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Microplastics pollution is major threat to ecosystems and is impacting abiotic and biotic components. Microplastics are diverse and highly complex contaminants that transport other contaminants and microbes. Current methods to remove microplastics include biodegradation, incineration, landfilling, and recycling. Here we review microplastics with focus on sources, toxicity, and biodegradation. We discuss the role of algae, fungi, bacteria in the biodegradation, and we present biotechnological methods to enhance degradation, e.g., gene editing tools and bioinformatics.

Biyobozunur polimerler, petrol türevli polimerlerin yerini almaya bir alternatiftir. Polilaktik asit (PLA), yenilenebilir kaynaklardan elde edilen ve biyolojik olarak parçalanabilen en yaygın kullanılan polimerdir. Kullanılan geleneksel atık yönetimi yaklaşımına göre, şimdiye kadar üretilen tüm plastiğin %60'ı, atık sahalarına veya doğal ortamlara atılmıştır. Bu da önemli bir çevre sorunu haline gelmiştir. Petrol bazlı plastiklere alternatif olan PLA’ların kullanım ömrü sonu seçenekleri, döngüsel ekonomi bağlamında tartışılmaktadır. Biyobozunur özellikleri olan bu polimerlerin, atık haline geldikten sonra toprak içerisindeki davranışlarını anlamak oldukça önemlidir. Bu çalışmada PLA numuneleri, ortam sıcaklığında, toprak içerisinde, ASTM 5988-18 standardına göre biyobozunmaya tabi tutulmuştur. 90 günlük inkübasyon süresinden sonra PLA’daki biyobozunma; fiziksel görünüş, kütle kaybı, FTIR ve SEM ile değerlendirilmiştir. Numunelerin, biyobozunmadan sonra ağırlık kaybı oranı %0,9’dur. PLA örneklerinin fiziksel görünüşleri, FTIR ve SEM sonuçları, PLA’nın toprakta ve ortam sıcaklığında biyobozunma hızlarının yavaş olduğunu ve bu ortamda tamamen bozunabilmeleri için daha uzun bir zamana ihtiyaç olduğunu göstermektedir. Biodegradable polymers are alternatives to petroleum-derived polymers. Polylactic acid (PLA) is the most widely used biodegradable polymer derived from renewable resources. According to the traditional waste management approach, 60% of all plastic ever produced ends up in landfills or natural environments. This has became an important environmental problem. End-of-life options for PLAs as an alternative to petroleum-based plastics are discussed in the context of circular economy. It is very important to understand the behaviour of these biodegradable polymers in soil after they become waste. In this study, the PLA samples were subjected to biodegradation in the soil at ambient temperature according to ASTM 5988 standard. Biodegradation in PLA after 90 days; physical appearances, mass loss, FTIR and SEM were evaluated. The weight loss rate of the samples after biodegradation was 0.9%. The physical appearances of PLA samples, FTIR and SEM results showed that the biodegradation rates of PLA in soil and ambient temperature are slow and it takes a longer time to fully degrade in this environment.

Aspergillus flavuswas isolated from the soil field cultivated with wheat crop (Triticum astevium L.), which was treated with Topik EC 100 (Clodinafop-propargyl) herbicide in Al-Fuhud city, southeast of Thi-Qar Governorate-Iraq. soil samples were collected at a depth of (0-15) cm for a period of 17 weeks, and the fungus were isolated from the soil by dilution method, the pH, electrical conductivity, organic matter and soil texture were measured. the results showed thatAspergillus flavuswas dominant in this study, where the percentage of appearance ofAspergillus flavuswas 86%. the fungus was treated with the active ingredient Clodinafop-propargyl of Topik 100 EC herbicide in solid and liquid media (Mineral salt medium). the fungus showed its ability to grow in the medium containing the active substance. the results showed thatAspergillus flavuscould biodegrade the active ingredient. the substances were measured by Fourier Transform Infrared spectroscopy and Gas chromatography- mass spectroscopy, the results showed that biodegradation percentage of the active ingredient Clodinafop-propargyl at a concentration 0.01 ppm byAspergillus flavuswas 80%.&nbsp

Pollution of the marine environment by microfibers is considered a problem for ecosystem conservation. The amount of microplastic, localization of sources, and associated ecotoxicity are well known in the literature. Wastewater from washing machines is the main source of microplastic fibers in the aquatic environment, and fabrics made from recycled plastic are widely reused. The circular economy also promotes recycling of dyed natural wool materials as a basis for making new clothing, but in this case, less research has been conducted on the behaviour and effects of recycled wool microfibers in marine ecosystems. MWool® (MW) and MWool® carded (MWc) products made from recycled wool fibers were tested in mesocosms to investigate the biodegradation of wool fibers over a 260-day period and the effects of this process on marine ecosystems in terms of microfiber inputs and the ecotoxicological effects of by-products and chemicals released during degradation. The early degradation process was associated with the loss of artificial pigments from the dyed wool, particularly pink and red, which occurred within 30–90 days of exposure. Mean release of microparticles into contact water is significantly different from control (T0, p < 0.01) at 90 days MWc (36.6 mg/L) and 180 days MW (42.9 mg/L). The biodegradation process is accompanied by swelling of wool fibers, which is associated with a significant increase in mean wool thickness (p < 0.05, 18.8 ± 2.1 µm at T0 vs. 24.0 ± 7.1 µm). In both cases, the contact water was not associated with signs of ecotoxicity for the marine species tested in this study (Phaeodactylum tricornutum, Brachionus plicatilis, and Paracentrotus lividus).

The intensive use of oil products is one of the most significant problems of environmental pollution. They pollute water, soil, and air. For these reasons, the search for effective methods of oil biodegradation is very important for solving environmental problems. The research aimed to isolate and select oildegrading microorganisms and to investigate their effectiveness in oil-contaminated soil “ex-situ”. Using microorganisms isolated from the contaminated soil, a biopreparation was developed consisting of bacteria, yeast and filamentous fungi. Microorganism isolates were identified using MALDI-TOF mass spectrometry (Bruker, USA). The biopreparation was tested in the soil treatment sites of GVT LT, Ltd (Kiškėnai village, Dovilai eldership, Klaipėda district) in two test variants. The count of microorganisms (CFU/g) in the soil was determined at the beginning of the research, after two weeks and every month thereafter until the end of the cleaning season by serial dilution method in media with 1% of diesel. The content of oil products (g/kg) was determined with the same periodicity according to LST EN ISO 16703. An effective biopreparation for the degradation of oil hydrocarbons has been developed. Within 5 months, it reduced the amount of oil products to 61,7% in variant No. 1 and 58,7% in variant No. 2.

