Synthesis of bacterial cellulose and bacterial cellulose nanocrystals for their applications in the stabilization of olive oil pickering emulsion

Preparation and characterization of liposoluble tea polyphenol based functional emulsion films and the regulation of its releasing property

Functional films based on hydroxypropyl methylcellulose (HPMC)/ sodium citrate (SC) porous film and liposoluble tea polyphenol (LTP)/water Pickering emulsions stabilized by different contents of starch nanoparticles (NPs) were prepared. Addition of Pickering emulsion endowed the film surface pores, decreased oxygen permeability, water vapor permeability (WVP), hydrophilicity and good anti-oxidant effect. With increasing NPs, more smaller emulsion droplets appeared in the emulsion and filled into the porous structures of the film, the light transmittance and contact angle of the film increased. Functional film with 2 % NPs showed the lowest WVP and Tg, and highest stable LTP release ratio (4-12 week). That more surficial holes appeared and more emulsion droplets protrusions accumulated near the cross-sectional pores during the releasing process might facilitate the higher release of film-2 % NPs. The functional films have great potential to be used as light-shielding coatings, antioxidant capsule shells and sustained fresh-keeping "cards" for different oil systems.

The properties of Pickering emulsions stabilized by bacterial cellulose nanofibrils and its retarding effect on lipid digestion

The rate of lipid digestion can be delayed by the interface modulation of O/W Pickering emulsions. In this study, bacterial cellulose nanofibrils prepared by ball milling synergized with electron beam irradiation (B-IB50) were used as stabilizers to prepare Pickering emulsions. Results showed that B-IB50 formed emulsion systems with good stability. Especially when the content of B-IB50 was >0.6 wt%, emulsions showed excellent storage and environmental stability. Notably, at pH 2.0, the electrostatic repulsion between fibrils was weakened leading to closer cross-linking and giving better protection to the oil droplets. When the content of B-IB50 in emulsions increased from 0.2 wt% to 1.0 wt%, the release of FFA decreased from 66.7 % to 37.8 % during digestion, which indicated that the presence of more B-IB50 inhibited the digestion of lipids. Main mechanisms were proposed for the results: (1) B-IB50 formed a dense interface layer that reduced the binding area of bile salts and lipases; (2) B-IB50 formed the three-dimensional network structure limiting the displacement of bile salts and lipases, thereby reducing the binding to lipids. This study provided theoretical ideas for developing emulsion-based functional foods with lipid-reducing effects.

Sulfhydryl-loaded bacterial cellulose nanoparticles alleviated intestinal damage caused by mycotoxin patulin in apple juice

Patulin (PAT), a toxic fungal metabolite, can directly damage the intestinal barrier and gut homeostasis via altering microbiota composition. Although there are several attempts for the control of PAT in vitro, there are currently few studies on the improvement of intestinal damage caused by patulin using in vivo assay. In this study, a nanoparticle formulation of spherical bacterial cellulose was obtained by dynamic fermentation of Acetobacter xylinum to prepare bacterial cellulose nanoparticles (BCNs) and then modified with 3-mercaptotetraethoxysilane to produce BCN(SH), to increase PAT adsorption in vitro. Meanwhile, results revealed that BCN(SH)s protected the small intestinal microbial barrier and can be used by microorganisms, such as Bacteroides, Firmicutes, and Actinomycetes, to produce short-chain fatty acids (SCFAs). BCN(SH)s appears as a promising edible material that can be used to alleviate intestinal damage from patulin, and has yet to be tested in other gut intoxication models.

Research progress on improving dispersion stability of nanocellulose in different media: A review

Nanocellulose has been widely used in various fields due to its good biocompatibility, mechanical properties, large specific surface area and environmental friendliness. Among these applications, uniformly dispersing nanocellulose in various media to improve its performance is an application with good development prospects. However, due to the presence of surface hydroxyl groups, nanocellulose tends to form aggregates between molecular chains and is less compatible with nonpolar solvents, thus making it difficult to be stably dispersed in solvents. How to break the aggregation between cellulose and improve its compatibility with the medium has become a challenging issue. In this paper, the dispersion system is classified into polar medium, nonpolar medium and polymer matrix according to the polarity and state of the medium, and a review is presented on how to improve the dispersion stability of nanocellulose in different media. The methods of using surface modification to improve the dispersion stability of nanocellulose in different media, such as carboxylation, amidation, and grafting of long-chain molecules to reduce the aggregation among nanocellulose and to improve the compatibility with solvents, are highlighted. Finally, suggestions are made for future research directions.

Rehydratable dry bacterial cellulose formulation and the role of sodium alginate in mitigating hornification

In this study, a cost-effective dry formulation of bacterial cellulose (BC) was developed by employing sodium alginate (SA) as a capping agent to reduce hornification during the drying process. The effects of different BC-to-SA ratios were assessed for reducing hornification and improving rehydration capabilities. The mechanism by which SA alleviated hornification in BC was explained at macroscopic, microscopic, and molecular levels. Compared with BC alone, the BC powder prepared with a 1:3 BC-to-SA ratio (BCSA3) demonstrated significantly better rehydration and redispersion capabilities, and a BC-to-SA ratio of 1:5 (BCSA5) exhibited the best rehydration performance. Sedimentation assay revealed that BCSA5 exhibited the lowest sedimentation ratio among the rehydrated formulations. Pore size distribution analysis indicated that SA effectively reduced the macropore volume of BC, preventing pore collapse during structural shrinkage. Furthermore, XRD and FTIR analyses confirmed that SA reduced hydrogen bonding in the amorphous regions of BC during drying, resulting in lower crystallinity. Rheological characterization of rehydrated samples further demonstrated the efficacy of SA in retaining functional properties. Compared with traditional freeze-drying, our findings revealed that formulating BC with SA at appropriate ratios could lead to rehydratable products via oven-drying, a more cost-effective and scalable approach for large-scale production and industrial applications.

