Biodegradable Plastics Research Articles

Stimulation of Purchase Behavior Toward Biodegradable Bags: The Role of Green Skepticism

Today, the habit of using light, durable, and disposable plastics that are poorly managed is one of the main reasons for environmental pollution, biodiversity loss, and climate change in Vietnam. Besides, due to the lack of consumption, most plastic companies in Vietnam refuse to switch their production to biodegradable plastic bags. The study is conducted to promote the purchase behavior of biodegradable plastic bags, which can reduce the consumption of non-degradable plastic in Vietnam. A non-probability sampling method was applied, with a sample size of 828 consumers who lived in Southeast Vietnam. SmartPLS software was applied to examine the hypotheses. The results show that attitudes, coping appraisal, and threat positively influence the purchase behavior of biodegradable plastic bags. Green skepticism negatively moderates the relationship between attitudes, coping appraisal, threat appraisal, and purchase intention toward biodegradable plastic bags. This study also added psychological factors, such as green skepticism, to fill the perception-behavior gap from previous studies and extend the protection-motivation theory. Some managerial implications will be proposed for plastic companies in Vietnam to switch their production toward biodegradable plastic bags. Besides, consumers will also be given guidance and encouragement to use these products through integrated marketing communication strategies. Doi: 10.28991/ESJ-2024-08-03-04 Full Text: PDF

Making biodegradable plastic with bacteria

Making biodegradable plastic with bacteria

Synthesis of Biodegradable Plastic Film from Chitosan-Glycerol with Cellulose Nanowhiskers of Coconut Coir as Reinforcing Agent

Abstract This research was conducted to synthesize biodegradable plastic films from chitosan and glycerol with the addition of cellulose nanowhiskers as a reinforcing agent. Cellulose synthesis of nanowhiskers from coconut husks was carried out with 3 phases, i.e., pre-treatment, bleaching, and sulphuric acid hydrolysis with a concentration of 55%. The result of cellulose hydrolysis in the form of needle-like nanowhiskers with an average of 223.6 nm particle size and a crystallinity index of 34.27% were shown through the results of FTIR, SEM, PSA, and XRD. Plastic film was made by blending method, which was mixing whole material then stirred until homogeneous and printed at room temperature. This study showed that the addition of cellulose nanowhiskers 3% can increase the tensile strength value up to 50 MpA, water resistance by 88.86%, and the biodegradation rate by 0.51 mg/day, but the value decreased if the addition of cellulose nanowhiskers was more than 3%. This was influenced by the rigid properties of cellulose nanowhiskers and experienced aggregation if it was added in excess. In conclusion, the addition of cellulose nanowhiskers with precise concentration can increase the tensile strength, water resistance, and the rate of biodegradation in the plastic film from chitosan-glycerol.

High-cell-density fed-batch strategy to manufacture tailor-made P(HB-co-HHx) by engineered Ralstonia eutropha at laboratory scale and pilot scale.

The transition towards a sustainable bioeconomy requires the development of highly efficient bioprocesses that enable the production of bulk materials at a competitive price. This is particularly crucial for driving the commercialization of polyhydroxyalkanoates (PHAs) as biobased and biodegradable plastic substitutes. Among these, the copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) (P(HB-co-HHx)) shows excellent material properties that can be tuned by regulating its monomer composition. In this study, we developed a high-cell-density fed-batch strategy using mixtures of fructose and canola oil to modulate the molar composition of P(HB-co-HHx) produced by Ralstonia eutropha Re2058/pCB113 at 1-L laboratory scale up to 150-L pilot scale. With cell densities >100 g L-1 containing 70-80 wt% of PHA with tunable HHx contents in the range of 9.0-14.6 mol% and productivities of up to 1.5 g L-1 h-1, we demonstrate the tailor-made production of P(HB-co-HHx) at an industrially relevant scale. Ultimately, this strategy enables the production of PHA bioplastics with defined material properties on the kilogram scale, which is often required for testing and adapting manufacturing processes to target diverse applications.

