Cellulose Crystals Research Articles

Cell wall configuration and ultrastructure of cellulose crystals in green seaweeds

Green seaweeds (Chlorophyta) are often considered a nuisance, but may in fact constitute a potential climate-friendly renewable resource in the new bioeconomy. Utilization of green seaweed polysaccharides could in particular enable a new type of green growth in coastal regions in developing countries e.g. in West Africa. The carbohydrate constituents, including cellulose, are lignin-free, but only limited knowledge is available on the cellulose ultrastructure and cellulose crystallinity in commonly occurring green seaweeds. Abundantly available green seaweeds along the coast in West Africa include Chaetomorpha linum, Caulerpa taxifolia, Ulva fasciata and Ulva flexuosa. Here, using X-ray diffraction (XRD), on cellulose gently purified from the green seaweeds, we determined that mainly cellulose Iα was present in both C. linum and U. flexuosa. We also found that the crystallite diameter was particularly large, 16 nm, in both the Ghanaian and the Danish C. linum samples, especially compared to the crystallite diameter of 2.5–5 nm in most terrestrial vascular plants (Tracheophytes), which mainly contain cellulose Iβ. For U. flexuosa, increasing crystallinity of the cellulose was achieved during purification. Cellulose purification was not achievable for C. taxifolia, indicating that in this species the glucose is mainly a constituent of other carbohydrates, presumably notably of starch. Transmission electron microscopy (TEM) confirmed the large size of the crystallites of C. linum showing the cellulose forming a multi-lamellar structure with alternating perpendicular and parallel layers along the fibre axis. The cell wall nano-structure appeared amorphous in C. taxifolia and as a network in U. fasciata and U. flexuosa. As glucose was most abundant in C. linum and its cellulose was crystalline, this green seaweed species appears particularly promising as a source for manufacturing of novel cellulose-based materials, e.g. specialized paper or cellulose-based composite materials.

Structure of the Bacterial Cellulose Ribbon and Its Assembly-Guiding Cytoskeleton by Electron Cryotomography.

Cellulose is a widespread component of bacterial biofilms, where its properties of exceptional water retention, high tensile strength, and stiffness prevent dehydration and mechanical disruption of the biofilm. Bacteria in the genus Gluconacetobacter secrete crystalline cellulose, with a structure very similar to that found in plant cell walls. How this higher-order structure is produced is poorly understood. We used cryo-electron tomography and focused-ion-beam milling of native bacterial biofilms to image cellulose-synthesizing Gluconacetobacter hansenii and Gluconacetobacter xylinus bacteria in a frozen-hydrated, near-native state. We confirm previous results suggesting that cellulose crystallization occurs serially following its secretion along one side of the cell, leading to a cellulose ribbon that can reach several micrometers in length and combine with ribbons from other cells to form a robust biofilm matrix. We were able to take direct measurements in a near-native state of the cellulose sheets. Our results also reveal a novel cytoskeletal structure, which we have named the cortical belt, adjacent to the inner membrane and underlying the sites where cellulose is seen emerging from the cell. We found that this structure is not present in other cellulose-synthesizing bacterial species, Agrobacterium tumefaciens and Escherichia coli 1094, which do not produce organized cellulose ribbons. We therefore propose that the cortical belt holds the cellulose synthase complexes in a line to form higher-order cellulose structures, such as sheets and ribbons.IMPORTANCE This work's relevance for the microbiology community is twofold. It delivers for the first time high-resolution near-native snapshots of Gluconacetobacter spp. (previously Komagataeibacter spp.) in the process of cellulose ribbon synthesis, in their native biofilm environment. It puts forward a noncharacterized cytoskeleton element associated with the side of the cell where the cellulose synthesis occurs. This represents a step forward in the understanding of the cell-guided process of crystalline cellulose synthesis, studied specifically in the Gluconacetobacter genus and still not fully understood. Additionally, our successful attempt to use cryo-focused-ion-beam milling through biofilms to image the cells in their native environment will drive the community to use this tool for the morphological characterization of other studied biofilms.

How to control interactions of cellulose-based biomaterials with skin: the role of acidity in the contact area.

