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The utilization of biodegradable hydrogels based on natural polysaccharides in the agricultural and biomedical sectors is anticipated to be a growing field of interest. Due to increasing environmental pollution, the current global goal is to synthesize sustainable materials based on natural polysaccharides to conserve natural resources for the future. In this study, we synthesized an amla-based hydrogel, denoted as AL-g-poly(MAA), using the graft-free radical polymerization method. Methacrylic acid (MAA) was employed as the monomer, N,N′-methylenebisacrylamide (MBA) served as the crosslinker, and ammonium persulfate (APS) acted as the initiator. The synthesized hydrogel, AL-g-poly(MAA), underwent optimization by adjusting seven parameters: initiator, solvent, time, monomer, power, pH, and crosslinker, to achieve the highest swelling percentage. The optimized values were as follows: solvent: 10 ml, time: 150 s, monomer: 0.039 mol/L, power: 60%, pH: 7, and crosslinker: 0.0648 mol/L. The cross-linking process was confirmed through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) techniques. The swelling behavior of the synthesized hydrogels was determined in saline solutions with varying ionic strengths and concentrations, revealing maximum swelling in solutions with lower ionic strengths and concentrations. Additionally, the density and porosity of the hydrogels were examined. The biodegradability of AL-g-poly(MAA) was tested through soil burial and vermicomposting experiments, demonstrating its significant potential for agriculture applications. Furthermore, both the backbone and the synthesized hydrogel were evaluated for antibacterial activity against four bacterial strains (Burkholderia gladioli, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus cereus), revealing strong potential as an antimicrobial agent and therefore having applications in the biomedical field. The mechanism underlying the inhibitory effect of synthesized AL-g-poly(MAA) hydrogel on bacterial cell membranes is also discussed. [ABSTRACT FROM AUTHOR]

This study assessed bioplastics made from different mass proportions of commercial chitosan and banana plant pseudostem-derived hemicelluloses. The bioplastics were prepared by the casting method and characterized for moisture content, water solubility, opacity, water absorption, tensile strength, and thermogravimetric properties. The formulations with hemicelluloses addition showed higher moisture content and water solubility than the chitosan-only bioplastic, the maximum values of these properties (22.3 and 22.4%) were achieved when hemicelluloses were added at the proportion of 10 and 5%, respectively. A positive linear correlation (r = 0.86) was found between added hemicelluloses and opacity, with the highest opacity (1.95 mm−1) achieved in the formulation with the maximum hemicellulose incorporation. The bioplastics containing hemicelluloses exhibited lower swelling (water absorption) than that made only of chitosan, with the formulation featuring the highest hemicelluloses content showed the lowest swelling (229.2%). A negative linear correlation (r = 0.95) was observed between added hemicelluloses and swelling values. The formulation with the highest hemicelluloses content demonstrated statistically significant differences and exhibited the highest tensile strength (18.7 MPa) and Young's modulus (66.1 MPa). Thermogravimetric analysis revealed four stages of mass loss in the bioplastics. Hemicelluloses addition decreased the temperature at maximum mass loss, and the formulation with the lowest hemicelluloses content showed a higher degradation rate than the others. [ABSTRACT FROM AUTHOR]

With a growing population of about 7.8 billion, humans are generating tons of waste in the form of non-biodegradable plastics on a daily basis that ends up in landfills and oceans. The introduction of packaging has been a blessing to mankind by facilitating the ease of convenience in transportation, delivery and general usage. The downside, however, is that majority of the packaging currently available is harmful to the environment and takes thousands of years to decay. This paper discusses the use of chitosan from shrimp shells and other marine animals' exoskeleton waste in food packaging industries. Chitosan extracted from marine organisms is modulated in the form of packaging material. Compared to conventional packaging, chitosan films are 73.4% biodegradable in soil under laboratory conditions whereas 100% degraded in an open field. Chitosan with metal oxides, essential oils, natural extracts, proteins and other polymers show enhanced tensile strength, water vapor permeability, oxygen and ultraviolet barrier. Chitosan and composite film show antimicrobial activity against gram positive and negative bacteria. Comparative approaches on environmental impacts between conventional plastics and chitosan films are enlightened, thereby highlighting the importance of natural polymers as packaging films that are considered economic based on the addition of additives. [ABSTRACT FROM AUTHOR]

There are several physical and chemical methods for synthesizing nanomaterials, while the most appropriate techniques involve using green chemistry and eco-friendly material. Recently, green synthesized materials for different applications have gained attention as a result of their environmental friendliness and cost-effectiveness. Applying green synthesized nanoparticles (NPS) in food packaging has been extensively investigated. Biopolymers require filler to enhance the optical, barrier, thermal, antimicrobial, and mechanical properties of packaging. Biopolymer packaging incorporated with green synthesized NPs is expected to simultaneously enhance performance while reducing environmental damage. The current review article focuses on biopolymer films with bio (green)-synthesized nanomaterials and their effectiveness in reducing the negative environmental implications of synthetic packaging. It also covers the general concepts of green synthesis of NPs, their production methods, their performance, and characterization, and discusses the potential, performance and recent developments of bio-nanocomposite films/coatings in biodegradable food packaging. Recent reports and trends provide more insight into the impact of green synthesized nanomaterials on food packaging. [ABSTRACT FROM AUTHOR]

Cellulose is the most attractive renewable natural polymer, carrying off a 211 billion USD market size that entered the plastic world for industrial application. However, the extraction of cellulose forms (micro/nano) in an economical manner is still challenging for researchers who have been trying different cellulose-based sources and methods. Henceforth, the present study focused on extracting cellulose microfibers (CMFs) from agro biomass to mitigate the cost of satisfying industrial demands. The waste fallen dried leaves were used to extract micro cellulose through alkaline peroxide treatment and studied the essential characteristics like morphology, spectral and crystallinity, and CMFs having 45.8 µm size with rough morphology and the spectral peak of 3339 cm−1, and 2890 cm−1 corresponding to hydrogen bond O–H, and C–H of cellulose respectively. Further, the various % (5–15) of CMFs were reinforced to polyvinyl alcohol (PVA) to prepare CMFs/PVA composites through the solution casting method. The experimental results showed that the composites having chemical interaction bond at 3260 cm−1 and 2θ = 19.6◦ diffraction peak. The optimized % of CMFs showing tensile strength 80.37 MPa and 2.51 GPa and decreased 9.37% elongation at break. CMFs loading significantly enhanced biodegradation by about 21.44%. This improvement in biodegradation highlights the potential environmental benefits of utilizing CMFs in plastic film production. In conclusion, this study provides the idea of economically obtaining micro cellulose and designing biodegradable plastic for packaging application. [ABSTRACT FROM AUTHOR]

