Bacterial Nanocellulose-A Biobased Polymer for Active and Intelligent Food Packaging Applications: Recent Advances and Developments

Spectrochemical Analysis of Nutritional and Toxic Metals in Different Brands of Candies Using Advanced Diagnostic Approaches

Candies are frequently consumed sweetened food products among children, and their consumption can expose them to potential toxins and contamination. The present study employed calibration-free-laser-induced breakdown spectroscopy (CF-LIBS) as a steadfast diagnostic technique to analyze the presence of nutritional and heavy metals in candies from various brands available in local markets in Haripur, Pakistan. A pulsed Nd-YAG laser was used to create a microplasma on the target surface. The emitted light was collected using a dedicated spectrometer to analyze and quantify the species present in the candies. The analysis revealed the presence of micronutrients, macronutrients, and trace toxic metals such as Ca, K, Mg, Fe, Na, Al, Pb, Cr, Mn, Zn, Cu, and Ni. The optimization of our LIBS system was achieved through a parametric dependence study. The confirmation of the assumption of local thermodynamic equilibrium was achieved by assessing McWhirter's criterion and considering the relaxation time and the diffusion length of atoms in plasma. The highest concentrations (measured in mg/kg) of Pb, Cr, and Mn were determined to be 15 mg/kg, 340 mg/kg, and 880 mg/kg, respectively. The levels of Pb and Cr were found to be well above the maximum accepted limit set by the WHO. Similarly, the concentration of Mn in S-4 and S-5 exceeded the permissible limits set by the WHO. However, Zn, Cu, and Ni were found within safe limits in all the collected samples. In addition, the abundance obtained through CF-LIBS was compared to the concentration of similar (duplicate) candies samples analyzed using a standard analytical technique like inductively coupled plasma-optical emission spectroscopy. Excellent harmony could be seen in both outcomes. Moreover, energy-dispersive X-ray spectroscopy (EDX) was also utilized to confirm the presence of detected toxins. The significance of our findings lies in creating awareness among the public about the health risks associated with consuming toxins through candies, thereby protecting numerous human lives.

Complete genome sequence and transcriptome response to vitamin C supplementation of Novacetimonas hansenii SI1 - producer of highly-stretchable cellulose

Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin C in the culture medium increases the porosity of the membranes and their stretchability making them highly moldable. To better understand the genetic background of this strain, we obtained its complete genome sequence using a hybrid sequencing and assembly strategy. We described the functional regions in the genome which are important for the synthesis of BNC and acetan-like II polymer. We next investigated the effect of 1% vitamin C supplementation on the global gene expression profile using RNA sequencing. Our transcriptomic readouts imply that vitamin C functions mainly as a reducing agent. We found that the changes in cellular redox status are balanced by strong repression of the sulfur assimilation pathway. Moreover, in the reduced conditions, glucose oxidation is decreased and alternative pathways for energy generation, such as acetate accumulation, are activated. The presence of vitamin C negatively influences acetan-like II polymer biosynthesis, which may explain the lowered yield and changed mechanical properties of BNC. The results of this study enrich the functional characteristics of the genomes of the efficient producers of the N. hansenii species. Improved understanding of the adaptation to the presence of vitamin C at the molecular level has important guiding significance for influencing the biosynthesis of BNC and its morphology.

Application of Natural Functional Additives for Improving Bioactivity and Structure of Biopolymer-Based Films for Food Packaging: A Review

The global trend towards conscious consumption plays an important role in consumer preferences regarding both the composition and quality of food and packaging materials, including sustainable ones. The development of biodegradable active packaging materials could reduce both the negative impact on the environment due to a decrease in the use of oil-based plastics and the amount of synthetic preservatives. This review discusses relevant functional additives for improving the bioactivity of biopolymer-based films. Addition of plant, microbial, animal and organic nanoparticles into bio-based films is discussed. Changes in mechanical, transparency, water and oxygen barrier properties are reviewed. Since microbial and oxidative deterioration are the main causes of food spoilage, antimicrobial and antioxidant properties of natural additives are discussed, including perspective ones for the development of biodegradable active packaging.

The Development of a Bacterial Nanocellulose/Cationic Starch Hydrogel for the Production of Sustainable 3D-Printed Packaging Foils

Polymers have become an important part of everyday life, but most of the polymers currently used are petroleum-based. This poses an environmental problem, especially with respect to products that are quickly discarded. For this reason, current packaging development focuses on sustainable materials as an alternative to synthetic ones. Nanocellulose, a relatively new material derived from cellulose, has unique properties such as high strength, low density, high surface area, and good barrier properties, making it popular in various applications. Additionally, 3D printing technologies have become an important part of industrial and commercial processes, enabling the realization of innovative ideas and functionalities. The main aim of this research was to develop a hydrogel of bacterial nanocellulose with suitable rheological properties for the 3D printing of polymer foils. Three variations of bacterial nanocellulose hydrogel differing in ratios of bacterial nanocellulose to cationic starch were produced. The rheological studies confirmed the suitability of the hydrogels for 3D printing. Foils were successfully 3D-printed using a modified 3D printer. The physical-mechanical, surface, and optical properties of the foils were determined. All foils were homogeneous with adequate mechanical properties. The 3D-printed foils with the highest amount of cationic starch were the most homogeneous and transparent and, despite their rigidity, very strong. All foils were semi-transparent, had a non-glossy surface, and retained poor water wettability.

