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Corn pericarp (CP) results from wet milling of the corn industry. It is an abundant agro-industrial byproduct in Mexico, with potential use as sugars source to obtain ethanol and other economically relevant chemicals. In this work, CP was pretreated with dilute sulfuric acid at 121 °C; using a 23 full factorial design, factors were sulfuric acid, reaction time, and CP concentration. After pretreatment, the capacity of activated charcoal to remove inhibitory compounds in the liquid fraction was studied. Then, the detoxified liquid fraction was fermented using Scheffersomyces stipitis, whereas the solid fraction was exposed to enzymatic hydrolysis by a commercial cellulase (Cellic® CTec2). The most promising pretreatments utilized 2% (v/v) sulfuric acid, 20% (w/v) of CP, and 30 min reaction time producing 109.38 ± 6.73 g/L reducing sugars. The solid fraction obtained from CP pretreatment resulted in cellulose conversion up to 85.60% ± 1.87% after 94 h, significantly higher than conversion achieved using untreated CP of 32.54% ± 5.58%. The detoxification process allowed yeast fermentation to reach ethanol yields (g ethanol/g consumed substrate) between 0.09 ± 0.02 and 0.29 ± 0.006. S. stipitis was able to produce between 4.62 ± 1.73 and 14.22 ± 0.98 g/L of ethanol from the hydrolyzed liquid fraction. The dilute acid pretreatment on CP produced a solid fraction, which upon enzymatic treatment caused high cellulose conversion into reducing sugars. Additionally, the fermentability of the sugars present in the liquid fraction was increased after the detoxification process. Thus, CP is a material that shows good potential to obtain value-added products such as ethanol.

The aim of this work was the isolation of endophytic cacti fungi producer of pigments. Twenty different endophytic fungi were isolated from Ferocactus latispinus using a standard method. One of these was an orange pigment producer and was identified with molecular biology techniques amplifying internal transcribe spacer region. The fungus identified was Fusarium solani; it is a producer of polyketides from naphthoquinones family. Experiments with different carbon and nitrogen sources were performed, and it was found that both glycerol and ammonia sulphate promote the naphthoquinones biosynthesis. It was also found that the carbon/nitrogen ratio and pH value had an effect on this biosynthesis phenomenon; increasing productivity being observed at the initial C: N ratio of 59.6, pH 6 and time of 113.3 h. This C: N ratio exhibited a stress condition for fungi in the pigment biosynthesis process in liquid media. The optimum value of total naphthoquinones (476 μmol/L) was obtained using a central rotable composite design.

Corn pericarp (CP) is an inexpensive agroindustrial by-product that is available in large quantity in Mexico. This work aimed to optimize the use of a dilute sulfuric acid pretreatment for CP hydrolysis to maximize the reducing sugars yield. A 2-step experimental design was used, first a full factorial followed by a central composite design (CCD). The CCD involved sulfuric acid (1.5% to 5%, v/v), a treatment at 121 ºC (15 min to 40 min), and varying CP content (10% to 20%, w/v). The response variables were the reducing sugars, glucose, and solubilized solids. Maximal responses were achieved at 3.4% (v/v) sulfuric acid, 20% (w/v) CP, and 22.3 min. A significant (R2 = 0.99) second-order model predicted maximal operational conditions that were experimentally validated: 80.1 g/L reducing sugars, 12.8 g/L glucose, and 69.2% solubilization of CP solids. The dilute sulfuric acid pretreatment solubilized all hemicellulose in CP.

Fungi provide a readily available alternative source of naturally derived pigmented molecules that may be utilized in different areas as foods, textile, medicine and cosmetics. These have been considered as potent biocompounds under two perspectives: for coloring to products, or as powerful chemical structures with biological functions. Both properties are also often found in their study and application in these areas. The present review presents an overview of diverse aspects that have been studied on the obtaining of fungal pigments, including pigment class, and metabolic pathway of biosynthesis, producer’s species of pigment, physicochemical condition of biosynthesis, extracting, isolation, purifying and storage. Commercial production and application of fungal pigments status is also described in this research as main findings.

This study demonstrates that using beeswax hydrolyzates (Hw), short- or medium-chain-length polyhydroxyalkanoates (scl-mcl-PHA) can be obtained by a three stages fed-batch fermentation system. The fed batch fermentations were conducted with a strain of Cupriavidus necator . Glucose and ammonium sulphate as carbon and nitrogen sources, respectively, were used in a first and second culture stages. In the third stage (production of scl-mcl-PHA) a fresh medium was fed with Hw as a carbon source at a concentration of 5 g/L, obtaining 8.91 g/L of intracellular scl-mcl-PHA and 13.64 g/L of biomass, which resulted in 65.3 % w/w of scl-mcl-PHA. Using nuclear magnetic resonance, the presence of scl and mcl monomers, 3-hydroxybutyrate (3HB) and 3-hydroxydecanoate (3HD) was determined. The percentage of comonomer incorporation different to 3HB was 4.6 mol %. A glass transition temperature (T g ) of –50 oC and a melting temperature (T m ) of 79.8 oC were determined for the scl-mcl-PHA (3HB-co-3HDD).

Poly(β-hydroxybutyrate) [PHB] is a biodegradable and biocompatible polymer produced by some bacteria genders. To improve mechanical properties, PHB has been blended with other polymers. Compression-molded blends of PHB and poly(e-caprolactone) [PCL] (70/30 mass ratio) were cooled to room temperature following five different thermal treatments after molding at 180 °C. Blends processed with higher cooling rates were easier to biodegrade, nevertheless elongation at break and tensile strength decreased. Slower cooling kinetics and isothermal treatments increased perfection of crystals, as seen in differential scanning calorimetry and X-ray diffraction and spherulites size. A descriptive model is proposed herein where thermal, biodegradation, tensile properties, and crystal features were related to cooling kinetics applied. It is proposed that properties of 70/30 (PHB/PCL) blends can be predetermined by an adequate control of thermal conditions during processing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43569.

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.