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"Polymers Biodegradation."
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Biopolymers : reuse, recycling, and disposal
Biopolymers Reuse, Recycling and Disposal is the first book covering all aspects of biopolymer waste management and post-usage scenarios, embracing existing technologies, applications, and the behavior of biopolymers in various waste streams. The book investigates the benefits and weaknesses, social, economic and environmental impacts, and regulatory aspects of each technology. It covers different types of recycling and degradation, as well as life cycle analysis, all supported by case studies, literature references, and detailed information about global patents. Patents in particular-comprising 80% of published technical literature in this emerging field, widely scattered, and often available in Japanese only-are a key source of information. Dr. Niaounakis draws on disciplines such as polymer science, management, biology and microbiology, organic chemistry, environmental chemistry, and patent law to produce a reference guide for engineers, scientists and other professionals involved in the development and production of biopolymers, waste management, and recycling. This information is also valuable for regulators, patent attorneys and academics working in this field. Explores techniques and technologies involved in managing biopolymers in the waste stream, including recycling and upcyclingProvides waste management and recycling professionals the knowledge they need to plan for the exponential growth in biopolymer wasteHelps engineers and product designers fully consider the end-of-life aspects of their environmentally sustainable 'green' products and solutions
eBook
Marine-Derived Actinomycetes: Biodegradation of Plastics and Formation of PHA Bioplastics—A Circular Bioeconomy Approach
Plastics are present in the majority of daily-use products worldwide. Due to society’s production and consumption patterns, plastics are accumulating in the environment, causing global pollution issues and intergenerational impacts. Our work aims to contribute to the development of solutions and sustainable methods to mitigate this pressing problem, focusing on the ability of marine-derived actinomycetes to accelerate plastics biodegradation and produce polyhydroxyalkanoates (PHAs), which are biodegradable bioplastics. The thin plastic films’ biodegradation was monitored by weight loss, changes in the surface chemical structure (Infra-Red spectroscopy FTIR-ATR), and by mechanical properties (tensile strength tests). Thirty-six marine-derived actinomycete strains were screened for their plastic biodegradability potential. Among these, Streptomyces gougerotti, Micromonospora matsumotoense, and Nocardiopsis prasina revealed ability to degrade plastic films—low-density polyethylene (LDPE), polystyrene (PS) and polylactic acid (PLA) in varying conditions, namely upon the addition of yeast extract to the culture media and the use of UV pre-treated thin plastic films. Enhanced biodegradation by these bacteria was observed in both cases. S. gougerotti degraded 0.56% of LDPE films treated with UV radiation and 0.67% of PS films when inoculated with yeast extract. Additionally, N. prasina degraded 1.27% of PLA films when these were treated with UV radiation, and yeast extract was added to the culture medium. The main and most frequent differences observed in FTIR-ATR spectra during biodegradation occurred at 1740 cm−1, indicating the formation of carbonyl groups and an increase in the intensity of the bands, which indicates oxidation. Young Modulus decreased by 30% on average. In addition, S. gougerotti and M. matsumotoense, besides biodegrading conventional plastics (LDPE and PS), were also able to use these as a carbon source to produce degradable PHA bioplastics in a circular economy concept.
Journal Article
Polyhydroxybutyrate (PHB) biodegradation using bacterial strains with demonstrated and predicted PHB depolymerase activity
The biodegradation of polyhydroxybutyrate (PHB) has been broadly investigated, but studies typically focus on a single strain or enzyme and little attention has been paid to comparing the interaction of different PHB depolymerase (PhaZ)-producing strains with this biopolymer. In this work, we selected nine bacterial strains—five with demonstrated and four with predicted PhaZ activity—to compare their effectiveness at degrading PHB film provided as sole carbon source. Each of the strains with demonstrated activity were able to use the PHB film (maximum mass losses ranging from 12% after 2 days for Paucimonas lemoignei to 90% after 4 days for Cupriavidus sp.), and to a lower extent Marinobacter algicola DG893 (with a predicted PhaZ) achieved PHB film mass loss of 11% after 2 weeks of exposure. Among the strains with proven PhaZ activity, Ralstonia sp. showed the highest specific activity since less biomass was required to degrade the polymer in comparison to the other strains. In the case of Ralstonia sp., PHB continued to be degraded at pH values as low as pH 3.3–3.7. In addition, analysis of the extracellular fractions of the strains with demonstrated activity showed that Comamonas testosteroni, Cupriavidus sp., and Ralstonia sp. readily degraded both PHB film and PHB particles in agar suspensions. This study highlights that whole cell cultures and enzymatic (extracellular) fractions display different levels of activity, an important factor in the development of PHB-based applications and in understanding the fate of PHB and other PHAs released in the environment. Furthermore, predictions of PhaZ functionality from genome sequencing analyses remain to be validated by experimental results; PHB-degrading ability could not be proven for three of four investigated species predicted by the polyhydroxyalkanoates (PHA) depolymerase engineering database.