Degradable chitosan-based bioplastic packaging: Design, preparation and applications

Food packaging is an essential part of food transportation, storage and preservation. Biodegradable biopolymers are a significant direction for the future development of food packaging materials. As a natural biological polysaccharide, chitosan has been widely concerned by researchers in the field of food packaging due to its excellent film-forming property, good antibacterial property and designability. Thus, the application research of chitosan-based food packaging films, coatings and aerogels has been greatly developed. In this review, recent advances on chitosan-based food packaging materials are summarized. Firstly, the development background of chitosan-based packaging materials was described, and then chitosan itself was introduced. In addition, the design, preparation and applications of films, coatings and aerogels in chitosan-based packaging for food preservation were discussed, and the advantages and disadvantages of each research in the development of chitosan-based packaging materials were analyzed. Finally, the application prospects, challenges and suggestions for solving the problems of chitosan-based packaging are summarized and prospected.

Fabrication of Poly(ethylene furanoate)/Silver and Titanium Dioxide Nanocomposites with Improved Thermal and Antimicrobial Properties

Poly(ethylene furanoate) (PEF)-based nanocomposites were fabricated with silver (Ag) and titanium dioxide (TiO2) nanoparticles by the in-situ polymerization method. The importance of this research work is to extend the usage of PEF-based nanocomposites with improved material properties. The PEF-Ag and PEF-TiO2 nanocomposites showed a significant improvement in color concentration, as determined by the color colorimeter. Scanning electron microscopy (SEM) photographs revealed the appearance of small aggregates on the surface of nanocomposites. According to crystallinity investigations, neat PEF and nanocomposites exhibit crystalline fraction between 0-6%, whereas annealed samples showed a degree of crystallinity value above 25%. Combining the structural and molecular dynamics observations from broadband dielectric spectroscopy (BDS) measurements found strong interactions between polymer chains and nanoparticles. Contact angle results exhibited a decrease in the wetting angle of nanocomposites compared to neat PEF. Finally, antimicrobial studies have been conducted, reporting a significant rise in inhibition of over 15% for both nanocomposite films against gram-positive and gram-negative bacteria. From the overall results, the synthesized PEF-based nanocomposites with enhanced thermal and antimicrobial properties may be optimized and utilized for the secondary packaging (unintended food-contact) materials.

Preparation and characterization of chitosan/dialdehyde carboxymethyl cellulose composite film loaded with cinnamaldehyde@zein nanoparticles for active food packaging

In this study, zein-loaded cinnamaldehyde (Cin@ZN) nanoparticles were incorporated into Chitosan (CS)/dialdehyde carboxymethyl cellulose (DCMC) matrix to fabricate the active food packaging materials possessing outstanding antioxidant and antibacterial properties. The research investigated how varying levels of Cin@ZN nanoparticles affected the morphology, microstructure, physicochemical properties of CS/DCMC composite films. The inclusion of Cin@ZN could significantly improve the mechanical strength, reduce the water vapor and oxygen permeability of CS/DCMC composite films and endow films with UV-light blocking properties. It's worth noting that the antibacterial and antioxidant capacities of CS/DCMC films had an astonishing enhancement with Cin@ZN blending, in which ABTS scavenging ratio of the composite films (100 mg) with different Cin@ZN contents reached >90 %. Furthermore, CS/DCMC/Cin@ZN 35 % composite film has the ability to efficiently protect strawberries from microbial damage and decelerate the spoilage rate of strawberries under ambient condition. Consequently, the CS/DCMC/Cin@ZN composite film can be applied as packaging material to extend the lifespan of fruits.

Animal derived biopolymers for food packaging applications: A review

It is essential to use environment-friendly, non-toxic, biodegradable and sustainable materials for various applications. Biopolymers are derived from renewable sources like plants, microorganisms, and agricultural wastes. Unlike conventional polymers, biopolymer has a lower carbon footprint and contributes less to greenhouse gas emission. All biopolymers are biodegradable, meaning natural processes can break them down into harmless products such as water and biomass. This property is of utmost importance for various sustainable applications. This review discusses different classifications of biopolymers based on origin, including plant-based, animal-based and micro-organism-based biopolymers. The review also discusses the desirable properties that are required in materials for their use as packaging material. It also discusses the different processes used in modifying the biopolymer to improve its properties. Finally, this review shows the recent developments taking place in using specifically animal origin-based biopolymer and its use in packaging material. It was observed that animal-origin-based biopolymers, although they possess unique properties however, are less explored than plant-origin biopolymers. The animal-origin-based biopolymers covered in this review are chitosan, gelatin, collagen, keratin, casein, whey, hyaluronic acid and silk fibroin. This review will help in renewing research interest in animal-origin biopolymers. In summary, biopolymer offers a sustainable and environment-friendly alternative to conventional polymers. Their versatility, biocompatibility will help create a more sustainable future.

CALU-3 lung cells three-dimensionally assembled onto CellFate® matrix present angiotensin-converting enzyme-2 activity