Oil Recovery Improvements Based on Pickering Emulsions Stabilized by Cellulose Nanoparticles and Their Underlying Mechanisms: A Review

The use of nanocellulose (NC)-based Pickering emulsions represents an advancement in chemically enhanced oil recovery (cEOR) methods. The main challenge of cEOR is to develop stable and efficient fluids for applications under reservoir conditions. Pickering emulsions have emerged as a possible solution for stabilizing chemical injection fluids. These emulsions are stabilized by solid particles instead of surfactants and have been the focus of research over the past decade because of their high stability. Although these emulsions present promising solutions, most research has focused on nonbiodegradable inorganic particles, raising concerns about their environmental impact. In this context, nanocellulose (NC) has emerged as an innovative and sustainable alternative due to its biodegradability, abundance, and unique surface chemistry. This contribution presents an exploratory literature review on the use of Pickering emulsions, focusing on nanocellulose in the context of enhanced oil recovery (EOR) as an alternative for fluid stabilization under reservoir conditions. The main mechanisms of oil recovery, such as interfacial tension reduction, in situ crude oil emulsification, capillary disjunction, pressure, and fluid rheological behavior, are discussed. This Review highlights the great potential of nanocellulose-based Pickering emulsions to make EOR processes more sustainable and emphasizes the need for further studies to understand the mechanisms involved. A total of 176 scientific articles were analyzed and evaluated to provide insights and contribute to the advancement of cEOR, in addition to addressing the challenges encountered.

Applications of bacterial cellulose in the food industry and its health-promoting potential

Bacterial cellulose (BC) is a naturally occurring biomaterial with a wide range of potential applications in the food industry because of its exceptional mechanical qualities, unique nanofiber structure, high purity, and outstanding biocompatibility. Beyond its physical attributes, BC has gained interest recently due to research demonstrating its potential health benefits as a functional food ingredient. This article examines the many uses of BC in the food business, with a focus on how it may enhance food texture, operate as a bioactive carrier, and have promise in the packaging sector. Further research was done on the health-promoting properties of BC in functional foods, particularly with regard to its functions as a blood glucose regulator, and gastrointestinal health. This review seeks to bring fresh ideas for the study of bioactive components in the food industry by providing a summary of the existing research and demonstrating the possible role of BC in food. It also suggests future paths for research.

Optimizing the Production of Bacterial Cellulose Nanofibers and Nanocrystals Through Strategic Fiber Pretreatment

Bacterial cellulose (BC) has unique properties such as high tensile strength, high crystallinity, and high purity. The fiber length of BC causes different attributes. Therefore, the degradation of BC has been studied extensively. In this study, the fibers of BC were rearranged via a DMAc-LiCl solvent and BC was degraded in the wet state. Two different degradation methods were applied: milling with liquid nitrogen and autoclave treatment. The degraded BCs were characterized by FTIR, TEM, AFM, TGA, and XRD. The solvent helps to align the fibers, making them more crystalline. The degraded BCs had a lower crystalline ratio than untreated BC, due to increased hydrogen bonding during degradation in the wet state. Degradation with an autoclave produced two different degraded BCs: nanofibrils and spherical nanocrystals, with and without solvent pretreatment, respectively. The nanofibril lengths were between 312 and 700 nm depending on the applied method, and the spherical nanocrystal size was 56 nm. The rearrangement via solvent causes an important difference in the degradation of BC. Nanofibrils and nanocrystals can be obtained, depending on the rearrangement of fibers before the degradation process.

Pérez S, Velásquez. Cock JA, Vélez-Acosta L, Gañán-Rojo P, Zuluaga-Gallego R. A Novel French-Style Salad Dressing Based on Pickering Emulsion of Oil-Water Lycopene from Guava and Cellulose Nanofibers

The objective of this research was to assess the potential of a Pickering emulsion based on lycopene extracted from guava by sunflower oil-water and cellulose nanofibers (CNFs) isolated from banana residues as a novel ingredient for a French-style salad dressing. The aim was to determine the impact of this emulsion on the stability and rheological properties of the dressing as well as ascertain the presence of lycopene in the final product. The particle size distribution, rheological properties, and emulsion stability of the Pickering emulsion and salad dressing were evaluated. The sample exhibiting the optimal stability condition contained 0.5 wt.% of CNFs (EPI0.5). In order to prepare the French salad dressing based on this Pickering emulsion, three concentrations of vinegar were analyzed. All samples contained white salt and sugar. The findings suggest that alterations in emulsion stability may be influenced by the vinegar content and the presence of salt, particularly during the storage period, which also affects the concentration of lycopene. Notwithstanding these findings, the untrained panelists expressed a favorable opinion and acceptance of the dressings, indicating that the product could serve as an alternative means of enriching food through the incorporation of beneficial substances such as lycopene.

