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Keywords = circular plastic bioeconomy

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18 pages, 4319 KiB  
Article
Exploring the Synthesis of Lactic Acid from Sugarcane Molasses Collected in Côte d’Ivoire Using Limosilactobacillus fermentum ATCC 9338 in a Batch Fermentation Process
by Asengo Gerardin Mabia, Harinaivo Anderson Andrianisa, Chiara Danielli, Leygnima Yaya Ouattara, N’da Einstein Kouadio, Esaïe Kouadio Appiah Kouassi, Lucia Gardossi and Kouassi Benjamin Yao
Bioengineering 2025, 12(8), 817; https://doi.org/10.3390/bioengineering12080817 - 29 Jul 2025
Viewed by 244
Abstract
Lactic acid (LA) is a high-value chemical with growing demand for the production of polymers and plastics and in the food and pharmaceutical industries. However, production costs remain a significant constraint when using conventional food-grade substrates. This study investigates Ivorian sugarcane molasses, an [...] Read more.
Lactic acid (LA) is a high-value chemical with growing demand for the production of polymers and plastics and in the food and pharmaceutical industries. However, production costs remain a significant constraint when using conventional food-grade substrates. This study investigates Ivorian sugarcane molasses, an abundant agro-industrial by-product, as a low-cost carbon source for LA production via batch fermentation with Limosilactobacillus fermentum ATCC 9338. Molasses was pretreated by acid hydrolysis to improve fermentability, increasing glucose and fructose concentrations. Comparative fermentations using raw and pretreated molasses showed a 75% increase in LA production (32.4 ± 0.03 g/L) after pretreatment. Optimisation using Box–Behnken design revealed that the initial sugar concentration, inoculation rate, and stirring speed significantly influenced lactic acid production. Under optimal conditions, a maximum LA concentration of 52.4 ± 0.49 g/L was achieved with a yield of 0.95 g/g and productivity of 0.73 g/L·h. Kinetic analysis confirmed efficient sugar utilisation under the optimised conditions, and polarimetry revealed a near-racemic lactic acid. A simplified cost analysis showed that molasses could reduce carbon source costs by over 70% compared to refined sugars, supporting its economic viability. This work demonstrates the potential of pretreated molasses under robust fermentation conditions as a sustainable and cost-effective substrate for LA production in resource-limited contexts. The approach aligns with circular bioeconomy principles and presents a replicable model for decentralised bioproduction in a developing country like Côte d’Ivoire. Full article
(This article belongs to the Special Issue Development of Biocatalytic Processes and Green Energy Technologies)
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44 pages, 10756 KiB  
Review
The Road to Re-Use of Spice By-Products: Exploring Their Bioactive Compounds and Significance in Active Packaging
by Di Zhang, Efakor Beloved Ahlivia, Benjamin Bonsu Bruce, Xiaobo Zou, Maurizio Battino, Dragiša Savić, Jaroslav Katona and Lingqin Shen
Foods 2025, 14(14), 2445; https://doi.org/10.3390/foods14142445 - 11 Jul 2025
Viewed by 723
Abstract
Spice by-products, often discarded as waste, represent an untapped resource for sustainable packaging solutions due to their unique, multifunctional, and bioactive profiles. Unlike typical plant residues, these materials retain diverse phytochemicals—including phenolics, polysaccharides, and other compounds, such as essential oils and vitamins—that exhibit [...] Read more.