Currently, there is a great need for the development of three-dimensional (3D) in vitro lung models. Particularly, the production of a suitable 3D model of pulmonary epithelium for understanding the pathophysiology of diseases such as the COVID-19 must consider the tissue architecture and presence, for example, of the angiotensin-converting enzyme-2 (ACE-2) in the cells. Different polymeric membranes are being used to support cell culturing, especially of lung cells, however, there is still no information about the culture of these cells onto bacterial nanocellulose (BNC) matrices. We have used the BNC matrix CellFate® as a support for the assembly of a 3D in vitro model of lung epithelium, composed of human lung fibroblasts (HLF) and lung adenocarcinoma cells (CALU-3). CellFate® matrices were made from bacterial fermentation resulting in a natural and biocompatible biopolymer. Cells were cultured onto CellFate® and maintained in a 5% CO2 humidified atmosphere at 37°C. Cell viability was assessed by the resazurin method The samples were, then, exposed to the air-liquid interface (ALI), and histologically analyzed. ACE-2 activity was verified on the hydrolyze of the fluorogenic substrate Mca-APK(Dnp)-OH, and its presence was evaluated by flow cytometry. The expression of the anionic transporter SLCO3A1 was evaluated by qPCR. Cell viability analysis indicates that CellFate® was not toxic to these cells. By flow cytometry, the presence of the ACE-2 was identified in the CALU-3 cells surface corroborating the results obtained from enzymatic activity analysis. The SLCO3A1 transporter expression was identified in cells cultured onto CellFate®, but not in cells cultured onto the transwell (control). CALU-3 cells cultivated onto CellFate® resulted in a pseudostratified organization, a typical morphology of the human respiratory tract epithelium. The current model opens perspectives for studies involving physiological characterization, improving its relevance for the understanding of the pathophysiology of diseases as well as the response to drugs.

In-situ biofabrication of bacterial nanocellulose (BNC)/graphene oxide (GO) nano-biocomposite and study of its cationic dyes adsorption properties

In the present study, bacterial nanocellulose/graphene oxide nano-biocomposites (BNC-GO-NBCs) were fabricated by Komagataeibacter saccharivorans NUWB1 using an in-situ method involving three time-dependent approaches. Physicochemical studies showed that the chosen dried BNC-GO-NBC possessed a three-dimensional interconnected porous structure of BNC with GO layers embedded within the BNC fibrils. BNC-GO-NBC had a crystallinity index of 74.21 %, higher thermostability up to 380 °C and could withstand a tensile load of 84.72 MPa. N2 adsorption-desorption isotherm of the BNC-GO-NBC was found to be of type IV, suggesting a mesoporous type structure with a total pore volume and surface area of 6.232e-04 cc g-1 and 10.498 m2. BNC-GO-NBC exhibited remarkable adsorption capacity for two cationic dyes, Rhodamine B (RhB) and Acridine Orange (AO), and the adsorption data conformed well to the Langmuir isotherm (R2 = 0.99) and pseudo-second-order model. Thermodynamic studies indicated that the adsorption process was spontaneous and endothermic. Additionally, the BNC-GO-NBC displayed the potential for regeneration, with the ability to be recycled up to five times. Further, the antibacterial activity, cell cytotoxicity and oxidative stress assays of the BNC-GO-NBC revealed its non-cytotoxic nature. The findings of the present investigation evidently suggest the potentiality of BNC-GO-NBC in the application of dye adsorption and other environmental applications.

Lignocellulosic Bionanomaterials for Biosensor Applications

The rapid population growth, increasing global energy demand, climate change, and excessive use of fossil fuels have adversely affected environmental management and sustainability. Furthermore, the requirements for a safer ecology and environment have necessitated the use of renewable materials, thereby solving the problem of sustainability of resources. In this perspective, lignocellulosic biomass is an attractive natural resource because of its abundance, renewability, recyclability, and low cost. The ever-increasing developments in nanotechnology have opened up new vistas in sensor fabrication such as biosensor design for electronics, communication, automobile, optical products, packaging, textile, biomedical, and tissue engineering. Due to their outstanding properties such as biodegradability, biocompatibility, non-toxicity, improved electrical and thermal conductivity, high physical and mechanical properties, high surface area and catalytic activity, lignocellulosic bionanomaterials including nanocellulose and nanolignin emerge as very promising raw materials to be used in the development of high-impact biosensors. In this article, the use of lignocellulosic bionanomaterials in biosensor applications is reviewed and major challenges and opportunities are identified.

Insight into the Latest Medical Applications of Nanocellulose

Nanocelluloses (NCs) are appealing nanomaterials that have experienced rapid development in recent years, with great potential in the biomedical field. This trend aligns with the increasing demand for sustainable materials, which will contribute both to an improvement in wellbeing and an extension of human life, and with the demand to keep up with advances in medical technology. In recent years, due to the diversity of their physical and biological properties and the possibility of tuning them according to the desired goal, these nanomaterials represent a point of maximum interest in the medical field. Applications such as tissue engineering, drug delivery, wound dressing, medical implants or those in cardiovascular health are some of the applications in which NCs have been successfully used. This review presents insight into the latest medical applications of NCs, in the forms of cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs) and bacterial nanocellulose (BNC), with an emphasis on the domains that have recently experienced remarkable growth, namely wound dressing, tissue engineering and drug delivery. In order to highlight only the most recent achievements, the presented information is focused on studies from the last 3 years. Approaches to the preparation of NCs are discussed either by top-down (chemical or mechanical degradation) or by bottom-up (biosynthesis) techniques, along with their morphological characterization and unique properties, such as mechanical and biological properties. Finally, the main challenges, limitations and future research directions of NCs are identified in a sustained effort to identify their effective use in biomedical fields.

