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Cassava pulp (CP) generated annually in Thailand has become the major agro-industrial solid waste problem, but its potential for volatile fatty acids (VFAs) production has not been intensively explored. Waste-derived VFAs gained attention due to their broad applications as substrates for biomethane and bioplastic or bio-based chemicals, replacing petrochemical-based ones. This study proposed the next generation of CP waste management for VFAs production as renewable and inexpensive substrates for biogas and bioplastic prospects. A microbial consortium enriched with hydrolytic and acidogenic bacteria (EHA) was used as inoculum seed for anaerobic fermentation of CP to produce VFAs. The stepwise increasing substrate to 5% CP resulted in VFAs yield of up to 0.16 g acetic acid and 0.22 g butyric acids per g of CP added, requiring only 1% of microbial inoculum. Acid-tolerant spore-forming Clostridium dominated the EHA consortium and was easy to maintain during stress conditions. If the annual CP generated is subjected to this proposed waste management system, 0.31 million tons of acetic acid and 0.43 million tons of butyric acid can be produced annually. These VFAs can be further used as mixed VFAs for biomethane and bioplastic production prospects or extracted as a pure VFA and sold to the chemicals market. Moreover, bio-transformation of CP into VFAs through fermentation using the special EHA consortium requires minimum operational cost and produces high-economy products while minimizing greenhouse gas emissions to the atmosphere. This next-generation CP waste utilization will be of good use in the future by contributing to sustainable development goals. [ABSTRACT FROM AUTHOR]

Biodegradable bioplastics are becoming the best solution ever to combat the environmental pollution caused by petroleum-based synthetic plastics. In this study, potato peel starch (PPS)–based bioplastic film was developed by a method of gelatin casting, in which the effect of 13.33, 23.33, and 33.33% v/w (HCl or glycerol to PPS ratio) concentration of HCl and glycerol as well as drying temperature (45 °C, 55 °C, and 65 °C) was studied. The experiment was designed and optimized by a three-variable, three-level Box-Behnken design using Response Surface Methodology (Design Expert® software version 13.0.1). The ANOVA analysis showed that the model was significant with p < 0.0001. The optimum values of the influencing factors were found to be HCl concentration 23.33%v/w, glycerol 20%v/w, and 48 °C drying temperature. The FTIR results confirmed that the compatibility between false banana (Ensete ventricosum) fiber and PPS was attributed to the intermolecular hydrogen bonding and uniform dispersion of fiber during the blending and film formation. The micrograph for pure bioplastic film showed uniform and dense matrix except the irregular dimpled surface formed during the gelatinization process. Peaks were demonstrated at 2θ values of 15.19°, 17.31°, 22.96°, and 24.1° by PPS in the XRD spectrum. Under optimal conditions, a bioplastic film with tensile strength of 6.449 MPa, percent elongation at break of 19.87%, biodegradability of 83.92%, and water absorption of 59.94% was synthesized in this study. Biodegradability studies on the PPS-based bioplastic synthesized by the plasticization of glycerol and sorbitol have shown a biodegradation % of 81.42 and 70.25 in moist soil, respectively. The produced bioplastic film had sufficient physicochemical properties confirming the usage of waste potato peel as a source of starch for the synthesis of biodegradable bioplastics that can substitute conventional plastics. [ABSTRACT FROM AUTHOR]

Bioplastics were produced by mixing starch with sorbitol, glacial acetic acid, and carboxymethyl cellulose (CMC) during the manufacturing process. The physical characteristics of the bioplastics were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Tensile strength, elongation, and Young's modulus tests were utilized to assess the mechanical characteristics of bioplastics. The bioplastic with the highest tensile strength was BP3 (7.03 ± 0.34 N/mm2), whereas BP0 had a tensile strength of 1.57 ± 0.11 N/m2. The addition of CMC increased the viscosity of the solution and, consequently, the strength of the bioplastic. The range of bioplastic hydrophobicity was ~ 128.32–323.74%. FTIR and XPS test results indicated that the physical mixing utilized during synthesis did not result in the addition of functional groups other than the native functional groups of the substances since no chemical reaction occurred. The thermal behavior investigation revealed that increasing the amount of CMC added to TPS can increase the presence of O–H functional groups in bioplastics, contributing to an increase in the glass transition temperature. Furthermore, both bioplastics broke down at ~ 250 °C. [ABSTRACT FROM AUTHOR]

Fossil fuel-based products should be replaced by products derived from modern biomass such as plant starch, in the context of the future circular economy. Starch production globally surpasses 50 million tons annually, predominantly sourced from maize, rice, and potatoes. Here, we review plant starch with an emphasis on structure and properties, extraction, modification, and green applications. Modification techniques comprise physical, enzymatic, and genetic methods. Applications include stabilization of food, replacement of meat, three-dimensional food printing, prebiotics, encapsulation, bioplastics, edible films, textiles, and wood adhesives. Starch from maize, potatoes, and cassava shows amylose content ranging from 20 to 30% in regular varieties to 70% in high-amylose varieties. Extraction by traditional wet milling achieves starch purity up to 99.5%, while enzymatic methods maintain higher structural integrity, which is crucial for pharmaceutical applications. Enzymatic extraction improves starch yield by of up to 20%, reduces energy consumption by about 30%, and lowers wastewater production by up to 50%, compared to conventional methods. Sustainable starch modification can reduce the carbon footprint of starch production by up to 40%. Modified starches contribute to approximately 70% of the food texturizers market. The market of starch in plant-based meat alternatives has grown by over 30% in the past five years. Similarly, the use of biodegradable starch-based plastics by the bioplastic industry is growing over 20% annually, driven by the demand for sustainable packaging.Kindly check and confirm the layout of Table 1.Layout is right [ABSTRACT FROM AUTHOR]

Anaerobic digestion under hydrogen (H2)/carbon dioxide (CO2)-versus nitrogen (N2)-purged conditions was examined for the potential for biogas enhancement in the presence of polylactic acid. With or without polylactic acid, H2/CO2 purging demonstrated a 25% higher methane (CH4) production, reaching approximately 160 NmL CH4/g VSadd compared to N2 purging. When H2/CO2 was purged with polylactic acid, there was reduced dominance of Spirochaetales, resulting in fewer intermediates that caused a similar amount of CH4 yield. Despite similar CH4 yield to conditions without polylactic acid, verification through Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) confirmed extensive polylactic acid decomposition. DSC revealed double melting peaks at 151.8 °C and 156.1 °C, indicating increased crystallinity and vigorous polylactic acid decomposition, particularly in the amorphous region, under H2/CO2 purging. This aligned with the decrease in the FTIR carbonyl index, visually confirmed using SEM. Metagenome sequencing highlighted the prevalence of hydrogenotrophic methanogens, Anaerolineales, Bacteroidales, and Thermoanaerobacterales under H2/CO2 purging, demonstrating higher polylactic acid degradation compared to N2 purging conditions. This study revealed a potential for biogas upgrading with waste management of polylactic acid. [ABSTRACT FROM AUTHOR]

Cellulose acetate (CA) is a sustainable alternative to low-density polyethylene (LDPE), which is a major source of plastic waste. However, the barrier properties and mechanical strength of CA may limit its application as single-use food plastic packaging. This study aims to overcome these limitations by incorporating polyethylene glycol (PEG) 1450 ranging from 10 to 50% w/w. PEG 1450 improved water vapor barrier but increased moisture content, though both values remained similar up to 50% w/w PEG 1450. CA bioplastic films showed significantly higher (p < 0.05) UV–Vis absorbances at 40% w/w PEG 1450, suggesting that a high concentration of PEG 1450 can prevent lipid oxidation but also increase opacity as reflected on the physical appearance. The reduced transparency was caused by aggregation and physical exclusion of PEG 1450 from the CA matrix which was observed under a scanning electron microscope (SEM). Meanwhile, PEG 1450 was miscible and compatible with CA at low concentration. In terms of mechanical properties, inclusion of PEG 1450 at 10 and 20% w/w improved the tearability of CA bioplastic films. In short, the incorporation of PEG 1450 improved barriers against UV and water vapor and tearability, making it superior to commercial LDPE plastic in some respects but lacking in others. Nonetheless, its advantages make it suitable for producing single-use food packaging, hence potentially replacing LDPE. [ABSTRACT FROM AUTHOR]