Fossil fuels are a major source of energy worldwide and serve as raw materials for the production of plastics. However, they have disadvantages such as uneven distribution, price instability, limited availability, and environmental impact. Consequently, there is a need to find alternatives to fossil fuels for both energy and polymer production in the short term. This review focuses on the synthesis of poly(hydroxyalkanoate)s (PHAs), a type of biopolymer, using different bioethanol stream wastes. PHAs exhibit properties comparable to petroleum-based plastics, making them promising replacements. There has been a significant increase in research studies exploring alternatives to fossil fuels and synthetic polymers, as evidenced by the growing number of publications. While biopolymers currently account for only 1% of global polymer production derived from petroleum, the PHA industry is experiencing rapid growth. The market value of PHAs was estimated at $ 168.9 million in 2020, and it is projected to reach $ 440 million by 2031, indicating a compound annual growth rate of 9.2%. The production of this biopolymer is already contributing to an expanding industrial value chain, which is expected to further growth with increased availability of commercial PHAs. [ABSTRACT FROM AUTHOR]

Biodegradable polymer nanocomposites (BPNCs) are advanced materials that have gained significant attention over the past 20 years due to their advantages over conventional polymers. BPNCs are eco-friendly, cost-effective, contamination-resistant, and tailorable for specific applications. Nevertheless, their usage is limited due to their unsatisfactory physical and mechanical properties. To improve these properties, nanofillers are incorporated into natural polymer matrices, to enhance mechanical durability, biodegradability, electrical conductivity, dielectric, and thermal properties. Despite the significant advances in the development of BPNCs over the last decades, our understanding of their dielectric, thermal, and electrical conductivity is still far from complete. This review paper aims to provide comprehensive insights into the fundamental principles behind these properties, the main synthesis, and characterization methods, and their functionality and performance. Moreover, the role of nanofillers in strength, permeability, thermal stability, biodegradability, heat transport, and electrical conductivity is discussed. Additionally, the paper explores the applications, challenges, and opportunities of BPNCs for electronic devices, thermal management, and food packaging. Finally, this paper highlights the benefits of BPNCs as biodegradable and biodecomposable functional materials to replace traditional plastics. Finally, the contemporary industrial advances based on an overview of the main stakeholders and recently commercialized products are addressed. [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 the course of the past two decades, biodegradable polymers have established to serve in form of compostable or soil-biodegradable items as sustainable alternatives to standard plastics in applications where their property of biodegradability adds value. BASF has been a pioneer in this field of action with their commercially available products ecoflex® and ecovio®. Based on continuous research and development at the edge between polymer chemistry and microbiology, not only new developments were realized in the recent past but also a deep understanding about biodegradation under various conditions could be generated. This chapter provides an up-to-date picture about the chemistry and biodegradation, about processing, applications as well as the sustainability contribution of ecoflex® and ecovio®. [ABSTRACT FROM AUTHOR]

Biodegradability standards measure ultimate biodegradation of polymers by exposing the material under test to a natural microbial inoculum. Available tests developed by the International Organization for Standardization (ISO) use inoculums sampled from different environments e.g. soil, marine sediments, seawater. Understanding whether each inoculum is to be considered as microbially unique or not can be relevant for the interpretation of tests results. In this review, we address this question by consideration of the following: (i) the chemical nature of biodegradable plastics (virtually all biodegradable plastics are polyesters) (ii) the diffusion of ester bonds in nature both in simple molecules and in polymers (ubiquitous); (iii) the diffusion of decomposers capable of producing enzymes, called esterases, which accelerate the hydrolysis of esters, including polyesters (ubiquitous); (iv) the evidence showing that synthetic polyesters can be depolymerized by esterases (large and growing); (v) the evidence showing that these esterases are ubiquitous (growing and confirmed by bioinformatics studies). By combining the relevant available facts it can be concluded that if a certain polyester shows ultimate biodegradation when exposed to a natural inoculum, it can be considered biodegradable and need not be retested using other inoculums. Obviously, if the polymer does not show ultimate biodegradation it must be considered recalcitrant, until proven otherwise. [ABSTRACT FROM AUTHOR]

Quantification and characterization of microplastics, synthetic polymers less than 5 mm in diameter, requires extraction methods that can reduce non-plastic debris without loss or alteration of the polymers. Nitric acid has been used to extract plastic particles from zooplankton and other biota because it completely digests tissue and exoskeletons, thus reducing interferences. While the impact of acid digestion protocols on several polymers has been demonstrated, advice for quantifying microplastic and interpreting their spectra following nitric acid digestion is lacking. Fourier transform infrared (FTIR) and/or Raman spectroscopy was performed on plastics from > 50 common consumer products (including a variety of textiles) pre- and post-nitric acid treatment. The percent match and assigned polymer were tabulated to compare the accuracy of spectral identification before and after nitric acid digestion via two open spectral analysis software. Nylon-66, polyoxymethylene, polyurethane, polyisoprene, nitrile rubber, and polymethyl methacrylate had ≥ 90% mass loss in nitric acid. Other less-impacted polymers changed color, morphology, and/or size following digestion. Thus, using nitric acid digestion for microplastic extraction can impact our understanding of the particle sizes and morphologies ingested in situ. Spectral analysis results were compiled to understand how often (1) the best-hit matches were correct (30–60% of spectra), (2) the best-hit matches exceeding the (arbitrary) threshold of 65% match were correct (53–78% of spectra), and (3) the best-hit matches for anthropogenic polymers were incorrectly identified as natural polymers (12–15% of spectra). Based on these results, advice is provided on how nitric acid digestion can impact microplastics as well as spectral interpretation. [ABSTRACT FROM AUTHOR]

The packaging sector is one of the main responsible of post-consumer plastic waste in the European Union. The increasing consumer pressure and the banning or limitation of some materials are pushing producers towards new solutions. Polyhydroxyalkanoates (PHA) are a class of compostable bioplastics, easily degraded in composting facilities as well as on soil and aquatic environment. Three different blends of P(3HB)(3HH), poly-3-hydroxybutyrate-co-3-hydroxyhexanoate, and of P(3HB)(4HB), poly-3-hydroxybutyrate-co-4-hydroxybutyrrate are studied to achieve a thin film suitable for the manufacturing of films for food packaging. The compounds were produced by twin-screw extrusion and then processed by cast film extrusion. The increasing percentage of P(3HB)(4HB) leads to a higher elongation at break, a lower maximum stress and elastic modulus. The OTR sensibly increases whereas the increase in WVTR is less remarked. The properties of the films confirm the possibility of employing these PHA-based films as packaging with low environmental footprint. [ABSTRACT FROM AUTHOR]

The development of environmentally friendly materials based on natural and biodegradable sources, such as starch, represents an interesting alternative to attend to the environmental problems caused by excess waste from petroleum-based packaging. The use of emulsions to obtain edible films is a novel strategy to be explored to determine how formulation and constitution affect film properties. In such context, gelatinized tapioca starch (TS) and oregano essential oil (OEO) were used to produce new active edible films using casting technique and their physical and antimicrobial properties were studied. Regarding the emulsion constitution, which was obtained employing an high-speed homogenizer, exposure to ultrasound (US) and surfactant Tween 80 (T80) content, had relevant effects on micro (0.2 to 105 μm) and nanometric (63 to 212 nm) size distributions of the TS particles and the OEO droplets. Exposure to US reduced (4.8–34 μm) and stabilized microparticles but promoted nanoparticle aggregation during storage, independently of T80 addition. T80 helped to stabilize coarse emulsions showing a Sauter diameter of 21.4 μm along storage. Films from coarse emulsions containing OEO and T80 were stiffer (stress at break: 1.8 MPa), less soluble in water (≈ 35%) and yellowish than films without T80. In addition, surfactant promoted a discontinuous microstructure of the film matrix. Both films containing OEO showed a good capacity to inhibit the growth of spoilage microorganisms (≈ 2.5–4 log cycles reductions). Due to their performance as physical and antimicrobial barriers, the films can be proposed as active packaging alternatives to stabilize and release natural preservatives to promote food preservation during storage and as a tool to support environmental sustainability. [ABSTRACT FROM AUTHOR]