Production of nanocellulose from corn husk for the development of antimicrobial biodegradable packaging film

Packaging is a potential way of keeping food products safe from various environmental pollutants, and biological, chemical, & physical deterioration. Hence, the demand for an effective antimicrobial active packaging material is increasing tremendously to improve the shelf-life of food products. Thus, we extracted nanocellulose from corn husks and developed a eugenol-incorporated biodegradable antimicrobial active packaging film. The extracted nanocellulose showed a particle size of 149.67 ± 3.56 nm and an overall surface charge of -20.2 mV ± 0.76 V. The film casting method is one of the promising methods to fabricate biodegradable films using plant-based biopolymers. Therefore, different concentrations of eugenol (0.5-5 % v/v) were incorporated to formulate the functional film (FF0.5-FF5) by employing the casting process. FF exhibited comparable tensile strength as compared to the control film (CF), however, FF5 showed the least tensile strength (85 MPa). Based on the mechanical characterization, the FF3 film sample was further selected for characterization. The morphological evaluation revealed that the surface of the film was smooth and non-porous with reduced moisture content and density. The film exhibited high thermal stability as the degradation occurred above 400 °C, indicating the strong hydrogen bonding between the hydroxyl groups of the film. The Fourier transform infrared spectroscopy analysis revealed the existence of COOH vibration and COC stretching groups of cellulose and eugenol. The antimicrobial studies showed high efficacy against Staphylococcus aureus followed by Salmonella typhmurium, Pseudomonas aeruginosa, and Klebsiella pneumoniae bacteria. Overall, eugenol-incorporated nanocellulose-based biodegradable packaging film could be an excellent candidate as an alternative to active packaging material and provide an opportunity for the efficient utilization of corn husk.

Study of PLA pre-treatment, enzymatic and model-compost degradation, and valorization of degradation products to bacterial nanocellulose

It is well acknowledged that microplastics are a major environmental problem and that the use of plastics, both petro- and bio- based, should be reduced. Nevertheless, it is also a necessity to reduce the amount of the already spread plastics. These cannot be easily degraded in the nature and accumulate in the food supply chain with major danger for animals and human life. It has been shown in the literature that advanced oxidation processes (AOPs) modify the surface of polylactic acid (PLA) materials in a way that bacteria more efficiently dock on their surface and eventually degrade them. In the present work we investigated the influence of different AOPs (ultrasounds, ultraviolet irradiation, and their combination) on the biodegradability of PLA films treated for different times between 1 and 6 h. The pre-treated samples have been degraded using a home model compost as well as a cocktail of commercial enzymes at mesophilic temperatures (37 °C and 42 °C, respectively). Degradation degree has been measured and degradation products have been identified. Excellent degradation of PLA films has been achieved with enzyme cocktail containing commercial alkaline proteases and lipases of up to 90% weight loss. For the first time, we also report valorization of PLA into bacterial nanocellulose after enzymatic hydrolysis of the samples.

Innovative processes in smart packaging. A systematic review

Smart packaging provides one possible solution that could reduce greenhouse gas emissions. In comparison with traditional packaging, which aims to extend the product's useful life and to facilitate transport and marketing, smart packaging allows increased efficiency, for example by ensuring authenticity and traceability from the product's origin, preventing fraud and theft, and improving security. Consequently, it may help to reduce pollution, food losses, and waste associated with the food supply chain. However, some questions must be answered to fully understand the advantages and limitations of its use. What are the most suitable smart packaging technologies for use in agro-industrial subsectors such as meat, dairy, fruits, and vegetables, bakery, and pastry? What are the opportunities from a perspective of life extension, process optimization, traceability, product quality, and safety? What are the future challenges? An up-to-date, systematic review was conducted of literature relevant to the application of indicator technologies, sensors, and data carriers in smart packaging, to answer these questions. © 2022 Society of Chemical Industry.

The use of essential oils in chitosan or cellulose-based materials for the production of active food packaging solutions: a review

In recent decades, interest in sustainable food packaging systems with additional functionality, able to increase the shelf life of products, has grown steadily. Following this trend, the present review analyzes the state of the art of this active renewable packaging. The focus is on antimicrobial systems containing nanocellulose and chitosan, as support for the incorporation of essential oils. These are the most sustainable and readily available options to produce completely natural active packaging materials. After a brief overview of the different active packaging technologies, the main features of nanocellulose, chitosan, and of the different essential oils used in the field of active packaging are introduced and described. The latest findings about the nanocellulose- and chitosan-based active packaging are then presented. The antimicrobial effectiveness of the different solutions is discussed, focusing on their effect on other material properties. The effect of the different inclusion strategies is also reviewed considering both in vivo and in vitro studies, in an attempt to understand more promising solutions and possible pathways for further development. In general, essential oils are very successful in exerting antimicrobial effects against the most diffused gram-positive and gram-negative bacteria, and affecting other material properties (tensile strength, water vapor transmission rate) positively. Due to the wide variety of biopolymer matrices and essential oils available, it is difficult to create general guidelines for the development of active packaging systems. However, more attention should be dedicated to sensory analysis, release kinetics, and synergetic action of different essential oils to optimize the active packaging on different food products. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Novel Features of Cellulose-Based Films as Sustainable Alternatives for Food Packaging

Packaging plays an important role in food quality and safety, especially regarding waste and spoilage reduction. The main drawback is that the packaging industry is among the ones that is highly dependent on plastic usage. New alternatives to conventional plastic packaging such as biopolymers-based type are mandatory. Examples are cellulose films and its derivatives. These are among the most used options in the food packaging due to their unique characteristics, such as biocompatibility, environmental sustainability, low price, mechanical properties, and biodegradability. Emerging concepts such as active and intelligent packaging provides new solutions for an extending shelf-life, and it fights some limitations of cellulose films and improves the properties of the packaging. This article reviews the available cellulose polymers and derivatives that are used as sustainable alternatives for food packaging regarding their properties, characteristics, and functionalization towards active properties enhancement. In this way, several types of films that are prepared with cellulose and their derivatives, incorporating antimicrobial and antioxidant compounds, are herein described, and discussed.

