The aim of this work was the isolation and taxonomic characterization of endophytic fungi from Taxus globosa at the Sierra Alta Hidalguense, Mexico. A total of 116 fungi were isolated from the bark, branches, leaves and roots of healthy yew trees. Based on morphological characteristics 57 were selected for taxonomic characterization through phylogenetic analysis of their 28S rDNA sequences. The fungal isolates belonged to Ascomycota (77.2%) and Basidiomycota (22.8%). Twelve different fungal groups were identified: Coniochaetales, Eurotiales, Hypocreales, Phyllachorales, Pleosporales, Pezizales, Sordariomycetidae, Sordariales, Trichosphaeriales, Xylariales, Agaricales and Polyporales. The taxa Alternaria sp. Aspergillus sp., Cochliobolus sp., Coprinellus domesticus, Hypoxylon sp., Polyporus arcularius, Xylaria juruensis and Xylariaceae were the most frequently isolated. The genera Annulohypoxylon, Cercophora, Conoplea, Daldinia, Lecythophora, Letendraea, Massarina, Phialophorophoma, Sporormia, Xylomelasma, Coprinellus, Polyporus and Trametes for the first time were isolated from yews; this suggests that T. globosa harbours novel and highly diverse fungi. The Shannon-Weaver and Simpson diversity index values for the overall fungal community were H′ = 3.139 and 1-D = 0.941 respectively.

Cross-linking of magnetic nanoparticles with proteins plays a significant role in the preparation of new materials for biotechnological applications. The aim was the maximization of the magnetic mass attracted and protein loading of magnetic iron oxide nanoparticles coated with chitosan, synthesized in a single step by alkaline precipitation. Chitosan-coated magnetite particles (Fe₃O₄@Chitosan) were cross-linked to a xylanase and a cellulase (Fe₃O₄@Chitosan@Proteins), showing a 93% of the magnetic saturation of the magnetite. X-ray diffraction pattern in composites corresponds to magnetite. Thermogravimetry and differential scanning calorimetry showed that 162 mg of chitosan was coating one gram of composite and 12 mg of protein was cross-linked to each gram of magnetic support. Cross-linking between enzymes and Fe₃O₄@Chitosan was confirmed by infrared spectroscopy with Fourier transform, X-ray energy, and X-ray photoelectron spectroscopy dispersion analysis. From dynamic light scattering, transmission and electron microscopy the average particle size distribution was 230 nm and 430 nm for Fe₃O₄@Chitosan and Fe₃O₄@Chitosan@Proteins, showing agglomerates of individual spherical particles, with an average diameter of 8.5 nm and 10.8 nm, respectively. The preparation method plays a key role in determining the particle size and shape, size distribution, surface chemistry, and, therefore, the applications of the superparamagnetic nanoparticles.

The increase in consumer demand for more sustainable packaging materials represents an opportunity for biopolymers utilization as an alternative to reduce the environmental impact of plastics. Cellulose (C) and chitosan (CH) are attractive biopolymers for film production due to their high abundance, biodegradability and low toxicity. The objective of this work was to incorporate cellulose nanocrystals (NC) and C extracted from corn cobs in films added with chitosan and to evaluate their properties and biodegradability. The physicochemical (water vapor barrier, moisture content, water solubility and color) and mechanical properties of the films were evaluated. Component interactions using Fourier-transform infrared (FTIR) spectroscopy, surface topography by means of atomic force microscopy (AFM), biodegradability utilizing a fungal mixture and compostability by burying film discs in compost were also determined. The C-NC-CH compared to C-CH films presented a lower moisture content (17.19 ± 1.11% and 20.07 ± 1.01%; w/w, respectively) and water vapor permeability (g m⁻¹ s⁻¹ Pa⁻¹ × 10⁻¹²: 1.05 ± 0.15 and 1.57 ± 0.10; w/w, respectively) associated with the NC addition. Significantly high roughness (Rq = 4.90 ± 0.98 nm) was observed in films added to NC, suggesting a decreased homogeneity. The biodegradability test showed larger fungal growth on C-CH films than on CH films (>60% and <10%, respectively) due to the antifungal properties of CH. C extracted from corn cobs resulted in a good option as an alternative packaging material, while the use of NC improved the luminosity and water barrier properties of C-CH films, promoting strong interactions due to hydrogen bonds.