The motivation behind the work is stark. Global plastic consumption was estimated at 700 million tonnes in 2021, yet only about six percent of that material is recycled. Projections cited by the authors suggest that by 2050 worldwide plastic use could climb to between 753.5 and 832.4 million tonnes, with global recycling of plastic waste still languishing at roughly 13 percent. Because conventional petrochemical plastics do not biodegrade, they fragment into microparticles that contaminate ecosystems and can even enter the human food chain. Bioplastics made from renewable agricultural resources such as starch are an attractive alternative, but they suffer from two chronic weaknesses: they absorb water readily and they lack mechanical strength.

Starch is one of the cheapest and most abundant biopolymers available. Cassava, in particular, is a major crop in Cameroon, which produces more than five million tonnes of roots every year—about 40 percent of the world’s production. Yet most of that cassava is consumed as food, and the industrial starch market remains underdeveloped. The researchers, led by Herman Assonfack Lekane of the University of Yaoundé I, set out to upgrade cassava starch into a viable plastic by reinforcing it with acid-hydrolyzed cellulose derived from Ceiba pentandra, a tropical tree known locally as Eteng, and then modifying the resulting composite with acacia gum and bentonite.

The cellulose was extracted from Eteng wood and then treated with 60 percent sulfuric acid to produce acid-hydrolyzed cellulose, abbreviated NCE in the study. The acid dissolves the amorphous regions of cellulose, leaving behind highly crystalline nanoscale fibrils. Characterization by scanning electron microscopy revealed fibers only a few nanometers thick after treatment, while X-ray diffraction confirmed a higher crystallinity index for the hydrolyzed material than for the raw cellulose. Infrared spectroscopy detected new bands at 1264 and 804 per centimeter, signatures of sulfate ester groups grafted onto the cellulose surface during the acid reaction. These charged groups, measured at a density of 8 times ten to the minus six moles per gram by conductimetry, help the particles disperse and can enhance thermal stability.

Three film formulations were prepared and compared. The reference composite, labeled AN, combined five percent cassava starch suspension with glycerol as a plasticizer, sodium carbonate, and ten percent NCE relative to starch mass. A second formulation, ANG, added 12.5 percent acacia gum—an exudate from African Vachellia nilotica trees supplied by a traditional production unit in northern Cameroon. The third, ANBG, further incorporated 30 percent bentonite clay relative to starch mass. Each suspension was gelatinized at 70 degrees Celsius for 30 minutes, cast into molds, and dried at 50 degrees Celsius for three days.

The most striking result concerned water. When films were exposed to a humid atmosphere of 87 percent relative humidity, the reference starch-cellulose film absorbed water rapidly, reaching a maximum uptake of about 30 percent after 300 minutes. Adding acacia gum cut that figure to roughly 20 percent, and the gum-bentonite combination reduced it to about 10 percent—a reduction of 18 percent relative to the gum-only film and a dramatic improvement over the pristine composite. Infrared analysis explained why: the gum and clay form hydrogen bonds with the starch and cellulose chains, occupying the molecular sites that water molecules would otherwise bind to. The intensity of the hydroxyl stretching band and the free-water deformation band both dropped in the modified films, confirming tighter internal bonding and less adsorbed water.

Mechanical testing delivered equally impressive numbers. The reference film had a Young’s modulus of 39.9 megapascals and a tensile strength of 1.46 megapascals. With acacia gum added, the modulus soared to 150.7 megapascals and the tensile strength climbed to 7.14 megapascals—nearly a fivefold increase in stiffness. The researchers attribute this hardening effect to the gum’s chemical functionality, which improves adhesion between the starch matrix and the cellulose reinforcement. Small molecules from the gum appear to intercalate between polymer chains, facilitating chain sliding while simultaneously building a denser network of bonds. Interestingly, adding bentonite on top of the gum partially reversed the gains: the gum-clay film reached a modulus of 133.3 megapascals and a strength of 4.13 megapascals, still well above the reference but below the gum-only material. The clay particles appear to interfere with polymer-gum networking and to aggregate into fragile domains that limit elongation.