Spice by-products, often discarded as waste, represent an untapped resource for sustainable packaging solutions due to their unique, multifunctional, and bioactive profiles. Unlike typical plant residues, these materials retain diverse phytochemicals—including phenolics, polysaccharides, and other compounds, such as essential oils and vitamins—that exhibit controlled release antimicrobial and antioxidant effects with environmental responsiveness to pH, humidity, and temperature changes. Their distinctive advantage is in preserving volatile bioactives, demonstrating enzyme-inhibiting properties, and maintaining thermal stability during processing. This review encompasses a comprehensive characterization of phytochemicals, an assessment of the re-utilization pathway from waste to active materials, and an investigation of processing methods for transforming by-products into films, coatings, and nanoemulsions through green extraction and packaging film development technologies. It also involves the evaluation of their mechanical strength, barrier performance, controlled release mechanism behavior, and effectiveness of food preservation. Key findings demonstrate that ginger and onion residues significantly enhance antioxidant and antimicrobial properties due to high phenolic acid and sulfur-containing compound concentrations, while cinnamon and garlic waste effectively improve mechanical strength and barrier attributes owing to their dense fiber matrix and bioactive aldehyde content. However, re-using these residues faces challenges, including the long-term storage stability of certain bioactive compounds, mechanical durability during scale-up, natural variability that affects standardization, and cost competitiveness with conventional packaging. Innovative solutions, including encapsulation, nano-reinforcement strategies, intelligent polymeric systems, and agro-biorefinery approaches, show promise for overcoming these barriers. By utilizing these spice by-products, the packaging industry can advance toward a circular bio-economy, depending less on traditional plastics and promoting environmental sustainability in light of growing global population and urbanization trends. Full article
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18 pages, 5617 KiB  
Article
Static Magnetic Field Increases Polyhydroxyalkanoates Biosynthesis in Haloferax mediterranei: Parameter Optimization and Mechanistic Insights from Metabolomics
by Ze-Liang Gao and You-Wei Cui
Polymers 2025, 17(9), 1190; https://doi.org/10.3390/polym17091190 - 27 Apr 2025
Viewed by 581
Abstract
Polyhydroxyalkanoates (PHAs), as biosynthetic and biodegradable polymers, serve as alternatives to petroleum-based plastics, yet face critical cost barriers in large-scale production. While magnetic field (MF) stimulation enhances microbial activity, the optimal MF parameters and metabolic mechanisms for PHA biosynthesis remain unexplored. This study [...] Read more.
Polyhydroxyalkanoates (PHAs), as biosynthetic and biodegradable polymers, serve as alternatives to petroleum-based plastics, yet face critical cost barriers in large-scale production. While magnetic field (MF) stimulation enhances microbial activity, the optimal MF parameters and metabolic mechanisms for PHA biosynthesis remain unexplored. This study optimized magnetic field parameters to increase PHA biosynthesis in Haloferax mediterranei. A custom-engineered electromagnetic system identified 110 mT of static magnetic field (SMF) as the optimal level for biosynthesis, reaching 77.97 mg/(L·h) PHA volumetric productivity. A pulsed magnetic field caused oxidative stress and impaired substrate uptake despite increasing PHA synthesis. Prolonged SMF exposure (72 h) maximized PHA productivity, while 48 h of exposure attained 90% efficiency. Metabolomics revealed that SMF-driven carbon flux redirection via regulated butanoate metabolism led to a 2.10-fold increase in (R)-3-hydroxybutanoyl-CoA), while downregulating acetoacetate (0.51-fold) and suppressing PHA degradation (0.15-fold). This study pioneers the first application of metabolomics in archaea to decode SMF-induced metabolic rewiring in Haloferax mediterranei. Our findings establish SMF as a scalable bioenhancement tool, offering sustainable solutions for the circular bioeconomy. Full article
(This article belongs to the Section Biobased and Biodegradable Polymers)
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40 pages, 2483 KiB  
Review
Valorization of Agri-Food Waste into PHA and Bioplastics: From Waste Selection to Transformation
by Marta Arriaga, Francisco Javier Pinar, Irene Izarra, Jesús del Amo, Javier Vicente, Francisco Jesús Fernández-Morales and Javier Mena
Appl. Sci. 2025, 15(3), 1008; https://doi.org/10.3390/app15031008 - 21 Jan 2025
Cited by 3 | Viewed by 3118
Abstract
The valorization of agri-food waste is a pivotal component in developing the circular economy, wherein waste is given a second life through various conversion technologies. This review aims to provide an overview of the current state of knowledge on the valorization of agri-food [...] Read more.
