitosan, a valuable biopolymer, has traditionally been derived from marine sources. However, exploring fungal alternatives offers a sustainable supply. This research investigates the potential of chitosan production from fungal sources, focusing on the optimization of abiotic factors using two novel Penicillium strains (IITISM-ANK1 and IITISM-ANK2) isolated from dry aged sludge. Box-Behnken model and standard statistical analysis were deployed to develop an equation predicting the effect of carbon and nitrogen sources, pH, and temperature on chitosan production. Batch experiments validate the model's accuracy under optimized conditions. The results indicate that mixed organic and inorganic nitrogen sources in the form of peptone, nitrate, and ammonium salts enhanced chitosan yield in both isolates. At optimal conditions for the chitosan production of IITISM-ANK2 and IITISM-ANK1 were found to be 293.29 mg/L and 325.01 mg/L, with the degree of deacetylation of over 74 % which is a critical parameter for chitosan quality. Thus, these isolates can be used as a potent microbe for industrial chitosan production and contribute to advancing sustainable chitosan production and its potential industrial applications.

Developing Enzyme Immobilization with Fibrous Membranes: Longevity and Characterization Considerations

Fibrous membranes offer broad opportunities to deploy immobilized enzymes in new reactor and application designs, including multiphase continuous flow-through reactions. Enzyme immobilization is a technology strategy that simplifies the separation of otherwise soluble catalytic proteins from liquid reaction media and imparts stabilization and performance enhancement. Flexible immobilization matrices made from fibers have versatile physical attributes, such as high surface area, light weight, and controllable porosity, which give them membrane-like characteristics, while simultaneously providing good mechanical properties for creating functional filters, sensors, scaffolds, and other interface-active biocatalytic materials. This review examines immobilization strategies for enzymes on fibrous membrane-like polymeric supports involving all three fundamental mechanisms of post-immobilization, incorporation, and coating. Post-immobilization offers an infinite selection of matrix materials, but may encounter loading and durability issues, while incorporation offers longevity but has more limited material options and may present mass transfer obstacles. Coating techniques on fibrous materials at different geometric scales are a growing trend in making membranes that integrate biocatalytic functionality with versatile physical supports. Biocatalytic performance parameters and characterization techniques for immobilized enzymes are described, including several emerging techniques of special relevance for fibrous immobilized enzymes. Diverse application examples from the literature, focusing on fibrous matrices, are summarized, and biocatalyst longevity is emphasized as a critical performance parameter that needs increased attention to advance concepts from lab scale to broader utilization. This consolidation of fabrication, performance measurement, and characterization techniques, with guiding examples highlighted, is intended to inspire future innovations in enzyme immobilization with fibrous membranes and expand their uses in novel reactors and processes.