Preparation of Cellulose Nanocrystals from Jujube Cores by Fractional Purification

Understanding nonwoody cellulose extractions, treatments, and properties for biomedical applications

Cellulose is a β1-4 glucan polymer that constitutes the most abundant polysaccharide on Earth. Recent advancements in its production have provided greater control and enabled the creation of functional celluloses with enhanced physical, mechanical, and chemical properties. With the increasing interest in polysaccharide materials, attention is now focused on alternative sources, particularly those derived from nonwoody plants such as jute, sisal, cotton, flax, or hemp. Compared to wood, nonwoody plants generally possess lower lignin content, shorter growing cycles with moderate irrigation requirements, high annual crops, and substantial annual cellulose yield. The discovery of nonwoody cellulose disintegration opens new avenues for environmentally friendly approaches, naturally paving the way for the exploration of new applications for this versatile material. Despite the broad range of potential applications, cellulose has primarily been utilized for industrial purposes, with only limited interest in the biomedical sector in the early stages. Therefore, this review focuses on nonwoody cellulose extraction and pretreatments while evaluating the compositions and properties of nonwoody plants, resulting in distinctive features beneficial for biomedical applications. This review aims to facilitate a deeper understanding of nonwoody cellulose and its prospects for biomedical applications.

Enhanced Sugar and Bioethanol Production from Broom Grass via NaOH-Autoclave Pretreatment

The effective utilization of nonfood biomass for bioethanol production represents a promising strategy for sustainable energy development. Moreover, limited research has been conducted on broom grass (Thysanolaena latifolia) as a potential feedstock for bioethanol production, particularly regarding the effects of NaOH autoclave pretreatment on its enzymatic digestibility and fermentability. This study optimized sodium hydroxide (NaOH) pretreatment combined with autoclaving to enhance the enzymatic digestibility of broom grass biomass. The effects of NaOH concentration (1-4%) and temperature (110-130 °C) on biomass composition, structural features, and enzymatic hydrolysis were systematically evaluated. Pretreatment with 2% NaOH at 120 °C emerged as optimal, achieving 74.7% lignin removal and 93.2% glucan recovery, thereby significantly improving enzymatic hydrolysis efficiency (88.0%) and glucose recovery (33.3%). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that these improvements were attributed to the increased surface porosity and the selective removal of amorphous components while maintaining cellulose crystallinity. The pretreated biomass hydrolysate exhibited excellent bioethanol production. Fermentation using Saccharomyces cerevisiae TISTR 5339 achieved an 86.4% ethanol conversion rate, yielding 147 g of bioethanol per 1000 g of pretreated biomass and representing a 2.6-fold increase compared to untreated feedstock. These findings demonstrate the potential of the NaOH autoclave pretreatment in enhancing bioethanol production from broom grass biomass, aiding the advancement of sustainable and cost-effective lignocellulosic biorefinery processes. The utilization of broom grass for bioethanol production presents an opportunity to valorize this multifaceted plant and expand its potential beyond its traditional uses.

Synthesis of Carboxylate-Dialdehyde Cellulose to Use as a Component in Composite Thin Films for an Antibacterial Material in Wound Dressing

Wound infections can lead to life-threatening infection and death. Antibacterial materials from biopolymers in the form of films are a promising strategy for wound dressings. Carboxylate-dialdehyde cellulose (CDAC) is a proper candidate for use as an antibacterial material due to its biocompatibility, nontoxicity, and antibacterial property. Additionally, CDAC can be synthesized from cellulose through environmentally friendly and nontoxic methods. Thus, this study aims to synthesize CDAC from microcrystalline cellulose (MCC) PH102 and use it in composite films for an antibacterial application. The CDAC was synthesized using Fe2+/H2O2, followed by NaIO4 oxidation. The obtained CDAC was characterized in terms of carboxylate and aldehyde content as well as FTIR and XRD spectra. The CDAC was mixed with HPMC in different ratios to prepare films. To determine the optimal formulation for clindamycin HCl loading, the films were evaluated for morphology, mechanical properties, and swelling ratio. Finally, the films containing clindamycin HCl were evaluated for drug loading content, in vitro drug release, and antibacterial activity. This study found that CDAC contained 2.1 ± 0.2 carboxylate and 4.15 ± 0.2 mmol/g of aldehyde content. The FTIR spectra confirmed the successful synthesis. X-ray diffractograms indicated that CDAC was less crystalline than MCC. The film, consisting of CDAC and HPMC E50 in the ratio of 2:1 (D2H1), was identified as the most suitable for clindamycin HCl loading due to its superior appearance, mechanical strength, and swelling properties compared to other formulations. D2H1 exhibited a high drug loading capacity (91.49 ± 5.48%) and demonstrated faster drug release than the film composed only of HPMC because of the higher swelling ratio and lower mechanical strength. This formulation was effective against Staphylococcus aureus (MSSA), S. aureus (MRSA), and Pseudomonas aeruginosa. Furthermore, the D2H1 film containing clindamycin HCl showed a larger inhibition zone against these bacteria, likely due to a synergistic effect. This study found that CDAC has the potential to be applied as an antibacterial material for wound dressing.