Enzymatically green-produced bacterial cellulose nanoparticle-stabilized Pickering emulsion for enhancing anthocyanin colorimetric performance of versatile films

To enhance the colorimetric performance of anthocyanin (Ant), a konjac glucomannan (KGM)-based multifunctional pH-responsive indicator film was fabricated by introducing enzymatically prepared bacterial nanocellulose (EBNC) stabilized camellia oil/camellia essential oil Pickering emulsion (BCCE). Specifically, optimized enzymatic hydrolysis time (36 h) was determined based on the particle size and microstructure. Then BCCE (containing 0.4% EBNC) was incorporated into Ant-containing KGM, and the novel active indicator film (KGM-Ant-BCCE) was constructed. Films with varying BCCE concentrations (3%-11%) exhibited enhanced UV shielding, thermal stability, mechanical strength, water vapor and oxygen permeability, hydrophobicity, and antioxidant performance. The pronounced color change of KGM-Ant-BCCE indicated its potential for visually detecting shrimp freshness. Moreover, the biodegradability (25 days) confirmed the environmentally benign property of the film. In summary, incorporating green-produced EBNC nanoparticle-stabilized BCCE offers an innovative pathway to improve the color indication capability of polysaccharide-based smart packaging.

Konjac glucomannan-based highly antibacterial active films loaded with thyme essential oil through bacterial cellulose nanofibers/Ag nanoparticles stabilized Pickering emulsions

The aim of this study was to develop novel konjac glucomannan (KGM)-based highly antibacterial active films, where five types of films were prepared and compared. The microstructure results showed that KGM-based films loaded with thyme essential oil (TEO) through bacterial cellulose nanofibers/Ag nanoparticles (BCNs/Ag nanoparticles) stabilized Pickering emulsions (Type V films) displayed the smoothest surface and the most evenly dispersed TEO droplets as compared with the other four types of films. Moreover, Type V films showed the highest contact angle value (86.28°), the best thermal stability and mechanical properties. Furthermore, Type V films presented the highest total phenol content (13.23 mg gallic acid equivalent/g film) and the best antioxidant activity (33.96 %) as well as the best sustained-release property, thus showing the best antibacterial activity, which was probably due to that BCNs/Ag nanoparticles and TEO displayed a synergistic effect to some extent. Consequently, Type V film-forming solutions were used as coatings for tangerines. The results showed that the tangerines treated with Type V coatings displayed excellent fresh-keeping properties. Therefore, the coatings, KGM-based film-forming solutions loaded with TEO through BCNs/Ag nanoparticles stabilized Pickering emulsions, have great potential for the preservation of fruits and vegetables.

Fully Biodegradable Packaging Films for Fresh Food Storage Based on Oil-Infused Bacterial Cellulose

Fully biodegradable packaging materials are demanded to resolve the issue of plastic pollution. However, the fresh food storage performance of biodegradable materials is generally much lower than that of plastics due to their high permeability, microbial friendliness, and limited stretchability and transparency. Here a biodegradable packaging material is reported with high fresh food storage performance based on an oil-infused bacterial cellulose (OBC) porous film. The oil infusion significantly improved cellulose's food-keeping performance by reducing its gas permeability, increasing its stretchability and transparency, and enabling the active release of green vapor-phase preservative molecules, while maintaining its intrinsically high degradability. Strawberries stored in a container with the OBC lid at 23 °C after 5 days exhibited a moldy rate of 0%, in contrast to the 100% moldy rate of those stored by poly(ethylene). Enhanced storage performance is also obtained on tomatoes, pork, and shrimp. The OBC film is naturally degraded after being buried in wet soil at 30 °C for 9 days, identical to the degradation rate of bacterial cellulose. The liquid seal strategy broadly applies to different celluloses, providing a general option for developing cellulose-based biodegradable packaging materials.

Caenorhabditis elegans endorse bacterial nanocellulose fibers as functional dietary Fiber reducing lipid markers

Bacterial nanocellulose (BNC) is a promising dietary fiber with potential as a functional food additive. We evaluated BNC fibers (BNCf) in the Caenorhabditis elegans model to obtain insight into the BNCf's biointeraction with its gastrointestinal tract while reducing the variables of higher complex animals. BNCf were uptaken and excreted by worms without crossing the intestinal barrier, confirming its biosafety regarding survival rate, reproduction, and aging for concentrations up to 34 μg/ml BNCf. However, a slight decrease in the worms' length was detected. A possible nutrient shortage or stress produced by BNCf was discarded by measuring stress and chemotactic response pathways. Besides, we detected a lipid-lowering effect of BNCf in N2 C. elegans in normal and high-caloric diets. Oxidative damage was computed in N2 worms and Rac1/ced-10 mutants. The GTPase Rac1 is involved in neurological diseases, where its dysregulation enhances ROS production and neuronal damage. BNCf reduced the lipid oxidative markers produced by ROS species in this worm strain. Finally, we detected that BNCf activated the genetic expression of the immunological response and lipid catabolic process. These results strengthen the use of BNCf as a functional dietary fiber and encourage the potential treatment of neurological disease by modulating diet.