Synthesis of novel L-lactic acid-based plasticizers and their effects on the flexibility, crystallinity, and optical transparency of poly(lactic acid)

Using bio-based plasticizers derived from biomass resources to replace traditional phthalates can avoid the biotoxicity and non-biodegradability caused by the migration of plasticizers during the application of plastics. In this study, L-lactic acid and levulinic acid were employed as the major biomass monomer to successfully fabricate L-lactic acid-based plasticizers (LBL-n, n = 1.0, 1.5, 2.0, 2.5) containing a diverse number of lactate groups. The plasticizing mechanism was explained, manifesting that L-lactic acid-based plasticizers containing a substantial number of lactate groups could effectively improve the flexibility of poly (lactic acid) (PLA), and the elongation at break was 590 %–750 %. Compared to LBL-1.5 plasticized-PLA films, the tensile strength and modulus of ketonized-LBL-1.5 (KLBL-1.5) plasticized-PLA films increased to 59 % and 163 %, indicating the ketal functionality of plasticizers enhanced the strength of PLA. Meanwhile, the increment of lactate groups and the introduction of the ketal group in the plasticizer increased the crystallization, migration, and volatilization stability of plasticized-PLA films and also kept their outstanding optical transparency. Besides, the biodegradability of KLBL-1.5 was investigated by active soil and Tenebrio molitor experiments, and its degradation products were characterized. The findings indicated that KLBL-1.5 was fully decomposed. Taken together, this paper offers new promise for developing high-efficiency and biodegradable plasticizers.

Invasion of Trifolium repens L. aggravated by biodegradable plastics: adjustable strategy for foraging N and P

The invasion of alien plant and the pollution caused by soil microplastics have emerged as significant ecological threats. Recent studies have demonstrated aggravating effect of non-biodegradable microplastics on plant invasion. However, the impact of biodegradable microplastics (BMPs) on plant invasion remains unclear. Therefore, it is imperative to explore the impact of BMPs on plant invasion. In this study, a 30-day potting experiment with Trifolium repens L. (an invasive plant) and Oxalis corniculata L. (a native plant) was conducted to evaluate the influence of BMPs on T. repens's invasion. The findings revealed that BMPs results in a reduction in available N and P contents, thereby facilitating the colonization of arbuscular mycorrhizal fungi on T. repens 's roots. Consequently, T. repens adjusted its N and P foraging strategy by increasing P absorption ratio, and enhancing the accumulation of N and P in leaves. This ultimately led to the decrease of relative neighbor effect index of T. repens, indicating an aggravated invasion by T. repens. This study significantly enhances and expands the understanding of mechanisms by which microplastics aggravate plant invasion.

Plastiana Revolution: Tangents of Peels Converging the Dimensions of Bioplastic into Sustainable Treasure

To overcome the disastrous effects on the environment and human health due to plastic pollution, bioplastic is one of the most innovative and prominent alternatives for petroleum-based plastics. Bioplastics from organic waste, agriculture waste, vegetable oil, fruit, and vegetable stach are sustainable at the same time biodegradable. The present investigation gives insight into the synthesis of biodegradable plastic from Musa acuminata banana peels as it contains polymer chains called amylose and amylopectin which bond together to form bioplastic and also aim to study its characterization using FTIR, antibacterial, biodegradability, water solubility, and moisture content tests. From the observation, we found that the prepared bioplastic film with the optimum amount of plasticizer shows water solubility of about 3.27% which makes it worth commercial viability. With 100% biodegradability of prepared bioplastic within 42 days. Natural ingredients like lemon, neem, and Aloe Vera were added to further enhance its properties with the aim of creating an affordable yet natural product. The biofilm with lemon showed significant results in all the tests resisting water, microbes, and moisture. Through the antimicrobial properties of the bioplastic, a wider yield in films, bags, and wrappers can be acknowledged to reduce the use of plastics further. We believe that our research will play a pivotal role in the ongoing transition towards sustainable clean solutions and rejuvenate a compelling case for the adoption of bioplastic films, promoting a greener and more responsible approach to jeopardize plastic.

Conversion of Plastic Waste into Fuel by Pyrolysis

Abstract: Plastics have woven their way into our daily lives and now pose a tremendous threat to the environment. Over a 100 million tons of plastics are produced annually worldwide, and the used products have become a common feature at overflowing bins and landfills. Though work has been done to make futuristic biodegradable plastics, there have not been many conclusive steps towards cleaning up the existing problem. Here, the process of converting waste plastic into value added fuels is explained as a viable solution for recycling of plastics. Thus, two universal problems such as problems of waste plastic and problems of fuel shortage are being tackled simultaneously. In this study, plastic wastes (low density polyethylene) were used for the pyrolysis to get fuel oil that has the same physical properties as the fuels like petrol, diesel etc. Pyrolysis runs without oxygen and in high temperature of about 300°C which is why a reactor was fabricated to provide the required temperature for the reaction. The waste plastics are subjected to depolymerization, pyrolysis, thermal cracking and distillation to obtain different value-added fuels such as petrol, kerosene, and diesel, lube oil etc. Converting waste plastics into fuel hold great promise for both the environmental and economic scenarios. Thus, the process of converting plastics to fuel has now turned the problems into an opportunity to make wealth from waste.