Being able to control the interactions of biomaterials with living tissues and skin is highly desirable for many biomedical applications. This is particularly the case for cellulose-based materials which provide one of the most versatile platforms for tissue engineering due to their strength, biocompatibility and abundance. Achieving such control, however, requires detailed molecular-level knowledge of the dominant interaction mechanisms. Here, we employed both biased and unbiased atomic-scale molecular dynamics simulations to explore how cellulose crystals interact with model stratum corneum bilayers, ternary mixtures of ceramides, cholesterol, and free fatty acids. Our findings show that acidity in the contact area directly affects binding between cellulose and the stratum corneum bilayer: Protonation of free fatty acids in the bilayer promotes attractive cellulose-bilayer interactions. We identified two major factors that control the cellulose-skin interactions: (i) the electrostatic repulsion between a cellulose crystal and the charged (anionic due to deprotonated fatty acids) surface of a stratum corneum bilayer and (ii) the cellulose-stratum corneum hydrogen bonding. When less than half of the fatty acids in the bilayer are protonated, the first factor dominates and there is no binding to skin. At a larger degree of fatty acid protonation the cellulose-stratum corneum hydrogen bonding prevails yielding a tight binding. Remarkably, we found that ceramide molecules are the key component in hydrogen bonding with cellulose. Overall, our findings highlight the critical role of fatty acid protonation in biomaterial-stratum corneum interactions and can be used for optimizing the surface properties of cellulose-based materials aimed at biomedical applications such as wound dressings.

Shear-induced unidirectional deposition of bacterial cellulose microfibrils using rising bubble stream cultivation

In crystalline cellulose I, all glucan chains are ordered from reducing ends to non-reducing ends. Thus, the polarity of individual chains is added forming a large dipole within the crystal. If one can engineer unidirectional alignment (parallel packing) of cellulose crystals, then it might be possible to utilize the material properties originating from polar crystalline structures. However, most post-synthesis manipulation methods reported so far can only achieve the uniaxial alignment with bi-directionality (antiparallel packing). Here, we report a method to induce the parallel packing of bacterial cellulose microfibrils by applying unidirectional shear stress during the synthesis and deposition through the rising bubble stream in a culture medium. Driving force for the alignment is explained with mathematical estimation of the shear stress. Evidences of the parallel alignment of crystalline cellulose Iα domains were obtained using nonlinear optical spectroscopy techniques.

Enhancing the loading and swelling capacity of cellulose crystal through difunctional and multifunctional epoxy crosslinkers and the effects on the elasticity and plasticity: A computational study

Cellulose is known to have wide industrial applications because of its natural abundance and possibility of enhancing its physical properties through modification with crosslinkers. This study considers the impacts of the difunctional long chain and multifunctional epoxy crosslinkers. Strong agreement was observed between the computed and experimental properties which include low porosity, higher network, compactness and elasticity of multifunctional over the difunctional long-chain epoxy modified cellulose (called hydrogels). These consequentially affect the dynamic fluctuation of cellulose, plasticity, glass temperature, viscosity and conductivity. Hydrogels that were experimentally found to have higher porosity, swelling and loading ability were also observed to have stronger water interaction and gas absorption. The multivariance analysis and partial least squares (PLS) established a good relationship between the experimental and computational results. The general order of gases diffusion through the hydrogels is N2 > CH4 > O2 > CO2 with some slight variation in the specific hydrogels.

Drying-induced bending deformation of cellulose nanocrystals studied by molecular dynamics simulations

Drying cellulosic materials from their water-swollen state can collapse their ultrastructure and alter their macroscopic material properties such as mechanical strength and water-retention ability. However, at the single-crystal or molecular level, little is known about the deformation of cellulose upon drying. We thus investigate herein the drying-induced deformation of a cellulose crystal by using an atomistic molecular dynamics simulation that considers a hydrated system composed of two short cellulose crystals, a lower one fixed to a flat substrate and an upper one free to deform. To mimic vacuum drying, the water is gradually removed from the system. As the drying proceeds, the upper cellulose crystal bends and forms a tight contact with the lower cellulose crystal. This result underlines the importance of lateral deformation of cellulose crystals in the collapse of the cellulose ultrastructure and provides insights into the molecular mechanisms responsible for modifying the properties of cellulose materials.