The replacement of expensive components in microbial growth media with pretreated lignocellulosic waste component to increase the product spectrum and add value to the bioproducts has been encouraged to achieve sustainable and feasible utilization of waste biomass as per the biorefinery approach. This study demonstrates an integrated biorefinery approach towards utilization of sugarcane bagasse and biomass of Mucor circinelloides ZSKP. A maximum reducing sugar recovery of 80.67 g/l was achieved after combining pretreatment with saccharification. A low temperature, glycerol, and ammonium phosphate pretreatment method was established, where glycerol pretreatment conditions were reduced from 250 to 150 °C and from 120 to 45 min. The ammonium phosphate-containing hydrolysate yielded 12.89 g/l of fungal biomass after fermentation to add to 20.8 g lignin from the delignification step. The biomass production was further improved to 17.69 g/l after supplementation with corn steep solids and mineral salts. The fermentation process also yielded 2.36 g/l chitosan and 4.9 g/l of lipids after extraction from the oleaginous fungus. The lignin infused glycerol plasticized chitosan biocomposite plastic had a 100% improvement in thermogravimetric properties with almost 50% more energy needed to increase the temperature of the material when compared to glycerol only plasticized biocomposite. The fungal chitosan showed antimicrobial properties and was effective as a preservative spray for fresh tomatoes and apples extending their shelf life to at least 14 and 18 days, respectively. This study therefore demonstrated that a novel two-step pretreatment process could be environmentally beneficial and yielded multiple products for biotechnological applications. [ABSTRACT FROM AUTHOR]

Fish gelatin is a promising polymer for creating plastics derived from agro-industrial waste, offering a sustainable alternative to single-use plastics. This research aimed to develop fish gelatin films that can be used to replace conventional single-use plastics employed in food packaging. Specifically, our focus was on reducing the high hydrophilic behavior of fish gelatin films which limits their possible applications. To address this, mono-, bi-, and tri- layer films were fabricated from fish gelatin and amylopectin. The fish gelatin was cross-linked with the enzyme transglutaminase to reduce its hydrophilicity achieving two levels of cross-linking: 40 ± 2%, and 65 ± 4%. Micrographs confirmed crack-free films and bilayer/trilayer formation. The cross-linked films exhibited reduced solubility: about 30% in monolayer and 40–67% in bilayer and trilayer films compared to pure protein films. Regarding the water vapor transmission rate, the highly cross-linked trilayer film displayed a value of 0.95 g/m2 h which is significantly lower than pure protein films (2.89 g/m2 h) and amylopectin films (9.37 g/m2 h). Additionally, Young's modulus and the thermal stability were improved with the lamination. These results suggest an effective method for manufacturing films from fish waste, which could contribute to a circular economy for the fishing industry. Enhanced water resistance also makes the films potentially suitable for sustainable biopolymer-based active food packaging. [ABSTRACT FROM AUTHOR]

Polymer filament fabrication and its printability are influenced significantly by rheological behavior. This influence can pose a significant obstacle when attempting to transition fused deposition modeling (FDM) from the laboratory to industrial or clinical settings. The aim of this study is to demonstrate how machine learning (ML) approaches can speed up the development of polymer filaments for FDM. Four types of ML methods: artificial neural network, support vector regression, polynomial chaos expansion (PCE), and response surface model, were used to predict the rheological behaivior of polybutylene succinate. In general, all four approaches presented significantly high correlation values with respect to the training and testing data stages. Remarkably, the PCE algorithm repeatedly provided the highest correlation for each response variable in both the training and testing stages. Noteworthy, variation differs between response variables rather than between algorithms. Taken together, these modeling approaches could be used to optimize filament extrusion processes. [ABSTRACT FROM AUTHOR]

Background: Plastic is generating global pollution and the replacement such as bioplastic has been developed to mitigate the pollution. To this end, the fate, transformation and pathway of bioplastics need more research. For example, the fragmentation of bioplastic can release small debris that can be categorised as microplastics, which is tested herein by taking an example of a compostable plastic that is used as a bin bag on our kitchen table to collect the food residues. Results: First, we employ matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS) to identify the main components of the bioplastic bag as polymer and starch. Next, we use Raman imaging to monitor the stability under laser illumination, in an oven at ~ 60 °C for ~ 2 weeks, or in the presence of tap water for half a year. Basically, the compostable plastic is stable under these conditions. Thirdly, however, once used as table-bin bag with involvement of food residues, within ~ 1 week, the bioplastic bag is broken and biodegraded to release debris. The derivate surface groups are effectively monitored and directly visualised via Raman imaging, and cross-checked with scanning electron microscope (SEM). The yielded small molecule such as formic acid is also identified, along with the released debris of microplastics, with the help of on-site extraction of the fragmented sample and imaging analysis algorithm of the hyper spectrum. Conclusions: After one week, the bag in the waste bin fragments, releasing a significant amount of debris. This could pose a functional issue if users intend to use the bag for at least a week, and could become a potential environmental problem if the waste is dispersed uncontrollably. In general, further research is needed to potentially distinguish the persistent conventional microplastics from the bioplastic fragments, to effectively mitigate the plastic pollution. [ABSTRACT FROM AUTHOR]

Environmental friendly biocomposites are urgently needed to mitigate the pollution caused by huge consumption of petroleum-based polymers. Renewable carrageenan and polylactic acid (PLA) natural polymers have the potential to replace petroleum-origin polymers. Nevertheless, the carrageenan and PLA themselves inherit poor tensile strength, hydrophobicity and stability. The aim of this study is to underpin the mechanism of synthesis of carrageenan-PLA biocomposite using van't Hoff plot, 1HNMR and density functional theorem simulation. Strong hydrogen bonding was found at 1.88 Å between O atom (carrageenan) and H atom (PLA) and was validated in 1HNMR shifting at 5.3 ppm corresponding to –OH group from PLA. The interaction established in the biocomposite mixed at 50 °C leads to a stronger tensile strength of 75.37 MPa, higher hydrophobicity and thermal stability with highest activation energy of 45.39 kJ/mol. The biocomposite produced from renewable carrageenan-PLA material would be a future replacement for nondegradable plastic as a food packaging material. [ABSTRACT FROM AUTHOR]

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The escalating demand for sustainable alternatives to conventional plastics has inspired extensive research into bioplastic production. This study aims to help meet the demand for eco-friendly materials by exploring the potential of pear waste biomass as a valuable resource for polyhydroxyalkanoates (PHA) production in biorefineries. To meet the growing demand for bioplastics, it is crucial to develop novel PHA materials with desirable product quality from cost-effective waste-carbon substrates. Bioplastics, known for their biodegradability and ease of decomposition, offer a promising solution for alleviating the burden on municipal and industrial waste management. However, the bottleneck in industrial PHA production lies in the high cost of carbon substrates and the complexity of downstream processes. Bacterial PHA production has emerged as a promising approach because it utilizes agricultural and industrial waste as renewable carbon substrates, thereby eliminating waste management challenges. This process not only addresses the issues associated with synthetic plastics but also contributes to a more sustainable future. Specifically, agro-industrial waste from the pear fruit industry, including pear residues, pear twigs, and discarded paper bags, represents a promising feedstock for PHA production due to its abundant availability and potential to mitigate waste disposal issues. This review comprehensively examines state-of-the-art approaches, challenges, and opportunities in producing PHA from pear waste materials. Moreover, it highlights the potential of pear waste biomass as a resource for PHA production in biorefineries, emphasizing its role in addressing waste management challenges and contributing to the development of eco-friendly materials. [ABSTRACT FROM AUTHOR]

