Synthesis and Characterization of Cellulose Triacetate Obtained from Date Palm (Phoenix dactylifera L.) Trunk Mesh-Derived Cellulose.

Cellulosic polysaccharides have increasingly been recognized as a viable substitute for the depleting petro-based feedstock due to numerous modification options for obtaining a plethora of bio-based materials. In this study, cellulose triacetate was synthesized from pure cellulose obtained from the waste lignocellulosic part of date palm (Phoenix dactylifera L.). To achieve a degree of substitution (DS) of the hydroxyl group of 2.9, a heterogeneous acetylation reaction was carried out with acetic anhydride as an acetyl donor. The obtained cellulose ester was compared with a commercially available derivative and characterized using various analytical methods. This cellulose triacetate contains approximately 43.9% acetyl and has a molecular weight of 205,102 g·mol-1. The maximum thermal decomposition temperature of acetate was found to be 380 °C, similar to that of a reference sample. Thus, the synthesized ester derivate can be suitable for fabricating biodegradable and "all cellulose" biocomposite systems.

Bioprocess development for bacterial cellulose biosynthesis by novel Lactiplantibacillus plantarum isolate along with characterization and antimicrobial assessment of fabricated membrane.

Bacterial cellulose (BC) is an ecofriendly biopolymer with diverse commercial applications. Its use is limited by the capacity of bacterial production strains and cost of the medium. Mining for novel organisms with well-optimized growth conditions will be important for the adoption of BC. In this study, a novel BC-producing strain was isolated from rotten fruit samples and identified as Lactiplantibacillus plantarum from 16S rRNA sequencing. Culture conditions were optimized for supporting maximal BC production using one variable at a time, Plackett-Burman design, and Box Behnken design approaches. Results indicated that a modified Yamanaka medium supported the highest BC yield (2.7 g/l), and that yeast extract, MgSO4, and pH were the most significant variables influencing BC production. After optimizing the levels of these variables through Box Behnken design, BC yield was increased to 4.51 g/l. The drug delivery capacity of the produced BC membrane was evaluated through fabrication with sodium alginate and gentamycin antibiotic at four different concentrations. All membranes (normal and fabricated) were characterized by scanning electron microscope, Fourier transform-infrared spectroscopy, X-ray diffraction, and mechanical properties. The antimicrobial activity of prepared composites was evaluated by using six human pathogens and revealed potent antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans, with no detected activity against Pseudomonas aeruginosa and Candida albicans.

Antibacterial nanocellulose membranes coated with silver nanoparticles for oil/water emulsions separation.

The superhydrophilic/underwater superoleophobic nanocellulose-based membranes show great potential in oil/water emulsion separation. However, nanocellulose composed of polysaccharides inevitably suffered from bacterial erosion during use or storage, resulting in structural damage or reduced separation efficiency. In this work, silver nanoparticles (AgNPs) as effective bactericidal materials are uniformly deposited on tunicate cellulose nanocrystals (TCNCs) by in situ hydrothermal reduction of silver nitrate. TCNCs not only act as reducing agents for silver ions, but also work as dispersant and stabilizers of AgNPs. Nanocomposite membranes are fabricated by vacuum-assisted filtrating of AgNPs@TCNC suspension, which exhibit nanoporous structure, superhydrophilicity, and underwater superoleophobicity. These membranes could efficiently separate oil/water microemulsion with water flux (>324 L m-2 h-1 bar-1) and oil rejection (>99%). Importantly, these membranes show excellent antibacterial efficacy against E. coli and S. aureus, benefiting to their long-term use and storage.

Simultaneous Enzymatic Cellulose Hydrolysis and Product Separation in a Radial-Flow Membrane Bioreactor.