Preferred crystallographic orientation of cellulose in plant primary cell walls

Cellulose, the most abundant biopolymer on earth, is a versatile, energy rich material found in the cell walls of plants, bacteria, algae, and tunicates. It is well established that cellulose is crystalline, although the orientational order of cellulose crystallites normal to the plane of the cell wall has not been characterized. A preferred orientational alignment of cellulose crystals could be an important determinant of the mechanical properties of the cell wall and of cellulose-cellulose and cellulose-matrix interactions. Here, the crystalline structures of cellulose in primary cell walls of onion (Allium cepa), the model eudicot Arabidopsis (Arabidopsis thaliana), and moss (Physcomitrella patens) were examined through grazing incidence wide angle X-ray scattering (GIWAXS). We find that GIWAXS can decouple diffraction from cellulose and epicuticular wax crystals in cell walls. Pole figures constructed from a combination of GIWAXS and X-ray rocking scans reveal that cellulose crystals have a preferred crystallographic orientation with the (200) and (110)/(1bar 10) planes preferentially stacked parallel to the cell wall. This orientational ordering of cellulose crystals, termed texturing in materials science, represents a previously unreported measure of cellulose organization and contradicts the predominant hypothesis of twisting of microfibrils in plant primary cell walls.

Removal of N-linked glycans in cellobiohydrolase Cel7A from Trichoderma reesei reveals higher activity and binding affinity on crystalline cellulose

BackgroundCellobiohydrolase from glycoside hydrolase family 7 is a major component of commercial enzymatic mixtures for lignocellulosic biomass degradation. For many years, Trichoderma reesei Cel7A (TrCel7A) has served as a model to understand structure–function relationships of processive cellobiohydrolases. The architecture of TrCel7A includes an N-glycosylated catalytic domain, which is connected to a carbohydrate-binding module through a flexible, O-glycosylated linker. Depending on the fungal expression host, glycosylation can vary not only in glycoforms, but also in site occupancy, leading to a complex pattern of glycans, which can affect the enzyme’s stability and kinetics.ResultsTwo expression hosts, Aspergillus oryzae and Trichoderma reesei, were utilized to successfully express wild-types TrCel7A (WTAo and WTTr) and the triple N-glycosylation site deficient mutants TrCel7A N45Q, N270Q, N384Q (ΔN-glycAo and ΔN-glycTr). Also, we expressed single N-glycosylation site deficient mutants TrCel7A (N45QAo, N270QAo, N384QAo). The TrCel7A enzymes were studied by steady-state kinetics under both substrate- and enzyme-saturating conditions using different cellulosic substrates. The Michaelis constant (KM) was consistently found to be lowered for the variants with reduced N-glycosylation content, and for the triple deficient mutants, it was less than half of the WTs’ value on some substrates. The ability of the enzyme to combine productively with sites on the cellulose surface followed a similar pattern on all tested substrates. Thus, site density (number of sites per gram cellulose) was 30–60% higher for the single deficient variants compared to the WT, and about twofold larger for the triple deficient enzyme. Molecular dynamic simulation of the N-glycan mutants TrCel7A revealed higher number of contacts between CD and cellulose crystal upon removal of glycans at position N45 and N384.ConclusionsThe kinetic changes of TrCel7A imposed by removal of N-linked glycans reflected modifications of substrate accessibility. The presence of N-glycans with extended structures increased KM and decreased attack site density of TrCel7A likely due to steric hindrance effect and distance between the enzyme and the cellulose surface, preventing the enzyme from achieving optimal conformation. This knowledge could be applied to modify enzyme glycosylation to engineer enzyme with higher activity on the insoluble substrates.

Micro-Fibrillated Cellulose Fabrication from Empty Fruit Bunches of Oil Palm

Micro-fibrillated celluloses (MFCs) are made from oil palm empty fruit bunches (EFB). EFB is processed through several stages of the process, including washing, alkalization, and bleaching to remove impurities, lignin, and hemicellulose. Each treatment stage was characterized by differential scanning calorimeter (DSC) and thermogravimetric (TGA) analysis. Morphological analysis was characterized using Scanning Electron Microscope (SEM). The process results show that MFC has an average length and thickness of 450 and 80 microns for coarse fibers respectively, averaging 50 and 5 microns for fine fibers, respectively. Fibrillation fibers appear on the surface of fibers which are treated using alkalization and bleaching processes. The TGA results showed a decrease in weight occurred at a temperature of 40 to 109 °C for the first stage of the heating process and at a temperature of 247 to 382 °C for the second stage. The decrease in fiber weight is caused by evaporation of water content and degradation of cellulose compounds at each stage. The glass transition temperature of MFC was obtained at 236 °C. The thermal stability of cellulose from fibers treated using alkalization and bleaching processes proved the formation of cellulose crystals. Removal of lignin and hemicellulose is shown by the absorption of O-H and C-C bonds in FTIR spectroscopy. From these results, it is stated that micro-fibrillation cellulose is formed well through a series of processes given.