This work aimed to develop films based on pequi (Caryocar brasiliense) pulp added of gelatin and plasticizer (glycerol or sorbitol) and characterize their properties and biodegradation in different soils. The films were presented with a good appearance, easy to handle, and with a predominant yellowish color. The greater the addition of plasticizers (3.5%), the greater the elongation and the lower the tensile strength of the films. The higher the gelatin (7%) and the lower the plasticizer (1.5%) concentrations, the higher the tensile strength. Thermal analysis allowed to observe a desirable characteristic for packing films: a band between 2Ɵ = 21° for both glycerol and sorbitol films, which is present in low crystalline films, reducing the incidence of light in the products. Films were at the most 100% degraded over a period of 5 to 9 days. Thus, the films obtained are recommended to be utilized for food packaging applications. [ABSTRACT FROM AUTHOR]

Pollution caused by petroleum-based plastics, especially single-use food packaging, has become a global problem. In order to offer sustainable alternatives to traditional plastic, it is important to explore the use of new biodegradable plastic materials made from renewable sources. Bioplastics made from seaweed extracts, such as carrageenan and alginate, show promise as viable options. However, these phycocolloids are expensive and require a lengthy extraction process. This report presents the development of bioplastics using the entire biomass of a red seaweed (Kappaphycus sp.). The initial focus of the study was to optimize the concentration of the main ingredients, which included biomass and glycerol (plasticizer agent). The concentration range that was tested included a biomass-to-water ratio of 1:50 to 1:90 and a plasticizer concentration of 1% to 5% (v/v). Subsequently, bioplastics were created by incorporating natural dye extracts from butterfly pea flower (Clitoria ternatea), bougainvillea flower (Bougainvillea glabra), and dragon fruit peel (Hylocereus polyrhizus) using a casting method at the selected optimum concentrations. The resulting bioplastics were then characterized for their physicochemical properties (including shelf-life and biodegradability), and antimicrobial activity using standard methods. The study successfully developed bioplastics with a thickness of less than 100 µm and a moisture content below 40%. Within the tested range, the most optimal concentrations were a biomass-to-water ratio of 1:50 to 1:60 and 1% glycerol, based on factors such as tensile strength (TS), water vapor transmission rate (WVTR), elasticity, appearance, shelf-life, and biodegradability. All of the bioplastics completely degraded during a soil burial test within 13-15 days. The inclusion of brightly coloured plant extracts increased the bioplastics' antioxidant properties by more than 10% in scavenging activity. Furthermore, the dyed bioplastics had a shelf-life that was 20-30% longer. While these biomass bioplastics have lower tensile strength, elasticity, and water vapor permeation rate (<10 MPa, <30 MPa, and >2 g m-2 h-1, respectively), they show potential for applications where high tensile strength is not required, such as food packaging or wrapping. [ABSTRACT FROM AUTHOR]

Biodegradable plastics developed from renewable resources are currently being actively promoted as viable alternatives to reduce plastic pollution, particularly for single-use food packaging. Seaweeds, an abundant and relatively inexpensive biomass, demonstrate good film-forming properties ideal for bioplastic production. In this study, whole biomass (WS) of the red seaweed Kappaphycus sp. was used as the main ingredient to develop thin bioplastic sheets. To enhance physical properties, commercial sodium alginate (CA) was added at the ratios of (WS:CA) 100:0, 75:25, 50:50, 25:75, and 0:100 with 1.0% (v/v) glycerol as a plasticizer. Using standard methods, the bioplastics were then analysed for functional group, visual appearance, mechanical property, thermal property, water barrier property, and biodegradability. As a result, bioplastics with 0.050–0.054 mm thickness (within the range of commercial food packaging) were developed. With higher CA content, the visual appearance of bioplastics decreased in terms of colour difference and opacity. At around 23% moisture content, tensile strength (< 10 MPa) and thermal stability decreased with higher CA content while elasticity and water barrier property increased. All the bioplastics became fully degraded within 15 days. The results suggest that adding sodium alginate may have reduced the hydrophobicity of the WS bioplastics. This study demonstrates the potential of using WS biomass blended with commercial sodium alginate as base material to produce highly degradable bioplastics with the added benefits of protective and nutritious qualities naturally occurring in seaweed biomass. [ABSTRACT FROM AUTHOR]

Climate change, largely attributable to the extensive use of fossil fuels and deforestation, poses a critical global issue. There is a pressing need for innovative and sustainable solutions. This study highlights a significant advancement in materials science: a biomass-sourced transparent composite developed from cellulose nanofibers (CNFs) and isosorbide polycarbonates (ISB-PC). This green glazing material serves as a potential replacement for heavy, easily shattered glass in the construction and automotive industries, exhibiting remarkable thermal properties, light transmittance, and mechanical resilience. Notably, the thermal dimensional stability and transparency of the composite matches that of conventional glass. An integral accomplishment is the development of a multi-layered sheet with a thickness beyond 350 μm. These sheets achieved a light transmittance of 62.0% and coefficient of thermal expansion below 60 ppm K−1 (30–120 °C). Another distinguishing feature of this composite is its potential for carbon sequestration owing to its non-degradability. This study underscores the composite's potential as an eco-friendly alternative to glass. [ABSTRACT FROM AUTHOR]

Due to the massive growth in population and urbanization, there has been a huge increase in the volume of food waste globally. The Food and Agriculture Organization (FAO) has estimated that around one-third of all food produced each year is wasted. Food waste leads to the emission of greenhouse gas and depletion of the soil fertility. Nevertheless, it has immense potential for the recovery of high-value energy, fuel, and other resources. This review summarizes the latest advances in resource recovery from food waste by using technologies that include food waste–mediated microbial fuel cell (MFC) for bioenergy production. In addition to this, utilization of food waste for the production of bioplastic, biogas, bioethanol, and fertilizer has been also discussed in detail. Competitive benefits and accompanying difficulties of these technologies have also been highlighted. Furthermore, future approaches for more efficient use of food waste for the recovery of valuable resources have been also offered from an interdisciplinary perspective. [ABSTRACT FROM AUTHOR]