The valorization of agri-food waste is a pivotal component in developing the circular economy, wherein waste is given a second life through various conversion technologies. This review aims to provide an overview of the current state of knowledge on the valorization of agri-food waste, with a particular focus on volatile fatty acids (VFAs) and subsequent bioplastics production. To this end, a comprehensive literature search was conducted using specialist bibliographic databases. The study primarily focuses on reviewing the biological production of PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)), a type of PHA, due to its relevance as a substitute for fossil-based plastics. Significant attention has been directed toward exploring the potential of agri-food wastes, such as whey, potato peelings, and brewery bagasse, as raw materials for their transformation into a tailor-made VFA solution, rich in valeric and propionic acids. Additionally, existing operational strategies and waste co-treatments have been reviewed. The produced VFAs present multiple applications, including single-cell oils, Omega-3-rich oils, and different types of PHA. Factors influencing the bio-polymerization of VFAs to PHBV, such as the type of substrate, operating conditions (pH and retention time), and the presence of specific microorganisms, have also been reviewed. Due to its physicochemical properties, PHBV has applications in sectors such as agriculture and packaging. This review concludes that transforming agri-food waste into PHBV has the potential to integrate environmental and economic benefits within a circular bioeconomy model, fostering technological innovation and the sustainable use of waste resources. Full article
(This article belongs to the Section Energy Science and Technology)
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19 pages, 1712 KiB  
Article
Circular Economy and Technological Innovation in the Forest-Based Sector: A Study on Wood–Plastic Composites Business Plan and Cost Calculations
by Mária Osvaldová and Marek Potkány
Forests 2025, 16(1), 52; https://doi.org/10.3390/f16010052 - 30 Dec 2024
Cited by 2 | Viewed by 1150
Abstract
It is currently essential to seek innovative solutions for sustainability and the efficient use of resources, rooted in bioeconomy principles and linked to the concepts of the circular economy. Technological innovations supporting the production of wood–plastic composites, using recycled materials, reduce the ecological [...] Read more.
It is currently essential to seek innovative solutions for sustainability and the efficient use of resources, rooted in bioeconomy principles and linked to the concepts of the circular economy. Technological innovations supporting the production of wood–plastic composites, using recycled materials, reduce the ecological footprint. The aim of the study was to present conclusions of the evaluation of the business plan concept’s effectiveness and to propose applications of traditional and innovative cost calculations resulting from the implementation of technological innovations in the production of wood–plastic composites in the forest-based sector in accordance with the principles of the circular economy. Using dynamic methods for evaluating business plan net present value, profitability index, internal rate of return, and discounted payback period, positive recommendations for project rentability were identified under both realistic and pessimistic scenarios. By applying traditional markup calculation, material cost savings of EUR 3.99/m3 were quantified, representing a relative saving of over 2% compared to traditional particle board. Verification of alternative machine hour rate calculation allows for more precise allocation of overhead costs into product pricing and provides the ability to respond swiftly to changes in input parameters. The findings have practical implications for the forest-based sector, as the use of recycled plastics can reduce production costs and increase the competitiveness of production. Full article
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25 pages, 1406 KiB  
Review
An Overview on Bioeconomy in Agricultural Sector, Biomass Production, Recycling Methods, and Circular Economy Considerations
by Ioana-Maria Toplicean and Adina-Daniela Datcu
Agriculture 2024, 14(7), 1143; https://doi.org/10.3390/agriculture14071143 - 15 Jul 2024
Cited by 18 | Viewed by 4587
Abstract
This review examines the essential components of a circular economy (CE) in relation to the agricultural sector. The bioeconomy and circular economy are crucial for sustainable global industrial growth, focusing on closed-loop systems. The sustainability debate centers on intergenerational equity and natural capital. [...] Read more.