Structure and electrical resistivity of individual carbonised natural and man-made cellulose fibres

Carbon fibres were produced from two natural and two man-made cellulose fibres, respectively, in a high-temperature carbonisation process. The structure of the fibres was analysed by means of wide-angle X-ray scattering and Raman spectroscopy. It was found that longitudinal shrinkage of the fibres during carbonisation is correlated with the degree of orientation of cellulose crystals as determined by wide-angle X-ray scattering. Numerous micro-scale defects were found in carbonised natural cellulose fibres, particularly hemp, whereas the structural integrity of carbonised man-made cellulose was better preserved. Both Raman spectroscopy and wide-angle X-ray scattering revealed a trend of diminishing electrical resistivity with increasing structural (graphitic) order in the fibres. Overall, the electrical resistivity of cellulose-derived carbon fibres was between 40 and 70 Ω µm, which exceeds the resistivity of fossil-based carbon fibre by a factor ten.

BcsAB synthesized cellulose on nickel surface: polymerization of monolignols during cellulose synthesis alters cellulose morphology

The bacterial BcsA-B cellulose synthase synthesizes cellulose II when immobilized on nickel surfaces. To explore how lignin interacts with cellulose, lignin was polymerized either during or after cellulose formation from surface immobilized BcsA-B, leading to significant alterations in cellulose and lignin morphology. To facilitate lignin detection, polymerized coniferyl alcohol monolignols were detected by lignin autofluorescence. This compound was previously demonstrated as a suitable lignin monolignol exhibiting autofluorescence that enables lignin detection even at low concentrations. Cellulose and lignin coated nickel surfaces were studied under confocal microscopy, as well as by atomic force microscopy and X-ray diffractometry (XRD). As a consequence of simultaneous lignin and cellulose deposition on the surface, cellulose microfibril morphology was altered. XRD data indicated that cellulose crystal size was significantly decreased by polymerized lignin incorporation, suggesting that simultaneous lignin polymerization prevents the proper assembly of cellulose microfibrils. In contrast, polymerizing lignin after cellulose synthesis yielded a cellulose that was very similar in character to control (lignin-free) samples in terms of crystal morphology.

Biodegradable kinetics and behavior of bio-based polyblends under simulated aerobic composting conditions

The current study evaluates aerobic biodegradation of melt extruded poly(lactic acid) PLA based blends under composting conditions. Samples of neat PLA (NPLA) and bio-based polyblend composites of PLA/LLDPE (linear low-density polyethylene) having different concentration of MCC (microcrystalline cellulose crystal) were analyzed to understand the biodegradation behavior of these blends under simulated composting conditions. Biodegradation kinetics revealed that higher content of MCC and PLA accelerated the biodegradation process of the polymeric blends. Increase in the spherulite growth size and decrease in the spherulite density of the biodegraded samples confirmed the decline in amorphous portion of the test samples due to microbial assimilation, leaving behind the crystalline portion. Surface morphological analysis revealed that the samples of PLA/LLDPE/MCC blends underwent surface erosion prior to bulk biodegradation (50–80%) until the 90th day and the PLA formed fibril-like structures after degradation. This study would help in the design and preparation of biodegradable bio-based commercial blends in the future.

Changes in supramolecular structure and improvement in reactivity of dissolving pulp via enzymatic pretreatment with processive endoglucanase EG1 from Volvaria volvacea

Processive endoglucanase EG1 and its core domain, EG1(CD), were used to pretreat the commercial dissolving pulp to improve cellulose reactivity. The Fock reactivity of the pulp which was treated with EG1 and EG1 (CD) at 50 U/g enzyme loading increased from 74.3% of the control to 90.6% and 88.4%, respectively. Refining also improved the Fock reactivity of the pulp, but not as effective as EG1 or EG1(CD) treatment. Refining prior to EG1 or EG1(CD) treatment could slightly further improve the Fock reactivity, to 91.6% and 90.0%, respectively. After enzymatic treatment and (or) refining, the water retention value, differential scanning calorimetry and alkaline solubility analysis indicated that enzyme treatment, especially by EG1, significantly increased the accessibility of fibers to reaction reagents. Combined with the characteristics of soluble reducing sugar produced by EG1 treatment and the changes of degree of polymerization, it is inferred that a small fraction of cellulose crystallization regions are destroyed in the enzymatic hydrolysis process due to the processive acting ability of EG1, and some microchannels in the fiber cell wall were created, which is similar to the effect of “drilling holes”, so that the reaction reagent can reach the inside of the cell wall evenly, thus obviously improving the reactivity of the dissolved pulp.