Cacao mucilage exudates (CMEs), byproducts of cacao beans fermentation, are effluents rich in sugars and low-molecular-weight organic acids. In this study, we utilized CMEs to formulate culture media for the biosynthesis of polyhydroxyalkanoates (PHAs) using a native Bacillus megaterium strain (B2). Our investigation followed the adaptation process of B2 to the CMEs-based media, and we closely monitored the development of the microorganism in terms of consumption of acids and sugars. Upon successful adaptation to the CMEs-based media, we transferred the strain to a 4-L batch bioreactor to evaluate the impact of operational variables on PHAs production. We examined the microorganisms' yield, productivity, and growth kinetics using the CME-based media. Our results showed a product yield of 0.98 g PHA/g carbon source, with an accumulation percentage of 57% and a productivity increase of 33% compared to PHA produced from residual glycerol using the same microorganism. The biopolymer's structure was confirmed to be of a polyhydroxybutyrate homopolymer (PHB) type using various molecular characterization techniques, including Matrix-Assisted Laser Desorption/Ionization mass spectrometry (MALDI-TOF-MS), infrared spectroscopy (IR), elemental composition (EC), ultraviolet–visible spectroscopy (UV–VIS), and thermal analysis (TGA, DSC). [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is known for wide applications, biocompatibility, and degradability; however, it cannot be commercialized due to conventional recovery using solvents. The present study employed mechanical cell-disruption methods, such as Pestle and mortar, sonication, and glass bead vortexing, for solvent-free extraction of PHA from Bacillus sp. Different time intervals were set for grinding (5, 10, 15 min), sonicating (1, 3 and 5 min), and vortexing (2, 5 and 8 g glass beads with 5, 10 and 15 min each) hence studying their effect on cell lysis to release PHA. Tris buffer containing phenylmethyl sulfonyl fluoride (PMSF) (20 mM Tris–HCl, pH 8.0, 1 mM PMSF) was employed as a lysis buffer to study its action over Bacillus cells. Its presence was checked with the above methods in cell lysis. Sonicating cells for 5 min in the presence of lysis buffer achieved a maximum PHA yield of 45%. Cell lysis using lysis buffer yielded 35% PHA when vortexing with 5 g glass beads for 15 min. Grinding cells for 15 min showed a maximum yield of 34% but lacked a lysis buffer. The overall results indicated that the action of lysis buffer and physical extraction methods improved PHA yield by %. Therefore, the study sought to evaluate the feasibility of applying laboratory methods for cell disruption. These methods can showcase possible opportunities in large-scale applications. The polymer yield results were compared with standard sodium hypochlorite extraction. Confirmation of obtained polymers as polyhydroxy butyrate (PHB) was made through FTIR and 1HNMR characterization. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) production from lignocellulosic biomass using mixed microbial cultures (MMC) is a potential cheap alternative for reducing the use of petroleum-based plastics. In this study, an MMC adapted to acidogenic effluent from dark fermentation (DF) of exhausted sugar beet cossettes (ESBC) has been tested in order to determine its capability to produce PHAs from nine different synthetic mixtures of volatile fatty acids (VFAs). The tests consisted of mixtures of acetic, propionic, butyric, and valeric acids in the range of 1.5–9.0 g/L of total acidity and with three different valeric:butyric ratios (10:1, 1:1, and 1:10). Experimental results have shown a consistent preference of the MMC for the butyric and valeric acids as carbon source instead other shorter acids (propionic or acetic) in terms of PHA production yield (estimated in dry cell weight basis), with a maximum value of 23% w/w. Additionally, valeric-rich mixtures have demonstrated to carry out a fast degradation process but with poor final PHA production compared with high butyric mixtures. Finally, high initial butyric and valeric concentrations (1.1 g/L and 4.1 g/L) have demonstrated to be counterproductive to PHA production. [ABSTRACT FROM AUTHOR]

Biodegradable polymers are an important part of the solution toolbox to achieve circularity in the plastic economy and overcome negative impacts of a linear plastic economy. Biodegradable polymers need to excel not only on a mechanical performance level in the application to fulfill their function during the use phase but also on a biodegradation performance level after use. The biodegradation performance is tailored to the application and the receiving environment of the polymer product after use, which can be both engineered systems (e.g., compost, anaerobic digestors, wastewater treatment plants) and natural systems (e.g., soils, freshwater, or marine environments). This chapter addresses key aspects of polymer biodegradability and biodegradation in both natural and engineered systems with the goal to advance a more holistic view on the topic and, thereby, provide guidance for all stakeholders working on developing, testing, and regulating biodegradable polymers. These aspects include definitions of biodegradability and biodegradation, elucidating polymer- and environmental factors that control the biodegradation process, a discussion of the analytical chemistry of polymer biodegradation, polymer biodegradability testing and certification, as well as a brief overview of research needs. In accordance with the diverse backgrounds of the authors of the chapter, this chapter targets all stakeholder groups from academics to industry and regulators. [ABSTRACT FROM AUTHOR]

In this study, bacterial strains isolated from olive oil mill wastewater assigned to Bacillus (n = 4) and Klebsiella (n = 1) genera, were evaluated for their ability to accumulate intracellular PHA granules using Sudan Black staining. A maximum PHA production of 0.14 g/L (i.e., 30.2% wt./wt. in dry biomass) was observed in Bacillus amyloliquefaciens strain OM81 after 72 h of incubation in the presence of 2% glucose (synthetic medium). To reduce bioplastic production costs and recover a polluting product, olive mill wastewater was tested as a carbon source. In this context, the maximum growth (1.45 g/L) was observed in the presence of 50% olive mill wastewater. After extracting the biopolymers with chloroform, quantitative and qualitative analyses were conducted using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). FTIR showed an absorption band at 1730 cm−1 assigned to the elongation of the PHB carbonyl groups. This approach offers a dual benefit of reducing pollution and bioplastic production costs. The Bacillus amyloliquefaciens strain OM81 showed promising results for PHAs production, making it a potential candidate for further investigation. [ABSTRACT FROM AUTHOR]

The feasibility of potato-based bioplastics as food or fresh produce packaging materials was investigated using glycerol and sorbitol plasticizers at three different concentrations (30, 50, and 70%). The effects of plasticizers on the tensile strength, water vapour transmission rate, water absorption, and contact angle of the plasticized bioplastic were compared to the pure potato starch-based bioplastic. At same concentration, glycerol-plasticized bioplastic films were more flexible and stickier than sorbitol-plasticized bioplastic films. At all concentrations, however, the tensile strength and elongation at break were consistently lower than the latter. The experimental results revealed that glycerol with a higher hydrophilicity produced bioplastic films with higher water vapour transmission (63.68–80.91%), water absorption (252.65–432.71%), and lower contact angle (36.669°–50.506°) in comparison with sorbitol-plasticized bioplastics. In Fourier transform infrared spectroscopy, the major absorption bands characteristics of all bioplastics, with or without the presence of plasticizers, were found to be identical. A weight loss test on strawberries stored at different temperatures was used to investigate the feasibility of plasticized potato starch-based bioplastics for use as food and fresh produce packaging materials. Increase in the concentration of both plasticizers from 30 to 70% reduced the weight loss of strawberries kept at 4 °C and room temperature, with no significant difference in weight loss observed at the same concentration of the plasticizers. It was also found that when strawberries were wrapped in plasticized bioplastics and kept at 4 °C, water loss was reduced by 4 to 6.8 fold compared to room temperature. [ABSTRACT FROM AUTHOR]

The production and disposal of plastics have become a major global concern owing to its non-biodegradable properties in the environment. The recycling of apple biowaste as a value-added bioplastic precursor offers a solution to this waste disposal issue. In this study, readily available apple waste was converted into bioplastic through the delignification of cellulose cum reinforcement by nanocrystalline cellulose (NCC) extracted from the biowaste. The results indicated that the inclusion of apple waste and delignification effect had improved the bioplastic storage modulus (0.42–4.23 MPa) and brittleness in terms of hardness (5.22–0.51 kg). Morphological analysis revealed that the NCC had an average size of 70 nm and was homogeneously blended within the bioplastic matrix. The integration of the apple waste into the bioplastic promoted biodegradability, evident from the maximum weight loss of 58.1% after 4 weeks of biodegradation test, thus presenting a novel and alternative biodegradable plastic. The obtained results support apple waste as a potential filler for bioplastic development in food packaging, medical implants, 3D printing and water bottles. [ABSTRACT FROM AUTHOR]

An improvement of solid-state fluorescence from a luminous nanocomposite made from corn-starch-based bioplastic by adding intentionally Cu-doped carbon quantum dots (CQDs) has been reported. An affordable, environmentally sustainable, one-step hydrothermal technique was employed to synthesize CQDs from Brassica juncea flower extract. The morphological, structural, and physicochemical characteristics of the material were investigated. The quasi-circular shaped CQDs have been found to have a size distribution of 2–5 nm, to have yellow-greenish fluorescence upon UV stimulation, to have excellent photostability, and to be highly water soluble, with a quantum yield of up to 18.4%. Interestingly, the fluorescence spectra of intentionally Cu-doped CQDs (hereafter N, Ca, Cu-doped CQDs) were found to be brighter after 280 nm illumination than unintentional one. Furthermore, as a solid-phase dispersion matrix of CQDs, the environmentally benign and biodegradable bioplastic is appealing. As a result, this work demonstrated the effect of Cu-doping on solid-state fluorescence in the down-conversion of UVC tubes via a composite constructed by inserting CQDs into the solid-state matrix of corn-starch-based bioplastic nanocomposite, which demonstrated vivid greenish-yellow emission in the electroluminescent spectra with CIE chromatic coordinates (0.33, 0.58 vs. 0.31, 0.67). [ABSTRACT FROM AUTHOR]