Design and Preparation of a Biobased Colorimetric pH Indicator from Cellulose and Pigments of Bacterial Origin, for Potential Application as Smart Food Packaging

Nowadays, worldwide challenges such as global warming, pollution, unsustainable consumption patterns, and scarcity of natural resources are key drivers toward future-oriented bioeconomy strategies, which rely on renewable biobased resources, such as bacterial pigments and bacterial cellulose (BC), for materials production. Therefore, the purpose of this study was to functionalize bacterial cellulose with violacein, flexirubin-type pigment, and prodigiosin and test their suitability as pH indicators, due to the pigments’ sensitivity to pH alterations. The screening of the most suitable conditions to obtain the BC-pigment indicators was achieved using a full factorial design, for a more sustainable functionalization process. Then, the pH response of functionalized BC to buffer solutions was assessed, with color changes at acidic pH (BC-violacein indicator) and at alkaline pH (BC-violacein, BC-prodigiosin, and BC-flexirubin-type pigment indicators). Moreover, the indicators also revealed sensitivity to acid and base vapors. Furthermore, leaching evaluation of the produced indicators showed higher suitability for aqueous foods. Additionally, color stability of the functionalized BC indicators was carried out, after light exposure and storage at 4 °C, to evaluate the indicators’ capacity to maintain color/sensitivity. Thus, BC membranes functionalized with bacterial pigments have the potential to be further developed and used as pH indicators.

Use of carbohydrate-directed enzymes for the potential exploitation of sugarcane bagasse to obtain value-added biotechnological products

Microorganisms, such as fungi and bacteria, are crucial players in the production of enzymatic cocktails for biomass hydrolysis or the bioconversion of plant biomass into products with industrial relevance. The biotechnology industry can exploit lignocellulosic biomass for the production of high-value chemicals. The generation of biotechnological products from lignocellulosic feedstock presents several bottlenecks, including low efficiency of enzymatic hydrolysis, high cost of enzymes, and limitations on microbe metabolic performance. Genetic engineering offers a route for developing improved microbial strains for biotechnological applications in high-value product biosynthesis. Sugarcane bagasse, for example, is an agro-industrial waste that is abundantly produced in sugar and first-generation processing plants. Here, we review the potential conversion of its feedstock into relevant industrial products via microbial production and discuss the advances that have been made in improving strains for biotechnological applications.

Genipin-crosslinked amphiphilic chitosan films for the preservation of strawberry

As a material for films used to keep fruits fresh, chitosan has attracted extensive interest because of its advantages of degradability, environmental friendliness, and biocompatibility. In this study, two amphiphilic chitosan derivative films were prepared by crosslinking N-2-hydroxypropyl-3-butyl ether-O-carboxymethyl chitosan (HBCC) and N-2-hydroxypropyl-3-(2-ethylhexyl glycidyl ether)-O-carboxymethyl chitosan (H2ECC)) with genipin, an excellent natural cross-linking agent. The microstructures, mechanical properties, water vapor permeability, swelling ratios, light transmittance, wettability, thermal stability, antibacterial properties, and biocompatibility of the crosslinked films were characterized. The results showed that the crosslinked films had compact structures, low moisture permeability, strong water resistance, strong ultraviolet resistance, unaffected visible light transmittance, and good hydrophilicity. Compared with the uncrosslinked films, the tensile strength of the genipin-crosslinked ones was increased by 328.33 % (HBCC) and 397.83 % (H2ECC). More importantly, the crosslinked films had strong antibacterial activity against Staphylococcus aureus and Escherichia coli and were non-toxic to endothelial cells. The crosslinked films could effectively prolong the preservation time of strawberries, inhibit the decay of strawberries, and inhibit the reduction of vitamin C in strawberries. In conclusion, genipin-crosslinked HBCC and H2ECC films are potential fruit preservation materials.

Characterization of the Putative Acylated Cellulose Synthase Operon in Komagataeibacter xylinus E25

Bacterial cellulose is a natural polymer with an expanding array of applications. Because of this, the main cellulose producers of the Komagataeibacter genus have been extensively studied with the aim to increase its synthesis or to customize its physicochemical features. Up to now, the genetic studies in Komagataeibacter have focused on the first cellulose synthase operon (bcsI) encoding the main enzyme complex. However, the role of other accessory cellulose operons has been understudied. Here we aimed to fill this gap by performing a detailed analysis of the second cellulose synthase operon (bcsII), which is putatively linked with cellulose acylation. In this study we harnessed the genome sequence, gene expression and protein structure information of K. xylinus E25 and other Komagataeibacter species to discuss the probable features of bcsII and the biochemical function of its main protein products. The results of our study support the previous hypothesis that bcsII is involved in the synthesis of the acylated polymer and expand it by presenting the evidence that it may also function in the regulation of its attachment to the cell surface and to the crystalline cellulose fibers.

Design and Practical Considerations for Active Polymeric Films in Food Packaging

Polymeric films for active food packaging have been playing an important role in food preservation due to favorable properties including high structural flexibility and high property tunability. Over the years, different polymeric active packaging films have been developed. Many of them have found real applications in food production. This article reviews, using a practical perspective, the principles of designing polymeric active packaging films. Different factors to be considered during materials selection and film generation are delineated. Practical considerations for the use of the generated polymeric films in active food packaging are also discussed. It is hoped that this article cannot only present a snapshot of latest advances in the design and optimization of polymeric active food packaging films, but insights into film development to achieve more effective active food packaging can be attained for future research.