Hydrolysis is the heart of the lignocellulose-to-bioethanol conversion process. Using enzymes to catalyze the hydrolysis represents a more environmentally friendly pathway compared to other techniques. However, for the process to be economically feasible, solving the product inhibition problem and enhancing enzyme reusability are essential. Prior research demonstrated that a flat-sheet membrane bioreactor (MBR), using an inverted dead-end filtration system, could achieve 86.7% glucose yield from purified cellulose in 6 h. In this study, the effectiveness of flat-sheet versus radial-flow MBR designs was assessed using real, complex lignocellulose biomass, namely date seeds (DSs). The tubular radial-flow MBR used here had more than a 10-fold higher membrane surface area than the flat-sheet MBR design. With simultaneous product separation using the flat-sheet inverted dead-end filtration MBR, a glucose yield of 10.8% from pretreated DSs was achieved within 8 h of reaction, which was three times higher than the yield without product separation, which was only 3.5% within the same time and under the same conditions. The superiority of the tubular radial-flow MBR to hydrolyze pretreated DSs was confirmed with a glucose yield of 60% within 8 h. The promising results obtained by the novel tubular MBR could pave the way for an economic lignocellulose-to-bioethanol process.

Facile extraction and characterization of cellulose nanocrystals from agricultural waste sugarcane straw.

BACKGROUND: Sugarcane straw is an available but largely ignored lignocellulosic biomass to obtain cellulose nanocrystals (CNCs) with highly crystalline, tunable surface chemistries and a wide-ranging adaptability. Herein, we utilized sugarcane straw to obtain pure cellulose via purification processes, followed by subsequent preparation of CNCs via sulfuric acid hydrolysis. The properties of the purified fibers and obtained CNCs were assessed by their composition, morphology, chemical structure, crystallinity and thermal stability. RESULTS: After the purification process, alkali-treated fibers (ATFs) contained 886.33 ± 1.25 g kg-1 cellulose, and its morphological analysis revealed a smooth and slender fibrous structure. The CNCs obtained by treatment with 64 wt% sulfuric acid at 45 °C for 60 min were isolated in a yield of 21.8%, with a diameter and length of 6 to 10 nm and 160 to 200 nm, respectively. Moreover, crystallinity index of these CNCs reached 62.66%, and thermal stability underwent a two-step degradation. Short-term ultrasonication after hydrolysis was employed to enhance isolation of the CNC particles and improve the anionic charge with higher value -38.00 mV. CONCLUSION: Overall, isolation and characterization results indicated the potential for CNCs preparation using sugarcane straw, in addition to offering a fundamental understanding of this material and indicating potential applications. © 2021 Society of Chemical Industry.

Ecofriendly green biosynthesis and characterization of novel bacteriocin-loaded bacterial cellulose nanofiber from Gluconobacter cerinus HDX-1.

A new strain of bacterial cellulose (BC)-producing Gluconobacter cerinus HDX-1 was isolated and identified, and a simple, low-cost complexation method was used to biosynthesis Lactobacillus paracasei 1∙7 bacteriocin BC (BC-B) nanofiber. The structure and antibacterial properties of the nanofibers were evaluated. Solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) analysis showed that BC and BC-B nanofibers had typical crystalline form of the cellulose I. X-ray photoelectron spectrometer (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM) revealed that the bacteriocin and BC were successfully compounded, and the structure of BC-B nanofiber was tighter than BC nanofiber, with lower porosity, swelling ratio and water vapor transmission rate (WVTR). The tensile strength and Young's modulus of BC-B nanofibers were 13.28 ± 1.26 MPa and 132.10 ± 4.92 MPa, respectively, higher than that of BC nanofiber (6.12 ± 0.87 MPa and 101.59 ± 5.87 MPa), indicating that bacteriocin enhance the mechanical properties of BC nanofiber. Furthermore, the BC-B nanofibers exhibited significant thermal stability, antioxidant capacity and antibacterial activity than BC nanofiber. Therefore, bacteriocin-loaded BC nanofiber may be used as antimicrobial agents in active food packaging and medical material.

Characterization of Bacterial Cellulose Produced by Acetobacter xylinum Strain LKN6 Using Sago Liquid Waste as Nutrient Source.