D-Lactic acid is a chiral, three-carbon organic acid, that bolsters the thermostability of polylactic acid. In this study, we developed a microbial production platform for the high-titer production of D-lactic acid. We screened 600 isolates of lactic acid bacteria (LAB) and identified twelve strains that exclusively produced D-lactic acid in high titers. Of these strains, Lactobacillus saerimneri TBRC 5746 was selected for further development because of its homofermentative metabolism. We investigated the effects of high temperature and the use of cheap, renewable carbon sources on lactic acid production and observed a titer of 99.4 g/L and a yield of 0.90 g/g glucose (90% of the theoretical yield). However, we also observed L-lactic acid production, which reduced the product's optical purity. We then used CRISPR/dCas9-assisted transcriptional repression to repress the two Lldh genes in the genome of L. saerimneri TBRC 5746, resulting in a 38% increase in D-lactic acid production and an improvement in optical purity. This is the first demonstration of CRISPR/dCas9-assisted transcriptional repression in this microbial host and represents progress toward efficient microbial production of D-lactic acid. [ABSTRACT FROM AUTHOR]

The accumulation of plastic waste and rapid reduction of fossil reserves have pushed the development of packaging towards eco-friendly materials, such as bioplastics. However, most bioplastics are manufactured with chemical additives that are inorganic and entirely nondegradable. Therefore, bioplastics from renewable and biodegradable sources have been developed by incorporating cellulose, gelatine, and chitosan. This paper presents the optical properties, moisture content, swelling behaviour, assessment as packaging materials, and biodegradability tests of bioplastics. The considered bioplastics consisted of raw and cellulose from the whole, fibre, and bark of Pennisetum purpureum, with gelatine and chitosan fabricated using the solution-casting method. Cellulose was isolated using 8 wt% concentration of sodium hydroxide followed by 1.7 wt% concentration of sodium chlorite. The compatibility of fibre-matrix adhesion was improved by including cellulose from WPP, FPP, and BPP into the incorporation of chitosan and gelatine in bioplastics. Nevertheless, improving their optical properties, moisture content, and swelling behaviour had caused bioplastics to be more resistant to microbial activity and have the slower degradation rate. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHA) can be used to combat the challenges associated with plastic because it is biodegradable and can be produced from renewable resources. Extremophiles are considered to be potential PHA producers. An initial screening for the PHA synthesizing ability of a thermophilic bacteria Geobacillus stearothermophilus strain K4E3_SPR_NPP was carried out using Sudan black B staining. Nile red viable colony staining was used to further verify that the isolates produced PHA. Crotonic acid assays were used to determine the concentrations of PHA. The bacteria showed 31% PHA accumulation per dry cell weight (PHA/DCW) when glucose was used as a carbon source for growth. The molecule was identified to be medium chain length PHA, A copolymer of PHA containing poly(3-hydroxybutyrate)-poly(3-hydroxyvalerate)-poly(3-hydroxyhexanoate) (PHB-PHV-PHHX) using 1H-NMR. Six carbon sources and four nitrogen sources were screened for the synthesis of maximum PHA content, of which lactose and ammonium nitrate showed 45% and 53% PHA/DCW respectively. The important factors in the experiment are identified using the Plackett–Burman design, and optimization is performed using the response surface method. Response surface methodology was used to optimize the three important factors, and the maximum biomass and PHA productions were discovered. Optimal concentrations yielded a maximum of 0.48 g/l biomass and 0.32 g/l PHA, measuring 66.66% PHA accumulation. Dairy industry effluent was employed for the synthesis of PHA, yielding 0.73 g/l biomass and 0.33 g/l PHA, measuring 45% PHA accumulation. These findings add credibility to the possibility of adopting thermophilic isolates for PHA production using low-cost substrates. [ABSTRACT FROM AUTHOR]

Plastic waste generation has been increasing considerably, which bring about several environmental problems such as microplastics. In addition to the plastic pollution, the reduction in the use of petrochemical plastics is a key aspect to enhance sustainability. To alleviate the problems, the development of an innovative solution is rightly expected. Bioplastics are an alternative for conventional petrochemical plastics, recently gaining in a lot of attention. Microalgae can be an attractive source for the production of bioplastics given that they have a very distinctive growth yield in comparison to typical lignocellulosic biomass. Therefore, the employment of microalgae to produce bioplastics affords a golden opportunity to enhance sustainability of plastic usage. Given recent scientific research achievements in bioplastic production from microalgae, a review of the achievements is required. In this regard, this study was aimed at providing a review on the production of bioplastics using microalgae, which laid great emphasis on determining the current state of microalgal bioplastic production technologies and offering potential processes and applications. The prospect of bioplastic production based on microalgae is also discussed, and important points and challenges facing further research into the microalgal bioplastics are highlighted. [ABSTRACT FROM AUTHOR]

Black Soldier Fly (BSF) is a novel option to convert organic waste into high economic products such as protein, lipid, and chitin. Due to the drawbacks of petrochemical-based plastic, the biodegradable film has attracted much attention; among these, chitin-based packaging film is a promising material. This study extracted the chitin from BSF using a co-solvent of glycerol and hydrochloric acid (HCl). The chitin nanofiber has a dimension of 34 nm in width and 494 in length following Transmission Electron Microscopy analysis (TEM). Besides, the obtained chitin was also added to the gelatin-based film for packaging application. The chitin/gelation packaging was evaluated for its suitability in food application by testing its antioxidant activity, thickness, grammage, opacity, moisture, and water solubility. The film developed with more than 0.5 wt.% chitin and nanochitin showed high antioxidant activity, while adding chitin does not significantly change the thermal stability of the gelatin films. The chemical structure of chitin and bio-packaging was determined by Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), and Thermogravimetric Analysis (TGA). This study provides a green and facile approach for chitin production from BSF by using co-solvent and reveals the potential of insect chitin in creating active bio-packaging. [ABSTRACT FROM AUTHOR]

The demand for petroleum-based plastics is a major threat and has had several negative impacts on the environment. Biodegradable plastics are becoming increasingly attractive due to their cost-effectiveness and eco-friendly properties. This study aimed to develop and evaluate the properties of biodegradable plastic films produced using a low-cost starch source (potato) with a blend of glycerol and sorbitol as the plasticizers. A total of 10 bioplastic films were prepared by varying the type and concentration of plasticizers at a ratio of 0%, 10%, 20%, 30%, and the glycerol–sorbitol blend mixture at a ratio of 2:1, 1:2, and 1:1 (wt%) using the solution casting technique. Several characterization techniques were used to determine the morphological, structural, and chemical properties of the as-synthesized bioplastic films. Fourier transform infrared spectroscopy and morphology measurements verified the confirmation of potato starch bioplastics. Biofilms with glycerol: sorbitol blend plasticizer exhibited higher thermal stability and maximum tensile stress than films plasticized with glycerol. The results also showed that the films with a blend plasticizer exhibited better compatible morphology than those plasticized with glycerol. The results indicate that the synthesized bioplastic samples have great potential for various applications, especially as packaging materials. [ABSTRACT FROM AUTHOR]