Thermal analysis added further nuance. Differential scanning calorimetry showed that the melting of the starch component, recorded at 133 degrees Celsius in the reference film, shifted to 171 degrees Celsius with gum and rose a further 24 degrees with the gum-bentonite combination. The gum retards melting by increasing hydrogen bonding within the film, while the mineral clay acts as a barrier to heat diffusion through the matrix. Thermogravimetric analysis, evaluated with the Broido model between 300 and 350 degrees Celsius, revealed that activation energies decreased from 76.9 kilojoules per mole for the reference film to 69.9 with gum and 66.7 with gum plus bentonite, indicating progressively weaker internal interactions as additives were introduced. The authors propose an ordering of interaction energies: starch-cellulose bonding is strongest, followed by the gum-modified and then the gum-clay systems. Bentonite’s contribution is therefore physical rather than chemical—a heat shield rather than a bonding agent.

Perhaps the most consequential finding relates to biodegradation. Films were buried in soil from Mbalmayo in central Cameroon, with a pH of 5.1 and a composition of 65 percent sand, 29 percent clay and 21 percent silt, at 80 percent relative humidity and 25 degrees Celsius. Mass loss increased with burial time in all films, but the gum-containing formulations degraded noticeably more slowly. Because the microorganisms that decompose these materials depend on moisture, the reduced water uptake of the modified films starves them of the conditions they need to thrive. Bentonite further slows the process by drawing migrating water into the clay phase, leaving less available in the carbohydrate region where microbes operate. The authors suggest this controlled degradation could be a feature rather than a flaw: films that persist long enough to be useful but still break down naturally at end of life.

The study positions acacia gum as a genuine bio-hardener for starch-based plastics, echoing earlier work showing that African tree exudates can harden tannin-based wood adhesives. Because the gum is a natural, locally available material, it preserves the biodegradability of the composite while delivering performance that synthetic additives struggle to match. The gum-bentonite pairing, though less effective mechanically, offers a distinct advantage in moisture control and degradation management, pointing toward applications in food packaging, where limiting water uptake also limits bacterial growth. The authors note that the gum-bentonite films could serve for more than 200 minutes in highly humid conditions with less than 10 percent water uptake. For a field searching for sustainable materials that balance strength, cost and environmental fate, the message is clear: sometimes the answers are literally dripping from the trees.

Beyond the headline results, the study offers a useful reminder of how locally sourced materials can shape materials science outcomes. The acacia exudate used in the films came from a traditional production unit in northern Cameroon, meaning the hardening additive required no synthetic chemistry to obtain. Similarly, the bentonite and glycerol were standard commercial reagents, while the starch itself was extracted from cassava tubers softened in water for five days, washed, filtered, and air-dried at ambient temperature. The entire production chain relies on low-energy processing, with gelatinization carried out at just 70 degrees Celsius and drying at 50 degrees Celsius over three days.

The choice of Ceiba pentandra as the cellulose source is also notable. The tree, identified with assistance from the National Herbarium in Yaoundé, was collected in Mbalmayo, the same region whose soil later served as the biodegradation medium. Acid hydrolysis of the extracted cellulose followed established protocols, using repeated hot-water washing cycles, neutralization with dilute sodium hydroxide, ultrasonic dispersion, and freeze-drying to yield the final NCE powder. This level of procedural detail matters for reproducibility, since the surface chemistry of hydrolyzed cellulose, including its sulfate ester content, strongly influences how well the particles bond with a starch matrix.

Methodologically, the team combined a broad characterization toolkit: Fourier transform infrared spectroscopy and X-ray diffraction confirmed the presence and interactions of the additives, while coupled thermal analysis probed melting behavior and decomposition kinetics. Moisture uptake was tracked over 700 minutes in a controlled 87 percent relative humidity chamber, and mechanical response was quantified through stress-strain testing. The convergence of evidence from these independent techniques strengthens the authors’ interpretation that acacia gum acts primarily as a bonding agent between polymer chains, whereas bentonite functions as a physical barrier to both heat and water transport within the composite films.