In vitro degradation and antibacterial activity of bacterial cellulose deposited flax fabric reinforced with polylactic acid and polyhydroxybutyrate

The objective of this study was to prepare biocomposites through the solution casting method followed by compression moulding in which bacterial cellulose (BC) deposited flax fabric (FF) produced through fermentation is coated with minimal amount of polylactic acid (PLA) and polyhydroxybutyrate (PHB). Biocomposites incorporated with 60 % of PLA or PHB (% w/w) show enhanced tensile strength. Cross-sectional morphology showed good superficial interaction of these biopolymers with fibres of FF thereby filling up the gaps present between the fibres. The tensile strength of biocomposites at 60 % PLA and 60 % PHB improved from 37.97 MPa (i.e., BC deposited FF produced in presence of honey) to 67.17 MPa and 56.26 MPa, respectively. Further, 0.25 % of nalidixic acid (NA) (% w/w) and 6 % of oleic acid (OA) (% w/w) incorporation into the biocomposites imparted prolonged antibacterial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The in vitro cytotoxicity of biocomposites was determined using L929 mouse fibroblast cells. The 3-(4,5-cime- thylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity tests showed that the PHB derived biocomposites along with antibacterial compounds in it were non-toxic. In vitro degradation of biocomposites was measured for up to 8 weeks in the mimicked physiological environment that showed a gradual rate of degradation over the period.

Highly sensitive humidity sensor based on composite film of partially reduced graphene oxide and bacterial cellulose

Breathing is an important physiological activity of human body, which not only reflects the state of human movement, but also is one of the important health indicators. Breathing can change the concentration of water molecules, so monitoring humidity has gradually become a hot topic in modern research. In this study, a humidity sensing composite film with high sensitivity and short response time was made by using the mixture of graphene oxide (GO) and bacterial cellulose (BC) with simple dry film-forming method. L-ascorbic acid was used as reducing agent to reduce GO and improve the conductivity of GO/BC composite film (BG). The influence of different BC contents and the different reduction degree on the resistance change rate of composite film was investigated in details. The maximum resistance change rate of partially reduced BG humidity sensitive composite film reached up to 94%, and the response and recovery time were 13 s and 47 s respectively. Furthermore, the sensor shows obvious resistance change in noncontact sensing test and different breathing states. This kind of humidity sensitive film with fast response and high sensitivity has great potential in human health monitoring and noncontact sensing, and is of great significance in promoting health detection and intelligent life.

Preparation and functionalization of cellulose nanofibers using a naturally occurring acid and their application in stabilizing linseed oil/water Pickering emulsions

Finding efficient and environmental-friendly methods to produce and chemically modify cellulose nanofibers (CNFs) remains a challenge. In this study, lactic acid (LA) treatment followed by microfluidization was employed for the isolation and functionalization of CNFs. Small amounts of HCl (0.01, 0.1, and 0.2 M) were used alongside LA to intensify cellulose hydrolysis. FTIR spectroscopy and solid-state 13C NMR confirmed the successful functionalization of CNFs with lactyl groups during isolation, while SEM, AFM, and rheological tests revealed that the addition of HCl governed the fibers' sizes and morphology. Notably, the treatment with LA and 0.2 M HCl resulted in a more efficient defibrillation, yielding smaller nanofibers sizes (62 nm) as compared to the treatment with LA or HCl alone (90 and 108 nm, respectively). The aqueous suspension of CNFs treated with LA and 0.2 M HCl showed the highest viscosity and storage modulus. LA-modified CNFs were tested as stabilizers for linseed oil/water (50/50 v/v) emulsions. Owing to the lactyl groups grafted on their surface and higher aspect ratio, CNFs produced with 0.1 and 0.2 M HCl led to emulsions with increased stability (a creaming index increase of only 3 % and 1 %, respectively, in 30 days) and smaller droplets sizes of 23.4 ± 1.2 and 35.5 ± 0.5 μm, respectively. The results showed that LA-modified CNFs are promising stabilizers for Pickering emulsions.

Open roads and bridge: Preservation of fresh beef by a packaging film constructed from photosensitizing bacterial cellulose

Food packaging is now widely used in everyday life to protect food from certain environmental factors. In this work, we have successfully prepared a bacterial cellulose/chitosan-TPE-COOH composite film (BC/CS-TPE), which can achieve broad-spectrum killing of bacteria through a variety of antibacterial mechanisms and ensure the freshness of the beef. In this complex film, CS acts as "advance team", responsible for breaking through the cell wall or outer membrane of bacteria, while the reactive oxygen species produced by photosensitizer under irradiation attacks bacteria, further increasing the destructive effect on the bacterial cell membrane. This allows the film to have outstanding antibacterial properties that can kill 108 CFU/mL pathogens in 10 min. At the same time, cell experiments and hemolysis experiments proved that the film has good biocompatibility. Therefore, BC/CS-TPE film, as the efficient functional food packaging film, has a broad future application prospect.

A green versatile packaging based on alginate and anthocyanin via incorporating bacterial cellulose nanocrystal-stabilized camellia oil Pickering emulsions

This study aims to develop a versatile intelligent packaging based on alginate (Alg) and anthocyanin (Ant) by incorporating bacterial cellulose nanocrystal-stabilized camellia oil Pickering emulsions. Firstly, bacterial cellulose nanocrystals (BCNs) matrix produced from kombucha was incorporated with camellia oil into via ultrasonic triggering, forming a stable and multifunctional camellia oil-bacterial cellulose nanocrystal Pickering nanoemulsions (CBPE). The microstructure and rheology results of the emulsion confirmed the stabilized preparation of CBPE. Subsequently, the CBPE was integrated into the three-dimensional network structure composed of alginate/anthocyanin. The composite film (Alg-Ant-CBPE) was designed through Ca2+ crosslinking, intermolecular hydrogen bonding and dehydration condensation. The fabricated color indicator films with different concentrations of CBPE (0.1 %-0.4 %), showed varying degree of improvement in hydrophobicity, UV shielding, mechanical strength, thermal stability, water vapor barrier properties and antioxidant capacities. When applied to yogurt, the Alg-Ant-CBPE4 exhibited more pronounced color changes compared to Alg-Ant, enabling visual detection of food freshness. In conclusion, the incorporation of Pickering nanoemulsion provides an effective and promising approach to enhance the performance of polysaccharide-based intelligent packaging.