This review examines the essential components of a circular economy (CE) in relation to the agricultural sector. The bioeconomy and circular economy are crucial for sustainable global industrial growth, focusing on closed-loop systems. The sustainability debate centers on intergenerational equity and natural capital. The CE requires new environmental technologies and global coordination in order to combat climate change and biodiversity loss. In addition, efficient food production and waste reduction are essential due to population growth. However, biomass is vital for a bio-based economy, impacting food waste and climate change. Grasslands support sustainable dairy production and carbon sequestration. Thus, effective waste and wastewater management are critical, with biomass energy providing renewable alternatives. Nonetheless, biofuels remain key for sustainability, focusing on pollution control and Green Chemistry. It is well known that sustainable transportation relies on bioenergy, with ongoing research improving processes and discovering new fuels. One notable challenge is managing heavy metals in biofuel production, and this underscores the need for eco-friendly energy solutions. The main purpose for this review paper is to create a connection between circular economy aspects and the agricultural system, with focus on the following: bioeconomy research, biomass utilities, and biofuel production. Extensive research was performed on the specialized literature by putting in common the main problems. Key subjects in this paper include the use of biomass in agriculture, the problems of plastic recycling, and the function of the CE in mitigating climate change and biodiversity loss. Efficient food production and waste minimization are highlighted due to their relevance in a growing population. The study’s detailed research and discussion aim to give important insights into how these practices might promote economic development and sustainability. Furthermore, the study covers important waste management issues such as food waste, plant composting, and chemical waste neutralization. These topics are critical to understanding the circular economy’s broader implications for minimizing environmental damage and implementing sustainable waste management strategies. Full article
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18 pages, 2395 KiB  
Article
Polyhydroxyalkanoate Production by Actinobacterial Isolates in Lignocellulosic Hydrolysate
by Dzunani Mabasa, Amrita Ranjan, Marilize Le Roes-Hill, Thandekile Mthethwa and Pamela Jean Welz
Processes 2024, 12(6), 1112; https://doi.org/10.3390/pr12061112 - 28 May 2024
Cited by 2 | Viewed by 1756
Abstract
Polyhydroxyalkanoate (PHA) polymers are environmentally friendly alternatives to conventional plastics. In support of a circular bioeconomy, they can be produced by growing microbial strains in waste materials, including lignocellulosic biomass, such as Canola fines (straw). In this study, PHA and polyhydroxybutyrate (PHB) production [...] Read more.
Polyhydroxyalkanoate (PHA) polymers are environmentally friendly alternatives to conventional plastics. In support of a circular bioeconomy, they can be produced by growing microbial strains in waste materials, including lignocellulosic biomass, such as Canola fines (straw). In this study, PHA and polyhydroxybutyrate (PHB) production by a selection of seven wild-type actinobacterial strains, including three strains of Gordonia species, were assessed. When grown in defined media and hydrolysates of Canola fines, the highest amounts of PHB were produced by Nocardia gamkensis CZH20T (0.0476 mg/mL) and Gordonia lacunae BS2T (0.0479 mg/mL), respectively. Six strains exhibited a substrate preference for cellobiose over glucose, xylose, and arabinose in the hydrolysates. Analysis