La contaminación es el mayor impacto humano en el planeta, es decir, el medio ambiente está formado por los elementos naturales y artificiales, sus actividades físicas, químicas, biológicas, sociales y culturales y sus respectivas relaciones. El objetivo de esta indagación fue analizar la biodegradación de plásticos, a partir de larvas del escarabajo Tenebrio molitor, como aporte a la enseñanza de la biotecnología ambiental. Básicamente, la ejecución de este proyecto se basó en 3 etapas. La caracterización de las larvas Tenebrio molitor, la crianza de las larvas y la cuantificación de la capacidad para biodegradar el plástico. Los resultados obtenidos fueron, encontraron que la muestra 1 (M1) tuvo una productividad específica de biomasa de 6.6 gramos mientras que la muestra 2 (M2) una productividad específica de Se registraron 2,3 gramos y logró evidenciar un cambio en cuanto al color y la cantidad de las heces. Finalmente, la biodegradación del poliestireno influye en la producción de compost, beneficiando el consumo de plástico. Palabras clave: Biodegradación, Plástico, Tenebrio molitor, Biotecnología ambiental, larvas., Pollution is the greatest human impact on the planet, that is, the environment is made up of natural and artificial elements, their physical, chemical, biological, social and cultural activities and their respective relationships. The objective of this investigation was to analyze the biodegradation of plastics, from larvae of the Tenebrio molitor beetle, as a contribution to the teaching of environmental biotechnology. Basically, the execution of this project was based on 3 stages. The characterization of Tenebrio molitor larvae, the rearing of the larvae and the quantification of the capacity to biodegrade plastic. The results obtained were, they found that sample 1 (M1) had a specific biomass productivity of 6.6 grams while sample 2 (M2) a specific productivity of 2.3 grams was recorded and managed to show a change in terms of color and the amount of feces. Finally, the biodegradation of polystyrene influences the production of compost, benefiting the consumption of plastic. keywords : Biodegradation, Plastic, Tenebrio molitor, Environmental biotechnology, larvae.

Chitosan (CS) is a natural and biopolymer that are suitable biomedical properties such as; biocompatibility, non-toxicity, biodegradability and bioactive polymer that’s reason with a very large application (fabrication of biomedical scaffolds, implants). Some of the biocompatible thermoplastic polymers (PLA, PEEK, PLGA, PE, PP, PMMA, PET and etc.) are most widely used in biomedical field as per their properties from last two decades. Poly-vinyl chloride (PVC) thermoplastic polymer are most widely used in medical field but there are some limitations of their uses. For enhancement of PVC thermoplastic polymers properties sometimes add some bioactive and biocompatible fillers or other bioactive thermoplastic polymers. In this review paper try to link and discussed about the possible reinforcement CS in PVC thermoplastic polymer for biomedical applications.

Natural fibers do not have a long life in soil; therefore, they cannot replace synthetic textiles in many applications. However, in order to solve ever-increasing global environmental problems due to microplastics, more and more natural polymers must be used, creating a need for research into the sustainable life extension of natural fibers. Lignin is, along with cellulose, a main component of wood, and is produced in large quantities as waste during paper production. With appropriate processing, lignin can be exploited/used as a textile auxiliary to combine the strength-enhancing properties of textiles made from natural fibers with the protective properties of a lignin coating. However, there is not yet sufficient research on how to integrate lignin into textile applications. For this purpose, in this study, we have investigated whether thermoplastic lignin can be processed as a surface protective coating. We tested lignin as a yarn coating to extend the service life of cellulosic textiles. Cotton yarns have been coated with lignin in variations of coating mass, characterized and investigated by means of soil burial tests. As the soil burial tests conducted in climate chamber and outdoor field environments showed, the lifespan of textiles made from natural fibers can be significantly extended with a lignin coating. Long-term resilience has been demonstrated in standard burial tests. In the outdoor tests, the lignin coating was still fully intact, even after about 160 days of burial. The textile materials coated in this way enable sustainable applications, especially for geotextiles. They have an adjustable, sufficiently long service life; however, they are still biodegradable, and can therefore replace some applications, such as vegetating trench/brook slopes, with synthetic materials. Lignin-coated textiles have the potential to significantly reduce the carbon footprint, reduce not only the dependence on petroleum-based products but also the amount of microplastics entering the environment. Further research can be conducted to improve lignin compounding in terms of other interesting properties for specific textile applications. Process optimization could increase the protective effect and further extend the life of useful textiles in soil.

In open environment applications, fibers are increasingly being used that are expected to biodegrade in the soil after their desired service life. Biodegradable polymer fibers are a versatile alternative to natural fibers. In this study, the degradation behavior of fibers made from polylactic acid (PLA) and a polyhydroxy alkanoate (PHA) blend with PLA, as well as a bicomponent fiber (BICO) made from polybutylene succinate (PBS) and PLA, was investigated. The fibers were stored in topsoil at 23 °C for 12 weeks. In addition, fibers were stored in compost at 58 °C for 4 weeks to investigate the degradation behavior in an industrial composting plant. Reference materials were also stored without substrate under the same temperatures and humidity conditions. Samples were taken regularly, and mechanical testing, scanning electron microscopy (SEM), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and infrared spectroscopy (IR) were used to study the degradation of the fibers. After 12 weeks in soil at ambient temperatures, the PLA and BICO fibers showed no degradation. The PHA fibers showed cracks in SEM, a decrease in molecular weight, and changes in the IR spectrum. No evidence of biological influence (bacteria or fungi) was found. Under industrial composting conditions, all fibers showed a decrease in strength and molecular weight. For the BICO and the PHA fibers, the SEM images show significant changes. Especially in the PHA fibers, fungal mycelia can be seen. The studies provide a better insight into the processes involved in the degradation behavior under different environmental conditions.

Globally, people suffering from bone disorders are steadily increasing and bone tissue engineering is an advanced approach to treating fractured and defected bone tissues. In this study, we have prepared polymeric nanocomposite by free-radical polymerization from sodium alginate, hydroxyapatite, and silica with different GO amounts. The porous scaffolds were fabricated using the freeze drying technique. The structural, morphological, mechanical, and wetting investigation was conducted by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, universal tensile machine, and water contact angle characterization techniques. The swelling, biodegradation, and water retention were also studied. The biological studies were performed (cell viability, cell adherence, proliferation, and mineralization) against osteoblast cell lines. Scaffolds have exhibited different pore morphology SAG-1 (pore size = 414.61 ± 56 μm and porosity = 81.45 ± 2.17 %) and SAG-4 (pore size = 195.97 ± 82 μm and porosity = 53.82 ± 2.45 %). They have different mechanical behavior as SAG-1 has the least compression strength and compression modulus 2.14 ± 2.35 and 16.51 ± 1.27 MPa. However, SAG-4 has maximum compression strength and compression modulus 13.67 ± 2.63 and 96.16 ± 1.97 MPa with wetting behavior 80.70° and 58.70°, respectively. Similarly, SAG-1 exhibited the least and SAG-4 presented maximum apatite mineral formation, cell adherence, cell viability, and cell proliferation against mouse pre-osteoblast cell lines. The increased GO amount provides different multifunctional materials with different characteristics. Hence, the fabricated scaffolds could be potential scaffold materials to treat and regenerate fracture bone tissues in bone tissue engineering. We are grateful to the European Union's Horizon to support the research project. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 951747 . Scopus

Conventional plastics can be substituted for protein-based bioplastics due to their natural origin and their biodegradability. Nevertheless, their properties are inferior to those obtained for synthetic plastics. The chemical crosslinking of these bioplastics with aldehydes could improve their properties to compete in the actual market. Thus, the main goal of this article was to assess the influence of the incorporation of aldehydes with different aliphatic chain length on the physicochemical (crosslinking degree, colour and transparency), mechanical (flexural and tensile behaviour) and functional (water uptake capacity and biodegradability) properties of protein-based bioplastics. In this sense, pea protein, a by-product of food industry, was used as raw material, processing it by injection moulding to obtain the bioplastics. Formaldehyde, glyoxal and glutaraldehyde were the aldehydes used as crosslinking agents. The results show the rise of the mechanical properties with the incorporation of the aldehydes, depending on the degree of crosslinking they generate. All this also causes a consequent loss of the water uptake capacity and an increase in biodegradability time. In conclusion, this work opens a new alternative to develop sustainable bioplastics that can be used in the market., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Ministerio de Ciencia e Innovación- Agencia Estatal de Investigación (MCI/AEI/FEDER, EU) from the Spanish Government (Ref. PID2021-124294OB-C21). Junta de Andalucía and European Social Fund (Ref. PAIDI DOCTOR – Convocatoria 2019/2020, DOC_00586). Ministerio de Educación y Formación Profesional (Ref. FPU17/01718).