Subject of Research: Effects of acacia gum and bentonite additives on the mechanical, thermal, moisture and biodegradation properties of cassava starch and acid-hydrolyzed cellulose composite bioplastics

Article Title: Effects of acacia gum and bentonite on the properties of composite bioplastics made of starch and acid hydrolyzed cellulose

Article References: Assonfack Lekane, H., Cheumani Yona, A. M., Tsague, F. L., Abo, T. M., Kuete, M. A., Ndinteh, D. T., Mbey, J. A., & Ndikontar, M. K. (2026). Effects of acacia gum and bentonite on the properties of composite bioplastics made of starch and acid hydrolyzed cellulose. Discover Industrial Chemistry and Materials, 1(1), Article 15. https://doi.org/10.1007/s44508-026-00014-x

Image Credits: AI Generated

DOI: 10.1007/s44508-026-00014-x

Keywords: bioplastics, cassava starch, acid-hydrolyzed cellulose, acacia gum, bentonite, biodegradation, moisture absorption, Young's modulus, hydrogen bonding, thermal stability, nanocellulose, sustainable materials

Plastic production has surged exponentially over recent decades, with global output reaching nearly 400 million metric tons in 2022. This prolific growth underpins the material’s critical role in sectors such as packaging, agriculture, and consumer goods. Yet, the environmental toll from petrochemical feedstocks extraction and the accumulation of plastic waste jeopardizes ecological stability and public health. Against this backdrop, plant-based biocomposites are gaining traction as feasible, sustainable alternatives, with hemp emerging as a standout candidate due to its rapid growth rate, carbon sequestration capability, and inherent biodegradability.

While hemp fiber has attracted attention for industrial uses, the hurd—the inner woody core constituting almost half of the hemp plant’s biomass—has historically been undervalued. Typically relegated to low-value uses or waste streams, hemp hurd represents an untapped resource rich in cellulose and lignocellulosic content, which could be mechanically processed into high-performance microfibers. Such valorization not only improves resource efficiency but also aligns with circular economy principles by integrating agricultural residues into material supply chains without disrupting fiber markets.

In a groundbreaking study published in the Journal of Bioresources and Bioproducts, a team of researchers from the Korea Research Institute of Chemical Technology embarked on a comprehensive investigation of hemp hurd-based microfiber biocomposites. Employing both dry and wet milling techniques coupled with micro-fibrillation processes, they isolated refined hemp hurd fibers and integrated them into two prototype bioplastic products: packaging films incorporating polylactic acid (PLA) and agricultural mulch films blended with starch-based thermoplastics (TPS) and poly(butylene adipate-co-terephthalate) (PBAT). Mechanical characterization revealed that hemp microfiber inclusion enhanced tensile strength by approximately 20% in packaging films and an impressive 33% in mulch films relative to conventional materials, indicating robust reinforcement effects.

Crucially, the environmental implications of these biocomposites were evaluated through a rigorous cradle-to-grave Life Cycle Assessment (LCA), extending beyond mere production to encompass hemp cultivation, fiber processing, composite fabrication, transport logistics, consumer usage, and end-of-life treatment. The study contextualized its findings within South Korea’s national waste management framework, analyzing four disposal scenarios: incineration with energy recovery, incineration without energy recovery, industrial composting, and anaerobic digestion, juxtaposed against landfill disposal as the baseline.

Among these pathways, anaerobic digestion emerged as the superior end-of-life treatment, exhibiting the lowest global warming potential due to its capacity to convert biogas into electrical energy, thereby offsetting fossil energy use. Furthermore, the residual digestate presents value as an organic soil conditioner, closing nutrient loops and fostering sustainable agriculture. Quantitatively, this method achieved a substantial reduction in CO₂ emissions, approximately 6.1 kilograms per kilogram of mulch film processed, showcasing the tangible climate benefits of integrating biological waste-to-energy systems.