Evolution of the functionalities and structures of biochar in pyrolysis of poplar in a wide temperature range

This study studied the change of functionalities in the biochar formed in pyrolysis of poplar wood in a wide range of temperature. The in situ Diffuse Reflectance Infrared Fourier transform spectroscopy characterization indicated that aldehydes and ketones functionalities formation initiated at 100 °C, dominated at 300 to 500 °C. Carboxyl group was less stable than carbonyls. Cellulose crystal in poplar decomposed slightly at 300 °C and significantly at 350 °C. The temperature from 250 to 350 °C significantly affected biochar yields, while the drastic fusion of the ring structures in biochar occurred from 550 to 650 °C, making biochar more aliphatic while less more aromatic. High pyrolysis temperature also created more defective structures in the biochar and favored the absorption of the CO2 generated during the pyrolysis. The results provide the reference information for understanding the structural configuration and evolution of the functionalities during in pyrolysis of poplar biomass.

13C NMR and XRD studies on the enhancement of cellulose II crystallinity with low concentration NaOH post-treatments

In this study, methods of completing the structural conversion of partly crystalline cellulose II were studied by solid-state 13C CP/MAS NMR spectroscopy and X-ray diffraction. The study incorporated post-treatments of samples that had been mercerized or regenerated to yield somewhat crystalline cellulose II. These post-treatments used different temperatures, lower concentrations of NaOH than used in, for example, the original mercerization, and different neutralization methods. The cellulose employed was originally filter paper from wood pulp that was subsequently mercerized or dissolved and regenerated to create partly crystalline cellulose II. The variations in rate of each component were monitored at different NaOH concentrations and reaction temperatures during the treatment; these components include the crystalline and accessible surface as well as the inaccessible surface/amorphous region. Subsequently, neutralization was performed for the crystallization of cellulose II and the effects of the acid employed were also evaluated. It can be thought that controlling the partial Na-cellulose construction is important for improving the assembly of cellulose II; this is achieved by optimizing the concentration of NaOH, treatment temperature, and selection of acid for neutralization. NMR spectroscopy of the intermediate state of the NaOH detected the partial generation of Na-cellulose; further, another domain exhibited the spectrum of highly crystallized cellulose II. It is believed that the selective Na-cellulose construction in the inaccessible surface cellulose is the result of an increase in the size of cellulose II crystals. During the NaOH treatment, at a concentration of 10%, the crystallinity index evaluated by both NMR and X-ray was maximized; further, at the treatment temperature of 80 °C the crystallinity of the cellulose II evaluated by NMR improved. Moreover, the neutralization, which was conducted after the alkaline treatment with H2SO4, established the most suitable conditions for the crystallization of cellulose II.

Zwitterionic Polypeptides: Chemoenzymatic Synthesis and Loosening Function for Cellulose Crystals.

A polypeptide with a GlyHisGly repeating sequence containing zwitterionic structures that effectively interact with cellulose was synthesized for dissociation of cellulose crystals. Polypeptide with the GlyHisGly sequence was synthesized by chemoenzymatic polymerization and postfunctionalization of the His residues was performed to afford imidazolium butyrate on the side chains. The resulting zwitterionic polypeptide effectively dissociated bundles of tunicate cellulose nanocrystals, even when the conditions were mild and the concentration of the polypeptide was as low as 1-2 mg mL-1. Polypeptide treatment also affected the morphology of the cell walls in cultured plant cells, and the cellulose microfibril networks and amorphous polysaccharide layer were dissociated according to atomic force microscopy (AFM). The zwitterionic polypeptide treatment did not change the crystal structure of the cellulose nanocrystals. Analysis of the mechanical properties of the cellulose nanocrystals by force curve measurements using AFM revealed that the elastic modulus of the cellulose nanocrystals increased after treatment with the zwitterionic polypeptide, indicating that the amorphous part of the cellulose nanocrystals was removed by interactions with the polypeptide. At a concentration of the polypeptide that enabled the dissociation of the cellulose network, the zwitterionic polypeptide showed negligible cytotoxicity to the plant cells. The mild and noncytotoxic technique for loosening cellulose microfibrils/nanocrystals that was developed in this study has tremendous significance for the modification of cellulose in terms of polymer chemistry, material science, and plant biotechnology.

