A new method to produce cellulose nanofibrils from microalgae and the measurement of their mechanical strength

Cellulose from dinoflagellates as a versatile and environmentally friendly platform for the production of functionalised cellulose nanofibres

Cellulose nanofibres (CNFs), also known as nano-fibrillated cellulose, have emerged as highly promising sustainable biomaterials owing to their numerous advantages, including high accessibility, long-term sustainability, low toxicity, and mechanical properties. Recently, marine organisms have been explored as novel and environmentally friendly sources of cellulose fibers (CFs) due to their easy cultivation, extraction and biocompatibility. Dinoflagellates, a group of marine phytoplankton, have gained particular attention due to their unique cellulosic morphology and lignin-free biomass. Previously, we showed that the unique amorphous nature of dinoflagellate-derived cellulose offers various benefits. This study further explores the potential of dinoflagellate-derived CFs as a sustainable and versatile CNF source. Extracted dinoflagellate cellulose is effectively converted into CNFs via one-step TEMPO oxidation without significant polymer degradation. In addition, the biological compatibility of the CNFs is improved by amine-grafting using putrescine and folic acid. The products are characterised by conductometric titration, zeta potential measurements, TGA, GPC, FTIR, SEM/TEM, XRD, and XPS. Finally, in a proof-of-principle study, the application of the functionalised CNFs in drug delivery is tested using methylene blue as a drug model. Our findings suggest that dinoflagellate-derived CNFs provide an eco-friendly platform that can be easily functionalised for various applications, including drug delivery.

Green Synthesis of Bioplastics from Microalgae: A State-of-the-Art Review

The synthesis of conventional plastics has increased tremendously in the last decades due to rapid industrialization, population growth, and advancement in the use of modern technologies. However, overuse of these fossil fuel-based plastics has resulted in serious environmental and health hazards by causing pollution, global warming, etc. Therefore, the use of microalgae as a feedstock is a promising, green, and sustainable approach for the production of biobased plastics. Various biopolymers, such as polyhydroxybutyrate, polyurethane, polylactic acid, cellulose-based polymers, starch-based polymers, and protein-based polymers, can be produced from different strains of microalgae under varying culture conditions. Different techniques, including genetic engineering, metabolic engineering, the use of photobioreactors, response surface methodology, and artificial intelligence, are used to alter and improve microalgae stocks for the commercial synthesis of bioplastics at lower costs. In comparison to conventional plastics, these biobased plastics are biodegradable, biocompatible, recyclable, non-toxic, eco-friendly, and sustainable, with robust mechanical and thermoplastic properties. In addition, the bioplastics are suitable for a plethora of applications in the agriculture, construction, healthcare, electrical and electronics, and packaging industries. Thus, this review focuses on techniques for the production of biopolymers and bioplastics from microalgae. In addition, it discusses innovative and efficient strategies for large-scale bioplastic production while also providing insights into the life cycle assessment, end-of-life, and applications of bioplastics. Furthermore, some challenges affecting industrial scale bioplastics production and recommendations for future research are provided.

Bacterial cellulose: Nature's greener tool for industries

Bacteria are considered mini chemical factories that help us in providing a wide range of products for various purposes. These days, bacterial cellulose (BC) is getting attention by researchers due to its quality, eco-friendly nature, and excellent physical-mechanical qualities. It is being used in the fabrication of nanocomposites. Its nanocomposites can be used in various industries, including medicine, food, leather, textiles, environment, electronics, and cosmetics. This area of research is emerging and still in its infancy stage, as new applications are still coming up. Most of the work on BC has been done during the last two decades and serious inputs are required in this direction in order to make the production process commercially viable and ultimately the application part. Biowastes, such as fruits and vegetables wastes, can be used as a cost-effective medium to minimize the cost for large-scale production of BC-based nanocomposites thus will valorize the biowaste material into a valuable product. Using biowaste as media will also aid in better waste management along with reduction in detrimental environmental effects. This review will help the readers to understand the potential applications of BC and its nanocomposites as well as their vital role in our daily lives.