Large quantities of lignin are produced as by-streams via chemical pulping and emerging biorefinery processes. These lignins are typically water-insoluble; however, they can be converted into a water-soluble form by chemical modifications. A novel LigniOx technology solubilizes lignin using alkali-O2 oxidation. The product can be used for bio-based dispersants. This study evaluated the biodegradability of alkali-O2 oxidized kraft, organosolv, and hydrolysis lignin. The oxidized lignins exhibited higher biodegradation in soil and in aquatic environments in comparison to a commercial kraft lignin and a commercial lignosulfonate. In soil, the biodegradabililties of oxidized lignins were 19 to 44%, whereas the reference lignins exhibited only 5 to 12% conversion to CO2. Biodegradation of the oxidized lignins and references in the aquatic environment increased in a similar order as in the soil environment, although the degradation in each sample was slightly smaller, than in the soil. The improved biodegradability of the oxidized lignins was due to the altered chemical structure of lignin. Compared to the untreated lignin, the oxidized lignin contained structures formed in aromatic ring opening reactions, making the lignin more accessible to microbial degradation. In addition, the oxidized lignin contained carbon originating from small organic compounds, which are easily biodegradable

In this study, hot rolling is properly performed on pure magnesium and two of Zn, Ca and Mn containing magnesium alloys. Biodegradability and mechanical properties are investigated comparatively in their rolled state. While the average grain sizes of the two alloys were close to each other, it was observed that the Mg-1.01Zn-1.63Ca-0.30Mn alloy had higher hardness (61.5 ± 0.2 HV) at hot rolled state. The lowest corrosion rate in electrochemical corrosion test on Mg-1.07Zn-0.21Ca-0.31Mn alloy is observed to be 1.772 mm/yr. As for the immersion corrosion test on the same alloy, the lowest corrosion rate is detected to be 0.054 mm/yr. Moreover, Mg-1.07Zn-0.21Ca-0.31Mn alloy has the highest tensile strength. Based on the results, it is ascertained that hot-rolled Mg-1.07Zn-0.21Ca-0.31Mn alloy possesses a better biodegradability and mechanical properties compared to hot rolled commercially unalloyed Mg and 1.01Zn-1.63Ca-0.30Mn alloy.

Porous biodegradable Mg and its alloys are considered to have a great potential to serve as ideal bone substitutes. The recent progress in additive manufacturing (AM) has prompted its application to fabricate Mg scaffolds with geometrically ordered porous structures. Extrusion-based AM, followed by debinding and sintering, has been recently demonstrated as a powerful approach to fabricating such Mg scaffolds, which can avoid some crucial problems encountered when applying powder bed fusion AM techniques. However, such pure Mg scaffolds exhibit a too high rate of in vitro biodegradation. In the present research, alloying through a pre-alloyed Mg-Zn powder was ultilized to enhance the corrosion resistance and mechanical properties of AM geometrically ordered Mg-Zn scaffolds simultaneously. The in vitro biodegradation behavior, mechanical properties, and electrochemical response of the fabricated Mg-Zn scaffolds were evaluated. Moreover, the response of preosteoblasts to these scaffolds was systematically evaluated and compared with their response to pure Mg scaffolds. The Mg-Zn scaffolds with a porosity of 50.3% and strut density of 93.1% were composed of the Mg matrix and MgZn2 second phase particles. The in vitro biodegradation rate of the Mg-Zn scaffolds decreased by 81% at day 1, as compared to pure Mg scaffolds. Over 28 days of static immersion in modified simulated body fluid, the corrosion rate of the Mg-Zn scaffolds decreased from 2.3 ± 0.9 mm/y to 0.7 ± 0.1 mm/y. The yield strength and Young's modulus of the Mg-Zn scaffolds were about 3 times as high as those of pure Mg scaffolds and remained within the range of those of trabecular bone throughout the biodegradation tests. Indirect culture of MC3T3-E1 preosteoblasts in Mg-Zn extracts indicated favorable cytocompatibility. In direct cell culture, some cells could spread and form filopodia on the surface of the Mg-Zn scaffolds. Overall, this study demonstrates the great potential of the extrusion-based AM Mg-Zn scaffolds to be further developed as biodegradable bone-substituting biomaterials.

We studied the succession of bacterial communities during the biodegradation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). The communities originated from a mesocosm with soil from Bien Hoa airbase in Vietnam heavily contaminated with herbicides and dioxins. They were grown in defined media with different carbon and Gibbs energy sources and 2,3,7,8-TCDD. Cultures with dimethyl sulfoxide (DMSO) as the sole carbon and energy source degraded about 95% of 2,3,7,8-TCDD within 60 days of cultivation. Those with an additional 1 mM of vanillin did that in roughly 90 days. Further 16S rRNA gene amplicon sequencing showed that the increase in relative abundance of members belonging to the genera Bordetella, Sphingomonas, Proteiniphilum, and Rhizobium correlated to increased biodegradation of 2,3,7,8-TCDD in these cultures. A higher concentration of vanillin slowed down the biodegradation rate. Addition of alternative carbon and Gibbs energy sources, such as amino acids, sodium lactate and sodium acetate, even stopped the degradation of 2,3,7,8-TCDD completely. Bacteria from the genera Bordetella, Achromobacter, Sphingomonas and Pseudomonas dominated most of the cultures, but the microbial profiles also significantly differed between cultures as judged by non-metric multidimensional scaling (NMDS) analyses. Our study indicates that 2,3,7,8-TCDD degradation may be stimulated by bacterial communities preadapted to a certain degree of starvation with respect to the carbon and energy source. It also reveals the succession and abundance of defined bacterial genera in the degradation process.

Structural, mechanical, thermal and surface properties comprising biodegradable aromatic–aliphatic polymer poly(butylene adipate-co-terephthalate) (PBAT) and the wheat stalk-based nanocellulose (NCC) were studied. The materials were found to comprise the compatible and yet phase-segregated constituents which kept their identity in the nanocomposite materials. The NCC phase was found to be homogeneously dispersed in the PBAT matrix inside. Similar to the corresponding microcomposites, the investigated nanocomposites were found to be stable within their desired application temperature as packaging materials. The tensile properties of the nanocomposites degraded in terms of strain at break, tensile strength and tensile modulus. At higher filler content, the reinforcing effect dominated leading to an increase in indentation modulus and hardness, and a decrease in the work of elastic deformation. The wettability and the water absorption capacity of the materials increased with NCC content thereby enhancing the biodegradability of the composites.