Promising application of probiotic microorganisms as Pickering emulsions stabilizers

The purpose of this work was to study the ability of nineteen food-grade microorganisms as Pickering emulsion (PE) stabilizers. Medium-chain triacylglycerol (MCT) oil-in-water (50:50) PEs were fabricated by 10 wt% or 15 wt% of thermally-inactivated yeast, cocci, Bacillus spp. and lactobacilli cells. The characteristics of microorganisms related to "Pickering stabilization" including morphology, surface charge, interfacial tension, and "contact angle" were firstly studied. After that, the cells-stabilized PEs were characterized from both kinetic and thermodynamic viewpoints, microstructure and rheological properties. The interfacial tension and "contact angle" values of various microorganisms ranged from 16.33 to 38.31 mN/m, and from 15° to 106°, respectively. The mean droplet size of PEs ranged from 11.51 to 57.69 µm. Generally, the physical stability of cell-stabilized PEs followed this order: lactobacilli > Bacillus spp. > cocci > yeast. These variations were attributed to the morphology and cell wall composition. Increasing the microorganism concentration significantly increased the physical stability of PEs from a maximum of 12 days at 10 wt% to 35 days at 15 wt% as a result of better interface coverage. Shear-thinning and dominant elastic behaviors were observed in PEs. Physical stability was affected by the free energy of detachment. Therefore, food-grade microorganisms are suggested for stabilizing PEs.

Construction and Evaluation of Alginate Dialdehyde Grafted RGD Derivatives/Polyvinyl Alcohol/Cellulose Nanocrystals IPN Composite Hydrogels

To enhance the mechanical strength and cell adhesion of alginate hydrogel, making it satisfy the requirements of an ideal tissue engineering scaffold, the grafting of Arg-Gly-Asp (RGD) polypeptide sequence onto the alginate molecular chain was conducted by oxidation of sodium periodate and subsequent reduction amination of 2-methylpyridine borane complex (2-PBC) to synthesize alginate dialdehyde grafted RGD derivatives (ADA-RGD) with good cellular affinity. The interpenetrating network (IPN) composite hydrogels of alginate/polyvinyl alcohol/cellulose nanocrystals (ALG/PVA/CNCs) were fabricated through a physical mixture of ion cross-linking of sodium alginate (SA) with hydroxyapatite/D-glucono-δ-lactone (HAP/GDL), and physical cross-linking of polyvinyl alcohol (PVA) by a freezing/thawing method, using cellulose nanocrystals (CNCs) as the reinforcement agent. The effects of the addition of CNCs and different contents of PVA on the morphology, thermal stability, mechanical properties, swelling, biodegradability, and cell compatibility of the IPN composite hydrogels were investigated, and the effect of RGD grafting on the biological properties of the IPN composite hydrogels was also studied. The resultant IPN ALG/PVA/CNCs composite hydrogels exhibited good pore structure and regular 3D morphology, whose pore size and porosity could be regulated by adjusting PVA content and the addition of CNCs. By increasing the PVA content, the number of physical cross-linking points in PVA increased, resulting in greater stress support for the IPN composite hydrogels of ALG/PVA/CNCs and consequently improving their mechanical characteristics. The creation of the IPN ALG/PVA/CNCs composite hydrogels' physical cross-linking network through intramolecular or intermolecular hydrogen bonding led to improved thermal resistance and reduced swelling and biodegradation rate. Conversely, the ADA-RGD/PVA/CNCs IPN composite hydrogels exhibited a quicker degradation rate, attributed to the elimination of ADA-RGD by alkali. The results of the in vitro cytocompatibility showed that ALG/0.5PVA/0.3%CNCs and ADA-RGD/PVA/0.3%CNCs composite hydrogels showed better proliferative activity in comparison with other composite hydrogels, while ALG/PVA/0.3%CNCs and ADA-RGD/PVA/0.3%CNCs composite hydrogels displayed obvious proliferation effects, indicating that PVA, CNCs, and ADA-RGD with good biocompatibility were conducive to cell proliferation and differentiation for the IPN composite hydrogels.

A rapid removal of Phaeocystis globosa from seawater by peroxymonosulfate enhanced cellulose nanocrystals coagulation

Cellulose nanocrystals (CNC) are recognized as promising bio-based flocculants for controlling harmful algal blooms (HABs). Due to the charge shielding effect in seawater and the strong mobility of algae cells, CNC can't effectively remove Phaeocystis globosa from seawater. To solve this problem, peroxymonosulfate (PMS) was used to enhance the coagulation of CNC for rapidly removal of P. globosa. The results showed that 91.7% of Chl-a, 95.2% of OD680, and 97.2% of turbidity of P. globosa were reduced within 3 h with the use of 200 mg L-1 of CNC and 20 mg L-1 of PMS. The removal of P. globosa was consisted of inactivation and flocculation. Notably, electron paramagnetic resonance (EPR) spectrums and quenching experiments revealed that the inactivation of P. globosa was dominated by PMS oxidation and 1O2. Subsequently, CNC entrained inactivated algal cells to settle to the bottom to achieve efficient removal of P. globosa. The content of total organic carbon (TOC) and chemical oxygen demand (COD) decreased significantly, indicating that a low emission risk of algal cell effluent was produced in the CNC-PMS system. In view of the excellent performance on P. globosa removal, we believe that the CNC-PMS system has great potential for HABs treatments.