Residual Chlorella-Based Cellulose Nanofibers and Their Quaternization Modification and Efficient Anionic Dye Adsorption

Dye is an anionic common pollutant in industrial wastewater and poses a great threat to the environment and human health. Owing to its advantageous adsorption capacity, nanocellulose is widely used for wastewater treatment. The cell walls of Chlorella mainly comprise cellulose instead of lignin. In this study, residual Chlorella-based cellulose nanofiber (CNF) and cationic cellulose nanofiber (CCNF) with surface quaternization were prepared through homogenization. Moreover, Congo red (CR) was used as a model dye to measure the adsorption capacity of CNF and CCNF. The adsorption capacity was almost saturated when CNF and CCNF contacted CR for 100 min, and the adsorption kinetics coincided with the pseudo-secondary kinetics model. The initial concentration of CR considerably affected its adsorption on CNF and CCNF. Below the initial concentration of 40 mg/g, the adsorption on CNF and CCNF considerably increased with the increase in the initial concentration of CR. Based on the sorption isotherms analysis of CNF and CCNF, the Langmuir model fitted best with the experimental data. Thus, CNF and CCNF surfaces were uniform, and monolayer adsorption occurred. The adsorption of CR on CNF and CCNF was greatly affected by the pH value, and the acidic medium favored the adsorption of CR (especially for CCNF). CCNF showed a more advantageous adsorption capacity, with a maximum value of 1657.89 mg/g, compared to that of CNF (190.0 mg/g). According to the findings of this study, residual Chlorella-based CCNF could be a very promising adsorbent candidate for removing anionic dyes from wastewater.

Multiscale micromechanics modeling of plant fibers: upscaling of stiffness and elastic limits from cellulose nanofibrils to technical fibers

The mechanical properties of natural fibers, as used to produce sustainable biocomposites, vary significantly-both among different plant species and also within a single species. All plants, however, share a common microstructural fingerprint. They are built up by only a handful of constituents, most importantly cellulose. Through continuum micromechanics multiscale modeling, the mechanical behavior of cellulose nanofibrils is herein upscaled to the technical fiber level, considering 26 different commonly used plants. Model-predicted stiffness and elastic limit bounds, respectively, frame published experimental ones. This validates the model and corroborates that plant-specific physicochemical properties, such as microfibril angle and cellulose content, govern the mechanical fiber performance.

Algal biorefinery towards decarbonization: Economic and environmental consideration

Algae biomass contains various biological elements, including lipids, proteins, and carbohydrates, making it a viable feedstock for manufacturing biofuels. However, the biggest obstacle to commercializing algal biofuels is their high production costs, primarily related to an algae culture. The extraction of additional high value added bioproducts from algal biomass is thus required to increase the economic viability of producing algae biofuel. This study aims to discuss the economic benefits of a zero-carbon economy and an environmentally sustainable algae resource in decarbonizing the environment through the manufacture of algal-based biofuels from algae biomass for a range of potential uses. In addition, research on the algae biorefineries, with an emphasis on case studies for various cultivation methods, as well as the commercialization of biofuel and bioenergy. Overall, the algal biorefinery offers fresh potential for synthesizing various products.

Revalorization of Microalgae Biomass for Synergistic Interaction and Sustainable Applications: Bioplastic Generation

Microalgae and cyanobacteria are photosynthetic microorganisms’ sources of renewable biomass that can be used for bioplastic production. These microorganisms have high growth rates, and contrary to other feedstocks, such as land crops, they do not require arable land. In addition, they can be used as feedstock for bioplastic production while not competing with food sources (e.g., corn, wheat, and soy protein). In this study, we review the macromolecules from microalgae and cyanobacteria that can serve for the production of bioplastics, including starch and glycogen, polyhydroxyalkanoates (PHAs), cellulose, polylactic acid (PLA), and triacylglycerols (TAGs). In addition, we focus on the cultivation of microalgae and cyanobacteria for wastewater treatment. This approach would allow reducing nutrient supply for biomass production while treating wastewater. Thus, the combination of wastewater treatment and the production of biomass that can serve as feedstock for bioplastic production is discussed. The comprehensive information provided in this communication would expand the scope of interdisciplinary and translational research.