International audience; The present study aims to assess the temporal variations of some biotic and abiotic biodegradation parameters of 2 polymers (LDPE and PP) by the bacteria P. aeruginosa and S. aureus at acidic, neutral, and alkaline pH under mesophilic conditions. LDPE and PP fragments were immersed in the mineral solutions free of carbon sources containing P. aeruginosa or S. aureus cells. The initial pH values (pHi) of solutions were 5, 7 and 9. Incubation was carried out at 28°C for 10, 20, 30, 40, 50 and 60 days. Results showed that during incubations, the pH of the solutions varies over time. In most cases, the electrical conductivity and cell abundances increased. The weights of the polymers decreased. The cell abundance apparent increasing rates (CAAIR), the electrical conductivity apparent increasing rates (ECAIR), and the polymer weight apparent decreasing rates (PWADR) were estimated. The highest PWADR in the presence of LDPE was 0.4 mg/10days with P. aeruginosaat pHi 5 and 7, and 0.6 mg/10days with S. aureus under pHi 7. For PP, it was constant (0.7 mg/10days) under all pHi with S. aureus, but decreased in the presence of P. aeruginosa with increasing in pHi solutions. The ECAIR with LDPE decreased with increasing pHi with both bacterial species.The highest ECAIR of PP was recorded under pHi 5 with S. aureus and under pHi 7 with P. aeruginosa.The highest CAAIR with LDPE was 185.18 CFU/10days for P. aeruginosa at pHi 5 and 116.79 CFU/10days for S. aureus at pHi 7. With PP, it was 297.61 CFU/10days for P. aeruginosa at pHi 5 and 67.64 CFU/10days for S. aureusat pHi 7. The biodegradation parameters values recorded with of P. aeruginosa differed significantly (P

Cholinium-based ionic liquids are compounds increasingly studied in pharmaceutics and biomedicine to enhance bioavailability in drug delivery systems and as bioactive ingredients in pharmaceutical formulations. However, their potential as antimicrobial agents has scarcely been investigated. Herein, we explored the antimicrobial activity of a series of surface-active cholinium-based ionic liquids (Chol-ILs). For this purpose, Chol-ILs with alkyl chains of 10–16 carbon atoms were synthesized and their self-assembly in aqueous medium was investigated. Subsequently, their antimicrobial activity against a panel of clinically relevant bacteria and their ability to eradicate MRSA and P. aeruginosa PAO1 biofilms was evaluated. Finally, we analyzed the ecotoxicological profile of Chol-ILs in terms of susceptibility to aerobic biodegradation and acute aquatic toxicity against D. magna and V. fisheri. Our results reveal that cholinium-based ILs with alkyl chain lengths ≥12 C show a broad spectrum of antibacterial activity. Their antimicrobial efficacy depends on their hydrophobicity, with the C14–C16 homologs being the most effective compounds. These ILs exhibit antimicrobial activity similar to that of imidazolium ILs and quaternary ammonium antiseptics. Moreover, the longer alkyl chain Chol-ILs are able to eradicate established biofilms at concentrations as low as 16–32 µg/mL. The biodegradation rate of cholinium-based ILs decreases with alkyl chain elongation. Our results reinforce the suitability of Chol-ILs as promising multifunctional compounds for application in pharmaceutical and biomedical formulation.

In this investigation, an automotive component made of nylon as a structural element was studied by several characterization techniques to identify material properties. Firstly, a Fourier transform infrared spectroscopy (FTIR) was carried out to obtain information about composition, then, differential scanning calorimetry (DSC) was used to extract useful information on sample thermal behavior. The humidity and volatile materials percentage could be assessed by thermogravimetry analysis (TGA). Morphology and topography were carried out by optical microscopy, moreover, X-ray Tomography allows it to display the sample’s inner part. Characterization shows that the component could have been contaminated or exposed to conditions that promote degradation after the manufacturing process. Finally, computerized X-ray tomography displayed that both samples showed a difference in porosity in a fractured sample and a healthy sample. All the above implies a change in the mechanical integrity of the fractured material but might not omit the fact that it could have been subjected to any type of impact or mechanical effort.

Ionic liquid 1-butyl-3-methylimidazolium chloride [BMIM][Cl] was used to prepare cellulose (CELL), cellulose/polycaprolactone (CELL/PCL), cellulose/polycaprolactone/keratin (CELL/PCL/KER), and cellulose/polycaprolactone/keratin/ground calcium carbonate (CELL/PCL/KER/GCC) biodegradable mulch films. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy, optical microscopy, and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to verify the films’ surface chemistry and morphology. Mulch film made of only cellulose regenerated from ionic liquid solution exhibited the highest tensile strength (75.3 ± 2.1 MPa) and modulus of elasticity of 944.4 ± 2.0 MPa. Among samples containing PCL, CELL/PCL/KER/GCC is characterized by the highest tensile strength (15.8 ± 0.4 MPa) and modulus of elasticity (687.5 ± 16.6 MPa). The film’s breaking strain decreased for all samples containing PCL upon the addition of KER and KER/GCC. The melting temperature of pure PCL is 62.3 °C, whereas that of CELL/PCL film has a slight tendency for melting point depression (61.0 °C), which is a characteristic of partially miscible polymer blends. Furthermore, Differential Scanning Calorimetry (DSC) analysis revealed that the addition of KER or KER/GCC to CELL/PCL films resulted in an increment in melting temperature from 61.0 to 62.6 and 68.9 °C and an improvement in sample crystallinity by 2.2 and 3.0 times, respectively. The light transmittance of all studied samples was greater than 60%. The reported method for mulch film preparation is green and recyclable ([BMIM][Cl] can be recovered), and the inclusion of KER derived by extraction from waste chicken feathers enables conversion to organic biofertilizer. The findings of this study contribute to sustainable agriculture by providing nutrients that enhance the growth rate of plants, and hence food production, while reducing environmental pressure. The addition of GCC furthermore provides a source of Ca2+ for plant micronutrition and a supplementary control of soil pH.

BACKGROUND: A popular antiseptic spray in Switzerland (Merfen spray), containing chlorhexidine digluconate, benzoxonium chloride and lauramine oxide, is frequently used to treat skin wounds. However, it is also increasingly reported as a major cause of adverse skin reactions, including allergic contact dermatitis (ACD). OBJECTIVES: To investigate the contact allergens responsible for ACD from this antiseptic. PATIENTS/METHODS: Patch tests were performed on seven patients with a clinical history compatible with contact dermatitis from this antiseptic mixture. RESULTS: All patients presented with acute eczematous reactions following contact with either Merfen spray alone, or with multiple products including this spray. Patients showed positive reactions to this product in both patch tests and repeated open application tests (ROATs). Four patients showed dose-dependent reactions to both benzoxonium chloride and lauramine oxide. One patient showed a dose-dependent reaction to the former and a non-dose-dependent reaction to the latter. Finally, two subjects showed responses only to lauramine oxide. One patient reacted to chlorhexidine digluconate 0.5% aq. in addition to both other allergens. CONCLUSIONS: Two commercially unavailable allergens, that is, benzoxonium chloride and/or lauramine oxide were identified as major causes of ACD from Merfen antiseptic spray, whereas chlorhexidine digluconate was a contributing culprit in only one patient. ispartof: CONTACT DERMATITIS ispartof: location:England status: Published online

Biobased and biodegradable polymers (BBDs) such as poly(3-hydroxy-butyrate), PHB, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are considered attractive alternatives to fossil-based plastic materials since they are more environmentally friendly. One major problem with these compounds is their high crystallinity and brittleness. In order to generate softer materials without using fossil-based plasticizers, the suitability of natural rubber (NR) as an impact modifier was investigated in PHBV blends. Mixtures with varying proportions of NR and PHBV were generated, and samples were prepared by mechanical mixing (roll mixer and/or internal mixer) and cured by radical C–C crosslinking. The obtained specimens were investigated with respect to their chemical and physical characteristics, applying a variety of different methods such as size exclusion chromatography, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal analysis, XRD, and mechanical testing. Our results clearly indicate that NR–PHBV blends exhibit excellent material characteristics including high elasticity and durability. Additionally, biodegradability was tested by applying heterologously produced and purified depolymerases. pH shift assays and morphology analyses of the surface of depolymerase-treated NR–PHBV through electron scanning microscopy confirmed the enzymatic degradation of PHBV. Altogether, we prove that NR is highly suitable to substitute fossil-based plasticizers; NR–PHBV blends are biodegradable and, hence, should be considered as interesting materials for a great number of applications.