of Fourier transform infrared spectra indicated that the strains produced co-polymers of short- and medium-chain-length PHAs. None of the core phaABC genes were found on defined operons in the genomes of the top PHB-producing strains (all Gordonia strains, N. gamkensis CZH20T, and Streptomyces sp. strain HMC19). The Gordonia strains all harbored three phaA genes, a single phaB gene, and, with the exception of strain BG1.3 (with two predicted phaC genes), a single phaC gene. Predictive analyses of the proteins likely to be translated from the phaC genes revealed PhaC proteins of 37.7–39.2 kDa from Gordonia sp. strain BG1.3, G. lacunae BS2T, and N. gamkensis CZH20T; PhaC proteins of 106.5–107 kDa from Gordonia sp. strain JC51; and the second PhaC from Gordonia sp. strain BG1.3 and N. gamkensis CZH20T, possibly representing a new class of PHA synthases. Full article
(This article belongs to the Special Issue Advances in Biomass Pretreatment and Conversion Processes)
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25 pages, 1514 KiB  
Review
Biotechnological Plastic Degradation and Valorization Using Systems Metabolic Engineering
by Ga Hyun Lee, Do-Wook Kim, Yun Hui Jin, Sang Min Kim, Eui Seok Lim, Min Ji Cha, Ja Kyong Ko, Gyeongtaek Gong, Sun-Mi Lee, Youngsoon Um, Sung Ok Han and Jung Ho Ahn
Int. J. Mol. Sci. 2023, 24(20), 15181; https://doi.org/10.3390/ijms242015181 - 14 Oct 2023
Cited by 19 | Viewed by 8727
Abstract
Various kinds of plastics have been developed over the past century, vastly improving the quality of life. However, the indiscriminate production and irresponsible management of plastics have led to the accumulation of plastic waste, emerging as a pressing environmental concern. To establish a [...] Read more.
Various kinds of plastics have been developed over the past century, vastly improving the quality of life. However, the indiscriminate production and irresponsible management of plastics have led to the accumulation of plastic waste, emerging as a pressing environmental concern. To establish a clean and sustainable plastic economy, plastic recycling becomes imperative to mitigate resource depletion and replace non-eco-friendly processes, such as incineration. Although chemical and mechanical recycling technologies exist, the prevalence of composite plastics in product manufacturing complicates recycling efforts. In recent years, the biodegradation of plastics using enzymes and microorganisms has been reported, opening a new possibility for biotechnological plastic degradation and bio-upcycling. This review provides an overview of microbial strains capable of degrading various plastics, highlighting key enzymes and their role. In addition, recent advances in plastic waste valorization technology based on systems metabolic engineering are explored in detail. Finally, future perspectives on systems metabolic engineering strategies to develop a circular plastic bioeconomy are discussed. Full article
(This article belongs to the Special Issue Recent Advances in Systems Metabolic Engineering Strategies)
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23 pages, 793 KiB  
Review
Edible Coatings and Future Trends in Active Food Packaging–Fruits’ and Traditional Sausages’ Shelf Life Increasing
by Catarina Nunes, Mafalda Silva, Diana Farinha, Hélia Sales, Rita Pontes and João Nunes
Foods 2023, 12(17), 3308; https://doi.org/10.3390/foods12173308 - 2 Sep 2023
Cited by 84 | Viewed by 14165
Abstract
The global food production industry faces environmental concerns exacerbated by substantial food waste. European countries are striving to reduce food waste towards a circular bioeconomy and sustainable development. To address environmental issues and reduce plastic waste, researchers are developing sustainable active packaging systems, [...] Read more.