Microalgae Polysaccharides: An Alternative Source for Food Production and Sustainable Agriculture

Carbohydrates or polysaccharides are the main products derived from photosynthesis and carbon fixation in the Calvin cycle. Compared to other sources, polysaccharides derived from microalgae are safe, biocompatible, biodegradable, stable, and versatile. These polymeric macromolecules present complex biochemical structures according to each microalgal species. In addition, they exhibit emulsifying properties and biological characteristics that include antioxidant, anti-inflammatory, antitumor, and antimicrobial activities. Some microalgal species have a naturally high concentration of carbohydrates. Other species can adapt their metabolism to produce more sugars from changes in temperature and light, carbon source, macro and micronutrient limitations (mainly nitrogen), and saline stress. In addition to growing in adverse conditions, microalgae can use industrial effluents as an alternative source of nutrients. Microalgal polysaccharides are predominantly composed of pentose and hexose monosaccharide subunits with many glycosidic bonds. Microalgae polysaccharides can be structural constituents of the cell wall, energy stores, or protective polysaccharides and cell interaction. The industrial use of microalgae polysaccharides is on the rise. These microorganisms present rheological and biological properties, making them a promising candidate for application in the food industry and agriculture. Thus, microalgae polysaccharides are promising sustainable alternatives for potential applications in several sectors, and the choice of producing microalgal species depends on the required functional activity. In this context, this review article aims to provide an overview of microalgae technology for polysaccharide production, emphasizing its potential in the food, animal feed, and agriculture sector.

Microalgae-based bioplastics: Future solution towards mitigation of plastic wastes

Global demand for plastic materials has severely harm the environment and marine sea life. Therefore, bioplastics have emerged as an environmentally friendly alternative due to sustainability, minimal carbon footprint, less toxicity and high degradability. This review highlights the sustainable and environmentally friendly approach towards bioplastic production by utilizing microalgae as a feed source in several ways. First, the microalgae biomass obtained through the biorefinery approach can be processed into PHA under certain nutrient limitations. Additionally, microalgae biomass can act as potential filler and reinforcement towards the enhancement of bioplastic either blending with conventional bioplastic or synthetic polymer. The downstream processing of microalgae via suitable extraction and pre-treatment of bioactive compounds such as lipids and cellulose are found to be promising for the production of bioplastics. Moving on, the intermediate processing of bioplastic via lactic acid synthesized from microalgae has favoured the microwave-assisted synthesis of polylactic acid due to cost efficiency, minimum solvent usage, low energy consumption, and fast rate of reaction. Moreover, the reliability and effectiveness of microalgae-based bioplastics are further evaluated in terms of techno-economic analysis and degradation mechanism. Future improvement and recommendations are listed towards proper genetic modification of algae strains, large-scale biofilm technology, low-cost cultivation medium, and novel avocado seed-microalgae bioplastic blend.

Multiscale Mechanical Performance of Wood: From Nano- to Macro-Scale across Structure Hierarchy and Size Effects

This review describes methods and results of studying the mechanical properties of wood at all scales: from nano- to macro-scale. The connection between the mechanical properties of material and its structure at all these levels is explored. It is shown that the existing size effects in the mechanical properties of wood, in a range of the characteristic sizes of the structure of about six orders of magnitude, correspond to the empirical Hall-Petch relation. This “law” was revealed more than 60 years ago in metals and alloys and later in other materials. The nature, as well as the particular type of the size dependences in different classes of materials can vary, but the general trend, “the smaller the stronger”, remains true both for wood and for other cellulose-containing materials. The possible mechanisms of the size effects in wood are being discussed. The correlations between the mechanical and thermophysical properties of wood are described. Several examples are used to demonstrate the possibility to forecast the macromechanical properties of wood by means of contactless thermographic express methods based on measuring temperature diffusivity. The research technique for dendrochronological and dendroclimatological studies by means of the analysis of microhardness and Young’s modulus radial dependences in annual growth rings is described.

Swelling-based preparation of polypropylene nanocomposite with non-functionalized cellulose nanofibrils

Dispersion of nanofillers in a polymer matrix is one of the most important steps in preparing polymer nanocomposites. However, hydrophobic polymers and hydrophilic nanofillers are intrinsically incompatible, making it difficult to mix them homogeneously. Here, we propose the swelling-based particle adsorption method (SPA) providing a simple route to disperse cellulose nanofibrils (CNFs) within incompatible polypropylene (PP) matrix without surface functionalization of CNFs. The SPA enables CNFs to adsorb onto the surface of PP particles using a small amount of solvent. PP/CNFs composite films fabricated from the SPA showed increased Young's modulus by 80%, which agrees well with a theoretical prediction proving nano-dispersed. Furthermore, simply mixing a bit of polypropylene-graft-maleic anhydride can improve the tensile strength by 30% and the elongation at break by 10-fold than that of PP/CNFs composites. The SPA can be universally applied to any incompatible polymer-nanofiller pairs for the fabrication of nanocomposite materials.