In this study, lignin was chemically modified to promote hydrogel degradation as a source of carbon and nitrogen for a bacterial consortium consisting of P. putida F1, B. cereus and, B. paramycoides. A hydrogel was synthesized using acrylic acid (AA), acrylamide (AM), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and cross-linked with the modified lignin. The structural changes and mass loss in the hydrogel, as well as its final composition, were evaluated as functions of the growth of the selected strains in a culture broth with the powdered hydrogel. The average loss was 18.4% wt. The hydrogel was characterized using FTIR spectroscopy, scanning electronic microscopy (SEM), elemental analysis (EA), and thermogravimetric analysis (TGA) before and after bacterial treatment. FTIR showed that the carboxylic groups present in both the lignin and the acrylic acid of the hydrogel decreased during bacterial growth. The bacteria showed a preference for the biomaterial components of the hydrogel. SEM demonstrated superficial morphological changes in the hydrogel. The results reveal that the hydrogel was assimilated by the bacterial consortium while preserving the water retention capacity of the material and that the microorganisms carried out a partial biodegradation of the hydrogel. The results of the EA and TGA confirm that the bacterial consortium not only degraded the biopolymer (lignin), but also used the synthetic hydrogel as a carbon source to degrade its polymeric chains and modified original properties. This modification with lignin as a crosslinker (which is a waste product of the paper industry) is therefore proposed to promote hydrogel degradation.

The excessive presence of single-use plastics is rapidly degrading our natural environment on a global scale due to their inherent resistance to decomposition. Wet wipes used for personal or household purposes contribute significantly to the accumulation of plastic waste. One potential solution to address this problem involves developing eco-friendly materials that possess the ability to degrade naturally while retaining their washing capabilities. For this purpose, the beads from sodium alginate, gellan gum, and a mixture of these natural polymers containing surfactant were produced using the ionotropic gelation method. Stability studies of the beads by observing their appearance and diameter were performed after incubation in solutions of different pH values. The images showed that macroparticles were reduced in size in an acidic medium and swelled in solution of pH-neutral phosphate-buffered saline. Moreover, all the beads first swelled and then degraded in alkaline conditions. The beads based on gellan gum and combining both polymers were the least sensitive to pH changes. The compression tests revealed that the stiffness of all macroparticles decreased with the increasing pH of the solutions in which they were immersed. The studied beads were more rigid in an acidic solution than in alkaline conditions. The biodegradation of macroparticles was assessed using a respirometric method in soil and seawater. It is important to note that the macroparticles degraded more rapidly in soil than in seawater.

Biodegradable polymers offer a potential solution to marine pollution caused by plastic waste. The marine biofilms that formed on the surfaces of poly(lactide acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were studied. Bioplastics were exposed for 6 months to marine conditions in the Mediterranean Sea, and the biofilms that formed on their surfaces were assessed. The presence of specific PLA and PHBV degraders was also studied. PHBV showed extensive areas with microbial accumulations and this led to higher microbial surface densities than PLA (4.75 vs. 5.16 log CFU/cm2). Both polymers’ surfaces showed a wide variety of microbial structures, including bacteria, fungi, unicellular algae and choanoflagellates. A high bacterial diversity was observed, with differences between the two polymers, particularly at the phylum level, with over 70% of bacteria affiliated to three phyla. Differences in metagenome functions were also detected, revealing a higher presence of proteins involved in PHBV biodegradation in PHBV biofilms. Four bacterial isolates belonging to the Proteobacteria class were identified as PHBV degraders, demonstrating the presence of species involved in the biodegradation of this polymer in seawater. No PLA degraders were detected, confirming its low biodegradability in marine environments. This was a pilot study to establish a baseline for further studies aimed at comprehending the marine biodegradation of biopolymers.

Non-steroidal anti-inflammatory drugs (NSAIDs) are increasingly recognized as potential environmental contaminants that may induce toxicity in aquatic ecosystems. This 3-week microcosm experiment explores the acute impacts of NSAIDs, including diclofenac (DCF), ibuprofen (IBU), and acetylsalicylic acid (ASA), on bacterial communities using a wide range of these substances (200–6000 ppm). The results showed that the NSAID-treated microcosms had higher cell count values than control samples, though the diversity of microbial communities decreased. The isolated heterotrophic bacteria mostly belonged to Proteobacteria, particularly Klebsiella. Next-generation sequencing (NGS) revealed that NSAIDs altered the structure of the bacterial community composition, with the proportion of Proteobacteria aligning with the selective cultivation results. Bacteria had higher resistance to IBU/ASA than to DCF. In DCF-treated microcosms, there has been a high reduction of the number of Bacteroidetes, whereas in the microcosms treated with IBU/ASA, they have remained abundant. The numbers of Patescibacteria and Actinobacteria have decreased across all NSAID-treated microcosms. Verrucomicrobia and Planctomycetes have tolerated all NSAIDs, even DCF. Cyanobacteria have also demonstrated tolerance to IBU/ASA treatment in the microcosms. The archaeal community structure was also impacted by the NSAID treatments, with Thaumarchaeota abundant in all microcosms, especially DCF-treated microcosms, while Nanoarchaeota is more typical of IBU/ASA-treated microcosms with lower NSAID concentrations. These results indicate that the presence of NSAIDs in aquatic environments could lead to changes in the composition of microbial communities.

The accumulation of xenobiotic compounds in different environments interrupts the natural ecosystem and induces high toxicity in non-target organisms. Diclofenac is one of the commonly used pharmaceutical drugs that persist in the environment due to its low natural degradation rate and high toxicity. Therefore, this study aimed to isolate potential diclofenac-degrading bacteria, detect the intermediate metabolites formed, and determine the enzyme involved in the degradation process. Four bacterial isolates were selected based on their ability to utilize a high concentration of diclofenac (40 mg/L) as the sole carbon source. The growth conditions for diclofenac degradation were optimized, and bacteria were identified as Pseudomonas aeruginosa (S1), Alcaligenes aquatilis (S2), Achromobacter spanius (S11), and Achromobacter piechaudii (S18). The highest percentage of degradation was recorded (97.79 ± 0.84) after six days of incubation for A. spanius S11, as analyzed by HPLC. To detect and identify biodegradation metabolites, the GC-MS technique was conducted for the most efficient bacterial strains. In all tested isolates, the initial hydroxylation of diclofenac was detected. The cleavage step of the NH bridge between the aromatic rings and the subsequent cleavage of the ring adjacent to or in between the two hydroxyl groups of polyhydroxylated derivatives might be a key step that enables the complete biodegradation of diclofenac by A. piechaudii S18, as well as P. aeruginosa S1. Additionally, the laccase, peroxidase, and dioxygenase enzyme activities of the two Achromobacter strains, as well as P. aeruginosa S1, were tested in the presence and absence of diclofenac. The obtained results from this work are expected to be a useful reference for the development of effective detoxification bioprocesses utilizing bacterial cells as biocatalysts. The complete removal of pharmaceuticals from polluted water will stimulate water reuse, meeting the growing worldwide demand for clean and safe freshwater.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has gained attention as a possible substitute for conventional polymers that could be integrated into the organic recycling system. Biocomposites with 15% of pure cellulose (TC) and woodflour (WF) were prepared to analyze the role of lignin on their compostability (58 °C) by tracking the mass loss, CO2 evolution, and the microbial population. Realistic dimensions for typical plastic products (400 µm films), as well as their service performance (thermal stability, rheology), were taken into account in this hybrid study. WF showed lower adhesion with the polymer than TC and favored PHBV thermal degradation during processing, also affecting its rheological behavior. Although all materials disintegrated in 45 days and mineralized in less than 60 days, lignin from woodflour was found to slow down the bioassimilation of PHBV/WF by limiting the access of enzymes and water to easier degradable cellulose and polymer matrix. According to the highest and the lowest weight loss rates, TC incorporation allowed for higher mesophilic bacterial and fungal counts, while WF seemed to hinder fungal growth. At the initial steps, fungi and yeasts seem to be key factors in facilitating the later metabolization of the materials by bacteria., This research was financially supported by MCIN/AEI/10.13039/501100011033 and FEDER “Una manera de hacer Europa”, project number PID2021-128749OB-C32. This work has also been granted with the financial support of the Generalitat Valenciana (project AICO/2021/045) and by the Universitat Jaume I (project UJI-B2019-44). Kerly Samaniego Aguilar would like to acknowledge the MCIN/AEI/10.13039/501100011033 and FSE “El FSE invierte en tu futuro” for her FPI fellowship (PRE2019-091448).

