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Cellulose nanocrystals (CNCs) are inherently hydrophilic; even so, their dispersions in water based applications such as rheology modifiers, coatings, and emulsion systems do not often produce perfect dispersions with a minimum energy input. Supplying the CNCs in dry granular powder form is needed in the industrial scale of production because of its easier handling, storage and transportation characteristics. Spray drying is the preferred industrial method for drying acid hydrolyzed CNC suspensions. However, spray drying often causes poor dispersion of dried CNC granules into individual nanoparticles in aqueous solutions if not mixed with high energy input. This study investigates foam-spray drying of CNC particles to enhance their dispersibility in water. Non-ionic 10-mole ethoxylated octylphenol surfactant (OPE-100) and methyl cellulose polymer (MC) were used as additives to assist the foaming of CNC suspensions. Foam-spray drying experiments were carried out under constant process conditions such as inlet and outlet temperatures, gas and liquid flow rates and concentrations of CNCs. We focus on the effects of 10-mole ethoxylated octylphenol surfactant (OPE-100) and methyl cellulose polymer (MC) as additives and foaming of CNCs suspension on the morphology of dried CNC aggregates and their dispersion in water. Our work also describes the molecular interaction mechanisms of CNCs with methyl cellulose and OPE-100 by means of isothermal titration calorimetry and surface charge of the coated CNCs. The addition of nonionic surfactant OPE-100 along with methyl cellulose polymer resulted in spray drying of CNC aggregates with the best water dispersion characteristics. While methyl cellulose generated foams, OPE-100 lowered the inverse thermal gelling of methyl cellulose in spray drying.

Electrospun keratin nanofiber fabricated with non-toxic solvents and crosslinking reagents are promising scaffolds for tissue engineering applications. Keratin from chicken feathers was solubilized in aqueous alkaline conditions and electrospun using aqueous poly(vinyl alcohol)(PVA)/citric acid solution as electrospinning polymer aid. Keratin/PVA nanofibers were successfully prepared containing 10, 20 and 30% keratin to PVA mass ratio. The increase in keratin concentration from 0 to 20% resulted in decreased viscosity of keratin/PVA solutions leading to a reduction in the fiber diameter from 565 nm in to 274 nm. Further decrease in viscosity with 30% keratin resulted in beads-on-fiber type of morphology. Nanofibers were thermally cross-linked through esterification reaction between carbonyl groups in citric acid and hydroxyl groups in PVA. Cross-linked nanofibers maintained their morphology and pore structure after soaking in water. The incorporation of keratin in PVA nanofiber was confirmed by FTIR and XPS results. Proliferation of fibroblasts after 14 days was higher in scaffolds containing 20% keratin which was attributed to the superior biological properties of keratin and higher surface area to volume ratio compared to 30% keratin/PVA scaffolds. Safer extraction, electrospinning and crosslinking conditions of keratin/PVA nanofiber are important for potential uses in tissue engineering. Keywords: Nanofiber, Electrospinning, Keratin, Polyvinyl alcohol, Scaffold

Wood adhesives are mainly produced using petrochemical-based resins. However, concerns over environmental and health effects have prompted a renewed interest on developing bio-based adhesives. The potential of using canola protein for adhesives was explored with limited success. Similar to other proteins, canola adhesives also have weak adhesion and water resistance. The objective of this research was to develop and characterize nanomaterial reinforced canola protein adhesive with improved water resistance and adhesion strength. Hydrophilic bentonite (bentonite), surface modified nanoclay (SM-MMT), graphite oxide (GO), and nanocrystalline cellulose (NCC) were exfoliated at different addition levels (0, 1, 3, 5, 10% w/w) using an improved solution intercalation method. A significant increase (p < 0.05) in both dry and wet adhesion was found at addition levels of 1–3% (w/w). NCC and GO showed superior effect over bentonite and SM-MMT. The improvement in adhesive strength at low nanomaterial addition was a result of adequate exfoliation of nanomaterials in protein matrix, and increased exposure of functional groups for enhanced interaction with wood surface. This study demonstrated for the first time the potential of nanomaterials for improving adhesion and water resistance of protein-derived adhesive. Canola protein adhesive developed in this study showed its potential for replacing synthetic adhesives as green alternative adhesive materials.