The global food production industry faces environmental concerns exacerbated by substantial food waste. European countries are striving to reduce food waste towards a circular bioeconomy and sustainable development. To address environmental issues and reduce plastic waste, researchers are developing sustainable active packaging systems, including edible packaging made from industry residues. These innovations aim to increase food safety and quality, extend shelf life, and reduce plastic and food waste. Particularly important in the context of the growing demand for fresh and minimally processed fruits, edible coatings have emerged as a potential solution that offers numerous advantages in maintaining fruit quality. In addition to fruit, edible coatings have also been investigated for animal-based foods to meet the demand for high-quality, chemical-free food and extended shelf life. These products globally consumed can be susceptible to the growth of harmful microorganisms and spoilage. One of the main advantages of using edible coatings is their ability to preserve meat quality and freshness by reducing undesirable physicochemical changes, such as color, texture, and moisture loss. Furthermore, edible coatings also contribute to the development of a circular bioeconomy, promoting sustainability in the food industry. This paper reviews the antimicrobial edible coatings investigated in recent years in minimally processed fruits and traditional sausages. It also approaches bionanocomposites as a recently emerged technology with potential application in food quality and safety. Full article
(This article belongs to the Section Food Packaging and Preservation)
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46 pages, 1892 KiB  
Review
Lignocellulosic Agricultural Waste Valorization to Obtain Valuable Products: An Overview
by Alessandro Blasi, Alessandra Verardi, Catia Giovanna Lopresto, Sarah Siciliano and Paola Sangiorgio
Recycling 2023, 8(4), 61; https://doi.org/10.3390/recycling8040061 - 20 Jul 2023
Cited by 141 | Viewed by 18740
Abstract
The sustainable management of lignocellulosic agricultural waste has gained significant attention due to its potential for the production of valuable products. This paper provides an extensive overview of the valorization strategies employed to convert lignocellulosic agricultural waste into economically and environmentally valuable products. [...] Read more.
The sustainable management of lignocellulosic agricultural waste has gained significant attention due to its potential for the production of valuable products. This paper provides an extensive overview of the valorization strategies employed to convert lignocellulosic agricultural waste into economically and environmentally valuable products. The manuscript examines the conversion routes employed for the production of valuable products from lignocellulosic agricultural waste. These include the production of biofuels, such as bioethanol and biodiesel, via biochemical and thermochemical processes. Additionally, the synthesis of platform chemicals, such as furfural, levulinic acid, and xylose, is explored, which serve as building blocks for the manufacturing of polymers, resins, and other high-value chemicals. Moreover, this overview highlights the potential of lignocellulosic agricultural waste in generating bio-based materials, including bio-based composites, bio-based plastics, and bio-based adsorbents. The utilization of lignocellulosic waste as feedstock for the production of enzymes, organic acids, and bioactive compounds is also discussed. The challenges and opportunities associated with lignocellulosic agricultural waste valorization are addressed, encompassing technological, economic, and environmental aspects. Overall, this paper provides a comprehensive overview of the valorization potential of lignocellulosic agricultural waste, highlighting its significance in transitioning towards a sustainable and circular bioeconomy. The insights presented here aim to inspire further research and development in the field of lignocellulosic waste valorization, fostering innovative approaches and promoting the utilization of this abundant resource for the production of valuable products. Full article
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17 pages, 6475 KiB  
Article
Toward a Circular Bioeconomy: Development of Pineapple Stem Starch Composite as a Plastic-Sheet Substitute for Single-Use Applications
by Chanaporn Thongphang, Atitiya Namphonsane, Sombat Thanawan, Chin Hua Chia, Rungtiwa Wongsagonsup, Siwaporn Meejoo Smith and Taweechai Amornsakchai
Polymers 2023, 15(10), 2388; https://doi.org/10.3390/polym15102388 - 19 May 2023
Cited by 6 | Viewed by 6754
Abstract
Plastic waste poses a significant challenge for the environment, particularly smaller plastic products that are often difficult to recycle or collect. In this study, we developed a fully biodegradable composite material from pineapple field waste that is suitable for small-sized plastic products that [...] Read more.