<b>Background and Objective:</b> Bacterial Cellulose (BC) is an exopolysaccharide produced by bacteria with unique structural and mechanical properties and is highly pure compared to plant cellulose. This study aimed to produce novel bacterial cellulose using sago liquid waste substrate and evaluate its characteristics as a potential bioplastic.<b>Materials and Methods:</b> Production of BC by static batch fermentation was studied in sago liquid waste substrate usingAcetobacter xylinumLKN6. The BC structure was analyzed by Scanning Electron Microscopy (SEM) and Fourier Transform infrared spectroscopy (FT-IR). Mechanical properties were measured include tensile strength, elongation at break, elasticity (Young's modulus) and Water Holding Capacity (WHC). <b>Results:</b> The BC yield from sago liquid waste as a nutrients source was achieved 12.37 g L¹ and the highest BC yield 14.52 g L¹ in sago liquid waste medium with a sugar concentration of 10% (w/v) after 14 days fermentation period. The existence of bacterial cellulose is proven by FT-IR spectroscopy analysis based on the appearance of absorbance peaks, which are C-C bonding, C-O bonding, C-OH bonding and C-O-C bonding and represents the fingerprints of pure cellulose. The mechanical properties of BC from sago liquid waste were showed a tensile strength of 44.2-87.3 MPa, elongation at break of 4.8-5.8%, Young's Modulus of 0.86-1.64 GPa and water holding capacity of 85.9-98.6 g g¹. <b>Conclusion:</b> The results suggest that sago liquid waste has great potential to use as a nutrient source in the production of bacterial cellulose and BC's prospect as the bioplastic.

Correlation between rheological measurements and morphological features of lignocellulosic micro/nanofibers from different softwood sources.

The transition of nanocellulose production from laboratory to industrial scale requires robust monitoring systems that keeps a quality control along the production chain. The present work aims at providing a deeper insight on the main factors affecting the rheological behavior of (ligno)cellulose micro/nanofibers (LCMNFs) and cellulose micro/nanofibers (CMNFs) and how they could correlate with their characteristics. To this end, 20 types of LCMNFs and CMNFs were produced combining mechanical refining and high-pressure homogenization from different raw materials. Aspect ratio and bending capacity of the fibrils played a key role on increasing the viscosity of the suspensions by instigating the formation of entangled structures. Surface charge, reflected by the cationic demand, played opposing effects on the viscosity by reducing the fibrils' contact due to repulsive forces. The suspensions also showed increasing shear-thinning behavior with fibrillation degree, which was attributed to increased surface charge and higher water retention capacity, enabling the fibrils to slide past each other more easily when subjected to flow conditions. The present work elucidates the existing relationships between LCMNF/CMNF properties and their rheological behavior, considering fibrillation intensity and the initial raw material characteristics, in view of the potential of rheological measurements as an industrial scalable characterization technology.

Bacterial cellulose spheroids as building blocks for 3D and patterned living materials and for regeneration.

Engineered living materials (ELMs) based on bacterial cellulose (BC) offer a promising avenue for cheap-to-produce materials that can be programmed with genetically encoded functionalities. Here we explore how ELMs can be fabricated in a modular fashion from millimetre-scale biofilm spheroids grown from shaking cultures of Komagataeibacter rhaeticus. Here we define a reproducible protocol to produce BC spheroids with the high yield bacterial cellulose producer K. rhaeticus and demonstrate for the first time their potential for their use as building blocks to grow ELMs in 3D shapes. Using genetically engineered K. rhaeticus, we produce functionalized BC spheroids and use these to make and grow patterned BC-based ELMs that signal within a material and can sense and report on chemical inputs. We also investigate the use of BC spheroids as a method to regenerate damaged BC materials and as a way to fuse together smaller material sections of cellulose and synthetic materials into a larger piece. This work improves our understanding of BC spheroid formation and showcases their great potential for fabricating, patterning and repairing ELMs based on the promising biomaterial of bacterial cellulose.