Nanocellulose-based aerogels for water purification: A review

Water purification using thin membranes at high pressures through adsorption and size exclusion is the widely used mechanism due to its simplicity and enhanced efficiency compared to other traditional water purification methods. Aerogels have the potential to replace conventional thin membranes considering their unmatched adsorption/absorption capacity and higher water flux due to their unique highly porous (99 %) 3D structure, ultra-low density (~1.1 to 500 mg/cm³), and very high surface area. The availability of a large number of functional groups, surface tunability, hydrophilicity, tensile strength and flexibility of nanocellulose (NC) makes it a potential candidate for aerogel preparation. This review discusses the preparation and employment of NC-based aerogels in the removal of dyes, metal ions and oils/organic solvents. It also offers recent updates on the effect of various parameters that enhance its adsorption/absorption performance. The future perspectives of NC aerogels and their performance with the emerging materials chitosan and graphene oxide are also compared.

Integral Valorization of Grape Pomace for Antioxidant Pickering Emulsions

Full harnessing of grape pomace (GP) agricultural waste for the preparation of antioxidant Pickering emulsions is presented herein. Bacterial cellulose (BC) and polyphenolic extract (GPPE) were both prepared from GP. Rod-like BC nanocrystals up to 1.5 µm in length and 5-30 nm in width were obtained through enzymatic hydrolysis (EH). The GPPE obtained through ultrasound-assisted hydroalcoholic solvent extraction presented excellent antioxidant properties assessed using DPPH, ABTS and TPC assays. The BCNC-GPPE complex formation improved the colloidal stability of BCNC aqueous dispersions by decreasing the Z potential value up to -35 mV and prolonged the antioxidant half-life of GPPE up to 2.5 times. The antioxidant activity of the complex was demonstrated by the decrease in conjugate diene (CD) formation in olive oil-in-water emulsions, whereas the measured emulsification ratio (ER) and droplet mean size of hexadecane-in-water emulsions confirmed the physical stability improvement in all cases. The synergistic effect between nanocellulose and GPPE resulted in promising novel emulsions with prolonged physical and oxidative stability.

Efficient removal of Phaeocystis globosa from seawater with the persulfate activation by arbutin-modified cellulose nanocrystals

Harmful algal blooms (HABs) from seawater have a severe threat to human health, aquaculture, and coastal nuclear power safety. Thus, it is highly desirable to explore environmentally friendly, efficient, and economic methods for controlling HABs. Herein, the arbutin-modified cellulose nanocrystals (AT-CNC) activated persulfate (PS), as a novel heterogeneous Fenton-like process, was proposed to remove Phaeocystis globosa (P. globosa) from seawater. The AT-CNC was synthesized via the surface modification of AT on CNC. The effects of AT dosage, CNC dosage, and PS dosage on the removal performance of P. globosa were investigated. With the addition of 530 mg/L AT-CNC (6 wt% AT/CNC of AT loading) and 120 mg/L PS, the removal percentage of chlorophyll a (R_c), optical density at 680 nm (R_o) and turbidity (R_t) reached 97.7%, 91.9% and 85.2% at 24 h. According to electron paramagnetic resonance (EPR) spectra and radical quenching tests, the predominant free radicals inactivating P. globosa were hydroxyl radicals (^•OH). Additionally, the flocculation of the inactivated algae cells by AT-CNC was also critical for removing P. globosa. Moreover, a positive environmental impact was achieved in the AT-CNC-PS system due to the reduction of nitrogen, phosphorus and organic carbon contents. Based on the excellent removal performance for P. globosa, we believe that the AT-CNC activated persulfate is a promising option for HABs control.

Bacterial Cellulose Nanofibril-Based Pickering Emulsions: Recent Trends and Applications in the Food Industry

The Pickering emulsion stabilized by food-grade colloidal particles has developed rapidly in recent decades and attracts extensive attention for potential applications in the food industry. Bacterial cellulose nanofibrils (BCNFs), as green and sustainable colloidal nanoparticles derived from bacterial cellulose, have various advantages for Pickering emulsion stabilization and applications due to their unique properties, such as good amphiphilicity, a nanoscale fibrous network, a high aspect ratio, low toxicity, excellent biocompatibility, and sustainability. This review provides a comprehensive overview of the recent advances in the Pickering emulsion stabilized by BCNF particles, including the classification, preparation method, and physicochemical properties of diverse BCNF-based particles as Pickering stabilizers, as well as surface modifications with other substances to improve their emulsifying performance and functionality. Additionally, this paper highlights the stabilization mechanisms and provides potential food applications of BCNF-based Pickering emulsions, such as nutrient encapsulation and delivery, edible coatings and films, fat substitutes, etc. Furthermore, the safety issues and future challenges for the development and food-related applications of BCNFs-based Pickering emulsions are also outlined. This work will provide new insights and more ideas on the development and application of nanofibril-based Pickering emulsions for researchers.