Algal biopolymers as sustainable resources for a net-zero carbon bioeconomy

The era for eco-friendly polymers was ushered by the marine plastic menace and with the discovery of emerging pollutants such as micro-, nano-plastics, and plastic leachates from fossil fuel-based polymers. This review investigates algae-derived natural, carbon neutral polysaccharides and polyesters, their structure, biosynthetic mechanisms, biopolymers and biocomposites production process, followed by biodegradability of the polymers. The review proposes acceleration of research in this promising area to address the need for eco-friendly polymers and to increase the cost-effectiveness of algal biorefineries by coupling biofuel, high-value products, and biopolymer production using waste and wastewater-grown algal biomass. Such a strategy improves overall sustainability by lowering costs and carbon emissions in algal biorefineries, eventually contributing towards the much touted circular, net-zero carbon future economies. Finally, this review analyses the evolution of citation networks, which in turn highlight the emergence of a new frontier of sustainable polymers from algae.

Microalgal nanocellulose - opportunities for a circular bioeconomy

Over 3 billion years, photosynthetic algae have evolved complex uses for cellulose, the most abundant polymer worldwide. A major cell-wall component of lignocellulosic plants, seaweeds, microalgae, and bacteria, cellulose can be processed to nanocellulose, a promising nanomaterial with novel properties. The structural diversity of macro- and microalgal nanocelluloses opens opportunities to couple low-impact biomass production with novel, green-chemistry processing to yield valuable, sustainable nanomaterials for a multitude of applications ranging from novel wound dressings to organic solar cells. We review the origins of algal cellulose and the applications and uses of nanocellulose, and highlight the potential for microalgae as a nanocellulose source. Given the limited state of current knowledge, we identify research challenges and strategies to help to realise this potential.

Microalgae as Contributors to Produce Biopolymers

Biopolymers are very favorable materials produced by living organisms, with interesting properties such as biodegradability, renewability, and biocompatibility. Biopolymers have been recently considered to compete with fossil-based polymeric materials, which rase several environmental concerns. Biobased plastics are receiving growing interest for many applications including electronics, medical devices, food packaging, and energy. Biopolymers can be produced from biological sources such as plants, animals, agricultural wastes, and microbes. Studies suggest that microalgae and cyanobacteria are two of the promising sources of polyhydroxyalkanoates (PHAs), cellulose, carbohydrates (particularly starch), and proteins, as the major components of microalgae (and of certain cyanobacteria) for producing bioplastics. This review aims to summarize the potential of microalgal PHAs, polysaccharides, and proteins for bioplastic production. The findings of this review give insight into current knowledge and future direction in microalgal-based bioplastic production considering a circular economy approach. The current review is divided into three main topics, namely (i) the analysis of the main types and properties of bioplastic monomers, blends, and composites; (ii) the cultivation process to optimize the microalgae growth and accumulation of important biobased compounds to produce bioplastics; and (iii) a critical analysis of the future perspectives on the field.

Microwave-Assisted Defibrillation of Microalgae

The first production of defibrillated celluloses from microalgal biomass using acid-free, TEMPO-free and bleach-free hydrothermal microwave processing is reported. Two routes were explored: i. direct microwave process of native microalgae ("standard"), and ii. scCO2 pre-treatment followed by microwave processing. ScCO2 was investigated as it is commonly used to extract lipids and generates considerable quantities of spent algal biomass. Defibrillation was evidenced in both cases to afford cellulosic strands, which progressively decreased in their width and length as the microwave processing temperature increased from 160 °C to 220 °C. Lower temperatures revealed aspect ratios similar to microfibrillated cellulose whilst at the highest temperature (220 °C), a mixture of microfibrillated cellulose and nanocrystals were evidenced. XRD studies showed similar patterns to cellulose I but also some unresolved peaks. The crystallinity index (CrI), determined by XRD, increased with increasing microwave processing temperature. The water holding capacity (WHC) of all materials was approximately 4.5 g H2O/g sample. The materials were able to form partially stable hydrogels, but only with those processed above 200 °C and at a concentration of 3 wt% in water. This unique work provides a new set of materials with potential applications in the packaging, food, pharmaceutical and cosmetic industries.