Comprehensive characterization of raw and alkali (NaOH) treated natural fibers from Symphirema involucratum stem.

The present study investigated the effect of alkali treatment on the enhancement of Physico-chemical, tensile, thermal and surface properties of Symphirema involucratum stem fiber (SISF). The investigation of chemical constituents of optimally alkalized SISF revealed that ideal increment of cellulose content (68.69 wt%) and desired modification of other chemical components was accomplished through 60 min immersion period. An increase in the crystallinity index to 33.33% and small crystallite size to 3.21 nm was noted by X-ray diffraction analysis. Moreover, the treated fiber was found suitable for light-weight applications since physical analysis acknowledges that the density of the fiber augmented to 1424 kg/m3after surface treatment that reduces total weight percentage. The enhancements in tensile strength (471.2 ± 19.8 MPa), tensile modulus (5.82 ± 0.77 GPa) and thermal stability (371 °C) were noted that ensures the treated fiber has good mechanical and thermal properties required for composite preparation. These findings validated that the optimally surface-modified SISF is a suitable material for lightweight composite structures, for the time being.

Gelatin/chitosan based films loaded with nanocellulose from soybean straw and activated with "Pitanga" (Eugenia uniflora L.) leaf hydroethanolic extract in W/O/W emulsion.

Mechanical properties of biopolymer films can be a limitation for their application as packaging. Soybean straw crystalline nanocelluloses (NC) can act as reinforcement load to improve these material properties, and W/O/W double emulsion (DE) as encapsulating bioactive agents can contribute to produce active packaging. DE droplets were loaded with pitanga leaf (Eugenia uniflora L.) hydroethanolic extract. The mechanical, physicochemical, and barrier properties, and the microstructure of gelatin and/or chitosan films incorporated with NC or NC/DE were determined by classical methods. Film antioxidant activities were determined by ABTS and DPPH methods. The incorporation of NC/DE in gelatin and/or chitosan films (NC/DE films) changed the morphology of these films, which presented more heterogeneous air-side surfaces and cross-sections. They presented rougher topographies, notably greater resistance and stiffness, higher barrier properties to UV/Vis light and higher antioxidant activity than the NC films. Moisture content, solubility in water and water vapor permeability decreased due to the presence of DE. Overall, the NC/DE films improved all properties, when compared to the properties of NC films or those of films with only DE, from a previously published study. In spite of not having antimicrobial activity against the studied bacteria, NC/DE films did display a great antioxidant activity.

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose.

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy (SEM) together with energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The crystallinity indexes (CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high (94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293T (HEK293T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed (i.e., 0|‒|500 µg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.

Present Status and Future Prospects of Jute in Nanotechnology: A Review.

Nanotechnology has transformed the world with its diverse applications, ranging from industrial developments to impacting our daily lives. It has multiple applications throughout financial sectors and enables the development of facilitating scientific endeavors with extensive commercial potentials. Nanomaterials, especially the ones which have shown biomedical and other health-related properties, have added new dimensions to the field of nanotechnology. Recently, the use of bioresources in nanotechnology has gained significant attention from the scientific community due to its 100 % eco-friendly features, availability, and low costs. In this context, jute offers a considerable potential. Globally, its plant produces the second most common natural cellulose fibers and a large amount of jute sticks as a byproduct. The main chemical compositions of jute fibers and sticks, which have a trace amount of ash content, are cellulose, hemicellulose, and lignin. This makes jute as an ideal source of pure nanocellulose, nano-lignin, and nanocarbon preparation. It has also been used as a source in the evolution of nanomaterials used in various applications. In addition, hemicellulose and lignin, which are extractable from jute fibers and sticks, could be utilized as a reductant/stabilizer for preparing other nanomaterials. This review highlights the status and prospects of jute in nanotechnology. Different research areas in which jute can be applied, such as in nanocellulose preparation, as scaffolds for other nanomaterials, catalysis, carbon preparation, life sciences, coatings, polymers, energy storage, drug delivery, fertilizer delivery, electrochemistry, reductant, and stabilizer for synthesizing other nanomaterials, petroleum industry, paper industry, polymeric nanocomposites, sensors, coatings, and electronics, have been summarized in detail. We hope that these prospects will serve as a precursor of jute-based nanotechnology research in the future.