Journal Article
Genome-Based Exploration of Rhodococcus Species for Plastic-Degrading Genetic Determinants Using Bioinformatic Analysis
Plastic polymer waste management is an increasingly prevalent issue. In this paper, Rhodococcus genomes were explored to predict new plastic-degrading enzymes based on recently discovered biodegrading enzymes for diverse plastic polymers. Bioinformatics prediction analyses were conducted using 124 gene products deriving from diverse microorganisms retrieved from databases, literature data, omic-approaches, and functional analyses. The whole results showed the plastic-degrading potential of Rhodococcus genus. Among the species with high plastic-degrading potential, R. erythropolis, R. equi, R. opacus, R. qingshengii, R. fascians, and R. rhodochrous appeared to be the most promising for possible plastic removal. A high number of genetic determinants related to polyester biodegradation were obtained from different Rhodococcus species. However, score calculation demonstrated that Rhodococcus species (especially R. pyridinivorans, R. qingshengii, and R. hoagii) likely possess PE-degrading enzymes. The results identified diverse oxidative systems, including multicopper oxidases, alkane monooxygenases, cytochrome P450 hydroxylases, para-nitrobenzylesterase, and carboxylesterase, and they could be promising reference sequences for the biodegradation of plastics with C−C backbone, plastics with heteroatoms in the main chain, and polyesters, respectively. Notably, the results of this study could be further exploited for biotechnological applications in biodegradative processes using diverse Rhodococcus strains and through catalytic reactions.
Journal Article
Solid Waste Management: Degradation of Commercial and Newly Fabricated Cellulose Acetate Ultrafiltration Membranes
Treatment of polymeric solid waste, such as used membranes, is vital for environmental sustainability. Cellulose-based membranes are widely utilized in the water industry due to their resistance to biodegradation. These non-biodegradable membranes can persist in landfills and aquatic environments for extended periods. Our study assessed the biodegradation potential of Trametes versicolor on a newly fabricated cellulose acetate (CA) membrane and a commercially produced membrane under various conditions, including oxidative stress. Additionally, we employed T. versicolor encapsulated in a small bioreactor platform (SBP) for media inoculation and biomass augmentation. Treatment of the commercially produced CA membrane within a timeframe of 30 days was unsuccessful. This was primarily attributed to the structural stability of the membrane over time and the limited ability of the culture to attach to the membrane surface. These results underscore the necessity of exploring alternative biopolymer cellulose-based materials for ultrafiltration (UF) and microfiltration (MF) membrane applications. The custom-made UF membrane, treated by ozonation as a pretreatment, emerged as an effective approach for enhancing biodegradation. Combining these factors, we expect to achieve over 27.75 ± 1.5% weight loss in membrane solids by 30 days of treatment. This study represents the first inquiry into the biodegradation capabilities of T. versicolor on CA-based membranes.
Journal Article
Handbook of Polymer Applications in Medicine and Medical Devices
While the prevalence of plastics and elastomers in medical devices is now quite well known, there is less information available covering the use of medical devices and the applications of polymers beyond medical devices, such as in hydrogels, biopolymers and silicones beyond enhancement applications, and few books in which these are combined into a single reference. This book is a comprehensive reference source, bringing together a number of key medical polymer topics in one place for a broad audience of engineers and scientists, especially those currently developing new medical devices or seeking more information about current and future applications. In addition to a broad range of applications, the book also covers clinical outcomes and complications arising from the use of the polymers in the body, giving engineers a vital insight into the real world implications of the devices they're creating. Regulatory issues are also covered in detail. The book also presents the latest developments on the use of polymers in medicine and development of nano-scale devices.