Isolation and detection of microplastics (MP) in marine samples is extremely cost- and labor-intensive, limiting the speed and amount of data that can be collected. In the current work, we describe rapid measurement of net-collected MPs (net mesh size 300 µm) using a benchtop near-infrared hyperspectral imaging system during a research expedition to the subtropical North Atlantic gyre. Suspected plastic particles were identified microscopically and mounted on a black adhesive background. Particles were imaged with a Specim FX17 near-infrared linescan camera and a motorized stage. A particle mapping procedure was built on existing edge-finding algorithms and a polymer identification method developed using spectra from virgin polymer reference materials. This preliminary work focused on polyethylene, polypropylene, and polystyrene as they are less dense than seawater and therefore likely to be found floating in the open ocean. A total of 27 net tows sampled 2534 suspected MP particles that were imaged and analyzed at sea. Approximately 77.1% of particles were identified as polyethylene, followed by polypropylene (9.2%). A small fraction of polystyrene was detected only at one station. Approximately 13.6% of particles were either other plastic polymers or were natural materials visually misidentified as plastics. Particle size distributions for PE and PP particles with a length greater than 1 mm followed an approximate power law relationship with abundance. This method allowed at-sea, near real-time identification of MP polymer types and particle dimensions, and shows great promise for rapid field measurements of microplastics in net-collected samples. [ABSTRACT FROM AUTHOR]

The increasing use of synthetic polymers and their disposal has raised concern due to their adverse effects on the environment. Thus, other sustainable alternatives to synthetic plastics have been sought, such as polyhydroxyalkanoates (PHAs), which are promising microbial polyesters, mainly due to their compostable nature, biocompatibility, thermostability, and resilience, making this biopolymer acceptable in several applications in the global market. The large-scale production of PHAs by microorganisms is still limited by the high cost of production compared to conventional plastics. This review reports some strategies mentioned in the literature aimed at production and recovery, paving the way for the bio-based economy. For this, some aspects of PHAs are addressed, such as synthesis, production systems, process control using by-products from industries, and advances and challenges in the downstream. The bioplastics properties made them a prime candidate for food, pharmaceutical, and chemical industrial applications. With this paper, it is possible to see that biodegradable polymers are promising materials, mainly for reducing the pollution produced by polymers derived from petroleum. [ABSTRACT FROM AUTHOR]

The current era of industrialization includes a constantly increasing demand for plastic products, but because plastics are rarely recycled and are not biodegradable plastic pollution or "white pollution" has been the result. The consumption of petroleum-based plastics will be 20% of global annual oil by 2050, and thus there is an inevitable need to find an innovative solution to reduce plastic pollution. The biodegradable and environmentally benign bioplastics are suitable alternative to fossil-based plastics in the market due to sustainability, less carbon footprint, lower toxicity and high degradability rate. Microalgal species is an innovative approach to be explored and improved for bioplastic production. Microalgae are generally present in abundant quantity in our ecosystem, and polysaccharide in the algae can be processed and utilized to make biopolymers. Also, these species have a high growth rate and can be easily cultivated in wastewater streams. The review aims to determine the recent status of bioplastic production techniques from microalgal species and also reveal optimization opportunities involved in the process. Several strategies for bioplastic production from algal biomass are being discussed nowadays, and the most prominent are "with blending" (blending of algal biomass with bioplastics and starch) and "without blending" (microalgae as a feedstock for polyhydroxyalkanoates production). The advanced research on modern bioengineering techniques and well-established genetic tools like CRISPR–Cas9 should be encouraged to develop recombinant microalgae strains with elevated levels of PHA/PHB inside the cell. [ABSTRACT FROM AUTHOR]

Global pollution by plastics derived from petroleum has fostered the development of carbon–neutral, biodegradable bioplastics synthesized from renewable resources such as modern biomass, yet knowledge on the impact of bioplastics on ecosystems is limited. Here we review the polylactic acid plastic with focus on synthesis, biodegradability tuning, environmental conversion to microplastics, and impact on microbes, algae, phytoplankton, zooplankton, annelids, mollusk and fish. Polylactic acid is a low weight semi-crystalline bioplastic used in agriculture, medicine, packaging and textile. Polylactic acid is one of the most widely used biopolymers, accounting for 33% of all bioplastics produced in 2021. Although biodegradable in vivo, polylactic acid is not completely degradable under natural environmental conditions, notably under aquatic conditions. Polylactic acid disintegrates into microplastics faster than petroleum-based plastics and may pose severe threats to the exposed biota. [ABSTRACT FROM AUTHOR]

For a sustainable economy, biodegradable biopolymers polyhydroxyalkanoates (PHA) are desirable substitutes to petroleum-based plastics that contaminate our environment. Medium-chain-length (MCL) PHA bioplastics are particularly interesting due to their thermoplastic properties. To hamper the high cost associated to PHA production, the use of bacterial mixed cultures cultivated in open systems and using cheap resources is a promising strategy. Here, we studied the operating conditions favouring direct MCL accumulation by activated sludge, using oleic acid as a model substrate and phosphorus limitation in fed-batch bioreactors. Our results confirm the presence of PHA-accumulating organisms (PHAAO) in activated sludge able to accumulate MCL from oleic acid. A positive correlation between phosphorus (P) limitation and PHA accumulation was demonstrated, allowing up to 26% PHA/total biomass accumulation, and highlighted its negative impact on the MCL/PHA fraction in the polymer. Diversity analysis through 16S rRNA amplicon sequencing revealed a differential selection of PHAAO according to the P-limitation level. A differential behaviour for the orders Pseudomonadales and Burkholderiales at increasing P-limitation levels was revealed, with a higher abundance of the latter at high levels of P-limitation. The PHA accumulation observed in activated sludge open new perspectives for MCL-PHA production system based on P-limitation strategy applied to mixed microbial communities. Key points: • Direct accumulation of MCL-PHA in activated sludge was demonstrated. • MCL-PHA content is negatively correlated with P-limitation. • Burkholderiales members discriminate the highest P-limitation levels. [ABSTRACT FROM AUTHOR]