Conformational and rheological properties of bacterial cellulose sulfate.

In this study, a water-soluble bacterial cellulose sulfate (BCS) was prepared with sulfur trioxide pyridine complex (SO3· Py) in a lithium chloride (LiCl)/dimethylacetamide (DMAc) homogeneous solution system using bacterial cellulose (BC). The structural study showed that the value for the degrees of substitution of BCS was 1.23. After modification, the C-6 hydroxyl group of BC was completely substituted and the C-2 and C-3 hydroxyl groups were partially substituted. In an aqueous solution, the BCS existed as a linear polymer with irregular coil conformation, which was consistent with the findings observed using atomic force microscopy. The steady-state shear flow and dynamic viscoelasticity were systematically determined over a range of BCS concentrations (1 %-4 %, w/v) and temperature (5 °C-50 °C). Steady-state flow experiments revealed that BCS exhibited shear thinning behavior, which increased with an increase in concentration and a decrease in temperature. These observations were quantitatively demonstrated using the cross model. Moreover, based on the dynamical viscoelastic properties, we confirmed that BCS was a temperature-sensitive and weak elastic gel, which was somewhere between a dilute solution and an elastic gel. Therefore, considering the special synthetic strategy and rheological behavior, BCS might be used as a renewable material in the field of biological tissue engineering, especially in the manufacture of injectable hydrogels, cell scaffolds, and as a drug carrier.

Sustainable isolation of nanocellulose from cellulose and lignocellulosic feedstocks: Recent progress and perspectives.

As a type of sustainable nanomaterials, nanocellulose has drawn increasing attention over the last two decades due to its great potential in diverse value-added applications such as electronics, sensors, energy storage, packaging, pharmaceuticals, biomedicine, and functional food. Sourcing nanocellulose from lignocellulose is commonly accomplished via the use of mineral acids, oxidizers, enzymes, and/or intensive mechanical energy. Yet, the economic and environmental concerns associated with these conventional isolation techniques pose major obstacles for commercialization. Considerable progress has been achieved in the last few years in developing sustainable nanocellulose isolation technologies involving organic acid/anhydride, Lewis acid, solid acid, ionic liquid, and deep eutectic solvent. This paper provides a comprehensive review of these alternatives with regard to general procedures and key advantages. Important knowledge gaps, including total biomass utilization, complete life cycle analysis, and health/safety, require urgently bridging in order to develop economically competitive and operationally feasible nanocellulose isolation technology for commercialization.

Seaweed-based cellulose: Applications, and future perspectives.

Cellulose is a naturally occurring organic polymer extracted mainly from lignocellulosic biomass of terrestrial origin. However, the increasing production of seaweeds for growing global market demands has developed the opportunity to use it as an additional cellulose source. This review aims to prepare comprehensive information to understand seaweed cellulose and its possible applications better. This is the first review that summarizes and discusses the cellulose from all three types (green, red, and brown) of seaweeds in various aspects such as contents, extraction strategies, and cellulose-based products. The seaweed cellulose applications and future perspectives are also discussed. Several seaweed species were found to have significant cellulose content (9-34% dry weight). The review highlights that the properties of seaweed cellulose-based products were comparable to products prepared from plant-based cellulose. Overall, this work demonstrates that cellulose could be economically extracted from phycocolloids industrial waste and selected cellulose-rich seaweed species for various commercial applications.

Isolation and modification of nano-scale cellulose from organosolv-treated birch through the synergistic activity of LPMO and endoglucanases.