Fabrication of chitosan-protocatechuic acid conjugates to inhibit lipid oxidation and improve the stability of β-carotene in Pickering emulsions: Effect of molecular weight of chitosan

In this study, chitosan (CS) with different molecular weights was functionalized with protocatechuic acid (PA) by free-radical grafting reaction, and used for the inhibition of lipid oxidation and the enhancement of stability of β-carotene in Pickering emulsions. The order of grafting ratio of PA in CS-PA conjugates was CS400 (400 kDa CS) > CS200 (200 kDa CS) > CS100 (100 kDa CS). UV-vis, FT-IR and ¹H NMR spectra proved that PA was covalently bonded to CS through amino and ester linkages. Compared with native CS, three CS-PA conjugates exhibited reduced crystallinity and thermal stability and improved antioxidant activity, with a molecular weight-dependent relationship. Besides, CS-PA-conjugate particles formed by ionic gelling procedure were spherically shaped and homogeneously dispersed, which substantially improved the stability of β-carotene in Pickering emulsions than CS particles under ultraviolet irradiation, natural light exposure and heat treatment, and the retention rates of β-carotene were in the following order: CS200-PA- > CS400-PA- > CS100-PA-conjugate particles. Furthermore, the oxidation stability of Pickering emulsions fabricated by CS-PA-conjugate particles was also higher than that of CS particles. These results will provide valuable information for the application of CS-PA conjugates to protect bioactive components and inhibit lipid oxidation in emulsion systems.

Thermal insulation and antibacterial foam templated from bagasse nanocellulose /nisin complex stabilized Pickering emulsion

Foam packaging with good thermal insulation and antibacterial properties is promising for cold chain delivery to strengthen food safety. This study reports a novel antibacterial foam with thermal insulation templated from bagasse nanocellulose complex particle-stabilised acrylate epoxy soybean oil (AESO) Pickering emulsions. Nanocellulose/nisin complex particles (N-CNFs) were prepared by loading positively charged nisin onto negatively charged cellulose nanofibrils via electrostatic interactions, that highly enhanced the stability of nanocellulose at the AESO/water interface and imparted the corresponding foam with good antibacterial properties. The results show that the porosity of the foam prepared with N-CNFs increased from 10.9% to 29.9% compared with that of the foam corresponding with bare nanocellulose; the thermal conductivity of the N-CNF foam decreased substantially from 0.431 W/m·K to 0.197 W/m·K. Moreover, the prepared foam exhibited good antibacterial activity, and its bacteriostatic rate against Listeria monocytogenes was 91.33%. The incorporation of antibacterial peptides into nanocellulose has enriched the study of the Pickering emulsion templating method for preparing multifunctional foam materials and is expected to broaden the application of nanocellulose in the field of food packaging.

A fungal cellulose nanocrystals-based approach to improve the stability of triterpenes loaded Pickering emulsion

Depolysaccharide residues of edible fungus Pleurotus eryngii (dePSR-Pe), a mushroom industry waste, have abundant cellulose. In this study, the cellulose nanocrystals of P. eryngii (PeCNs) were extracted by hydrochloric acid. Results showed that the length of PeCNs is 469 ± 76.41 nm with a high aspect ratio of 40-100 and needle morphology. The structural characterization revealed that PeCNs had good thermal stability (approach 300 °C) and high crystallinity (84.2 %). An O/W Pickering emulsion stabilized with PeCNs was prepared to inhibit lipid oxidation and improve the loading capacity of triterpenes of P. coco. Unimodal size distribution of emulsion droplets was obtained under an optimized aqueous-phase condition to form a metastable emulsion, regardless of varying oil-water volume ratio <50/50. In vitro digestion study suggested that triterpenes-loaded Pickering emulsion had 1-3 times higher drug stability than bulk oil. These metastable Pickering emulsions call for fewer nanoparticles and provide a new strategy for the industry application of cellulose nanocrystals at less cost.

Cost-Effective Synthesis of Bacterial Cellulose and Its Applications in the Food and Environmental Sectors

Bacterial cellulose (BC), also termed bio-cellulose, has been recognized as a biomaterial of vital importance, thanks to its impressive structural features, diverse synthesis routes, high thermomechanical properties, and its ability to combine with multiple additives to form composites for a wide range of applications in diversified areas. Its purity, nontoxicity, and better physico-mechanical features than plant cellulose (PC) make it a better choice for biological applications. However, a major issue with the use of BC instead of PC for various applications is its high production costs, mainly caused by the use of expensive components in the chemically defined media, such as Hestrin-Schramm (HS) medium. Furthermore, the low yield of BC-producing bacteria indirectly accounts for the high cost of BC-based products. Over the last couple of decades, extensive efforts have been devoted to the exploration of low-cost carbon sources for BC production, besides identifying efficient bacterial strains as well as developing engineered strains, developing advanced reactors, and optimizing the culturing conditions for the high yield and productivity of BC, with the aim to minimize its production cost. Considering the applications, BC has attracted attention in highly diversified areas, such as medical, pharmaceutics, textile, cosmetics, food, environmental, and industrial sectors. This review is focused on overviewing the cost-effective synthesis routes for BC production, along with its noteworthy applications in the food and environmental sectors. We have made a comprehensive review of recent papers regarding the cost-effective production and applications of BC in the food and environmental sectors. This review provides the basic knowledge and understanding for cost-effective and scaleup of BC production by discussing the techno-economic analysis of BC production, BC market, and commercialization of BC products. It explores BC applications as food additives as its functionalization to minimize different environmental hazards, such as air contaminants and water pollutants.