Preparation of cellulose microfibril (CMF) from Gelidium amansii and feasibility of CMF as a cosmetic ingredient

Cellulose microfibrils (CMF) were successfully isolated from the red alga, Gelidium amansii. G. amansii was processed in two stages, microwave digestion and high-speed blending to remove agar and extract microfibrils, respectively. After pretreatment at 180 °C for 10 min, G. amansii containing 40.1 % glucan was microfibrillated through homogenization. Morphological analysis by SEM and FTIR, and analysis of the degree of fibrillation with water retention, sedimentation, and CtCBD3 protein binding of G. amansii-derived CMF were investigated. Functional analysis of CMF showed suppression of cyclooxygenase-2 expression in both in vitro and in vivo experiments. Additionally, suppression was evident in the: i) epidermal thickness of mice skin; ii) presence of proinflammatory cytokines; and iii) inhibition of JNK1/2 and p38 phosphorylation in human keratinocyte HaCaT cells. Such activity demonstrates its anti-inflammatory properties. The results in this study showed the possibility of using CMF derived from a red alga as an anti-inflammation material.

Physicochemical Characteristics of Cellulose Nanocrystals Derived from the Residue of Filamentous Microalga Tribonema utriculosum

Tribonema biomass is considered promising biorefinery feedstock for the co-production of biodiesel and valuable bioproducts; however, the extraction of these useful compounds produces large amounts of algal residues, which produce increased environmental concerns. Herein, cellulose was extracted from the waste residue of T. utriculosum via alkalization and bleaching, followed by the production of high-value-added cellulose nanocrystals (CNCs) via acid hydrolysis. The hydrolysis was performed with 60% (wt%) H₂SO₄ at a yield of 13.31%, resulting in the generation of rod-shaped nanoparticles averaging 39.5 nm in diameter and 239.2 nm in length. The structural characterization analysis revealed that the prepared CNCs had high crystallinity (73.0%) due to the removal of non-cellulose components and amorphous regions by chemical treatment, as well as possessing good aqueous suspension stability (zeta potential = - 40.1 mV). Although the CNCs showed lower thermal stability than extracted cellulose, they spanned a broader temperature range due to two-stage degradation behaviour, with higher residue weight (16.7%). This work represents the first report on the preparation of a high-value-added industrial product, CNCs, from the filamentous microalga T. utriculosum, aiming to maximize benefits from waste algal residue reutilization.

Hydrogel-Forming Algae Polysaccharides: From Seaweed to Biomedical Applications

With the increasing growth of the algae industry and the development of algae biorefinery, there is a growing need for high-value applications of algae-extracted biopolymers. The utilization of such biopolymers in the biomedical field can be considered as one of the most attractive applications but is challenging to implement. Historically, polysaccharides extracted from seaweed have been used for a long time in biomedical research, for example, agarose gels for electrophoresis and bacterial culture. To overcome the current challenges in polysaccharides and help further the development of high-added-value applications, an overview of the entire polysaccharide journey from seaweed to biomedical applications is needed. This encompasses algae culture, extraction, chemistry, characterization, processing, and an understanding of the interactions of soft matter with living organisms. In this review, we present algae polysaccharides that intrinsically form hydrogels: alginate, carrageenan, ulvan, starch, agarose, porphyran, and (nano)cellulose and classify these by their gelation mechanisms. The focus of this review further lays on the culture and extraction strategies to obtain pure polysaccharides, their structure-properties relationships, the current advances in chemical backbone modifications, and how these modifications can be used to tune the polysaccharide properties. The available techniques to characterize each organization scale of a polysaccharide hydrogel are presented, and the impact on their interactions with biological systems is discussed. Finally, a perspective of the anticipated development of the whole field and how the further utilization of hydrogel-forming polysaccharides extracted from algae can revolutionize the current algae industry are suggested.