Generation and Fate of Nanoplastics in the Intestine of Plastic-Degrading Insect (Tenebrio molitor Larvae) during Polystyrene Microplastic Biodegradation.

The insect Tenebrio molitor exhibits ultrafast efficiency in biodegrading polystyrene (PS). However, the generation and fate of nanoplastics (NPs) in the intestine during plastic biodegradation remain unknown. In this study, we investigated the biodegradation of PS microplastics (MPs) mediated by T. molitor larvae over a 4-week period and confirmed biodegradation by analyzing Δδ13C in the PS before and after biotreatment (-28.37‰ versus -24.88‰) as an effective tool. The ·OH radicals, primarily contributed by gut microbiota, and H2O2, primarily produced by the host, both increased after MP digestion. The size distribution of residual MP particles in excrements fluctuated within the micrometer ranges. PS NPs were detected in the intestine but not in the excrements. At the end of Weeks 1, 2, 3, and 4, the concentrations of PS NPs in gut tissues were 3.778, 2.505, 2.087, and 2.853 ng/lava, respectively, while PS NPs in glands were quantified at 0.636, 0.284, and 0.113 ng/lava and eventually fell below the detection limit. The PS NPs in glands remained below the detection limit at the end of Weeks 5 and 6. This indicates that initially, NPs generated in the gut entered glands, then declined gradually and eventually disappeared or possibly biodegraded after Week 4, associated with the elevated plastic-degrading capacities of T. molitor larvae. Our findings unveil rapid synergistic MP biodegradation by the larval host and gut microbiota, as well as the fate of generated NPs, providing new insights into the risks and fate associated with NPs during invertebrate-mediated plastic biodegradation.

Dual Application of p-Nitrophenol Alkanoate-Based Assay for Soil Selection and Screening of Microbial Strains for Bioplastic Degradation.

With an increase in the commercialization of bioplastics, the importance of screening for plastic-degrading strains and microbes has emerged. Conventional methods for screening such strains are time-consuming and labor-intensive. Therefore, we suggest a method for quickly and effectively screening plastic-degrading microbial strains through dual esterase assays for soil and isolated strains, using p-nitrophenyl alkanoates as substrates. To select microbe-abundant soil, the total amount of phospholipid fatty acids (PLFAs) included in each soil sample was analyzed, and esterase assays were performed for each soil sample to compare the esterase activity of each soil. In addition, by analyzing the correlation coefficients and sensitivity between the amount of PLFAs and the degree of esterase activity according to the substrate, it was confirmed that substrate pNP-C2 is the most useful index for soil containing several microbes having esterase activity. In addition, esterase assays of the isolated strains allowed us to select the most active strain as the degrading strain, and 16S rRNA results confirmed that it was Bacillus sp. N04 showed the highest degradation activity for polybutylene succinate (PBS) as measured in liquid culture for 7 days, with a degradation yield of 99%. Furthermore, Bacillus sp. N04 showed degradation activity against various bioplastics. We propose the dual application of p-nitrophenyl alkanoates as an efficient method to first select the appropriate soil and then to screen for plastic-degrading strains in it, and conclude that pNP-C2 in particular, is a useful indicator.

Enabling desired disposal of compostable plastic packaging: an evaluation of disposal instruction labels

Enabling desired disposal of compostable plastic packaging: an evaluation of disposal instruction labels

The Interaction of Microplastics and Microbioplastics with Soil and a Comparison of Their Potential to Spread Pathogens

Microplastics contribute to various environmental issues and serve as carriers for a wide range of toxic compounds such as pesticides, pharmaceuticals, and metal ions. Consequently, there is a gradual shift towards replacing them with biodegradable plastics (bioplastics). However, biodegradable plastics require specific conditions for complete biodegradation, and their biodeterioration often leads to the rapid production of smaller fragments, known as microbioplastics. In this review, we summarize selected issues related to the impact of plastic particles on soil properties and the soil microbiome. Findings from numerous studies indicate that both microplastics and microbioplastics induce adverse changes in soil microbiology, potentially increasing the abundance of soil-borne pathogens. Based on these observations, we argue that plastic particles could serve as carriers for colonies of soil-borne pathogens. Furthermore, the use of bioplastics may exacerbate this issue due to their easier and faster formation, increased support for biofilms, and more pronounced adverse effects on soil biota. However, further research is necessary to either substantiate or refute this perspective.