Plastic waste can serve as a symbolic expression of environmental pollution because of its prevalence and extremely slow degradation. A well-known example of synthetic plastics is low-density polyethylene (LDPE). A pragmatic approach to mitigate the environmental problems is to develop biodegradable plastic without compromising the quality of properties or increasing the price. To meet these requirements, one must turn to polymers from natural sources, such as starch. Starch is a fully biodegradable, semi-crystalline, non-toxic polymer with difficulties in processing. To obtain thermoplastic starch (TPS), a biodegradable glycerol plasticizer and sheer processing are necessary over a so-called gelatinization. Here, we aim to prepare and investigate sustainable and environmentally friendly packaging materials based on biodegradable blends, such as LDPE_TPS. The prepared blends were subjected to extensive physicochemical characterization to clarify the functional performance and biodegradability. Changes in structure, morphology and chemical composition before and after biodegradation were interpreted and correlated. Problems such as high interfacial tension due to high incompatibility between the non-polar polyolefin and the highly polar TPS were alleviated for some blends. The observation of mechanical, diffusive and composting parameters suggests that the modifier plays a crucial role in obtaining homogeneous polymer blends. The study of LDPE_TPS blends shows that it is possible to produce polymer blends with good biodegradability and balanced mechanical performance at a reasonable price. [ABSTRACT FROM AUTHOR]

The overwhelming production of plastic surpassed the rate at which they can decompose on the surface of the earth and caused environmental pollution globally, whereby packaging waste contributed almost one-third of plastic waste. Hence, as an alternative to plastic, algae emerged as one of the most sustainable alternative sources for bioplastic production due to their fast growth rate and the ability to withstand harsh environments and grow on non-arable land. These properties have outgrown most terrestrial plants as promising feedstocks for bioplastic production. This review provides a detailed survey of the literature published from 2010 to 2020 on the potential characteristics of different biopolymers derived from algae and their applications for packaging purposes. The sustainable development of algae as bioplastics for packaging contributes to minimising resource consumption, waste generation and regulating greenhouse gas emissions. The circular economy of algae-based bioplastic production is also discussed in this review. [ABSTRACT FROM AUTHOR]

Background: Biopolymers like polyhydroxyalkanoates (PHA) are the best natural macromolecules to use as alternative to the synthetic polymers. Many prokaryotes accumulate PHA as cytoplasmic intracellular granules and their accumulation is triggered by starving conditions. The PHAs are ecofriendly and used to create biodegradable plastics. The microbial synthesized PHA had acquired global importance in industrial and biomedical sectors. Results: Ten different bacterial strains were isolated for the screening of PHA producers from the estuarine region of the Bay of Bengal, Suryalanka in Bapatla. A yellowish slimy circular colony known as M4 is actively growing on selective minimal media and was screened for polymeric granules in its cytoplasm using Sudan Black B and confirmed with the fluorescent dye Nile blue A. All of the isolates were biochemically tested and isolate M4 is the most capable of growing at high NaCl concentrations (3.2 percent) and tests positive for catalase, methyl red. The M4 strain revealed clear hydrolysis of gelatin, starch, and casein. The 16S rRNA sequencing revealed that M4 is 99.72% of identity to Brachybacterium paraconglomeratum LMG 19861(T) in BLAST and the obtained strain was assigned with accession no. MTCC 13074 and deposited in NCBI with accession no. MW899045. The chief cellular fatty acids found in M4 were C14:0, C15:0, C16:0, C18:1cis-9, C18:0, iso-C15: 0, iso-C14: 0, anteiso-C17: 0 and C18:1-7. Crotonic acid formation from M4-PHB extract was detected at 235nm in a UV spectrophotometer. Methanolysis was done, and derivatives of polyhydroxybutyric acid (PHB) in the extract were analyzed using GC-MS. Increasing viscosity was seen in the extracts which confirms the presence of polymer in the extracts. Thermogravimetric analysis was studied to determine the thermal profile of the PHB in the extract of M4. Conclusion: In the study, the selective screening and extraction of ecofriendly PHB from M4 strain was highlighted. Brachybacterium paraconglomeratum is a novel strain showed its uniqueness by producing few monomeric derivatives of PHB. The strain was reporting for the first time as PHA producer. B. paraconglomeratum has promising characteristics according to its metabolic profile. In addition, this study also helps to understand the diversity of bacteria isolated from marine sources. [ABSTRACT FROM AUTHOR]

Biodegradable plastics are among the most promising materials to replace conventional petroleum-based plastics that have caused many adverse impacts on the environment, such as pollution (land, water, etc.) and global warming. Among a range of biodegradable plastics, poly lactic acid (PLA) is not only widely available but also safe to be decomposed after its usage without polluting the environment. PLA is also in parity with other conventional plastics such as PP, PET in terms of various properties suitable for industrial usage such as mechanical, physical, biocompatibility and processability. Thus, PLA has become the most used biopolymers in many industries such as agriculture, automotive and packaging by having these characteristics. Its higher demand has contributed to a stable increment in the global PLA market. In fact, over the years, the market for PLA has grown up and will keep on expanding in the future. Overall, the PLA-based bioplastic would be an excellent substitute for the existing conventional plastics in various applications, hence will serve to protect the environment not only from pollution but also work as a sustainable and economical product. This paper will review all the recent related works and literature on PLA as the biodegradable material regarding its properties, usability, productivity and substitute. [ABSTRACT FROM AUTHOR]

Global warming and plastic pollution result from the massive use of fossil fuels, calling for the development of sustainable bioplastics derived from modern biomass. Bioplastic production is expected to increase to 2.43 million tons globally in 2024. In particular, the production of biopolymers from bioresources and organic waste should highly reduce waste accumulation. Biopolymers can be produced by employing microbes or by using monomers from agro-resources. Here we review the use of lignin and polylactic acid for polymer production using enzymes and microorganisms. Carnobacterium, Enterococcus and Aspergillus niger show high lactic acid productivity of about 0.4–1.4 g/L/h. Lignin and polylactic acid can also be transformed into value-added chemicals such as muconic acid, hydrouronic acid, adipic acid and terephthalic acid. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WPU) prepolymer with acrylate terminal was prepared by using hydroxyethyl acrylate as an end-capping agent. Modified gelatin (mGH) was prepared by grafting vinyl groups which were obtained from hydrolysis and condensation of vinyl trimethoxysilane onto the renewable natural polymer material cold-water fish skin gelatin. Due to the excellent biodegradability and mechanical properties of cold-water fish skin gelatin, mGH was introduced into the WPU backbone by covalent bonding to improve WPU comprehensive property. The vinyl groups in mGH and the acrylate ends in the WPU prepolymer were connected by UV curing to prepare biodegradable and renewable mGH/WPU chemical hybrid materials. The test results showed that the film-forming properties, the water resistance and thermal stability of WPU were improved by covalent bonding. Water contact angle increased from79.6° to 96.5°, and the maximum thermal degradation rate temperature increased from 340 to 400 °C. In addition, incorporation of mGH with high modulus improved the moduli and yield strength of WPU, in which the yield strength increased from 11.3 to 18.2 MPa. The degradation performance of mGH/WPU chemical hybrid materials was also evaluated that the degradation rate reached 68% in 0.6% lipase PBS solution and 56% in soil after 60 days. The study provides a novel polymerization method for preparing high biodegradable decorative coatings and prints of specialty metals, polymer plastics and certain types of woodware as well as medical scaffold materials. [ABSTRACT FROM AUTHOR]