We are reporting the preparation of cellulose nanocrystal (CNC) particles stabilized Pickering hempseed oil-in-water emulsions and using them as feedstocks for the preparation of oil powders without using any other hydrophilic carrier agent. Oil powders were prepared in a spray drier by rapid evaporation of water. The effect of the ratio of HSO to CNCs was evaluated on the emulsion stability and droplet size of emulsified hempseed oil. A mass ratio of 18 g hempseed oil/g CNC or lower was found to be optimal for emulsion stability over 15 days and droplet size between 500 nm and 1–2 μm. The effective interfacial area coverage of oil droplets by CNCs was found to be fundamental for emulsion stability. For the first time, the spray drying of CNCs stabilized oil/water emulsion was used to produce stable encapsulated oil particles without any oil leakage. The microencapsulation efficiency was dependent on the hempseed oil/CNC mass ratio, which in turn influenced the effective coverage of oil droplets. The results suggested that about 10–14 layers of CNCs are required to effectively encapsulate hempseed oil droplets with minimal oil leakage. Less than eight theoretical layers of CNCs resulted in lower encapsulation efficiency with an increase of free-extractable oil. These results are of particular relevance in advanced formulations containing hempseed oil and other compounds that can be potentially stabilized and/or microencapsulated by CNCs.

Hydrogel prepared from keratin shows potential applications in tissue engineering. However, the importance of the keratin sources has not been considered. The objectives of this study were to characterize and compare the rheological (storage modulus), physical (porosity, pore size, swelling capacity, and water contact angle) and in vitro cell compatibility of hydrogel scaffolds prepared from various keratin sources. Keratins were characterized by means of their molecular weight, amino acid composition, thermal and conformational properties. Hydrogels from chicken feather keratins demonstrated substantially higher storage modulus (G′) than hair and wool keratin hydrogels. However, higher swelling capacity (>3000%) was determined in hair and wool over feather keratin (1500%) hydrogels. Our results suggest that small molecular weight and β-sheet conformation of feather keratin (~10 kDa) facilitated the self-assembly of rigid hydrogels through disulfide bond re-oxidation. Whereas, high molecular weight (10–75 kDa) stretchable α-helix conformation in hair and wool keratins resulted in weaker hydrogels. The cell cultures using fibroblasts showed the highest proliferation rate on chicken feather keratin hydrogel scaffolds. After 15 days of culture, partial breakdown of keratin fibers was observed. Results indicate that stiffer avian keratins can be used to fabricate more mechanically robust biomaterials than mammalian keratins.

Protein derived adhesives are extensively explored as a replacement for synthetic ones, but suffers from weak adhesion and water resistance. Graphite oxide (GO) has been extensively used in nanocomposites, but not in adhesives applications. The objectives of this study were to prepare functionally improved protein adhesive by exfoliating GO with different oxidation levels, and to determine the effect of GO on adhesion mechanism. GO were prepared by oxidizing graphite for 0.5, 2, and 4 h (GO-A, GO-B and GO-C, respectively). Increasing oxidation time decreased C/O ratio; while the relative proportion of C-OH, and C = O groups initially increased up to 2 h of oxidation, but reduced upon further oxidation. Canola protein-GO hybrid adhesive (CPA-GO) was prepared by exfoliating GO at a level of 1% (w/w). GO significantly increased (p 0.05) adhesion; where GO-B addition showed the highest dry, and wet strength of 11.67 ± 1.00, and 4.85 ± 0.61 MPa, respectively. The improvements in adhesion was due to the improved exfoliation of GO, improved adhesive and cohesive interactions, increased hydrogen bonding, increased hydrophobic interactions and thermal stability of CPA-GO. GO, as we proposed for the first time is easier to process and cost-effective in preparing protein-based adhesives with significantly improved functionalities.

The effect of 8 factors [(with/without) daily mixing and moisture control, incubation time (t), temperature, ratio between dry substrate mass and bed’s cross section area (MA), inoculum size (spores/g), wheat germ content (WG), initial pH, and moisture content (M)] in the production of a prolyl endopeptidase (PEP) by Aspergillus niger ATCC 11414 in solid state fermentation (SSF) was tested. Contribution of all the factors was significant (p

Thraustochytrids are marine protists found throughout the world in estuarine and marine habitats. These microorganisms have attracted interest, because their lipids contain different long chain polyunsaturated fatty acids (PUFAs). Those able to produce docosahexaenoic acid (C22:6 n-3, DHA) are the most studied because of the physiological importance of this PUFA in human beings. Their heterotrophic cultivation offers several challenges since biomass, lipid content, and fatty acid profile are dependent on growth conditions. In this work the effects of C source and its concentration on DHA production by different thraustochytrid strains are reviewed. Results obtained by different investigators on the use of alternative and low cost nutrient sources for production of DHA by thraustochytrids are also presented.