From raw microalgae to bioplastics: Conversion of Chlorella vulgaris starch granules into thermoplastic starch

Microalgae are emerging as a promising feedstock for bioplastics, with Chlorella vulgaris yielding significant amounts of starch. This polysaccharide is convertible into thermoplastic starch (TPS), a biodegradable plastic of industrial relevance. In this study, we developed a pilot-scale protocol for extracting and purifying starch from 430 g (dry weight – DW) of starch-enriched Chlorella vulgaris biomass. More than 200 gDW of starch were recovered, with an extraction yield and starch purity degree reaching 98 and 87 %, respectively. We have characterized this extracted starch and processed it into TPS using twin-screw extrusion and injection molding. Microalgal starch showed similar properties to those of native plant starch, but with smaller granules. We compared the mechanical properties of microalgal TPS with two controls, namely a commercial TPS and a TPS prepared from commercial potato starch granules. TPS prepared from microalgal starch showed a softer and more ductile behavior compared to the reference materials. This study demonstrates the feasibility of recovering high-purity microalgal starch at pilot scale with high yields, and highlights the potential of microalgal starch for the production of TPS using industrially relevant processes.

Biodegradation of polypropylene plastics in vitro and natural condition by Streptomyces sp. isolated from plastic-contaminated sites

Most plastic degradation studies are conducted under controlled laboratory conditions. The current study investigated the ability to degrade Polypropylene (PP) plastic by Streptomyces ardesiacus strain NBI0111 under both laboratory and natural conditions. This strain exhibited the ability to degrade PP when cultured in BH medium and using PP plastics as carbon sources. After a 90-day incubation period, the weight loss of PP plastics reached 17.52 % (p < 0.05). The surface of the PP plastic showed significant changes compared to the control group. Chemical changes in the plastic were also detected on the 60th and 90th days, as confirmed by FTIR and GC-MS analyses. This strain was applied to degrade PP plastic in soils under natural conditions. Strain NBI0111 also resulted in a notable weight loss. The biodegradation test group exhibited a significant 12.5 % decrease compared to only a 3.88 % decrease in the control group (p < 0.05). Furthermore, a strong positive correlation between the weight loss of PP plastic cups and the density of microbial populations was observed. The capabilities demonstrated by Streptomyces ardesiacus strain NBI0111 in this study hold great promise for on-site plastic remediation, offering a sustainable solution to the problem of plastic pollution in the future.

Using hyperspectral imaging to identify and classify large microplastic contamination in industrial composting processes

Compostable plastics are used as alternatives to conventional (non-compostable) plastics due to their ability to decompose through industrial composting comingled with food waste. However conventional (non-compostable) plastics sometimes contaminate this industrial composting process resulting in the formation of microplastics in the end compost. Therefore, it is crucial to effectively identify the types of plastics entering industrial composters to improve composting rates and enhance compost quality. In this study, we applied Hyperspectral Imaging (HSI) with various pre-processing techniques in the short-wave infrared (SWIR) region to develop an efficient model for identifying and classifying plastics and large microplastics during the industrial composting process. The materials used in the experimental analysis included compostable plastics such as PLA and PBAT, and conventional (non-compostable) plastics including PP, PET, and LDPE. Chemometric techniques, namely Partial Least Squares Discriminant Analysis (PLS-DA), was applied to develop a classification model. The Partial Least Squares Discriminant Analysis (PLS-DA) model effectively distinguished between virgin PP, PET, PBAT, PLA, and PHA plastics and soil-contaminated plastics measuring larger than 20 mm × 20 mm, achieving accuracy of 100%. Furthermore, it demonstrated a 90% accuracy rate in discriminating between pristine large microplastics and those contaminated with soil. When we tested our model on plastic samples during industrial composting we found that the accuracy of identification depended on parameters such as darkness, size, color, thickness and contamination level. Nevertheless, we achieved 85% for plastics and large microplastics detected within compost.

Development of biodegradable film from cactus (Opuntia Ficus Indica) mucilage loaded with acid-leached kaolin as filler