Plastic waste poses a significant challenge for the environment, particularly smaller plastic products that are often difficult to recycle or collect. In this study, we developed a fully biodegradable composite material from pineapple field waste that is suitable for small-sized plastic products that are difficult to recycle, such as bread clips. We utilized starch from waste pineapple stems, which is high in amylose content, as the matrix, and added glycerol and calcium carbonate as the plasticizer and filler, respectively, to improve the material’s moldability and hardness. We varied the amounts of glycerol (20–50% by weight) and calcium carbonate (0–30 wt.%) to produce composite samples with a wide range of mechanical properties. The tensile moduli were in the range of 45–1100 MPa, with tensile strengths of 2–17 MPa and an elongation at break of 10–50%. The resulting materials exhibited good water resistance and had lower water absorption (~30–60%) than other types of starch-based materials. Soil burial tests showed that the material completely disintegrated into particles smaller than 1 mm within 14 days. We also created a bread clip prototype to test the material’s ability to hold a filled bag tightly. The obtained results demonstrate the potential of using pineapple stem starch as a sustainable alternative to petroleum-based and biobased synthetic materials in small-sized plastic products while promoting a circular bioeconomy. Full article
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13 pages, 7267 KiB  
Article
Toward a Circular Bioeconomy: Exploring Pineapple Stem Starch Film as a Plastic Substitute in Single Use Applications
by Atitiya Namphonsane, Phattarakarn Suwannachat, Chin Hua Chia, Rungtiwa Wongsagonsup, Siwaporn Meejoo Smith and Taweechai Amornsakchai
Membranes 2023, 13(5), 458; https://doi.org/10.3390/membranes13050458 - 24 Apr 2023
Cited by 15 | Viewed by 4873
Abstract
In this study, biodegradable starch film was developed from pineapple stem waste as a substitute for non-biodegradable petroleum-based films for single-use applications where strength is not too demanding. High amylose starch from a pineapple stem was used as the matrix. Glycerol and citric [...] Read more.
In this study, biodegradable starch film was developed from pineapple stem waste as a substitute for non-biodegradable petroleum-based films for single-use applications where strength is not too demanding. High amylose starch from a pineapple stem was used as the matrix. Glycerol and citric acid were used as additives to adjust the ductility of the material. Glycerol content was fixed at 25% while that of citric acid varied from 0 to 15% by weight of starch. Films with a wide range of mechanical properties can be prepared. As more citric acid is added, the film becomes softer and weaker, and has greater elongation at the break. Properties range from a strength of about 21.5 MPa and 2.9% elongation to a strength of about 6.8 MPa and 35.7% elongation. An X-ray diffraction study showed that the films were semi-crystalline. The films were also found to be water-resistant and can be heat-sealed. An example of a single-use package was demonstrated. A soil burial test confirmed that the material was biodegradable and completely disintegrated into sizes smaller than 1 mm within one month. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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36 pages, 2770 KiB  
Review
Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives
by Marco Orlando, Gianluca Molla, Pietro Castellani, Valentina Pirillo, Vincenzo Torretta and Navarro Ferronato
Int. J. Mol. Sci. 2023, 24(4), 3877; https://doi.org/10.3390/ijms24043877 - 15 Feb 2023
Cited by 59 | Viewed by 12228
Abstract
The accumulation of synthetic plastic waste in the environment has become a global concern. Microbial enzymes (purified or as whole-cell biocatalysts) represent emerging biotechnological tools for waste circularity; they can depolymerize materials into reusable building blocks, but their contribution must be considered within [...] Read more.
The accumulation of synthetic plastic waste in the environment has become a global concern. Microbial enzymes (purified or as whole-cell biocatalysts) represent emerging biotechnological tools for waste circularity; they can depolymerize materials into reusable building blocks, but their contribution must be considered within the context of present waste management practices. This review reports on the prospective of biotechnological tools for plastic bio-recycling within the framework of plastic waste management in Europe. Available biotechnology tools can support polyethylene terephthalate (PET) recycling. However, PET represents only ≈7% of unrecycled plastic waste. Polyurethanes, the principal unrecycled waste fraction, together with other thermosets and more recalcitrant thermoplastics (e.g., polyolefins) are the next plausible target for enzyme-based depolymerization, even if this process is currently effective only on ideal polyester-based polymers. To extend the contribution of biotechnology to plastic circularity, optimization of collection and sorting systems should be considered to feed chemoenzymatic technologies for the treatment of more recalcitrant and mixed polymers. In addition, new bio-based technologies with a lower environmental impact in comparison with the present approaches should be developed to depolymerize (available or new) plastic materials, that should be designed for the required durability and for being susceptible to the action of enzymes. Full article
(This article belongs to the Special Issue Microbial Enzymes for Biotechnological Applications)
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12 pages, 2713 KiB  
Article
The Initial Development and Evaluation of Cross-Linked Casein Films for Sustainable Footwear
by Liliana Indrie, Steven McNeil, Mehmet Mete Mutlu, Sanda Bota, Dorina Camelia Ilieș and Hüseyin Ata Karavana
Coatings 2023, 13(2), 217; https://doi.org/10.3390/coatings13020217 - 17 Jan 2023
Cited by 5 | Viewed by 3506
Abstract
To increase the sustainability of footwear and align it with the circular bioeconomy, there is a pressing need to develop novel bio-based materials to replace the synthetic polymers currently used. In this study, casein-based films were prepared by solution casting with a tannic [...] Read more.
