Preparation of highly flexible and sustainable lignin-rich nanocellulose film containing xylonic acid (XA), and its application as an antibacterial agent

Fabrication of lignocellulose/liquid metal-based conductive eutectic hydrogel composite for strain sensors

High conductive and freeze-resistant hydrogels with adhesion function are ideal candidates for soft electronic devices. However, it remains a challenge to design appropriate conductive nanofillers to endow hydrogels with all these characteristics. Liquid metal (LM) exhibits exceptional electrical conductivity and convenient processability, rendering it a highly promising contender. Cellulose nanofibrils (CNFs) were employed as the interfacial stabilizer in synthesizing stable CNFs encapsulated LM solutions. Then the lignin was further coated on the surface of CNFs-LM (LCL) to prepare lignin-coated hybrid hydrogels. The obtained LCL displayed outstanding water-dispersible stability and were promising conductive nanofillers for hydrogels. During the fabrication of poly N-(hydroxymethyl) acrylamide (PHA) hydrogels, the LM was dispersed into LM particles with smaller sizes, leading to highly conductive LCL-PHA hydrogels (0.38 S·m-1). The prepared LCL-PHA hydrogels exhibited exceptional mechanical properties, including a strain at a break of 134.6 %, stress at a break of 22.7 Kpa, and a toughness of 16.3 KJ·m-3. Additionally, the LCL-PHA hydrogels demonstrated favorable electrical conductivity and adhesion. Notably, even after being subjected to freezing at -20 °C for 24 h, they remained suitable for effective real-time monitoring of all types of human activities, demonstrating superior environmental stability.

Lignin - A green material for antibacterial application - A review

Lignin's antibacterial properties have become increasingly relevant due to the rise of microbial infectious diseases and antibiotic resistance. Lignin is capable of interacting electrostatically with bacteria and contains polyphenols that cause damage to their cell walls. These features make lignin a desirable material to exhibit antibacterial behavior. Therefore, lignin in antibacterial applications offers a novel approach to address the growing need for sustainable and effective antibacterial materials. Recent research has explored the incorporation of lignin in various biomedical applications, such as wound dressings, implants, and drug delivery systems, highlighting their potential as a sustainable alternative to synthetic antibacterial agents. Furthermore, the development of lignin-based nanomaterials with enhanced antimicrobial activity is an active area of research that holds great promise for the future. In this review, we have provided a summary of how lignin can be incorporated into different forms, such as composite and non-composite synthesis of antibacterial agents and their performances. The challenges and future considerations are also discussed in this review article.

Construction of Super-Hydrophobic Lignocellulosic Nanofibrils Aerogels as Speedy Oil Absorbents

Lignocellulosic nanofibrils (LCNF) aerogels have a three-dimensional structure, with large specific surface area, low density, which is promising to be developed into a new type of adsorbent with high absorption capacity. However, LCNF aerogels have the problem of simultaneous oil and water adsorption. This high hydrophilicity directly leads to low adsorption efficiency in oil-water systems. This paper suggests a facile and economical method for the synthesis of biocompatible CE-LCNF aerogels using LCNF and Castor oil triglycidyl ether (CE) was successfully established. The use of LCNF enabled aerogels to possess remarkably uniform pore size and structural integrity, while the introduction of hydrophobic silica produced stable superhydrophobicity for more than 50 days at room temperature. These aerogels presented desirable hydrophobicity (131.6°), excellent oil adsorption capacity (62.5 g/g) and excellent selective sorption property, making them ideal absorbents for oil spill cleaning. The effects of ratios of LCNF to CE composition, temperatures and oil viscosity on the oil adsorption performance of aerogels were estimated. The results displayed that the aerogels had the maximum adsorption capacity at 25 °C. The pseudo-secondary model had higher validity in oil adsorption kinetic theories compared to the pseudo-first-order model. The CE-LCNF aerogels were excellent super-absorbents for oil removal. Moreover, the LCNF was renewable and nontoxic, which has the potential to promote environmental applications.