Polymers used as raw materials for synthetic packaging, i.e., those obtained from petroleum-derived sources, are resistant to degradation. Because of this, there is a growing concern in the world for the replacement of conventional packaging by renewable and biodegradable polymers. Polysaccharides are biopolymers commonly used as energy reserve by plants, but they can also be obtained from animals, algae, and microbes; regardless of the origin, their thermoplastic characteristics, renewability, high availability, low extraction cost, biodegradability, and good film-forming properties highlight their promising role as alternatives for this demand in decreasing the production and accumulation of synthetic plastics. This literature review addresses the main characteristics of film-type packaging and polysaccharide-based coatings for the food industry, emphasizing the main techniques used to obtain and characterize them. It is reported that the barrier and mechanical properties of a packaging composed only of polysaccharides are a challenge for the food industry; however, its quality has been improved with the addition of other biomolecules and reinforcement nanostructures. Using antimicrobial and antioxidant compounds to produce bioactive packaging adds value and is particularly favorable for this industrial field; additionally, the development of techniques for the production of polysaccharide packaging on an industrial scale is promising, and increases the competitiveness with those from non-biodegradable polymers. Therefore, films/coatings based on polysaccharides have the potential to minimize the use of materials of petrochemical origin. [ABSTRACT FROM AUTHOR]

Plastics have become inevitable for human beings in their daily life. Million tons of plastic waste is entering in oceans, soil, freshwater, and sediments. Invasion of plastics in different ecosystems is causing severe problems to inhabitants. Wild animals such as seabirds, fishes, crustaceans, and other invertebrates are mostly effected by plastic entanglements and organic pollutants absorbed and carried by plastics/microplastics. Plastics can also be potentially harmful to human beings and other mammals. Keeping in view the possible harms of plastics, some mitigation strategies must be adopted which may include the use of bioplastics and some natural polymers such as squid-ring teeth protein. This review focuses on the possible sources of intrusion and fate of plastics in different ecosystems, their potential deleterious effects on wildlife, and the measures that can be taken to minimize and avoid the plastic use. [ABSTRACT FROM AUTHOR]

Nitrogen, phosphorus, and potassium are the major nutrients solicited in the fertilization process, and their supply is highly useful to improve agricultural productivity. The conventional fertilizers suffer from low efficacy due to the fast release of nutrients. For that, the coating of granular fertilizer is considered as the best way to enhance their efficiency. Nowadays, biodegradable polymers are replacing synthetic polymers and avoiding the accumulation of nondegradable plastic residues in arable land. Since the coating of fertilizers by sulfur was criticized, many research studies investigated the use of polysaccharide such as cellulose, chitosan, carrageenan, lignin, and starch or aliphatic polyesters such as polylactide and polycaprolactone as coating matrix for granular fertilizer coating to delay or control the dissolution rate of nutrients. This review starts by apprising the readers about the environmental impact of conventional fertilizers (uncoated) and then an overview on the use of all those biopolymers and their combination for the coating agent mineral fertilizer. Furthermore, the present contribution provides an outline on different coating processes solicited in the field and the slow-release fertilizers criteria. [ABSTRACT FROM AUTHOR]

The microplastic that pollutes the ocean is a serious problem around the world. The bioplastic consisting of biopolymers which is degraded in nature, is one of the strategies to solve this problem. Although the bioplastics consisting of protein, polysaccharide, polylactic acid, etc., have been reported, which consist of DNA, one of the most important materials in the genetic process, have not been reported to the best of our knowledge. In addition, a large amount of DNA-containing materials, such as salmon milts, is discarded as industrial waste around the world. Therefore, we demonstrated the preparation of a bioplastic consisting of salmon milt DNA. The DNA plastic was prepared by the immersion of a DNA pellet in a formaldehyde (HCHO) solution and heating. As a result, the water-stable DNA plastics were obtained at the HCHO concentration of 20% or more. Particularly, the DNA plastic with a 25% HCHO treatment showed water-insoluble, thermally stable, and highly mechanical properties. These are due to the formation of a three-dimensional network via the crosslinking reaction between the DNA chains. In addition, since DNA in plastic possesses the double-stranded structure, these plastics effectively accumulated the DNA intercalator, such as ethidium bromide. Furthermore, the DNA plastics indicated a biodegradable property in a nuclease-containing aqueous solution and the biodegradable stability was able to be controlled by the HCHO concentration. Therefore, salmon milt DNA has shown the potential to be a biodegradable plastic. [ABSTRACT FROM AUTHOR]

Accumulation of non-biodegradable plastics has adversely affected the environment. Hence, there is a need of promoting biodegradable polymer packages as substitutes for non-biodegradable plastic packages. Various studies have focused on utilisation of seaweed-derived polysaccharides in the development of coatings and films because of their renewability and sustainability for food packaging. Alginate, agar, and carrageenan are seaweed-derived polysaccharides that are widely used in the development of coatings and films due to their gelling ability. Alginates are mainly extracted from brown algae. Agar and Carrageenan are extracted from certain types of red algae. These developed coatings could be successfully utilized to extend the shelf life and maintain proper quality parameters of food during the shelf life. Films can be used to partially replace non-biodegradable polymer packages found in the market. Thus, the article reviews the basic information and applications of edible coatings and films from seaweed-derived polysaccharides in the food industry. [ABSTRACT FROM AUTHOR]

Organic fraction of the municipal waste (OFMSW) is a valuable resource for biogas production through anaerobic digestion (AD). Bioplastics is widely used in daily activities, especially with food related items and collection bags, and can reach biogas plants through separate collection of OFMSW. PHAs, starch and cellulose based polymers with different compositions can degrade under anaerobic conditions. Cellulose and PHAs can degrade under both mesophilic and thermophilic conditions where, starch blends required thermophilic conditions in general. Other biopolymers, such as the most abundant PLA, are not able to degrade in the time frame of the facilities in most of the cases. Pre-treatment methods through abiotic and bio-augmentation, as well as post treatment methods, such as composting subsequent to AD are encountered as possible solutions for achieving better degradation or safer disposal of these polymers. The post-treatment/pre-disposal of the materials should be further studied as well as the pre-treatment methods. Studies on the effect of additives in biopolymers was not studied widely and requires further investigation. Degradation of biopolymers under AD, biogas production, pre-treatment and post-treatment methods as well as standard methods (or lack thereof) are discussed in detail in this paper, in order to point out to the possible scenarios that can be encountered when bioplastics end up in co-digestion conditions with organic material. [ABSTRACT FROM AUTHOR]

Non-biodegradable plastics are continually amassing landfills and oceans worldwide while creating severe environmental issues and hazards to animal and human health. Plastic pollution has resulted in the death of millions of seabirds and aquatic animals. The worldwide production of plastics in 2020 has increased by 36% since 2010. This has generated significant interest in bioplastics to supplement global plastic demands. Bioplastics have several advantages over conventional plastics in terms of biodegradability, low carbon footprint, energy efficiency, versatility, unique mechanical and thermal characteristics, and societal acceptance. Bioplastics have huge potential to replace petroleum-based plastics in a wide range of industries from automobiles to biomedical applications. Here we review bioplastic polymers such as polyhydroxyalkanoate, polylactic acid, poly-3-hydroxybutyrate, polyamide 11, and polyhydroxyurethanes; and cellulose-based, starch-based, protein-based and lipid-based biopolymers. We discuss economic benefits, market scenarios, chemistry and applications of bioplastic polymers. [ABSTRACT FROM AUTHOR]