Sausage Preservation Using Films Composed of Chitosan and a Pickering Emulsion of Essential Oils Stabilized with Waste-Jujube-Kernel-Derived Cellulose Nanocrystals

The purpose of this study was to prepare Pickering emulsions stabilized by waste jujube kernel cellulose nanocrystals (CNC) using composite essential oils (EOs) (i.e., cinnamon essential oil [CIN] combined with clove essential oil [CL]). The Pickering emulsions were blended with chitosan (CS) to generate a composite film (CS/CNC/EOs Pickering emulsions). We evaluated the mechanical properties, barrier properties, and microstructures of CS/CNC/EOs bio-based packaging films containing different concentrations of EOs. In addition, the fresh-keeping effects of the composite membranes on beef sausages were evaluated over a 12-day storage period. Notably, the EOs exhibited good compatibility with CS. With the increase in the EOs concentration, the droplet size increased, the composite films became thicker, the elongation at break decreased, the tensile strength increased, and the water vapor permeability decreased. When the composite films were used for preserving beef sausages, the antioxidant and antibacterial activity of the membranes improved as the concentration of EOs increased, effectively prolonging the shelf life of the sausages. Composite membranes with an EOs concentration of 2% exerted the best fresh-keeping effects. Overall, owing to their antioxidant and antimicrobial properties, the bio-based composite films prepared using CS/CNC/EOs Pickering emulsions demonstrated immense potential for application in the packaging of meat products.

Nanocellulose from agro-industrial wastes: A review on sources, production, applications, and current challenges

Significant volumes of agricultural and industrial waste are produced annually. With the global focus shifting towards sustainable and environmentally friendly practices, there is growing emphasis on recycling and utilizing materials derived from such waste, such as cellulose and lignin. In response to this imperative situation, nanocellulose materials have surfaced attracting heightened attention and research interest owing to their superior properties in terms of strength, stiffness, biodegradability, and water resistance. The current manuscript provided a comprehensive review encompassing the resources of nanocellulose, detailed pretreatment and extraction methods, and present applications of nanocellulose. More importantly, it highlighted the challenges related to its processing and utilization, along with potential solutions. After evaluating the benefits and drawbacks of different methods for producing nanocellulose, ultrasound combined with acid hydrolysis emerges as the most promising approach for large-scale production. While nanocellulose has established applications in water treatment, its potential within the food industry appears even more encouraging. Despite the numerous potential applications across various sectors, challenges persist regarding its modification, characterization, industrial-scale manufacturing, and regulatory policies. Overcoming these obstacles requires the development of new technologies and assessment tools aligned with policy. In essence, nanocellulose presents itself as an eco-friendly material with extensive application possibilities, prompting the need for additional research into its extraction, application suitability, and performance enhancement. This review focused on the wide application scenarios of nanocellulose, the challenges of nanocellulose application, and the possible solutions.

Preparation and properties of films loaded with cellulose nanocrystals stabilized Thymus vulgaris essential oil Pickering emulsion based on modified tapioca starch/polyvinyl alcohol

Pickering emulsions were prepared by stabilizing thymus vulgaris essential oil (TEVO) with cellulose nanocrystals (CNCs), which formed composite films by loading the emulsions into modified tapioca/polyvinyl alcohol (PVA)-based films. The results showed that the 1.0 % CNCs-15 % TEVO emulsion had optimal stability and smaller particle size. The emulsion increased the thickness of the composite film in the form of solid material additions (thickness, 0.062-0.099 mm), which opacity given the laminating film's superior UV-blocking ability compared to blank film. The emulsion plasticizing effect enhanced the film's elongation at break (EAB, 123-159 %). In addition, due to the hydrophobicity and influencing the diffusion path of water molecules in the emulsion, the denser microstructure composite film had a lower water vapor transmission coefficient (WVP, 6.22 × 10-11-5.35 × 10-11g∙cm/cm2∙s∙Pa) to impede moisture penetration. Meanwhile, the composite film can effectively maintain the color and inhibit the growth of microorganisms to extend the storage time of fish fillets.

Nanoporous Carbon from Oil Palm Leaves via Hydrothermal Carbonization-Combined KOH Activation for Paraquat Removal

In this study, nano-porous carbon was completely obtained from oil palm leaves (OPL) by hydrothermal pretreatment with chemical activation, using potassium hydroxide (KOH) as an activating agent. Potassium hydroxide was varied, with different ratios of 1:0.25, 1:1, and 1:4 (C: KOH; w/w) during activation. The physical morphology of nano-porous carbon has a spongy, sponge-like structure indicating an increase in specific surface area and porosity with the increasing amount of KOH activating agent. The highest specific surface area of OPL nano-porous carbon is approximately 1685 m²·g^-1, with a total pore volume of 0.907 cm³·g^-1. Moreover, the OPL nano-porous carbon significantly showed a mesoporous structure designed specifically to remove water pollutants. The adsorptive behavior of OPL nano-porous carbon was quantified by using paraquat as the target pollutant. The equilibrium analyzes were explained by the Langmuir model isotherm and pseudo-second-order kinetics. The maximum efficiency of paraquat removal in wastewater was 79%, at a paraquat concentration of 400 mg·L^-1, for 10 min in the adsorption experiment. The results of this work demonstrated the practical application of nano-porous carbon derived from oil palm leaves as an alternative adsorbent for removing paraquat and other organic matter in wastewater.