Preparation of Ag@lignin nanotubes for the development of antimicrobial biodegradable films from corn straw

Current environmental and energy issues have attracted considerable attention from industries, governments, and academia. Developing alternative diverse petrochemical-based plastics with biodegradable packaging materials from renewable resources is critical for ensuring both sustainability and safety. In this study, biodegradable films are fabricated from corn straw via a facile sol-gel process. Furthermore, these films are imbued with antimicrobial properties by coupling with silver@lignin nanotube hybrid antibacterial agents, formed via the in situ reduction of silver ions into elemental silver by lignin (mild reducing agent), followed by the self-assembly of lignin molecules into nanotubes assisted by an aqueous silver nitrate electrolyte solution. The developed antibacterial corn straw film exhibits strong mechanical and antibacterial properties, with a tensile strength and elongation at break of 68.7 MPa and 11.3 %, respectively, under optimum conditions and antibacterial activity against Escherichia coli and Staphylococcus aureus of 99.9 % and 97.2 %, respectively. The as-prepared corn straw films exhibit high hydrophobicity and ultraviolet resistance. The morphology, structure, and thermal properties of the corn straw films were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and thermogravimetric analysis. This study provides a straw-based biodegradable packaging film with antimicrobial properties.

Enhanced hybrid hydrogel based on wheat husk lignin-rich nanocellulose for effective dye removal

Polyvinyl alcohol (PVA) hydrogels were enhanced mechanically through the addition of lignin-rich nanocellulose (LCN), soluble ash (SA) and montmorillonite (MMT) for dye removal. The hybrid hydrogels reinforced with 33.3 wt% of LCN had a 163.0% increase in storage modulus as compared to the PVA/0LCN-33.3SM hydrogel. LCN can be added to the PVA hydrogel to alter its rheological properties. Additionally, hybrid hydrogels were highly efficient in removing methylene blue from wastewater, which was attributed to the synergistic effects of the PVA matrix supporting embedded LCN, MMT, and SA. The adsorption time (0–90 min) showed that the hydrogels containing MMT and SA had high removal efficiency, and the adsorption of methylene blue (MB) by PVA/20LCN-13.3SM was greater than 95.7% at 30°C. It was found that MB efficiency decreased with a high MMT and SA content. Our study provided a new method for the fabrication of polymers-based eco-friendly, low-cost and robust physical hydrogels for the MB removal.

Metabolomic Profiling, Antibacterial, and Molluscicidal Properties of the Medicinal Plants Calotropis procera and Atriplex halimus: In Silico Molecular Docking Study

The potential of plant-based natural compounds in the creation of new molluscicidal and antimicrobial medications has gained attention in recent years. The current study compared the metabolic profiles, antibacterial, and molluscicidal properties of the medicinal plants Calotropis procera (C. procera) and Atriplex halimus (A. halimus). In both plants, 118 metabolites were identified using gas chromatography-mass spectrometry. Palmitic acid, stigmasterol, and campesterol were the most prevalent constituents. C. procera extract showed stronger antibacterial activity than A. halimus against Escherichia coli and Proteus mirabilis. Both extracts exhibited molluscicidal activity against Biomphalaria alexandrina, with LC₅₀ values of C. procera (135 mg/L) and A. halimus (223.8 mg/L). Survival rates of snails exposed to sub-lethal concentrations (LC₂₅) of C. procera and A. halimus extracts were 5% and 20%, respectively. The hatchability of snail eggs exposed to both extracts has been dramatically reduced. Both extracts significantly decreased the levels of alkaline phosphatase, acid phosphatase, total protein, and albumin in snails, as well as causing DNA damage and resulting in numerous hermaphrodite and digestive gland damages and distortions. Molecular docking showed palmitic acid binding with acid, alkaline, and alanine aminotransferases in treated digestive gland snails. In conclusion, C. procera and A. halimus have antibacterial and molluscicidal properties.

A smart self-balancing biosystem with reversible competitive adsorption of in-situ anion exchange resin for whole-cell catalysis preparation of lignocellulosic xylonic acid

Xylonic acid (XA) bioproduction via whole-cell catalysis of Gluconobacter oxydans is a promising strategy for xylose bioconversion, which is hindered by inhibitor formation during lignocellulosic hydrolysates. Therefore, it is important to develop a catalytic system that can directly utilize hydrolysate and efficiently produce XA. Determination of the dynamic adsorption characteristics of 335 anion exchange resin resulted in a unique and interesting reversible competitive adsorption between acetic acid-like bioinhibitor, fermentable sugar and XA. Xylose in crude lignocellulosic hydrolysates was completely oxidized to 52.52 g/L XA in unprecedented self-balancing biological system through reversible competition. The obtained results showed that in-situ resin adsorption significantly affected the direct utilization of crude lignocellulosic hydrolysate for XA bioproduction (p ≤ 0.05). In addition, the resin adsorbed ca. 90 % of XA during bioconversion. The study achieved a multiple functions and integrated system, "detoxification, neutralization and product separation" for one-pot bioreaction of lignocellulosic hydrolysate.