The increase in environmental consciousness has promoted the use of renewable resources. A tremendous spike has been observed in the use of products that decompose into environment-friendly constituents, which leads to the protection of the environment. Such environment-centric thinking has reduced the volume of solid waste generated by consumers every year, together with reuse and recycling. However, the environmentally friendly initiatives and regulations face a setback when the cost is high. Often the quality of such products is compromised in comparison with synthetically derived products for consumer usage. Plastic is a ubiquitous pollutant with potentially harmful effects on living beings. The increasing population and a steady increase in petrochemical plastics' demand hamper global plastic waste management. The use of bioplastics has helped us to overcome these issues. Poly(hydroxybutyrate) (PHB) is commonly known, first synthesized bioplastic, which has strong potential in replacing conventional plastics. This review focuses on the PHB biopolymer's significant properties over plastic, its application in different fields, i.e., medical science, agriculture, construction, packaging, energy, etc. It also covers PHB biosynthesis using different waste products as a substrate to minimize the production process cost, degradation, and different analytical methods to characterize the PHB. Along with these, we have also discussed about the other polysaccharide based biodegradable polymers. [ABSTRACT FROM AUTHOR]

Biomass-derived isosorbide (ISB) is a promising alternative to petroleum-based monomers in industrial plastics. In this study, ISB-based thermoplastic polyurethanes (ISB-TPUs) were prepared using ISB as a biomass chain extender, and the effects of the preparation route on the structural and physical properties of the resultant polymers were investigated. Prepolymer methods were more suitable for obtaining the desired molecular weights (MWs) and physical properties of ISB-TPUs than the one-shot method. The presence of the solvent and catalyst in the prepolymer step had significant effects on the structural and physical properties of the resultant polymer. Among several prepolymer conditions, the solvent- and catalyst-free methods were the most suitable for preparing commercial-level ISB-TPUs, with number- and weight-average MWs (Mn and Mw) of 32,881 and 90,929 g mol−1, respectively, and a tensile modulus (E) and ultimate tensile strength (UTS) of 12.0 and 40.2 MPa, respectively. In comparison, the presence of a catalyst in the prepolymer step resulted in lower MWs and mechanical properties (81,033 g mol−1 and 18.3 MPa of Mw and UTS, respectively). The co-existence of the catalyst/solvent led to a further decline in the properties of ISB-TPUs (26,506 and 10.0 MPa of Mw and UTS, respectively). ISB-TPU prepared via the solvent- and catalyst-free methods exhibited remarkable elastic recovery when subjected to up to 1000% strain in mechanical cycling tests. Rheological characterization confirmed the thermo-reversible phase change (thermoplasticity) of the polymer. [ABSTRACT FROM AUTHOR]

Poly-hydroxy-butyrate (PHB) bioplastic resin can be made directly from atmospheric CO2 using cyanobacteria. However, higher PHB productivities are required before large-scale production is economically viable. Random mutagenesis offers a way to create new production strains with increased PHB yields and increased biomass densities without complex technical manipulation associated with genetically modified organisms. This study used staining with lipid fluorescent dye (BODIPY 493/593) and fluorescence-activated cell sorting (FACS) to select high lipid content mutants and followed this with a well plate growth screen. Thirteen mutants were selected for flask cultivation and two strains produced significantly higher PHB yields (29% and 26% higher than wild type), biomass accumulation (36% and 33% higher than wild type) and volumetric PHB density (75% and 67% higher than wild type). The maximum PHB yielding strain (% dcw) was 12.0%, which was 43% higher than the wild type (8.3% in this study). The highest volumetric PHB density was 18.8 mg PHB/L compared to 10.7 mg PHB/L by the wild type. To develop cyanobacterial strain with higher PHB productivities, the combination of random chemical mutagenesis and FACS holds great potential to promote cyanobacteria bioplastic production becoming economically viable. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) are an alternative to traditional organic solvents and ionic liquids and meet the requirements of “green” chemistry. They are easy to prepare using low-cost constituents, are non-toxic and biodegradable. The review analyzes literature on the use of DES in various fields of biotechnology, provides data on the types of DESs, methods for their preparation, and properties. The main areas of using DESs in biotechnology include extraction of physiologically active substances from natural resources, pretreatment of lignocellulosic biomass to improve enzymatic hydrolysis of cellulose, production of bioplastics, as well as a reaction medium for biocatalytic reactions. The aim of this review is to summarize available information on the use of new solvents for biotechnological purposes. [ABSTRACT FROM AUTHOR]

This contribution describes an algal fractionation scheme based on cell lysing and carbohydrate hydrolysis under acidic conditions, coupled with solvent extraction, that produces algal lipids, carbohydrates, and proteinaceous solid from partially dewatered algal biomass. A design of experiments analysis was employed to identify the effect of fractionation conditions on the yields of the three product streams. By selection of appropriate conditions, the process can be steered from simple lipid extraction to near complete fractionation of the biomass. Lipid purification and upgrading were respectively achieved with a low-cost adsorbent and an inexpensive Ni-based catalyst that deoxygenated the lipids via decarboxylation/decarbonylation, an approach offering several advantages over the hydrodeoxygenation-based processes typically employed to convert lipids to hydrocarbons. The proteinaceous solids obtained were found to have much lower ash content as well as higher protein content relative to the untreated algae, enhancing the suitability of this material as a feedstock for the production of bioplastics. [ABSTRACT FROM AUTHOR]

Plastics are undebatably a hot topic of discussion across international forums due to their huge ecological footprint. The onset of COVID-19 pandemic has exacerbated the issue in an irreversible manner. Bioplastics produced from renewable sources are a result of lookout for sustainable alternatives. Replacing a ton of synthetic plastics with biobased ones reduces 1.8 tons CO2 emissions. Here, we begin with highlighting the problem statement—Plastic accumulation and its associated negative impacts. Microalgae outperforms plants and microbes, when used to produce bioplastic due to superior growth rate, non-competitive nature to food, and simultaneous wastewater remediation. They have minimal nutrient requirements and less dependency on climatic conditions for cultivation. These are the reasons for current boom in the algal bioplastic market. However, it is still not at par in price with the petroleum-based plastics. A brief market research has been done to better evaluate the current global status and future scope of algal bioplastics. The objective of this review is to propose possible solutions to resolve the challenges in scale up of bioplastic industry. Various bioplastic production technologies have been comprehensively discussed along with their optimization strategies. Overall studies discussed show that in order to make it cost competitive adopting a multi-dimensional approach like algal biorefinery is the best way out. A holistic comparison of any bio-based alternative with its conventional counterpart is imperative to assess its impact upon commercialization. Therefore, the review concludes with the life cycle assessment of bioplastics and measures to improve their inclusivity in a circular economy. [ABSTRACT FROM AUTHOR]

Purpose: The pervasive use of plastics, coupled with inadequate waste management systems in many countries, has led to widespread leakage of plastics into the environment. In South Africa, the predominant type of shopping bags are single-use plastic bags; but paper, biodegradable plastic and re-usable bags have emerged as alternatives. To compare these alternatives in terms of environmental impacts across the whole product life cycle, we carried out a cradle-to-grave life cycle assessment (LCA) of 16 shopping bag types available in South Africa. Methods: The comparison includes single-use plastic, bioplastic and paper bags, as well as re-usable bags (typically made from plastic in South Africa). The functional unit was based on the estimated annual volume of groceries purchased per capita. An attributional LCA was carried out using the ReCiPe 2016 Midpoint(H) method, with 18 mid-point impact categories. In addition, given the lack of an impact category for plastic pollution in existing methods, we developed a mid-point indicator based on the persistence of plastics (and other materials) leaked to the environment (Persistence of leaked material, PersistenceLM). Specific attention was placed on modelling end-of-life and waste management in the South African context. Economic-based allocation at the point of substitution was used to apportion environmental impacts to virgin and recyclate material, and the production of recyclate was modelled using system expansion. Results and discussion: Re-usable bag types, specifically the 70 µm High Density Polyethylene (HDPE) and non-woven Polyester bags, had the lowest environmental impacts for all indicators, except PersistenceLM. Paper and biodegradable plastic bags had a lower PersistenceLM impact as compared to the petro-based plastic bags, and therefore may be preferable in terms of avoiding plastics accumulating in the environment. The re-usable bags need to be used at least 3 to 10 times to offer lower environmental impacts than single-use ones. Among the single-use bags, biodegradable bags made from imported Polybutylene Adipate Terepthalate (PBAT) plus starch showed the lowest environmental impacts across all impact categories, including PersistenceLM, followed by the Paper bag. The single-use 24 µm HDPE bag (HDPE_24) with no recycled content had the highest overall environmental impacts, while increasing the recycled content reduced overall environmental impacts by up to 52%. Compared to other countries, the high environmental impacts of plastic bags in South Africa can largely be attributed to the coal-to-liquids process used for polymer production, which is intensive in terms of both energy and raw materials. [ABSTRACT FROM AUTHOR]