Flexible MXene/Bacterial Cellulose Film Sound Detector Based on Piezoresistive Sensing Mechanism

Flexible pressure sensors have aroused extensive attention in health monitoring, human-computer interaction, soft robotics, and more, as a staple member of wearable electronics. However, a majority of traditional research focuses solely on foundational mechanical sensing tests and ordinary human-motion monitoring, ignoring its other applications in daily life. In this work, a paper-based pressure sensor is prepared by using MXene/bacterial cellulose film with three-dimensional isolation layer structure, and its sensing capability as a wearable sound detector has also been studied. The as-prepared device exhibits great comprehensive mechanical sensing performance as well as accurate detection of human physiological signals. As a sound detector, not only can it recognize different voice signals and sound attributes by monitoring movement of throat muscles, but also it will distinguish a variety of natural sounds through air pressure waves caused by sound transmission (also called sound waves), like the eardrum. Besides, it plays an important role in sound visualization technology because of the ability for capturing and presenting music signals. Moreover, millimeter-scale thickness, lightweight, and degradable raw materials make the sensor convenient and easy to carry, meeting requirements of environmental protection as well.

Development of biodegradable films using sunflower protein isolates and bacterial nanocellulose as innovative food packaging materials for fresh fruit preservation

This study presents the valorization of side streams from the sunflower-based biodiesel industry for the production of bio-based and biodegradable food packaging following circular economy principles. Bacterial cellulose (BC) was produced via fermentation in 6 L static tray bioreactors using nutrient-rich supplements derived from the enzymatic hydrolysis of sunflower meal (SFM) combined with crude glycerol as carbon source. Novel biofilms were produced using either matrices of protein isolates extracted from sunflower meal (SFMPI) alone or SFMPI matrices reinforced with nanocellulose biofillers of commercial or bacterial origin. Acid hydrolysis was employed for ex-situ modification of BC to nanostructures (56 nm). The biofilms reinforced with bacterial nanocellulose structures (SFMPI-BNC) showed 64.5% higher tensile strength, 75.5% higher Young’s modulus, 131.5% higher elongation at break, 32.5% lower water solubility and 14.1% lower water vapor permeability than the biofilms produced only with SFMPI. The biofilms were evaluated on fresh strawberries packaging showing that the SFMPI-BNC-based films lead to effective preservation at 10 °C considering microbial growth and physicochemical profile (weight loss, chemical characterization, color, firmness and respiration activity). The SFMPI-BNC-based films could be applied in fresh fruit packaging applications.

The Formation, Stabilization and Separation of Oil–Water Emulsions: A Review

Oil–water emulsions are widely generated in industries, which may facilitate some processes (e.g., transportation of heavy oil, storage of milk, synthesis of chemicals or materials, etc.) or lead to serious upgrading or environmental issues (e.g., pipeline plugging, corrosions to equipment, water pollution, soil pollution, etc.). Herein, the sources, classification, formation, stabilization, and separation of oil–water emulsions are systematically summarized. The roles of different interfacially active materials–especially the fine particles–in stabilizing the emulsions have been discussed. The advanced development of micro force measurement technologies for oil–water emulsion investigation has also been presented. To provide insights for future industrial application, the separation of oil–water emulsions by different methods are summarized, as well as the introduction of some industrial equipment and advanced combined processes. The gaps between some demulsification processes and industrial applications are also touched upon. Finally, the development perspectives of oil–water treatment technology are discussed for the purpose of achieving high-efficiency, energy-saving, and multi-functional treatment. We hope this review could bring forward the challenges and opportunities for future research in the fields of petroleum production, coal production, iron making, and environmental protection, etc.

Effect of Culture Conditions on Cellulose Production by a Komagataeibacter Xylinus Strain

Different fermentation conditions cause different shear forces, which have a great influence on BC synthesis. The shearing force activates the conversion of microbial cells to Cel^- mutants, and the accumulation of water-soluble exopolysaccharides is also observed. A substrate competitive relationship between these two polysaccharides is found, which is significant in terms of the optimization of cellulose production in commercial processes. This article is protected by copyright. All rights reserved.

Improved water dispersion and bioavailability of coenzyme Q10 by bacterial cellulose nanofibers

The purpose of this study was to investigate the potential of bacterial cellulose nanofiber suspension (BCNs) as stabilizer in anti-solvent precipitation and its effect on improving bioavailability of coenzyme Q10. Bacterial cellulose (BC) was hydrolyzed by sulfuric acid followed by the oxidation with hydrogen peroxide to prepare BCNs. The suspension of BCNs-loaded CoQ10 (CoQ10-BCNs) were prepared by antisolvent precipitation. The zeta potential of CoQ10-BCNs was about -36.01 mV. The properties of CoQ10, BCNs and CoQ10-BCNs were studied by scanning electron microscopy, transmission electron microscope, Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermo gravimetric analysis. The crystallinity of CoQ10 decreased in CoQ10-BCNs compared with the raw CoQ10, and CoQ10-BCNs have good physicochemical stability. In oral bioavailability studies, the area under curve (AUC) of CoQ10-BCNs was about 3.62 times higher than the raw CoQ10 in rats.