Low density polyethylene (LDPE) has been widely used commercially for decades; however, as a non-degradable material, its continuous accumulation has contributed to serious environmental issues. A fungal strain, Cladosporium sp. CPEF-6 exhibiting a significant growth advantage on MSM-LDPE (minimal salt medium), was isolated and selected for biodegradation analysis. LDPE biodegradation was analyzed by weight loss percent, change in pH during fungal growth, environmental scanning electron microscopy (ESEM), and Fourier transformed infrared spectroscopy (FTIR). Inoculation with the strain Cladosporium sp. CPEF-6 resulted in a 0.30 ± 0.06% decrease in the weight of untreated LDPE (U-LDPE). After heat treatment (T-LDPE), the weight loss of LDPE increased significantly and reached 0.43 ± 0.01% after 30 days of culture. The pH of the medium was measured during LDPE degradation to assess the environmental changes caused by enzymes and organic acids secreted by the fungus. The fungal degradation of LDPE sheets was characterized by ESEM analysis of topographical alterations, such as cracks, pits, voids, and roughness. FTIR analysis of U-LDPE and T-LDPE revealed the appearance of novel functional groups associated with hydrocarbon biodegradation as well as changes in the polymer carbon chain, confirming the depolymerization of LDPE. This is the first report demonstrating the capacity of Cladosporium sp. to degrade LDPE, with the expectation that this finding can be used to ameliorate the negative impact of plastics on the environment.

The future of panel housing estates is influenced by a number of factors. Although panel housing estates have seen their share of commentary and analysis from both supporters and de-tractors, there has been no comprehensive effort to explore the field of panel housing estates in terms of building thermal regeneration measures. This article focuses on the links between thermo-technical regeneration measures in panel housing estates, and the application of External Thermal Insulation Composite Systems (ETICS) and their impact on the urban environment of panel housing estates. The paper contains three main sections in which we (1) synthesize the literature, sources, building physics context, and assumptions for the occurrence of biodeterization in the facades of prefab residential housing located in housing estates; (2) compare the case studies and their results from the 2010–2021 field reconnaissance, in situ diagnostics, and laboratory analyses; and (3) identify/illustrate common features, the extent to which the quality of prefab residential housing located in housing estates with ETICS exterior surfaces is influenced by the environmental context, whereby we understand the whole process of the environmental assessment framework as an interrelated complexity of the interacting links between the environment, urban planning, architecture and construction sectors, supporting a holistic approach to the issue at hand. The results show that regeneration work, on the one hand, improves the urbanized environment and the energy potential of a housing estate; on the other hand, we encounter new manifestations of defects and disorders in the form of biodegradation of facades that we did not expect.

Microalgae have been widely employed in water pollution treatment since they are eco-friendly and economical. However, the relatively slow treatment rate and low toxic tolerance have seriously limited their utilization in numerous conditions. In light of the problems above, a novel biosynthetic titanium dioxide (bio-TiO2 NPs)—microalgae synergetic system (Bio-TiO2/Algae complex) has been established and adopted for phenol degradation in the study. The great biocompatibility of bio-TiO2 NPs ensured the collaboration with microalgae, improving the phenol degradation rate by 2.27 times compared to that with single microalgae. Remarkably, this system increased the toxicity tolerance of microalgae, represented as promoted extracellular polymeric substances EPS secretion (5.79 times than single algae), and significantly reduced the levels of malondialdehyde and superoxide dismutase. The boosted phenol biodegradation with Bio-TiO2/Algae complex may be attributed to the synergetic interaction of bio-TiO2 NPs and microalgae, which led to the decreased bandgap, suppressed recombination rate, and accelerated electron transfer (showed as low electron transfer resistance, larger capacitance, and higher exchange current density), resulting in increased light energy utilization rate and photocatalytic rate. The results of the work provide a new understanding of the low-carbon treatment of toxic organic wastewater and lay a foundation for further remediation application.

Loose assemblies of cellulose fibers could be employed in the clean-up of oil spills, but the difficulty to separate them from the spill after use makes them impractical. In an effort to tackle this issue, a non-woven sorbent based on recycled jute fibers from the carpet industry was developed. To enhance the porosity and hydrophobicity/oleophilicity of the sorbent, carbonization in an inert atmosphere was carried out. A comparison in oil sorption performance between non-carbonized and carbonized sorbents was made by evaluating the oil capacity in a water medium, buoyancy, oil retention and reusability. Carbonization of sorbent resulted in more than doubled oil sorption capacity independent of oil viscosity. Oil viscosity did not affect the oil sorption capacity of non-carbonized sorbent. Carbonized sorbent showed superior buoyancy in water even after 24 hours, oil retention of approximately 60–80% after 3 hours and only 12–20% decline of oil sorption capacity after five repeated sorption/desorption trials. However, the ability of oiled non-carbonized sorbent to efficiently biodegrade in model compost (up to 45% weight loss after 10 weeks) makes it a sustainable candidate for oil spill clean-up.

The worldwide use of the carbamate insecticide carbofuran has caused considerable concern about its environmental fate. Degradation of carbofuran by Sphingobium sp. strain CFD-1 is initiated via the hydrolysis of its ester bond by carbamate hydrolase CehA to form carbofuran phenol. In this study, another carbofuran-degrading strain, Sphingobium sp. CFD-2, was isolated. Subsequently, a cfd gene cluster responsible for the catabolism of carbofuran phenol was predicted by comparing the genomes of strains CFD-1, CFD-2, and Novosphingobium sp. strain KN65.2. The key genes verified to be involved in the catabolism of carbofuran phenol within the cfd cluster include the hydroxylase gene cfdC, epoxide hydrolase gene cfdF, and ring cleavage dioxygenase gene cfdE and are responsible for the successive conversion of carbofuran phenol, resulting in complete ring cleavage. These carbofuran-catabolic genes (cehA and the cfd cluster) are distributed on two plasmids in strain CFD-1 and are highly conserved among the carbofuran-degrading sphingomonad strains. The mobile genetic element IS6100 flanks cehA and the cfd gene cluster, indicating the importance of horizontal gene transfer in the formation of carbofuran degradation gene clusters. The elucidation of the molecular mechanism of carbofuran catabolism provides insights into the evolutionary scenario of the conserved carbofuran catabolic pathway. IMPORTANCE Owing to the extensive use of carbofuran over the past 50 years, bacteria have evolved catabolic pathways to mineralize this insecticide, which plays an important role in eliminating carbofuran residue in the environment. In this study, the cfd gene cluster, responsible for the catabolism of carbofuran phenol, was predicted by comparing sphingomonad genomes. The function of key enzymatic genes in this gene cluster was identified. Furthermore, the carbamate hydrolase gene cehA and the cfd gene cluster are highly conserved in different carbofuran-degrading strains. Additionally, the horizontal gene transfer elements flanking the cfd gene cluster were investigated. These findings help elucidate the molecular mechanism of microbial carbofuran degradation and enhance our understanding of the evolutionary mechanism of the carbofuran catabolic pathway.