Diatoms such as Phaeodactylum tricornutum are emerging as sustainable alternatives to traditional eukaryotic microbial cell factories. In order to facilitate a viable process for production of heterologous metabolites, a rational genetic design specifically tailored to metabolic requirements as well as optimised culture conditions are required. In this study we investigated the effect of constitutive and inducible expression of the heterologous poly-3-hydroxybutyrate (PHB) pathway in P. tricornutum using non-integrative episomes in 3 different configurations. Constitutive expression led to downregulation of at least one individual gene out of three (phaA, phaB and phaC) and was outperformed by inducible expression. To further asses and optimise the dynamics of PHB accumulation driven by the inducible alkaline phosphatase 1 promoter, we upscaled the production to lab-scale bioreactors and tested the effect of supplemented CO2 on biomass and PHB accumulation. While ambient CO2 cultivation resulted in a maximum PHB yield of 2.3% cell dry weight (CDW) on day 11, under elevated CO2 concentrations PHB yield peaked at 1.7% CDW on day 8, coincident with PHB titres at 27.9 mg L−1 that were approximately threefold higher than ambient CO2. With other more valuable bio-products in mind, these results highlight the importance of the genetic design as well as substrate availability to supply additional reduction equivalents to boost biomass accumulation and relieve potential enzymatic bottlenecks for improved product accumulation. [ABSTRACT FROM AUTHOR]

In this work, bioplastic was formulated through the incorporation of cellulose into refined carrageenan. Three different sizes of cellulose were used microcrystalline cellulose (MCC), cellulose nanowhisker (CNW) and nanofibrillated cellulose (NFC). The CNW was mechanically nano-grinded and NFC was ultrasonicated to produce nano particle for MCC. The CNW has the smallest particle size distribution and an average size of 54 nm. The abundance of hydroxyl groups in the cellulose structure forms intermolecular interactions with the carrageenan and increases the viscosity (293.90 mPas), shear stress (27.90 Pa) and tensile strength (19.87 MPa) of Carra-CNW bioplastic. This revealed increasing intensity and a shift of 1H-NMR due to hydrogen becoming closer to an electronegative atom in both micro and nano size cellulose. At a larger cellulose size, Carra-MCC is thermally stable and the activation energy (Ea) is 73.81 kJ/mol higher than Carra-CNW Ea at 47.14 kJ/mol. Cellulose incorporated into a carrageenan matrix is a potential eco-material that could replace conventional plastic where the sample decomposes up to 65 % of the initial weight in biodegradability and compostability test. The water vapour permeability value is in the range of 3.43 to 4.09×10−14 g s−1 m−1 Pa−1. In conclusion, carrageenan incorporated with cellulose potentially suitable for uses such as food packaging applications based on the results of the mechanical strength, thermal stability and decomposition tests conducted. [ABSTRACT FROM AUTHOR]

Poly(ε-caprolactone; PCL) is an attractive biodegradable polymer that has been increasingly used to solve environmental problems caused by plastic wastes. In the present study, 468 bacterial isolates were recovered from soil samples and screened for PCL degradation activity. Of the isolates, 37 (7.9%) showed PCL depolymerase activity on PCL agar medium, with the highest activity being by isolate S22 which was identified using 16S rRNA and rpoB gene sequencing as Acinetobacter seifertii. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed the degradation of PCL films after treatment with A. seifertii S22. The PCL depolymerase activity of A. seifertii S22 relied on the activity of esterase which occurred at an optimum temperature of 30–40 °C. The highest PCL depolymerase activity (35.5 ± 0.7 U/mL) was achieved after culturing A. seifertii S22 for 6 h in mineral salt medium (MSM) containing 0.1% Tween 20 and 0.02% ammonium sulfate as the carbon and nitrogen sources, respectively, which was approximately 20-fold higher than for cultivation in MSM supplemented with 0.1% PCL as sole carbon source. The results suggested that A. seifertii S22 or its enzymes could be used for PCL bioplastic degradation. [ABSTRACT FROM AUTHOR]

The present study focuses on the efficient and optimized co-production of poly(hydroxyalkanoate) (PHA) and rhamnolipids (Rhls) in a batch bioreactor using Pseudomonas aeruginosa mutant strain cultivated on soybean oil in the minimal media provided with three sole nitrogen sources of sodium nitrate, carbamide, and ammonium chloride at different agitation speeds and dissolved oxygen (DO) saturation (%). Herein, up to 3.81 g PHA L−1 and 1.63 g Rhls L−1 could be produced at 200 rpm and 40% DO saturation, which then improved to 3.95 and 2.04 g L−1, respectively, at 250 rpm and 50% DO saturation, both with carbamide as a sole nitrogen source. The Rhls hence produced were quantified using a modified methylene blue assay whereas the biopolymer was elucidated using the Fourier transform infrared spectroscopy, liquid chromatography-mass spectrometry, and differential scanning calorimetry. The results demonstrated that the PHA hence produced was a poly(3-hydroxybutyrate) of the molecular mass 448.5 amu. Highlights: Herein, simultaneous poly(hydroxyalkanoate) (PHA) and rhamnolipids (Rhls) production is done on a bioreactor scale. The effect of different nitrogen sources on PHA and Rhls yields was investigated under various fermentation conditions. Chemical analysis elucidated that produced polymer is poly(3-hydroxybutyrate) (PHB). The production process has been evaluated using fermentative kinetics. There is a need to further economize the PHB/Rhls production and recovery processes, and to explore their feasible applications. [ABSTRACT FROM AUTHOR]

Agri-food waste and by-products are being increasingly revalued, exploiting their potential. One of the attractive alternatives is their use as raw materials for the production of bioplastics due to their high protein content, generating eco-friendly bioplastics, since they come from renewable sources and are biodegradable. However, their industrial scalability is being difficult mainly due to their manufacturing process, which is generally expensive. Therefore, the objective of this work was to revalue a by-product from the industrial production of soybean oil as a raw material to process bioplastics by extrusion moulding (a process widely used in the manufacture of plastics). In this way, the use of this raw material could reduce costs and facilitate the scalability of these products. The results obtained in this work show that this by-product is a suitable raw material for the development of bioplastics. Furthermore, extrusion allowed obtaining bioplastics with different mechanical characteristics and water uptake capacity by modifying the temperature and screw speed of the process. Thus, higher temperatures generated better mechanical resistance, while lower temperatures improved the water uptake capacity. These results demonstrate the great capacity of this raw material and processing technique for the large-scale adaptation of bioplastics that can be used in different applications, such as packaging and hygiene products. [ABSTRACT FROM AUTHOR]