Overview of potential adverse health effects of oral exposure to nanocellulose

Nanocellulose is an emerging material for which several food-related applications are foreseen, for example, novel food, functional food, food additive or in food contact materials. Nanocellulose materials can display a range of possible shapes (fibers, crystals), sizes and surface modifications. For food-related applications in the EU, information on the safety of substances must be assessed. The present review summarizes the current knowledge on (possible) adverse health effects of nanocellulose upon oral exposure, keeping EU regulatory aspects in mind. The overview indicates that toxicity data, especially from in vivo studies, are limited and outcomes are not unambiguous. The hazard assessment is further complicated by: the diversity in morphologies and surface modifications, lack of standard reference materials, limited knowledge about intestinal fate and absorption, analytical difficulties in biological matrices, dispersion issues, the possible presence of impurities and interferences within biological assays. Two subchronic in vivo toxicity studies show no indications of toxicity for two specific nanocellulose materials, even at high doses. However, these studies may have missed certain early or nano-specific toxic effects, such as inflammation potential, for which other, subacute studies provide some indications. Most in vitro studies show no cytotoxicity; however, several indicate that effects on oxidative stress and inflammatory responses depend on differences in size or surface treatments. Further, too few studies assessed genotoxicity of nanocelluloses. Therefore, immunotoxicity, oxidative stress and genotoxicity require further attention, as do absorption and effects on nutrient uptake. Recommendations for future research facilitating the safety assessment and safe-by-design of nanocellulose in food-related applications are provided.

Recent advancement in isolation, processing, characterization and applications of emerging nanocellulose: A review

The emergence of nanocellulose from various natural resources as a promising nanomaterial has been gaining interest for a wide range application. Nanocellulose serves as an excellent candidate since it contributes numerous superior properties and functionalities. In this review, details of the three main nanocellulose categorised: cellulose nanocrystal (CNC), cellulose nanofibril (CNF), and bacterial nanocellulose (BNC) have been described. We focused on the preparation and isolation techniques to produce nanocellulose including alkaline pre-treatment, acid hydrolysis, TEMPO-mediated oxidation, and enzymatic hydrolysis. The surface modification of nanocellulose through esterification, silylation, amidation, phosphorylation, and carboxymethylation to improve the diverse applications has also been reviewed. Some invigorating perspectives on the applications, challenges, and future directions on the relevant issues regarding nanocellulose are also presented.

Characterization and application of porous polylactic acid films prepared by nonsolvent-induced phase separation method

Nonsolvent-induced phase separation (NIPS) method was employed to prepare polylactic acid (PLA) films using N-methyl-2-pyrrolidone (NMP) as a nonsolvent. The morphology and structure of PLA films were characterized, and the application of the films in pork preservation was investigated. When 10 wt% NMP was added, film with uniform porous structures was obtained. The crystalline and Fourier-transform infrared spectra analyses indicated that the addition of NMP during the preparation of PLA films caused their crystalline properties to change, but had no effect on their composition. However, the 10 wt% NMP/PLA film had improved thermal stability, water vapor transmission and oxygen permeability. The results on the changes in pH, total volatile basic nitrogen content and total viable counts of pork during refrigerated storage indicated that the 10 wt% NMP/PLA film could more effectively extend the shelf life of pork than polyethylene film. This work demonstrates the potential of the porous PLA film in pork packaging.

Comparative Analysis of Bacterial Cellulose Membranes Synthesized by Chosen Komagataeibacter Strains and Their Application Potential

This article presents a comparative analysis of bacterial cellulose membranes synthesized by several strains of the Komagataeibacter genus in terms of their specific physical, physico-chemical, and mechanical properties. Herein, the aim was to choose the most suitable microorganisms producing cellulosic materials with the greatest potential for the fabrication of bio-inspired nanocomposites. The selection was based on three main steps, starting from the evaluation of BNC biosynthetic efficiency with and without the addition of ethanol, followed by the assessment of mechanical breaking strength, and the physical parameters (compactness, structural integrity, appearance, and thickness) of the obtained biological materials. Ultimately, based on the performed screening procedure, three efficiently growing strains (K. hansenii H3 (6Et), K. rhaeticus K4 (8Et), and Komagataeibacter sp. isolated from balsamic vinegar (12Et)) were chosen for further modifications, enabling additional cellulose functionalization. Here, supplementation of the growth medium with five representative polymeric compounds (citrus/apple pectin, wheat starch, polyvinyl alcohol, polyethylene glycol) led to significant changes in BNC properties, especially dye loading abilities, mechanical strength, and water adsorption/retention capacities. The resulting nanocomposites can be potentially useful in various fields of medicine and industry, and in the future, they may become a practical and cost-effective competitor against commercial biomaterials currently available on the market.

Biopolymer: A Sustainable Material for Food and Medical Applications

Biopolymers are a leading class of functional material suitable for high-value applications and are of great interest to researchers and professionals across various disciplines. Interdisciplinary research is important to understand the basic and applied aspects of biopolymers to address several complex problems associated with good health and well-being. To reduce the environmental impact and dependence on fossil fuels, a lot of effort has gone into replacing synthetic polymers with biodegradable materials, especially those derived from natural resources. In this regard, many types of natural or biopolymers have been developed to meet the needs of ever-expanding applications. These biopolymers are currently used in food applications and are expanding their use in the pharmaceutical and medical industries due to their unique properties. This review focuses on the various uses of biopolymers in the food and medical industry and provides a future outlook for the biopolymer industry.