Microorganisms have been contemplated as a promising source for the inexhaustible synthesis of many novel materials utilizing renewable sources. Among many of such products, polyhydroxyalkanoate (PHA) remains as an essential biodegradable polymer with functions similar to conventional plastics. Bacillus endophyticus is capable of accumulating biopolymer PHA in nutrient limiting conditions with excess of carbon source. Screening and optimizing the parameters for increased PHA production was done statistically. The optimized medium gave a maximum yield of 46.57% which was in well agreement with the given predicted value provided by response surface methodology model yield of 47.02%. Optimal media conditions when extrapolated in bioreactor gave an even higher production percentage of 49.9. This is the first report highlighting 49% of polyhydroxybutyrate statistically using sucrose as a source. The main highlight of the study was the use of wild type strain for producing high quality PHA using simple carbon source which can be a starting platform for using this strain for large scale PHA production industrially. FTIR and 1HNMR analysis confirmed the polymer produced. [ABSTRACT FROM AUTHOR]

The plastics industry is proliferating continuously and the global plastics production in 2018 has reached around 360 million tones. This has further compounded the problem of waste plastics, which if not appropriately disposed cause serious environmental problems like land pollution, marine pollution and water source pollution. As an alternative, there has been a paradigm shift from substituting synthetic plastics i.e. fossil-based to bioplastics. However, the world of bioplastics is riddled with many problems as the current terminology used around such bioplastics is confusing and general public is not provided with reliable information about the true biodegradability/compostability of the products. As a result, "greenwashing" is on the rise, with brands even making spurious claims about the environmental benefits of their products. This review article scans the world of biodegradable/bioplastics, major players and production capacities, their current status with respect to production and application. The commercial biopolymers available in the market and their technology have been also discussed in detail. The article also reviews various technologies like enzyme-based technology and oxo-degradable technology being propagated as a tool to convert conventional plastics like PE/PP/PET etc. to a biodegradable plastic. Further, various issues with oxo-based technology and enzyme-based technology have been compiled. Besides, various standards, test methods (ASTM/ISO) related to testing, specifications of biodegradable plastics, their scope/limitations and potential misuse have been covered. Further, the review article discusses the limitation of the various standards and why changes in the standards are required. The article tries to focus on various myths & realities of biodegradable/bioplastics and the challenges and expectations of the real world. [ABSTRACT FROM AUTHOR]

Escalated production of plastic, their worldwide distribution and persistent nature finally results into their environmental accumulation causing severe threats to the ecological environment and biotic health. Thus, development of suitable measurements for environmental remediation of plastic may be an urgent issue in this plastic age. Some recent reviews have categorized the microbial species able to degrade different plastic polymers and the different factors effecting bio-degradation of plastic are poorly understood. This review comprehensively discusses bio-degradation of traditional and biodegradable plastic polymers both in natural and biological environment (gut microbes and fungi) to understand different factors regulating their degradation, and also shows how degradation of plastic polymers under abiotic factors influence subsequent biological degradation. Different physicochemical modifications like - breaking large polymers into small fragments by pre-treatment, functional groups enrichment, identifying potent microbial species (consortia) and engineering microbial enzymes might be crucial for bio-degradations of plastic. Effects of micro/nanoplastic and other chemical intermediates, formed during the bio-degradation of plastic, on species composition, abundance, growth, metabolism and enzymatic systems of microbes involved in the bio-degradation of plastic should be determined in future research. [ABSTRACT FROM AUTHOR]

Since biodegradable materials are unwittingly mixed with synthetic materials, this work aimed to study the feasibility of reliably identifying some biopolymers, treated as contaminants, in the recycling process of polyethylene terephthalate (PET). The results showed that the miscibility between PET-PLA and PET-PHB is good. However, PHB is degraded in the recycling of PET due to the high processing temperatures used; meanwhile, PET and TPS are poorly miscible, characteristics also reflected in the microstructure. The contaminants decrease the mechanical properties of the recycled PET. WCA, FTIR, and DSC, do not allow to identify of these contaminants. FESEM resulted in the most successful technique to detect the biodegradable polymers in the PET matrix. No significant degradation of PET under composting conditions was obtained due to the presence of biodegradable polymers, and the effects of the biodegradable contaminants continue to reduce the mechanical performance of the recycled PET after 1 year of storage. [ABSTRACT FROM AUTHOR]

Recycling plastic waste by mix with natural polymers for bio-plastic packaging produces plastics with high mechanical properties and easily degradable. In this study, the relation between the structural and the optical properties of composite SPF/starch/chitosan/polypropylene to the mechanical properties and degradation performance were analyzed. Structural and optical properties of composite bioplastic SPF/Starch/Chitosan/Polypropylene have analyzed using X-Ray diffraction (XRD), and Fourier transforms infrared (FTIR) spectroscopy, respectively. The composition was varied: the ratio between starch and chitosan are 35/65, 50/50, and 65/35 with additional SPF for each ratio is 1%, 3%, and 5%. The SPF effectively enhances the tensile strength due to the SPF's better dispersion and interaction in the starch/chitosan/polypropylene matrix. For SPF's effect on the degradation performance, the ratio starch/chitosan 50/50 increase for 1% SPF is 87.23%, for 3% SPF is 92.59%, and for 5 SPF is 94.12%. The refractive index (n), extinction coefficient (k), dielectric functions (ε), and energy loss function (Im (−1/ ε)) determined from the quantitative analysis of FTIR spectra by using Kramers–Kronig (K–K) relations. The crystalline phase increases with increasing the amount of SPF in composite bioplastic SPF/Starch/Chitosan /Polypropylene for ratio starch/chitosan is 35/65, which consistent with the distance between the wavenumber (D) of transversal and longitudinal optical phonon vibration mode become wider. We found that a good correlation between optical properties, structural properties, mechanical properties, and degradation performance for ratio starch/chitosan 35/65 and 50/50 with SPF 1% and 3% in the composite. Besides, the FTIR spectra could be useful for determining the optical phonon vibration, dielectric function, and energy loss function of composite bioplastic SPF/Starch/Chitosan /Polypropylene. The degradation performance by additional polypropylene from plastic waste shows a potential solution for decreasing plastic waste in the world. [ABSTRACT FROM AUTHOR]

The current materials predominately come from fossil feedstocks and minerals. The pressures from climate change and plastic pollution challenge us to develop a bioeconomy, replacing petroleum-based products with bio-based and biodegradable products. Cellulose emerges as a versatile biopolymer to make hydrogels for absorbents, aerogels for insulation, membranes for filters, films for packaging, and fibers for textiles and reinforcements. Wood-based cellulose is increasingly perceived by relevant stakeholders to be renewable, biodegradable, and sustainable. Can the properties of cellulose-based materials compete with conventional synthetic materials? Knowledge and discoveries concerning cellulose properties and applications are scattered throughout the scientific literature base. This paper surveys the mechanical properties of cellulose-based materials in the literature using tensile properties as indicators and visualizes the data compared with other competitive materials. The goal is to provide insights into the potential and challenges of using cellulose-based products to replace synthetic materials for a sustainable society. [ABSTRACT FROM AUTHOR]