To increase the sustainability of footwear and align it with the circular bioeconomy, there is a pressing need to develop novel bio-based materials to replace the synthetic polymers currently used. In this study, casein-based films were prepared by solution casting with a tannic acid cross-linker, and a glycerol plasticizer. The properties important to footwear materials were characterised, including tensile strength and elongation, stitch strength, hardness, grain cracking strength, water vapour permeability, and thermal properties. The tannic acid imparted a brown colour to the films with good resistance to light-induced fading. Their tensile strengths were 4–5 N/mm2, elongation at break 45%–73%, and water vapour permeability 0.2–0.6 mg/(cm2h), depending upon the levels of the cross-linker and plasticiser. The strength of the films was close to those of some non-leather footwear materials such as compact rubbers and insock materials, but below that required for leather shoe vamps/uppers. The casein films were successfully used in sneaker- and ballerina-style shoes as components of the insock and decorative design elements on the vamp. This work has demonstrated the concept of using casein films in footwear. The properties of the films could be improved by further research, particularly with respect to cross-linking, plasticizing, and combining with bio-based fibers and fabrics. Full article
(This article belongs to the Special Issue Advanced Materials for Highly Biocompatible Hydrogel Systems)
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21 pages, 3341 KiB  
Review
Biomass and Cellulose Dissolution—The Important Issue in Renewable Materials Treatment
by Marta Przypis, Agata Wawoczny and Danuta Gillner
Appl. Sci. 2023, 13(2), 1055; https://doi.org/10.3390/app13021055 - 12 Jan 2023
Cited by 23 | Viewed by 4856
Abstract
Sustainable development strategies, as well as the shift toward a circular bioeconomy, has led to high interest in the development and implementation of technologies that efficiently utilize biomass as a raw material. Switching from fossil-based to bio-based resources requires the consideration of many [...] Read more.
Sustainable development strategies, as well as the shift toward a circular bioeconomy, has led to high interest in the development and implementation of technologies that efficiently utilize biomass as a raw material. Switching from fossil-based to bio-based resources requires the consideration of many new challenges and problems. One of the crucial issues is the solubility of lignocellulose or at least its ingredients. According to the trends and legislation, the selected chemicals and methods of dissolution/treatment should also be environmentally friendly. The pretreatment processes prepare biomass for further transformations (e.g., chemical, thermal including pyrolysis, or biological) to valuable products such as biofuels, bio-oils, Fine Chemicals, solvents, plastics, and many others. This review discusses the latest findings on the dissolution of biomass and its ingredients. The application of novel, green solvents such as ionic liquids or deep eutectic solvents is discussed in detail. The impact of the composition and structure of these solvents on the biomass/cellulose dissolution process, as well as the mechanism of cellulose–ionic liquid interaction, is presented. Some novel achievements in the usage of inorganic salts and specific metal complexes are also overviewed. Full article
(This article belongs to the Topic Sustainable Environmental Technologies)
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