Nanocellulose isolation from lignocellulose is a tedious and expensive process with high energy and harsh chemical requirements, primarily due to the recalcitrance of the substrate, which otherwise would have been cost-effective due to its abundance. Replacing the chemical steps with biocatalytic processes offers opportunities to solve this bottleneck to a certain extent due to the enzymes substrate specificity and mild reaction chemistry. In this work, we demonstrate the isolation of sulphate-free nanocellulose from organosolv pretreated birch biomass using different glycosyl-hydrolases, along with accessory oxidative enzymes including a lytic polysaccharide monooxygenase (LPMO). The suggested process produced colloidal nanocellulose suspensions (ζ-potential -19.4 mV) with particles of 7-20 nm diameter, high carboxylate content and improved thermostability (To = 301 °C, Tmax = 337 °C). Nanocelluloses were subjected to post-modification using LPMOs of different regioselectivity. The sample from chemical route was the least favorable for LPMO to enhance the carboxylate content, while that from the C1-specific LPMO treatment showed the highest increase in carboxylate content.

Bacterial Nanocellulose toward Green Cosmetics: Recent Progresses and Challenges.

In the skin care field, bacterial nanocellulose (BNC), a versatile polysaccharide produced by non-pathogenic acetic acid bacteria, has received increased attention as a promising candidate to replace synthetic polymers (e.g., nylon, polyethylene, polyacrylamides) commonly used in cosmetics. The applicability of BNC in cosmetics has been mainly investigated as a carrier of active ingredients or as a structuring agent of cosmetic formulations. However, with the sustainability issues that are underway in the highly innovative cosmetic industry and with the growth prospects for the market of bio-based products, a much more prominent role is envisioned for BNC in this field. Thus, this review provides a comprehensive overview of the most recent (last 5 years) and relevant developments and challenges in the research of BNC applied to cosmetic, aiming at inspiring future research to go beyond in the applicability of this exceptional biotechnological material in such a promising area.

Effect of cellulose nanocrystals derived from Dunaliella tertiolecta marine green algae residue on crystallization behaviour of poly(lactic acid).

Marine green algae biomass residue (ABR), a waste by-product of Dunaliella tertiolecta, left behind after the extraction of oil from the algal biomass, was utilized for the fabrication of cellulose nanocrystals (CNCs). The fabricated sulphuric acid hydrolysed CNCs had needle-like morphology, with dominant cellulose type I polymorph and a high crystallinity index of 89 %. ICP-MS elemental analysis confirmed the presence of a variety of minerals in the ABR. Washed ABR (WABR)/PLA and CNC/PLA bio-composite films were developed via solvent casting technique with varying bio-filler loadings for comparing their effectiveness on the crystallization behaviour of PLA. FESEM, FTIR, XRD and TGA were used to characterize the bio-fillers. The nucleating and crystallization behaviour of the bio-composite films were confirmed using DSC, SAXS and POM analysis which indicated better effectiveness of CNCs with a significant reduction in cold crystallization temperature, and noteworthy increment in crystallinity and spherulite growth rate.

Valorization of fruit processing waste to produce high value-added bacterial nanocellulose by a novel strain Komagataeibacter xylinus IITR DKH20.

To date, the production of bacterial nanocellulose (BNC) by standard methods has been well known, while the use of low-cost feedstock as an alternative medium still needs to be explored for BNC commercialization. This study explores the prospect for the use of the different aqueous extract of fruit peel wastes (aE-FPW) as a nutrient and carbon source for the production of BNC. Herein, this objective was accomplished by the use of a novel, high- yielding strain, isolated from rotten apple and further identified as Komagataeibacter xylinus IITR DKH20 using 16 s rRNA sequencing analysis. The physicochemical properties of BNC matrix collected from the various aE-FPW mediums were similar or advanced to those collected with the HS medium. Statistical optimization of BNC based on Central Composite Design was performed to study the effect of significant parameters and the results demonstrated that the BNC yield (11.44 g L-1) was increased by 4.5 fold after optimization.