eBook
Determining the impact of common microplastic extraction methods from soil matrices on the biodegradable polymers polylactic acid and polyhydroxybutyrate
The use of conventional non-biodegradable plastic polymers in agricultural applications has raised concerns regarding their degradation into micro- and nano-plastics and accumulation in soils. As a result, biodegradable polymers are increasingly used in agricultural applications. Complete environmental biodegradation is expected to prevent the formation of persistent micro- and nano-plastics. However, incomplete biodegradation may result in the presence of fragments from biodegradable polymers. Understanding the environmental fate of biodegradable polymers is essential, and reliable extraction and analytical methods are needed to detect and quantify them in soil matrices that do not induce further polymer degradation. In this study, biodegradable polylactic acid (PLA) and polyhydroxybutyrate (PHB) polymer films were exposed to a commonly used protocol for the analysis of microplastics in soil samples. Specific steps were density separation with zinc chloride solution, oxidation with Fenton’s reagent and enzymatic digestion. Polymer degradation was assessed by comparison of polymer properties before and after exposure to the complete soil extraction protocol, and to each individual reagent. Degradation of both PLA and PHB films was observed after exposure to the complete soil extraction protocol. PLA showed significant degradation following exposure to protease, highlighting its vulnerability to this specific treatment step. This study highlights the need for appropriate polymer specific sample extraction methods to minimise extraction-induced degradation and ensure accurate measurements of biodegradable polymers. This is critical to allow future assessment of the environmental fate of biodegradable polymers.
Journal Article
Hydrocarbon-associated substrates reveal promising fungi for poly (ethylene terephthalate) (PET) depolymerization
Recalcitrant characteristics and insolubility in water make the disposal of synthetic polymers a great environmental problem to be faced by modern society. Strategies towards the recycling of post-consumer polymers, like poly (ethylene terephthalate, PET) degradation/depolymerization have been studied but still need improvement. To contribute with this purpose, 100 fungal strains from hydrocarbon-associated environments were screened for lipase and esterase activities by plate assays and high-throughput screening (HTS), using short- and long-chain fluorogenic probes. Nine isolates were selected for their outstanding hydrolytic activity, comprising the genera
Microsphaeropsis
,
Mucor
,
Trichoderma
,
Westerdykella
, and
Pycnidiophora
. Two strains of
Microsphaeropsis arundinis
were able to convert 2–3% of PET nanoparticle into terephthalic acid, and when cultured with two kinds of commercial PET bottle fragments, they also promoted weight loss, surface and chemical changes, increased lipase and esterase activities, and led to PET depolymerization with release of terephthalic acid at concentrations above 20.0 ppm and other oligomers over 0.6 ppm. The results corroborate that hydrocarbon-associated areas are important source of microorganisms for application in environmental technologies, and the sources investigated revealed important strains with potential for PET depolymerization.
Journal Article
Polypropylene film and beads biodegradation by Lysinibacillus macroides isolated from coastal area of Muara Angke in Jakarta - Indonesia
Polypropylene (PP) is one of the most frequently used polyolefins, with applications in a wide range of industries. PP is the most often used plastic in Indonesia. However, because to its resistance to microbial breakdown, it persists in the environment, causing environmental issues. In this study, Lysinibacillus macroides isolated from the coastal area of Muara Angke in Jakarta was screened for the ability to degrade polypropylene film and beads using Bushnell Hass media. After 50 days of incubation, biodegradation of polypropylene film and beads were examined. Both inoculated PP beads and film were examined by the percentage of weight loss, SEM analysis, and TG/DTA analysis. FTIR analysis and XRD analysis were also used to evaluate PP film degradation. Lysinibacillus macroides showed 1.33% PP film degradation and 2.93% PP beads degradation by weight loss in 50 days, respectively. Compared with the PP film, the degradation efficiency of the PP beads was significantly improved. This study can be used to assess the efficiency of different types of plastics in terms of bacterial decomposition. It also paves the way for the development of a more efficient screening approach for determining the most effective microbe for various types of plastic biodegradation. Despite the many optimizations that are required, the isolated strain demonstrated positive potential for polypropylene biodegradation of both films and beads.
Journal Article