In this era of green and sustainable manufacturing, natural fibre-reinforced polymer composites (NFPC) have been widely accepted as the potential alternatives for polymer matrix composites (PMC) or any other non-biodegradable composites. Despite the increasing need to replace plastic bottles, bags, disposable plastic plates and trays, seedling pots used in our day to day life, not many studies have been made in this direction. The current work aims at developing a hundred percent biodegradable composite by reinforcing waste Kibisu silk fibre into wheat gluten as a possible replacement of plastic disposables. The developed composites are made up of different mass fractions of Kibisu silk fibre reinforced into plasticised wheat gluten. The prepared composites have been characterised to obtain the best combination. The developed composites were found to have adequate tensile property, mass degradation at a considerably high temperature and most importantly, the outstanding rate of biodegradation under normal atmospheric conditions. The soil quality test before and after degradation also showed no significant changes in the quality of the soil. FTIR studies revealed improved interaction between wheat gluten, glycerol and Kibisu fibres upon addition of natural lemon extract as crosslinker. Overall results indicate that the developed biocomposites have the potential to substitute harmful plastic disposables like plastic seedling pots and plates, disposable hospital tray, dustbin, etc. [ABSTRACT FROM AUTHOR]

Biopolymers consisting of at least one monomer, which are produced from renewable carbon sources, are being highly sought out since ubiquitous plastics are mainly produced from petrochemical processes causing severe environmental pollution. Therefore, the development of microbial cell factories, which can efficiently synthesize diverse types of monomers and polymers, is also becoming increasingly important. The applicability of traditional metabolic engineering strategies has extended with the combination of systems biology, synthetic biology, and evolutionary engineering in a systemic and versatile manner, and are collectively termed as systems metabolic engineering. Accordingly, recent advances in biotechnology have paved the way for enabling the production of an increasing number of monomers and polymers by providing several tools and strategies associated with systems metabolic engineering. In this review, we have focused on the substantial efforts made on the development of different approaches of systems metabolic engineering, particularly based on synthetic biology and evolutionary engineering, for the efficient production of monomers and polymers. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this review is to evaluate previous life cycle assessment (LCA) studies of first- and second-generation bioplastics, to understand the state of the art and the main problems addressed during the development of new bioplastics. Furthermore, it provides an overview on land use change (LUC) impacts accounted for, methodologies chosen, and the results obtained. Methods: Studies related to the impact assessment of bioplastics and published between 2007 and 2018 were gathered. Five keyword strings were used to perform a wide search and select relevant LCA studies. The study aimed to analyze critical methodological aspects in LCA, in order to determine the most common choices made during biobased material analyses, as well as major limitations. Three filters were applied to select comparable studies, ending with a final number of 17 papers. Recommendations were obtained by comparing common practices performed by different authors with suggested best available practices mentioned in handbooks and guidelines. Interestingly, LUC metrics and impacts were, most of the time, neglected. Thus, a specific assessment and discussion was performed regarding the methods used to quantify LUC impacts, considering its importance during the production of biobased materials. Results and discussion: The study discussed the main environmental problems linked to the development of new biomaterials. LCA of agricultural products or systems, when compared with fossil-based counterparts, is expected to show higher environmental impacts in categories directly affected by fertilizer use, occupied and transformed land, among others. Thus, studies that included additional impact categories besides global warming (e.g., eutrophication or acidification) concluded that biobased materials present higher impacts, recommending improvements in farming practices to improve their overall environmental profile. Moreover, this review gathered methodologies used to account for LUC impacts and the results obtained. The main constraint of including LUC impacts was the lack of a standardized methodology, as well as large uncertainties in existing methodologies. Conclusions: Most studies concluded that improvements in farming practices might reduce the attributed environmental impacts with the reduction of the amount of land, fertilizer, pesticides, and water used. Studies computing LUC impacts agreed on the importance of including these impacts and concluded that greenhouse gas emissions of bioplastic production would increase, but in most cases would still be lower than the impact of their fossil-based counterparts. However, challenges remain when computing LUC impacts that need to be tackled when working with the available methodologies, including the collection of reliable inventory data (site-specific or regional data) and regionalized characterization factors. [ABSTRACT FROM AUTHOR]

Microbial polyhydroxyalkanoates (PHAs) are biopolyesters produced by microorganisms as intracellular granules under nutrient stress. Due to non-toxic and biodegradable behavior these polyesters are a sustainable source of wide range of biomaterials such as bioplastics. As a result of excellent polymeric properties such as melting temperatures (Tm), glass transition temperature (Tg), crystallinity, Young's modulus and stress to break ratio these polyesters are capable of replacing the synthetic plastics. Bioplastics produced using PHAs as biomass source can be used for packaging material and disposable products on the other hand biofuels can also be generated using PHAs. PHAs find countless applications in industry, agriculture, pharmaceuticals and health. A large number of bacterial, microalgal and fungal species can produce these polyesters. Bacterial species such as Bacillus megaterium, Pseudomonas aeruginosa, P. oleovorans, P. stutzeri and Cupriavidus necator are some highly studied microorganisms for PHA production. This review summarizes the most important aspects of PHAs, crystalline and granular structure of PHA biosynthesizing genes and their relevant proteins. Thermal and physical properties, sources, extraction, purification methods of PHAs are briefly discussed. Applications of PHAs, phylogenetic analysis of Pseudomonas sp. in term of its PHAs synthesizing genes, future prospects and possible outcomes are discussed. [ABSTRACT FROM AUTHOR]

Current research in industrial microbiology and biotechnology focuses on the production of biodegradable microbial polymers as an environmentally friendly alternative to still dominant fossil-based plastics. Microbial polymers have an extensive biotechnological potential and are already widely used in a variety of fields ranging from medicine to technology. However, their increase in production and wider use is hampered by the high cost of raw materials and therefore requires a focus on cheaper inputs, including dairy by-products and waste such as cheese whey (CW). This is an environmentally unfriendly by-product of milk processing and reducing it would also reduce the risk of environmental pollution. This review summarises current knowledge on the use of CW and derived products to obtain commercially important microbial polymers, including information about producer cultures, fermentation techniques and methods used, composition of culture medium, cultivation conditions and productivity of bioprocesses. The main methods and applications of cheese whey pre-treatment are also summarised. [ABSTRACT FROM AUTHOR]

Biobased degradable plastics have received significant attention owing to their potential application as a green alternative to synthetic plastics. A dye-based procedure was used to screen poly-3-hydroxybutyrate (PHB)-producing marine bacteria isolated from the Red Sea, Saudi Arabia. Among the 56 bacterial isolates, Pseudodonghicola xiamenensis, identified using 16S rRNA gene analyses, accumulated the highest amount of PHB. The highest PHB production by P. xiamenensis was achieved after 96 h of incubation at pH 7.5 and 35 °C in the presence of 4% NaCl, and peptone was the preferred nitrogen source. The use of date syrup at 4% (w/v) resulted in a PHB concentration of 15.54 g/L and a PHB yield of 38.85% of the date syrup, with a productivity rate of 0.162 g/L/h, which could substantially improve the production cost. Structural assessment of the bioplastic by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy revealed the presence of methyl, hydroxyl, methine, methylene, and ester carbonyl groups in the extracted polymer. The derivative products of butanoic acid estimated by gas chromatography-mass spectrometry [butanoic acid, 2-amino-4-(methylseleno), hexanoic acid, 4-methyl-, methyl ester, and hexanedioic acid, monomethyl ester] confirmed the structure of PHB. The present results are the first report on the production of a bioplastic by P. xiamenensis, suggesting that Red Sea habitats are a potential biological reservoir for novel bioplastic-producing bacteria. [ABSTRACT FROM AUTHOR]