Actuality. The modern market of oil and oil products requires the creation and maintenance of fuel stocks at fuel supply enterprises in proper quality. This depends on the efficiency of rational storage and use of petroleum products, studying the possibilities of reducing the negative impact of physical and chemical processes that exist during the interaction of fuels with construction materials. Problem setting. Processes of corrosive destruction of materials as a result of chemical or electrochemical interactions between the material and the environment are an actual problem today. Fuel, in the composition of which harmful substances may appear during storage, causes a corrosive effect on the materials of the technological equipment during each stage of its life cycle. The goal of the work. Study of the mechanism of the influence of corrosive and biocorrosive factors on the deterioration of the quality of hydrocarbon fuels during their storage; impact on the operational condition of technological equipment. Research results. The result of the vital activity of microbiological contamination of fuels (bacteria, fungi) is the arrival of undesirable compounds, which contributes to a change in the pH of the fuel medium. This leads to increased corrosion of technological equipment. Also, the course of the fuel oxidation process is accompanied by the further formation of corrosion-active compounds. They lead to the destruction of the structural material and the formation of harmful compounds, which negatively affect the fuel quality indicators. Conclusions. Undoubtedly, the course of corrosion processes caused by the microbiological fuel factor has a negative effect on technological equipment and fuel quality. The mechanism of the course of corrosion processes in the fuel environment investigated in the work testifies to the presence of a biocorrosive factor in operational conditions that affects the deterioration of the quality of hydrocarbon fuels, especially during their long-term storage. Актуальність. Сучасний ринок нафти та нафтопродуктів вимагає створення і утримання запасів палив на підприємствах паливозабезпечення у належній якості, з мінімальними витратами на обслуговування та забезпеченням екологічної безпеки. Це, в свою чергу, залежить від ефективності раціонального зберігання та використання нафтопродуктів, вивчення можливостей зменшення негативного впливу тих фізико-хімічних процесів, що мають місце внаслідок взаємодії палив з конструкційними матеріалами під час їх зберігання та транспортування. Постановка проблеми. Процеси корозії або так зване руйнування матеріалів внаслідок хімічних або електрохімічних взаємодій між матеріалом та середовищем – актуальна багатопланова проблема сьогодення. Паливо, у складі якого під час зберігання можуть з’являтися шкідливі речовини, спричинює корозійну дію на матеріали технологічного обладнання, з якими вони контактують на кожному етапі свого життєвого циклу. Мета роботи Дослідження механізму впливу корозійного та біокорозійного чинників на погіршення якості вуглеводневих палив під час їх довготривалого зберігання, вплив на експлуатаційний стан технологічного обладнання. Результати досліджень. Результатом життєдіяльності мікробіологічних забруднень палив (бактерії, гриби) стає надходження небажаних сполук, що сприяє зміні pН паливного середовища, відповідно посилюючи корозію технологічного обладнання. Також перебіг процесу окиснення палив супроводжується подальшим утворенням корзійноактивних сполук, що призводить до неминучого руйнування конструкційного матеріалу та утворення, в свою чергу, шкідливих сполук, що негативно впливають на показники якості палива. Висновки. Безсумнівно, перебіг корозійних процесів, спричинених мікробіологічним паливним чинником, негативно впливає на технологічне обладнання та якість палива. Досліджений в роботі механізм перебігу корозійних процесів у паливному середовищі засвідчує про наявність в експлуатаційних умовах біокорозійного чинника, що впливає на погіршення якості вуглеводневих палив, особливо під час їх довготривалого зберігання.

Two indigenous ascomycetes fungi, Trichoderma lixii strain FLU1 (TlFLU1) and Talaromyces pinophilus strain FLU12 (TpFLU12), were isolated from benzo(b)fluoranthene-enriched activated sludge and tested for bio-catalytically degrade fluoranthene as a sole carbon source. TlFLU1 and TpFLU12 degraded 98 and 99% of 400 mg/L of fluoranthene after 16 and 12 d incubation period, respectively. Degradation correlated with the upregulation of expression of ligninolytic enzymes. The GC-MS and FTIR analysis of the degradation products suggest that the degradation is initiated at the C1-C2 position of the compound ring via oxygenation and ring cleavage to form 9-oxo-9H-fluorene-1-carboxylic acid before undergoing ring cleavage to yield fluorenone, which then proceeds through the ß-Ketoadipate pathway via benzene-1,2,3-tricarboxylic acid. The degradation rate is better fitted in the first-order and zero-order kinetic model for TlFLU1 and TpFLU12, respectively. The metabolites from the TlFLU1 degradation media are shown to be toxic in Vibryo parahaemolyticus after 6 h of exposure with effective concentration (EC50) and toxicity unit (TU) values of 14.25 mg/L and 7.018%, respectively, while also being observed as non-toxic from TpFLU12 degradation media with an EC50 and TU values of 197.1 mg/L and 0.507%, respectively. Results from this study show efficient metabolism of fluoranthene into an innocuous state by TlFLU1 and TpFLU12.

Glyphosate is a non-selective herbicide that is used to control perennial weeds in agriculture. However, its vast application may result in glyphosate residues in the food chain. Due to its toxicity to non-target organisms, glyphosate-contaminated soils needed to be remediated, and bioremediation is a conventional remedial method. The success of this depends on the isolation of bacteria with the ability to degrade glyphosate. The goal of this study was to isolate glyphosate-degrading bacteria from the rhizosphere of maize and wheat with a repeated application history of glyphosate for 5–10 years and test their roles in promoting the growth of maize (Zea mays) and glyphosate degradation in vitro. Eleven isolated bacteria were inoculated, and their role in plant growth was compared at different levels (100 and 200 mg/kg) of glyphosate. The results revealed that E. ludwigii improved the highest shoot length by 26% and the root length by 34% compared to the control at 100 mg/kg. The relative water contents in leaves significantly improved by 58% using P. aeruginosa at 100 mg/kg. The maximum electrolyte leakage from leaves significantly reduced by 73% using E. ludwigii at 100 mg/kg compared to the control (uninoculated). A high-pressure liquid chromatography instrument was used to assess the glyphosate concentrations. The highest degradation of glyphosate was observed in treatments inoculated with E. ludwigii (99 and 40%), P. aeruginosa (95 and 39%), K. variicola, (91 and 38%) E. cloacae (92 and 38%), and S. liquefaciens (87 and 36%), respectively, at 100 and 200 mg/kg within 28 days. These five strains demonstrated a great potential for degrading glyphosate and promoting the growth of maize in vitro, and they will be further exploited for the biodegradation of glyphosate and the growth promotion of broader crop species in situ in the near future.

Four different bacteria capable of degrading butachlor, as well as five different syntrophic pairs of bacteria able to break down butachlor, were isolated from rice paddy soils in Korea. Genetic and phenotypic analyses were conducted to better understand their characteristics and behavior. All single isolates and syntrophic pairs were able to utilize butachlor as a sole carbon and energy source. Analysis of the 16S rRNA sequence showed that the isolates were related to members of the genus Rhodococcus and a new type of butachlor-degrading genus Sphingobium. The chromosomal DNA fingerprinting patterns of the butachlor-degrading bacteria and syntrophic pairs were analyzed using a technique called repetitive-sequence-based PCR (REP-PCR). The results showed that there were two different REP-PCR patterns found among the four independent butachlor-degrading bacteria, and ten strains of five different syntrophic pairs produced a total of eight distinct DNA fingerprints. Through the use of gas chromatography–mass spectrometry (GC-MS) analysis, it was observed that the syntrophic pair was capable of breaking down butachlor using various chemical pathways, such as 2-chloro-N-(2,6-diethylphenyl) acetamide (CDEPA), 2,6-diethylphenyl isocyanate, 2,6-diethylaniline (DEA), and 2-ethylaniline.