Highly Stretchable Bacterial Cellulose Produced by Komagataeibacter hansenii SI1

A new strain of bacteria producing cellulose was isolated from Kombucha and identified as Komagataeibacter hansenii, named SI1. In static conditions, the strain synthesises bacterial nanocellulose with an improved ability to stretch. In this study, utilisation of various carbon and nitrogen sources and the impact of initial pH was assessed in terms of bacterial nanocellulose yield and properties. K. hansenii SI1 produces cellulose efficiently in glycerol medium at pH 5.0-6.0 with a yield of 3.20-3.60 g/L. Glucose medium led to the synthesis of membrane characterised by a strain of 77%, which is a higher value than in the case of another Komagataeibacter species. Supplementation of medium with vitamin C results in an enhanced porosity and improves the ability of bacterial nanocellulose to stretch (up to 123%). The properties of modified membranes were studied by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and mechanical tests. The results show that bacterial nanocellulose produced in SH medium and vitamin C-supplemented medium has unique properties (porosity, tensile strength and strain) without changing the chemical composition of cellulose. The method of production BNC with altered properties was the issue of Polish patent application no. P.431265.

Nanocellulose from Nata de Coco as a Bioscaffold for Cell-Based Meat

The three-dimensional formation of bio-engineered tissue for applications such as cell-based meat requires critical interaction between the bioscaffold and cellular biomass. To explore the features underlying this interaction, we have assessed the commercially available bacterial nanocellulose (BNC) product from Cass Materials for its suitability to serve as a bioscaffold for murine myoblast attachment, proliferation, and differentiation. Rigorous application of both scanning electron microscopy and transmission electron microscopy reveals cellular details of this interaction. While the retention rate of myoblast cells appears low, BNC is able to provide effective surface parameters for the formation of anchor points to form mature myotubes. Understanding the principles that govern this interaction is important for the successful scaling of these materials into edible, commercially viable, and nutritious biomass.

Bacterial nanocellulose: engineering, production, and applications

Bacterial nanocellulose (BNC) has been emerging as a biomaterial of considerable significance in a number of industrial sectors because of its remarkable physico-chemical and biological characteristics. High capital expenses, manufacturing costs, and a paucity of some well-scalable methods, all of which lead to low BNC output in commercial scale, are major barriers that must be addressed. Advances in production methods, including bioreactor technologies, static intermittent, and semi-continuous fed batch technologies, and innovative outlay substrates, may be able to overcome the challenges to BNC production at the industrial scale. The novelty of this review is that it highlights genetic modification possibilities in BNC production to overcome existing impediments and open up viable routes for large-scale production, suitable for real-world applications. This review focuses on various production routes of BNC, its properties, and applications, especially the major advancement in food, personal care, biomedical and electronic industries.

Green Coating Polymers in Meat Preservation

Edible coatings, including green polymers are used frequently in the food industry to improve and preserve the quality of foods. Green polymers are defined as biodegradable polymers from biomass resources or synthetic routes and microbial origin that are formed by mono- or multilayer structures. They are used to improve the technological properties without compromising the food quality, even with the purpose of inhibiting lipid oxidation or reducing metmyoglobin formation in fresh meat, thereby contributing to the final sensory attributes of the food and meat products. Green polymers can also serve as nutrient-delivery carriers in meat and meat products. This review focuses on various types of bio-based biodegradable polymers and their preparation techniques and applications in meat preservation as a part of active and smart packaging. It also outlines the impact of biodegradable polymer films or coatings reinforced with fillers, either natural or synthesized, via the green route in enhancing the physicochemical, mechanical, antimicrobial, and antioxidant properties for extending shelf-life. The interaction of the package with meat contact surfaces and the advanced polymer composite sensors for meat toxicity detection are further considered and discussed. In addition, this review addresses the research gaps and challenges of the current packaging systems, including coatings where green polymers are used. Coatings from renewable resources are seen as an emerging technology that is worthy of further investigation toward sustainable packaging of food and meat products.

Bionanocellulose/Poly(Vinyl Alcohol) Composites Produced by In-Situ Method and Ex-Situ/Impregnation or Sterilization Methods

The purpose of the work was to obtain composites based on bionanocellulose (BNC) and poly(vinyl alcohol) (PVA) for specific biomedical and cosmetic applications and to determine how the method and conditions of their preparation affect their utility properties. Three different ways of manufacturing these composites (in-situ method and ex-situ methods combined with sterilization or impregnation) were presented. The structure and morphology of BNC/PVA composites were studied by ATR-FTIR spectroscopy and scanning microscopy (SEM, AFM). Surface properties were tested by contact angle measurements. The degree of crystallinity of the BNC fibrils was determined by means of the XRD method. The mechanical properties of the BNC/PVA films were examined using tensile tests and via the determination of their bursting strength. The water uptake of the obtained materials was determined through the gravimetric method. The results showed that PVA added to the nutrient medium caused an increase in biosynthesis yield. Moreover, an increase in base weight was observed in composites of all types due to the presence of PVA. The ex-situ composites revealed excellent water absorption capacity. The in-situ composites appeared to be the most durable and elastic materials.

Disposable Food Packaging and Serving Materials-Trends and Biodegradability

Food is an integral part of everyone’s life. Disposable food serving utensils and tableware are a very convenient solution, especially when the possibility of the use of traditional dishes and cutlery is limited (e.g., takeaway meals). As a result, a whole range of products is available on the market: plates, trays, spoons, forks, knives, cups, straws, and more. Both the form of the product (adapted to the distribution and sales system) as well as its ecological aspect (biodegradability and life cycle) should be of interest to producers and consumers, especially considering the clearly growing trend of “eco-awareness”. This is particularly important in the case of single-use products. The aim of the study was to present the current trends regarding disposable utensils intended for contact with food in the context of their biodegradability. This paper has summarized not only conventional polymers but also their modern alternatives gaining the attention of manufacturers and consumers of single-use products (SUPs).