Most of the products used in our everyday life are made of plastics. Even though plastics are very cheap and durable but plastic has a significant problem as due to its non-biodegradable nature plastic causes littering in river and sea, blockage in drains, degradation of landfill and it also causes various other environmental problems when dumped. To find out suitable alternatives of these plastic materials, researchers have preferred starch, an abundantly found and cheapest natural polymer and researchers have found some ways to convert starch in to thermoplastic material. Among these techniques, esterification process has gained most attention. This paper has tried to review some important researchers published on esterifying starch. By analyzing the research results of these researches this paper will try to find out the factors which control the end product properties so that the desired end product can be produced. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) are biopolymers synthesized by a wide range of bacteria, which serve as a promising candidate in replacing some conventional petrochemical-based plastics. PHA synthase (PhaC) is the key enzyme in the polymerization of PHA, and the crystal structures were successfully determined using the catalytic domain of PhaC from Cupriavidus necator (PhaCCn-CAT) and Chromobacterium sp. USM2 (PhaCCs-CAT). Here, we review the beneficial mutations discovered in PhaCs from a structural perspective. The structural comparison of the residues involved in beneficial mutation reveals that the residues are near to the catalytic triad, but not inside the catalytic pocket. For instance, Ala510 of PhaCCn is near catalytic His508 and may be involved in the open-close regulation, which presumably play an important role in substrate specificity and activity. In the class II PhaC1 from Pseudomonas sp. 61-3 (PhaC1Ps), Ser325 stabilizes the catalytic cysteine through hydrogen bonding. Another residue, Gln508 of PhaC1Ps is located in a conserved hydrophobic pocket which is next to the catalytic Asp and His. A class I, II-conserved Phe420 of PhaCCn is one of the residues involved in dimerization and its mutation to serine greatly reduced the lag phase. The current structural analysis shows that the Phe362 and Phe518 of PhaC from Aeromonas caviae (PhaCAc) are assisting the dimer formation and maintaining the integrity of the core beta-sheet, respectively. The structure-function relationship of PhaCs discussed in this review will serve as valuable reference for future protein engineering works to enhance the performance of PhaCs and to produce novel biopolymers. [ABSTRACT FROM AUTHOR]

During the last decades, biopolymers experienced a renaissance. The increasing limitation of fossil resources in combination with a public demand for environmental-friendly and sustainable processes has led to the formation of a market for biobased plastics. Especially non-biodegradable bioplastics are very interesting materials, as they combine the benefits of reduced carbon footprint during production and increased resource efficiency with the persistence to microbial degradation. Consequently, persistent biomass-derived plastic materials are highly promising to substitute conventional fossil-based plastics in applications, which require durability and longevity. Non-biodegradable bioplastics derived from renewable resources represent 57% of all bioplastics with partially biobased polyethylene terephthalate currently leading the market, followed by biobased polyamides and fully biomass-derived polyethylene. An exceptional biopolymer with thermoplastic properties was discovered only two decades ago, when—for the first time—polythioesters were synthesized by microbial fermentation. Though synthesized by bacteria, it turned out that polythioesters are non-biodegradable by microorganisms in contrast to all other biopolymers and thus, represent a novel non-biodegradable bioplastic material. This review gives an overview about the recent development and progress regarding bioplastics with special focus on persistent bioplastics. We describe the generation of the respective monomers from biomass-derived substrates and summarize the current status of production, which range from the laboratory-scale up to large-scale industrial processes. [ABSTRACT FROM AUTHOR]

With growing interest in the use of eco-friendly composite materials, biodegradable polymers and composites from renewable resources are gaining popularity for use in commercial applications. However, the long-term performance of these composites and the effect of compatibilization on their weathering characteristics are unknown. In this study, five types of biodegradable biopolymer/wood fiber (WF) composites were compatibilized with maleic anhydride (MA), and the effect of accelerated UV weathering on their performance was evaluated against composites without MA and neat biopolymers. The composite samples were prepared with 30 wt% wood fiber and one of the five biodegradable biobased polymer: poly(lactic) acid (PLA), polyhydroxybutyrate (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Bioflex (PLA blend), or Solanyl (starch based). Neat and composite samples were UV weathered for 2000 h (hours), and characterized for morphological, physical, thermal, and mechanical properties before and after weathering. Compared to composites without MA, composites containing MA grafted polymers exhibited improved properties due to increased interfacial adhesion between the fiber and matrix. Upon accelerated weathering, thermal and mechanical properties of 70% of the samples substantially decreased. Surfaces of all the samples were roughened, and drastic color changes were observed. Water absorption of all the samples increased after weathering exposure. Even though the compatibilization is shown to improve composite properties before weathering, it did not affect weathering of samples, as there were no considerable differences in properties exhibited by the composites with MA and without MA after weathering. The results suggest that compatibilization improves properties of biodegradable biobased composites without affecting its UV degradation properties. [ABSTRACT FROM AUTHOR]

Nanoclay particles have been usually introduced into protein-based bioplastics to obtain composite materials, showing enhanced mechanical properties. However, the addition of partially exfoliated nanoclay particles in these protein matrices may also involve an increase of others properties such as water absorption capacity, which may lead to the obtention of super absorbent biodegradable materials. Processing technologies exerted a remarkable influence on the techno-functional properties of the soy-based bioplastics studied in this research. On the one hand, extrusion technique led to bioplastics which showed enhanced mechanical properties. On the other hand, injection moulding technique yielded to non-exfoliated nanoclay particles within the protein matrix, which involved improvements of water absorption capacity. The development of superabsorbent protein-based biodegradable materials implied a deep knowledge of physicochemical properties of proteins and processing conditions of bioplastics. Extrusion or injection moulding techniques could be selected to obtain tailored protein-based bioplastics with enhanced properties. [ABSTRACT FROM AUTHOR]

Plastics play a very important role in our daily life. They are used for various purposes. But the disposal of these petrochemical-derived plastics causes a risk to the human and marine population, wildlife and environment. Also, due to the eventual depletion of petrochemical sources, there is a need for the development of alternate sources for the production of plastics. Biodegradable polymers produced by microorganisms can be used as substitutes for conventional plastics derived from petrochemical sources since they have similarity in their properties. Polyhydroxyalkanoate (PHA) is one such biopolymer that will be accumulated inside the cells of microorganisms as granules for energy storage under limiting conditions of nutrients and high concentration of carbon. Research on the microbial production of PHA should focus on the identification of cost-effective substrates and also identification of a suitable strain of organism for production. The major focus of this review is the production of PHA from various cost-effective substrates using different bacterial species. The review also covers the biosynthetic pathway of PHA, extraction method, characterization technique, and applications of PHA in various sectors. [ABSTRACT FROM AUTHOR]