Eucalyptus bleached kraft pulp-ionic liquid inks for 3D printing of ionogels and hydrogels.

3D printing has been recently recognized as one of the most promising technologies due to the multiple options to fabricate cost-effective and customizable objects. However, the necessity to substitute fossil fuels as raw materials is increasing the research on bio-based inks with recyclable and eco-friendly properties. In this work, we formulated inks for the 3D printing of ionogels and hydrogels with bleached kraft pulp dissolved in [Emim][DMP] at different concentrations (1-4 wt%). We explored each ink's rheological properties and printability and compared the printability parameters with a commercial ink. The rheological results showed that the 3 % and 4 % cellulose-ionic liquid inks exhibited the best properties. Both had values of damping factor between 0.4 and 0.7 and values of yield stress between 1900 and 2500 Pa. Analyzing the printability, the 4 wt% ink was selected as the most promising because the printed ionogels and the hydrogels had the best print resolution and fidelity, similar to the reference ink. After printing, ionogels and hydrogels had values of the elastic modulus (G') between 103 and 104 Pa, and the ionogels are recyclables. Altogether, these 3D printed cellulose ionogels and hydrogels may have an opportunity in the electrochemical and medical fields, respectively.

Cellulose ionogels, a perspective of the last decade: A review.

Cellulose ionogels have been extensively studied due to the variability of their properties and applications. The capability of trapping an ionic liquid in a biodegradable solid matrix without losing its properties makes this type of material a promising substitute for fossil fuel-derived materials. The possibility to formulate ionogels chemically or physically, to choose between different ionic liquids, cellulose types, and the possibility to add a wide range of additives, make these ionogels an adaptable material that can be modified for each target application in many fields such as medicine, energy storage, electrochemistry, etc. The aim of this review is to show its versatility and to provide a summary picture of the advances in the field of cellulose ionogels formulation (chemical or physical methods), as well as their potential applications, so this review will serve as a stimulus for research on these materials in the future.

CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars.

BACKGROUND: Filamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood. RESULTS: A fed-batch system with plant biomass-derived sugars D-xylose, L-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and L-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways. CONCLUSION: This work has identified two additional CAZyme inducers for T. aurantiacus, L-arabinose and cellobiose, along with D-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures.

Purification and characterization of a native lytic polysaccharide monooxygenase from Thermoascus aurantiacus.

Lytic polysaccharide monooxygenases (LPMOs) have emerged as key proteins for depolymerization of cellulose. These copper-containing enzymes oxidize C-1 and/or C-4 bonds in cellulose, promoting increased hydrolysis of the oxidized cellulose chains. The LPMO from Thermoascus aurantiacus, a thermophilic ascomycete fungus, has been extensively studied and has served as a model LPMO. A method was developed to purify the LPMO from culture filtrates of T. aurantiacus along with its native cellobiohydrolase and endoglucanase. The activity of the purified LPMO was measured with a colorimetric assay that established the Topt of the native LPMO at 60 °C. Purification of the components of the T. aurantiacus cellulase mixture also enabled quantification of the amounts of cellobiohydrolase, endoglucanase and LPMO present in the T. aurantiacus culture filtrate, establishing that the LPMO was the most abundant protein in the culture supernatants. The importance of the LPMO to activity of the mixture was demonstrated by saccharifications with Avicel and acid-pretreated corn stover.