Properties and Application of Edible Modified Bacterial Cellulose Film Based Sago Liquid Waste as Food Packaging

Bacterial cellulose (BC) based on sago liquid waste has been developed to be used as food packaging. This study investigated the physicochemical and mechanical properties of modified BC film and its application as food packaging. The modified BC film performed carboxymethyl cellulose (CMC) as a stabilizer and glycerol as a plasticizer. Films were prepared by casting technique using BC as the primary material and composites with various concentrations of CMC and glycerol (0.5%, 1%, and 1.5%, v/v). BC film was applied as the packaging of meat sausage, and the quality of meat sausage was measured based on weight loss, moisture content, pH, protein content, and total microbial count. The addition of CMC and glycerol influences the physical and mechanical properties of BC composites film. The best mechanical properties of edible BC film were collected by adding 1% CMC and 1% glycerol with a tensile strength of 17.47 MPa, elongation at a break of 25.60%, and Young’s modulus of 6.54 GPa. FTIR analysis showed the characteristic bands of BC, and the addition of CMC and glycerol slightly changed the FTIR spectrum of the composites. The utilization of modified BC-based sago liquid waste film as the packaging of meat sausage could maintain sausage quality during 6 days of storage at room temperature. Therefore, edible BC film has the potential to be used as food packaging.

Weaving of bacterial cellulose by the Bcs secretion systems

Cellulose is the most abundant biological compound on Earth and while it is the predominant building constituent of plants, it is also a key extracellular matrix component in many diverse bacterial species. While bacterial cellulose was first described in the 19th century, it was not until this last decade that a string of structural works provided insights into how the cellulose synthase BcsA, assisted by its inner-membrane partner BcsB, senses c-di-GMP to simultaneously polymerize its substrate and extrude the nascent polysaccharide across the inner bacterial membrane. It is now established that bacterial cellulose can be produced by several distinct types of cellulose secretion systems and that in addition to BcsAB, they can feature multiple accessory subunits, often indispensable for polysaccharide production. Importantly, the last years mark significant progress in our understanding not only of cellulose polymerization per se but also of the bigger picture of bacterial signaling, secretion system assembly, biofilm formation and host tissue colonization, as well as of structural and functional parallels of this dominant biosynthetic process between the bacterial and eukaryotic domains of life. Here, we review current mechanistic knowledge on bacterial cellulose secretion with focus on the structure, assembly and cooperativity of Bcs secretion system components.

Green-based active packaging: Opportunities beyond COVID-19, food applications, and perspectives in circular economy-A brief review

The development of biodegradable packaging, based on agro-industrial plant products and by-products, can transform waste into products with high added value and reduce the use of conventional nonrenewable packaging. Green-based active packaging has a variety of compounds such as antimicrobials, antioxidants, aromatics, among others. These compounds interact with packaged products to improve food quality and safety and favor the migration of bioactive compounds from the polymeric matrix to food. The interest in the potential hygienic-sanitary benefit of these packages has been intensified during the COVID-19 pandemic, which made the population more aware of the relevant role of packaging for protection and conservation of food. It is estimated that the pandemic scenario expanded food packaging market due to shift in eating habits and an increase in online purchases. The triad health, sustainability, and circular economy is a trend in the development of packaging. It is necessary to minimize the consumption of natural resources, reduce the use of energy, avoid the generation of waste, and emphasize the creation of social and environmental values. These ideas underpin the transition from the emphasis on the more subjective discourse to the emphasis on the more practical method of thinking about the logic of production and use of sustainable packaging. Presently, we briefly review some trends and economic issues related to biodegradable materials for food packaging; the development and application of bio-based active films; some opportunities beyond COVID-19 for food packaging segment; and perspectives in circular economy.

Advanced Functional Materials Based on Nanocellulose for Pharmaceutical/Medical Applications

Nanocelluloses (NCs), with their remarkable characteristics, have proven to be one of the most promising "green" materials of our times and have received special attention from researchers in nanomaterials. A diversity of new functional materials with a wide range of biomedical applications has been designed based on the most desirable properties of NCs, such as biocompatibility, biodegradability, and their special physicochemical properties. In this context and under the pressure of rapid development of this field, it is imperative to synthesize the successes and the new requirements in a comprehensive review. The first part of this work provides a brief review of the characteristics of the NCs (cellulose nanocrystals-CNC, cellulose nanofibrils-CNF, and bacterial nanocellulose-BNC), as well as of the main functional materials based on NCs (hydrogels, nanogels, and nanocomposites). The second part presents an extensive review of research over the past five years on promising pharmaceutical and medical applications of nanocellulose-based materials, which have been discussed in three important areas: drug-delivery systems, materials for wound-healing applications, as well as tissue engineering. Finally, an in-depth assessment of the in vitro and in vivo cytotoxicity of NCs-based materials, as well as the challenges related to their biodegradability, is performed.

Chronicle of Nanocelluloses (NCs) for Catalytic Applications: Key Advances

Nanocellulose (NC) is a biomaterial with growing interest in the field of nanocomposites and sustainable materials. NC has various applications including biodegradable materials, reinforcing agents, packaging films, transpiring membranes and medical devices. Among the many applications, the use of NC functionalized with organic and inorganic groups has found wide use as a catalyst in chemical transformations. The goal of this review is to collect the current knowledge on its catalytic applications for chemical groups conversion. We have chosen to organize the manuscript according to subdivision of NC into Bacterial Nanocellulose (BNC), Cellulose Nanocrystals (CNCs), and Cellulose Nanofibers (CNFs) and their role as inorganic- and organic-functionalized NC-catalysts in organic synthesis. However, in consideration of the fact that the literature on this field is very extensive, we have decided to focus our attention on the scientific productions of the last five years.