The dairy market is one of the most important sectors worldwide, and milk packaging contributes to over one-third of the global dairy packaging demand. The end of life of the disposable packages is a critical stage of their life cycle, as demonstrated by the fact that disposable bottles are one of the litter items that are most found on beach shores. The aim of this paper is to analyse the performance of bioplastic bottles compared to other alternatives currently in use in the milk packaging sector, using the life cycle assessment (LCA) methodology. Bio-compostable plastic can be a powerful means to create a circular economy for disposable items. A PLA-based bottle is compared to a PET bottle, a HDPE bottle, a multilayer carton, and a glass bottle. In the analysis, also secondary and tertiary packaging is included. The functional unit chosen is "the packaging needed to contain 1 L of ESL milk and to guarantee a shelf life of 30 days". Two sensitivity analyses are also performed in order to assess the influence of the end-of-life stage on the total impact. The results show that, in accordance with the assumptions of an ideal scenario, bioplastic system has a better performance than fossil-based systems and multilayer carton in the categories of climate change, ozone depletion, human toxicity, freshwater eutrophication, particular matter, and land use. The recycling scenario strongly changes the impact of the glass packaging system in the considered categories. [ABSTRACT FROM AUTHOR]

Regenerated cellulose (RC)-based materials, a major biomass resource, have been widely used in various applications, owing to their degradability, sustainability, and green nature. Here, we constructed silver nanowire (AgNW)-based conductive microelectrodes on various RC substrates. The AgNW patterns on glass substrates fabricated by polyethylene glycol photolithography were transferred onto the RC hydrogel surface by the coagulation and regeneration of the cellulose solution. The dried AgNW-patterned RC films exhibited a high optical transmittance of 79% at 550 nm, an excellent tensile strength of 210 MPa, and excellent sheet resistance of 1.03 Ω/sq. Moreover, they exhibited good adhesion stability and excellent bending durability, compared to AgNW-coated/patterned polyethylene terephthalate films. After 5000 bending and 30 peeling test cycles, no significant increase in the sheet resistance was observed in the AgNW-patterned RC films. The AgNW-patterned RC films were converted into the AgNW-patterned RC hydrogel films by a spontaneous swelling process in an aqueous solution. This conductive hydrogel film can be used as important components, such as the membrane and coating in bioelectronics interfaced with biological systems. We anticipate that this approach combined with conductive AgNW patterns and ecofriendly RC substrates can render these microelectrodes suitable candidates in the development of next-generation green electronics and high-performance bioelectronics. [ABSTRACT FROM AUTHOR]

The development of novel biodegradable and ultraviolet (UV) shielding packaging materials has become a research hotspot, which could avoid "white pollution". Chitosan is an ideal raw material for food packaging but lacks sufficient UV shielding property. In this work, we used an alkali/urea/zincate aqueous solvent to dissolve chitosan, and the resulting chitosan solution was heated with the existence of chemical crosslinker to convert Zn(OH)42− into ZnO particles directly. Then, the chitosan/ZnO composite hydrogel sheets were obtained, which were converted to chitosan/ZnO composite bioplastic (CCZP) by a fixing and drying process. The structure and properties of CCZP were investigated with X-ray diffraction (XRD), scanning electron microscopy, XPS, water uptake and tensile testing etc. The results indicated that the in-situ synthesized ZnO particles had distributed evenly in the chitosan matrix. The optical transmittance of the obtained CCZP reached 0.01% at 300 nm and 51.6% at 800 nm, respectively, showing excellent UV shielding performance and relatively good visible light transmittance. Meanwhile, the mechanical properties of the chitosan bioplastic were improved by the incorporation of ZnO, and the tensile strength of CCZP reached up to 49.8 MPa, showing potential application as food packaging materials. [ABSTRACT FROM AUTHOR]

Purpose: Bioplastics are an often-touted alternative to reduce the environmental impacts of plastic usage, and potentially reduce reliance on petroleum sources, when compared to conventional plastics. Life cycle assessment (LCA) is a tool used to quantify the comparable environmental impacts throughout a product's life cycle. Although existing literature has focused on the raw materials and includes stylized use and disposal scenarios, gaps exist related to the role of human behavior and its subsequent environmental impact due to the real-world usage and disposal of bioplastic products. This is in part due to challenges in fully understanding the role of human behavior and incorporating it into LCA to generate meaningful results. This work seeks to identify these gaps through a review of current literature. The work contained herein is written from a United States (US) perspective with its solid waste infrastructure in mind and challenges specific to the US. Materials and methods: A review of existing literature on human behavior in disposal of conventional plastics and bioplastics, and the degree of incorporation of in LCA studies, is conducted. This allowed for the identification of current gaps within the literature, such as the role of human behavior and decision-making, within the end-of-life scenarios. Results and discussion: There is a significant body of literature that analyzes the cradle-to-gate impact of bio-based bioplastics from an LCA perspective. However, user behavior and end of life are studied less due to the challenges of predicting human behavior at disposal, modeling the boundaries, and issues of location specificity. There is conflicting evidence as to the benefits and adverse impacts of bioplastics when compared with conventional plastics, which may be further clarified through the incorporation of human behavior in the end of life of the bioplastic and conventional plastic products. Conclusions: Bioplastics have been suggested as an opportunity to reduce the environmental impacts of plastic usage throughout their life cycle. Portions of the bioplastic life cycle have been well quantified in literature, such as raw materials and manufacturing, while the end of life has largely been incorporated as stylized scenarios. Bioplastic LCA literature does not fully capture the effects of true disposal in its findings. In order to capture these effects, a focus on the junction between end-of-consumer-use and entry into waste collection system is needed. To generate more comprehensive and holistic assessments, more research is required as to the role of human behavior and its consequential environmental impacts. This will lead to more realistic modeling and society level forecasts as to the comparative environmental impacts of bioplastic usage. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHA) are a group of biopolymers produced naturally by microorganisms with properties similar to various petroleum-based plastics. However, to date their commercial production has remained uncompetitive due to substrate, sterilization, aeration and processing costs. Purple non-sulfur bacteria (PNSB) are a group of anoxygenic photoheterotrophic bacteria that have the ability to accumulate PHA under unbalanced conditions in anaerobic environments and constant feeding with high conversion ratios. Such characteristics could potentially overcome some of the bottlenecks of conventional chemoheterotrophic PHA production. Yet these organisms have received relatively limited attention. This review explores the factors involved in the PHA accumulation process from PNSB, highlighting the differences to conventional PHA production and the areas yet to be optimized. The roles of fermentation systems, carbon substrate, feeding conditions, nutrients, pH and various aspects of light are reviewed to understand their role in PHA accumulation in PNSB. [ABSTRACT FROM AUTHOR]

Purpose: The most abundant among the separately collected waste materials in Italy is food waste. This research aims to evaluate the influence of the type of collection bag on the food waste management chain. In Italy, the food waste collection is mainly based on bioplastic bags. As an alternative, a new type of recycled paper bag shows potential advantages. Methods: The two types of collection bag were compared evaluating the weight loss of food waste during the household storage, by means of an experimental assessment simulating the domestic dynamic bag filling. Moreover, the biomethane production of bags under anaerobic conditions was measured at the lab-scale level with Biochemical Methane Potential (BMP) tests. Results: During the household storage, the breathable fabric of the paper allows for higher weight losses, ranging on average between + 29 and + 44% compared to bioplastic. BMP tests, carried out under different conditions (temperature, inoculum), showed a 2–14 times higher generation of methane by paper bags compared to bioplastic bags, when referred to 1 kg of inserted food waste. Conclusions: Collecting the food waste inside paper bags shows advantages compared to the use of bioplastic bags. First, the waste collection is benefitted thanks to the lower weight of material to be transported to treatment plants, leading also to the possibility of decreasing the collection frequency. Moreover, paper resulted more compatible than bioplastic with the anaerobic digestion treatment, which is currently rapidly increasing as a food waste management option. [ABSTRACT FROM AUTHOR]