In contrast, industrial composting, while environmentally progressive compared to incineration, incurred higher direct carbon emissions linked to the energy-intensive nature of thermal treatments—even when accounting for electricity recovered from combustion. Notably, incineration without power recovery manifested as an environmentally unfavorable option, and conventional landfilling displayed the poorest environmental performance attributable to methane emissions and insufficient gas capture, buttressing South Korea’s strategic emphasis on minimizing landfill reliance.

The study also articulated optimization strategies within composite manufacturing—specifically advocating increased hemp microfiber content coupled with elevated biopolyester proportions to maximize carbon sequestration and emissions savings. Projections indicated potential reductions reaching 4.25 kilograms of CO₂ per kilogram of mulch film in optimized formulations, signifying considerable advancements in ecological footprint minimization achievable through material engineering.

Manufacturing methodologies further influenced environmental outcomes, as highlighted by the drying stage of microfiber production. Oven drying demonstrated lower environmental impacts relative to spray drying, mainly because the latter’s reliance on coal combustion and elevated electricity demand inflated associated carbon emissions. This finding underscores the critical role of process design choices in attaining sustainable material production and substantiates the importance of integrating clean energy solutions throughout manufacturing supply chains.

Beyond emission reductions, the research addresses broader systemic issues tied to circular economies and agricultural waste valorization. Utilizing hemp hurd for biocomposite fabrication sidesteps the extraction pressures on hemp fiber markets, ensuring that fiber availability for conventional applications remains unaffected while simultaneously converting a former waste stream into high-value products. This strategy epitomizes sustainable resource management, fostering enhanced economic and environmental resilience.

Ultimately, the study’s authors conclude that hemp hurd-based biocomposites, when synergized with appropriate disposal technologies like anaerobic digestion, present not only a technically feasible but also environmentally advantageous alternative to conventional fossil-derived plastics. As global energy infrastructures advance toward decarbonization and biological waste management infrastructure expands, such bio-based materials are poised to become integral components of sustainable packaging and agriculture, offering scalable solutions to some of the most pressing environmental challenges of our era.

This research represents an important stride toward closing material loops and reimagining biomass residues as critical inputs in bioeconomies. The multidisciplinary approach combining mechanical innovation with lifecycle environmental evaluation exemplifies the pathways required to transition toward truly sustainable plastic alternatives, blending scientific rigor with actionable societal impact. As demand for resilient and eco-friendly material solutions escalates worldwide, hemp hurd biocomposites stand out as a compelling candidate capable of mitigating climate change while promoting circular bioeconomy principles.

Subject of Research: Not applicable

Article Title: Environmental Life Cycle Assessment of Hemp Hurd-Based Biocomposites for Packaging and Mulch Film Applications

News Publication Date: 25-Apr-2026

Web References: http://dx.doi.org/10.1016/j.jobab.2026.100264

Image Credits: Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), Ulsan 44429, South Korea

Keywords: Biomass, Environmentalism, Energy resources conservation, Plastics, Composite materials, Fibers, Plant products, Materials engineering, Research methods, Thin films, Surface science

Plastics dominate the global market due to their versatility and durability; however, their reliance on non-renewable petroleum sources and their inability to biodegrade contribute significantly to environmental degradation. As organizations and researchers seek alternatives that can alleviate these issues, the focus shifts towards finding biodegradable materials that do not compromise on performance. PDCA emerges as a promising candidate due to its remarkable physical properties that compete with those of traditional plastics. It possesses qualities that could rival even the most commonly used petroleum-derived products, thus paving the way for its potential integration into various industries.

The research group, led by bioengineer TANAKA Tsutomu, has taken an innovative approach to bioengineer E. coli to produce PDCA. Traditionally, the production of biodegradable plastics has been fraught with challenges related to the yield and purity of the materials produced. This study showcases a novel method for producing PDCA at concentrations that exceed previous benchmarks by more than seven-fold. The researchers emphasize that their method also eliminates unwanted byproducts, making the synthesis cleaner and more efficient.