Potential of an Automated- and Image-Based Cell Counter to Accelerate Microalgal Research and Applications

Efforts to achieve Sustainable Development Goals (SDGs) have resulted in enhancement of the position of microalgae in feedstocks for food, feed, healthcare, and biofuels. However, stabile microalgal biorefineries require a sustainable and reliable management system of microalgae, which are sensitive to environmental changes. To expand microalgal applicability, assessment and maintenance of microalgal quality are crucial. Compared with conventional methods, including hemocytometry and turbidity, an automated- and image-based cell counter contributes to the establishment of routine management of microalgae with reduced work burden. This review presents the principle of an automated cell counter and highlights the functional capacities of the device for microalgal management. The method utilizing fluorescence function to evaluate the chlorophyll integrity of microalgae may lay the groundwork for making a large variety of microalgal biorefineries, creating an important step toward achieving SDGs.

Thermal and Morphology Properties of Cellulose Nanofiber from TEMPO-oxidized Lower part of Empty Fruit Bunches (LEFB)

Cellulose nanofiber (CNF) gel has been obtained from TEMPO-oxidized differently treated lower part of empty fruit bunches (LEFB) of oil palm. Three kinds of materials were initially used: (i) α-cellulose, (ii) raw LEFB fiber two-times bleaching, and (iii) raw LEFB three-times bleaching. The obtained nanofibers (CNF1, CNF2 and CNF3, respectively) were then characterized using several methods, e.g. FT-IR, SEM, UV-Visible, TEM, XRD and TGA. The LEFB at different levels of bleaching showed that the Kappa number decreased with the increase of the bleaching levels. The decrease of lignin and hemicellulose content affected the increase of the yield of fibrillation and optical transmittance of CNF2 and CNF3 gels. The FT-IR analysis confirmed the presence of lignin and hemicellulose in the CNF2 and CNF3 film. Based on TEM analysis, the lignin and hemicellulose content significantly affected the particle structure of CNFs,i.e. CNF1 was found as a bundle of fibril, while the CNF2 and CNF3 were visualized as individual fibers and interwoven nanofibril overlapping each other, respectively. The XRD data of the CNF’s film showed that CNF2 and CNF3 have a lower crystallinity index (CI) than CNF1. The presence of lignin and hemicellulose in the CNFs decreased its decomposition temperature.

Thermoplastic Processing of PLA/Cellulose Nanomaterials Composites

Over the past decades, research has escalated on the use of polylactic acid (PLA) as a replacement for petroleum-based polymers. This is due to its valuable properties, such as renewability, biodegradability, biocompatibility and good thermomechanical properties. Despite possessing good mechanical properties comparable to conventional petroleum-based polymers, PLA suffers from some shortcomings such as low thermal resistance, heat distortion temperature and rate of crystallization, thus different fillers have been used to overcome these limitations. In the framework of environmentally friendly processes and products, there has been growing interest on the use of cellulose nanomaterials viz. cellulose nanocrystals (CNC) and nanofibers (CNF) as natural fillers for PLA towards advanced applications other than short-term packaging and biomedical. Cellulosic nanomaterials are renewable in nature, biodegradable, eco-friendly and they possess high strength and stiffness. In the case of eco-friendly processes, various conventional processing techniques, such as melt extrusion, melt-spinning, and compression molding, have been used to produce PLA composites. This review addresses the critical factors in the manufacturing of PLA-cellulosic nanomaterials by using conventional techniques and recent advances needed to promote and improve the dispersion of the cellulosic nanomaterials. Different aspects, including morphology, mechanical behavior and thermal properties, as well as comparisons of CNC- and CNF-reinforced PLA, are also discussed.

Cellulose defibrillation and functionalization by plasma in liquid treatment

Submerged liquid plasma (SLP) is a new and promising method to modify powder materials. Up to now, this technique has been mostly applied to carbonaceous materials, however, SLP shows great potential as a low-cost and environmental-friendly method to modify cellulose. In this work we demonstrate the modification of microcrystalline cellulose (MCC) by applying the SLP combined with ultrasonication treatments. The plasma generated either in an inert (argon) or reactive (argon: oxygen or argon:nitrogen) gas was used in MCC dispersions in water or acetonitrile:water mixtures. An enhanced defibrillation of MCC has been observed following the application of SLP. Furthermore, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy have been applied to investigate the surface functionalization of MCC with oxygen or nitrogen moieties. Depending on the plasma treatment applied, poly (3-hydroxybutyrate) composites fabricated with the plasma modified cellulose fibers showed better thermal stability and mechanical properties than pristine PHB. This submerged liquid plasma processing method offers a unique approach for the activation of cellulose for defibrillation and functionalization, aiming towards an improved reinforcing ability of biopolymers.