Nowadays, substituting petroleum-based plastics with biodegradable polymers made from polysaccharides loaded with various reinforcing materials has recently gained attention due to the impact of conventional plastics wastes. In this study, polysaccharidic mucilage from Ethiopian cactus (Opuntia Ficus Indica) was derived using microwave-assisted extraction technique to develop biodegradable polymers that were inexpensive, readily available, simple to make, and ecofriendly. The effect of microwave power 300–800 W, solid-liquid (cactus-sodium hydroxide solution) ratio 1:5–1:25, sodium hydroxide concentration 0.1–0.8 mol/L, and extraction time 2–10 min on mucilage extraction were studied and the maximum yield of mucilage was attained at optimized parameters of 506 W, 1:20, 0.606 mol/L, and 9.5 min, respectively. Biodegradable polymers made with mucilage alone have poor mechanical characteristics and are thermally unstable. Thus, to overcome the stated problems, glycerol as a plasticizer and acid-leached kaolin crosslinked with urea as a reinforcing material were used. Moreover, the effect of acid-leached kaolin and glycerol on the physico-chemical properties of the films was studied, and a maximum tensile strength of 6.74 MPa with 18.45 % elongation at break, thermally improved biodegradability of 26 %, were attained at 10 % acid-leached kaolin and 20 % glycerol crosslinking with 2 % urea. But the maximum degradability of 53.5 % was attained at 30 % glycerol content. The control and reinforced biodegradable films were characterized using TGA, FTIR, SEM, and XRD to determine the thermal, functional group, morphology, and crystallinity of the bioplastics, respectively. These biodegradable plastics may be used for packaging application.

Super-tough polylactic acid blends via tunable dynamic vulcanization of polyurethanes with ultrahigh bio-based content

Polylactic acid (PLA), a biodegradable plastic derived from renewable resources, is commercially available but has been limited in application owing to its inherent brittleness. To address this, researchers explored a reactive blending strategy using polyurethane (PU) to enhance PLA toughness. This method is straightforward and effective, yet most PUs are derived from petroleum or containing low bio-based content. Herein, we developed a bio-based PU (BPU) with double bonds for dynamic vulcanization to toughen PLA, using 1,3-polypropanediol (PO3G) and 1,5-pentane diisocyanate (PDI) with an ultrahigh bio-based content of 93.8 %. The toughness and tensile strength of the PLA/BPU blends were adjustable by modifying the BPU content. In particular, the toughness of the blends could reach 68.69 kJ/m2 by varying the amount of BPU. In addition, the BPU20–0.1 sample demonstrated an optimal balance of stiffness and toughness, exhibiting a tensile strength of 47.8 MPa and a notched impact strength of 54.86 kJ/m2. This research broadens the scope for toughening PLA using BPUs, thereby diminishing the dependency on petrochemical resources.

Incorporating Graphene Nanofiller for the Improvement of Hydrophobic Properties of Cassava Peel Starch Bioplastic

Cassava starch bioplastics have been known well as an alternative plastic replacing conventional petrochemical plastics, which have difficulty degrading rapidly in the environment. Cassava peels as waste is a potential eco-friendly starch source for biodegradable plastic. This study investigated the effect of graphene as a nanofiller on the hydrophobic properties of cassava peel starch film. Bioplastic was synthesized using the melt blending method by adding graphene in various amounts, which were 3 wt%, 5 wt%, and 7 wt%. Graphene was found to be able to increase the contact angle of the films up to 93° with the addition of 5 wt%. Graphene also affects water absorption properties. These results indicate that the hydrophobic properties of cassava peel starch films could be modified by adding graphene nanofiller.

Economic and carbon emission assessment of compostable plastics as a substitute for petrochemical plastics: a case study in Yunnan Province

Economic and carbon emission assessment of compostable plastics as a substitute for petrochemical plastics: a case study in Yunnan Province

Development of cellulose/ZnO based bioplastics with enhanced gas barrier, UV-shielding effect and antibacterial activity

Development of renewable and biodegradable plastics with good properties, such as the gas barrier, UV-shielding, solvent resistance, and antibacterial activity, remains a challenge. Herein, cellulose/ZnO based bioplastics were fabricated by dissolving cellulose carbamate in an aqueous solution of NaOH/Zn(OH)42−, followed by coagulation in aqueous Na2SO4 solution, and subsequent hot-pressing. The carbamate groups detached from cellulose, and ZnO which transformed from cosolvent to nanofiller was uniformly immobilized in the cellulose matrix during the dissolution/regeneration process. The appropriate addition of ZnO (below 10.67 wt%) not only improved the mechanical properties but also enhanced the water and oxygen barrier properties of the material. Additionally, our cellulose/ZnO based bioplastic demonstrated excellent UV-blocking capabilities, increased water contact angle, and enhanced antibacterial activity against S. aureus and E. coli, deriving from the incorporation of ZnO nanoparticles. Furthermore, the material exhibited resistance to organic solvents such as acetone, THF, and toluene. Indeed, the herein developed cellulose/ZnO based bioplastic presents a promising candidate to replace petrochemical plastics in various applications, such as plastic toys, anti-UV guardrails, window shades, and oil storage containers, offering a combination of favorable mechanical, gas barrier, UV-blocking, antibacterial, and solvent-resistant properties.