Facile treatment to fine-tune cellulose crystals in cellulose-silk biocomposites through hydrogen peroxide

The modulation of structural fibrous protein and polysaccharide biopolymers for the design of biomaterials is still relatively challenging due to the non-trivial nature of the transformation from a biopolymer's native state to a more usable form. To gain insight into the nature of the molecular interaction between silk and cellulose chains, we characterized the structural, thermal and morphological properties of silk-cellulose biocomposites regenerated from the ionic liquid, 1-ethyl-3-methylimidazolium acetate (EMIMAc), as a function of increasing coagulation agent concentrations. We found that the cellulose crystallinity and crystal size are dependent on the coagulation agent, hydrogen peroxide solution. The interpretation of our results suggests that the selection of a proper coagulator is a critical step for controlling the physicochemical properties of protein-polysaccharide biocomposite materials.

Fabrication of superporous cellulose beads via enhanced inner cross-linked linkages for high efficient adsorption of heavy metal ions

One of the most important problems in adsorption of heavy metal ions is its slow adsorption kinetics resulting from the narrow pore structure of adsorbents. Herein, a novel superporous spherical cellulose adsorbent was fabricated by a facile yet effective preliminary chemical cross-linking strategy for high efficient adsorption of heavy metal ions. By this strategy, the neighboring cellulose chains were cross-linked and assembled into large cellulose clusters, by which unique superpores with the pore size of 0.5–1.0 μm were formed. Meanwhile, the preliminary chemical cross-linking method prevented the growth of cellulose crystallization, leading to the formation of more amorphous regions, which contributed to high specific surface area (152 m2 g−1). Further, the proposed superporous cellulose beads were modified with glutamic acid and then applied for adsorption evaluation. It was worth mentioning that the adsorbent displayed outstanding adsorption capabilities toward heavy metal ions (98.86 mg g−1 for Cu2+ and 102.29 mg g−1 for Co2+) and fast separation (equilibrium within 30 min). In addition, the cellulose beads also showed excellent recyclability and regeneration. Together with low-cost and eco-friendly cellulose support, the superporous cellulose beads are regard as green and sustainability, and have great potential for industrial application of heavy metal ions treatment.

Isolation of microcrystalline cellulose from corn stover with emphasis on its constituents: Corn cover and corn cob

This study investigates the isolation of microcrystalline cellulose (MCC) from corn stover biomass by acid hydrolysis method with aiming towards its constituents viz; corn cover and corn cob. The process comprises chemical treatments with varying concentrations to optimize the concentrations of chemical reactants. The cellulose crystals produced with optimized concentrations of 2% w/v NaOH, 2% w/v acidified NaClO2 and 10% v/v H2SO4 gives the yield of 25.90%, 29.60% and 39.32% of cellulose from corn cover, corn cob and corn stover respectively. The isolated needle-shaped MCC from corn stover showed the particle dimension in the range of 1.3–2.5 µm solely with a narrow distribution.

The stabilizing effect of cellulose crystals in O/W emulsions obtained by ultrasound process.

The encapsulation of lipophilic bioactive compounds, such as flaxseed oil, is usually done using O/W emulsions as carrier matrix. The aim of this study was to understand the stabilization mechanism of micro-nano cellulose crystals produced from acid hydrolysis in O/W emulsion. Effects of emulsification process conditions using ultrasound on the cellulose particles properties were evaluated varying the proportion of oil-cellulose particles in the emulsion formulation. Cellulose structure did not change using different conditions of emulsification and X-ray diffraction showed major presence of cellulose I. Particle size distribution of cellulose was bimodal and mean particle size reduced after hydrolysis. Emulsions stabilized by cellulose were opaque, homogeneous and showed good kinetic stability. The largest microcrystals were displayed between the oil droplets, preventing the flocculation of the droplets while smaller particles were adsorbed on the oil-water interface. The mechanism of droplets stabilization was not associated to the reduction of interfacial tension. Stabilization was associated to significant effect of electrostatic repulsion and increase in viscosity. Moreover, the flaxseed oil droplets were completely surrounded by cellulose nanocrystals, showing also Pickering-type stabilization. Therefore, emulsions with cellulose crystals were stabilized by different mechanisms and have interesting properties and characteristics for the protection of lipophilic compounds that could be applied in food and cosmetics products.