At the core of this research is the team’s ability to harness cellular metabolism effectively. While many biomass-based strategies focus on synthesizing compounds primarily composed of carbon, hydrogen, and oxygen, the team took a bold step to include nitrogen in their production process. This strategic choice is crucial, as nitrogen-containing compounds have shown immense potential in enhancing the properties of plastics. By developing a mechanism to incorporate nitrogen into PDCA without the hindrance of byproducts, the researchers opened avenues to optimize the molecular composition of high-performance plastics.

Despite the excitement surrounding their findings, Tanaka and his team encountered several hurdles along the way, particularly concerning the production process. One significant challenge was a bottleneck related to the introduction of a specific enzyme that inadvertently generated hydrogen peroxide, a compound known for its reactivity. This reactive oxygen species posed a risk by attacking the very enzyme responsible for its production, leading to decreased efficacy in the synthesis process. To address this, the researchers refined the culture conditions, incorporating a scavenging agent that helped neutralize hydrogen peroxide. While this solution effectively overcame the immediate issue, it also presents future economic and logistical considerations for large-scale production.

The implications of this research extend beyond the laboratory. As the global community faces escalating problems related to plastic waste, the potential for environmentally friendly materials becomes increasingly critical. The ability to produce PDCA in sufficient quantities creates a solid foundation for commercial-scale applications. Moreover, Tanaka highlights how this research expands the toolbox for bio-manufacturing, allowing for the potential development of a wider array of biodegradable materials that could meet the demands of various consumer products.

As the quest for sustainable alternatives to traditional plastics continues, the techniques demonstrated in this study may serve as a blueprint for future endeavors in material science. The convergence of bioengineering with material innovation is paving the way for a new paradigm where sustainability is at the forefront of product development. This research not only addresses current environmental concerns but also offers an opportunity for industries reliant on plastics to rethink their materials and sourcing practices.

The advancement of PDCA production techniques underscores the significance of interdisciplinary collaboration in solving complex global challenges. Institutions like Kobe University are investing in research that blends social sciences and natural sciences to cultivate leaders capable of transformative change. By fostering innovation and supporting research initiatives that prioritize sustainability, universities are setting the stage for a future where environmental considerations are integral to the development of new technologies.

The journey toward the widespread implementation of PDCA and similar biodegradable materials is not without its challenges. However, the improvements in production methodologies described in this study indicate a promising future for bioplastics. The groundwork laid by Tanaka and his team is a testament to what can be achieved through dedication and ingenuity in research.

In summary, the successful production of PDCA offers a compelling narrative in the ongoing effort to address the environmental impacts of plastic. As researchers continue to explore the intricacies of microbial metabolism and synthesizing complex compounds, the potential for creating sustainable materials that meet performance expectations while being biodegradable continues to grow. As we advance, the lessons learned from this research may inspire further innovations, ensuring that future generations are equipped with the tools needed for a sustainable ecosystem.

As this work progresses, it is vital to maintain a focus on practical applications, scalability, and cost-effectiveness, ensuring that this bioengineered solution can transition from laboratory excellence to everyday usage. The strides made by Kobe University in the field of biodegradable plastics may very well be a turning point in how society approaches the challenges posed by plastic waste in our environment.

Subject of Research: Cells
Article Title: Biosynthesis of 2,5-pyridinedicarboxylate from glucose via p-aminobenzoic acid in Escherichia coli
News Publication Date: 25-Aug-2025
Web References: Metabolic Engineering Journal DOI
References: Not available.
Image Credits: Credit: TANAKA Tsutomu

Keywords

Biodegradable Plastics, PDCA, Bioengineering, E. coli, Sustainable Materials, Environmental Impact, Microbial Synthesis, Biotechnology, Kobe University, Hydrogen Peroxide, Nitrogen Metabolism.