Waste tires from traffic are a well-known environmental problem today. For this reason, the toxicity and potential biodegradation of crushed tires were tested in a respiration test with microorganisms. A non-specific soil microbial community was used. Two experimental designs and their effect on the results were compared—a test with the eluate from tires and a contact test, i.e., the solution containing tire particles during the test. The consumption of dissolved oxygen was measured in the assay over 28 days. The values obtained indicated zero biodegradation of all samples, but the toxicity of the eluates to microorganisms was different depending on whether the microorganisms were exposed only to the leachate or whether tire shred particles were still present in the leachate. In the presence of particles in solutions, the toxicity of the samples for microorganisms was higher. Additionally, the MTT (methyl tetrazolium test) viability assay was performed. The results indicated a 28% inhibition of the viability of microorganisms in samples with tire particles in comparison with eluate, where 9% inhibition was observed. The results confirmed that the contact assay (with the presence of particles) is a more natural and thorough method than the use of leachate.

Inorganic elements in crude oil have been used in the reconstruction of the sedimentary environment and oil–oil (source) correlations; however, the effect of biodegradation on these elements has not been investigated sufficiently. In this study, 14 crude oils from the Miaoxi Sag of the Bohai Bay Basin, eastern China, were analyzed using molecular markers, trace elements, and major elements to determine the effect of biodegradation on inorganic elements. The molecular markers indicated that the oils are in the low maturity stage and are derived from similar parent materials in lacustrine source rocks. The high-sulfur oil came from a more reductive and saltier environment compared with the low-sulfur oil. The oils were subjected to varying degrees of biodegradation. The concentrations of Mg, Ca, Mn, Fe, Be, Sc, Rb, Sr, Zr, Pb, Th, and U increased significantly throughout the biodegradation process, while the concentrations of Na, K, Ti, Al, Cr, Zn, Cs, Nb, Ba, Hf, and Tl increased considerably only during the intense biodegradation stage (PM < 4). The concentrations of P, Li, V, Co, Ni, Cu, Ga, Sn, and Ta were not correlated with the level of biodegradation. The V/Ni, V/Co, Ni/Co, Cr/V, Sc/V, and Th/U ratios were affected by biodegradation when PM ≥ 4. Several ratios, including Mg/P, Ca/P, Mn/P, and Fe/P, are proposed as favorable indicators of the level of biodegradation. Differential enrichment of these elements is associated with the effects of organic acids generated by biodegradation on the oil–water–rock interactions in the reservoir.

Bibliometric reviews, carried out from access to databases of scientific articles associated with software for data processing, can be helpful for qualitative and quantitative assessments of existing publications on a given topic. Several petroleum hydrocarbons are carcinogenic and immunotoxic agents, causing adverse effects on the biota, and the study of metabolites generated in bioremediation processes has been the object of current research. Therefore, in this work, the use of bibliometric analysis as a tool for surveying studies on the applied metabolomics bioremediation of areas impacted by hydrocarbons is presented. A bibliometric review was carried out in the Scopus Preview and Web of Science databases with data analysis using RStudio software with the bibliometrix package. The survey gathered the studies and prominent publications of the last seven years, making it possible to present gaps and opportunities in the area.

Plastic pollution is one of the most serious environmental issues, causing severe environmental damage. It is of vital importance to find an efficient and eco-friendly approach to biodegrading plastics. The aim of this study was to isolate and characterize different bacterial isolates from water samples in the Al-Ahsa region of Saudi Arabia. The ability to degrade low-density polyethylene (LDPE) plastic was evaluated using multiple approaches, including changes in the media pH values, weight loss, Fourier transform infrared (FTIR), and gas chromatography–mass spectrometry (GC–MS). The water samples were collected from plastic-contaminated sites in Al-Ahsa, and bacterial isolates were obtained using a mineral nutrient medium (MNM) enriched with LDPE as the only carbon and energy source. Two bacterial isolates (APCK5 and APCZ14) were obtained and they showed potential LDPE degradation, as evidenced by changes in media pH (from 7.0 ± 0.03 to 6.17 ± 0.05 and 6.22 ± 0.03), LDPE weight reduction (8.1 ± 0.63% and 18.85 ± 0.96%, respectively), and FTIR and GC–MS analyses. Based on 16S rRNA gene similarities, APCZ14 and APCK5 were determined to be most closely related to the genus Brucella. APCZ14 exhibited a 99.48% homology with Brucella cytisi, whereas APCK5 showed a 99.33% similarity level to Brucella tritici. In conclusion, both bacterial strains had high efficiency in plastic biodegradation and could be developed for wide use as an eco-friendly method to remove or reduce plastic pollutants from the environment.

Following an oil spill into water, bacteria can biodegrade petroleum hydrocarbons which could lead to petrogenic carbon assimilation by aquatic biota. We used changes in the isotope ratios of radio- (Δ14C) and stable (δ13C) carbon to examine the potential for assimilation of petrogenic carbon into a freshwater food web following experimental spills of diluted bitumen (dilbit) into a boreal lake in northwestern Ontario, Canada. Different volumes (1.5, 2.9, 5.5, 18, 42, 82, and 180 L) of Cold Lake Winter Blend (a heavy crude blend of bitumen and condensate) dilbit were applied to seven 10-m diameter littoral limnocorrals (approximate volume of 100 m3), and two additional limnocorrals had no added dilbit to serve as controls. Particulate organic matter (POM) and periphyton from oil-treated limnocorrals had lower δ13C (up to 3.2‰ and 2.1‰ for POM and periphyton, respectively) than the control at every sampled interval (3, 6 and 10 weeks for POM and 6, 8 and 10 weeks for periphyton). Dissolved organic and inorganic carbon (DOC and DIC, respectively) had lower Δ14C in the oil-treated limnocorrals relative to the control (up to 122‰ and 440‰ lower, respectively). Giant floater mussel (Pyganodon grandis) housed for 25 days in aquaria containing oil-contaminated water from the limnocorrals did not show significant changes in δ13C values of muscle tissue compared to mussels housed in control water. Overall, the changes in δ13C and Δ14C observed indicated small amounts (up to 11% in DIC) of oil carbon incorporation into the food web. The combined δ13C and Δ14C data provide evidence for minimal incorporation of dilbit into the food web of this oligotrophic lake, suggesting that microbial degradation and subsequent incorporation of oil C into the food web may play a relatively small role in the ultimate fate of oil in this type of ecosystem.

Extensive plastic production has become a serious environmental and health problem due to the lack of efficient treatment of plastic waste. Polyethylene terephthalate (PET) is one of the most used polymers and is accumulating in landfills or elsewhere in nature at alarming rates. In recent years, enzymatic degradation of PET by Ideonella sakaiensis PETase (IsPETase), a cutinase-like enzyme, has emerged as a promising strategy to completely depolymerize this polymer into its building blocks. Here, inspired by the architecture of cutinases and lipases homologous to IsPETase and using 3D structure information of the enzyme, we rationally designed three mutations in IsPETase active site for enhancing its PET-degrading activity. In particular, the S238Y mutant, located nearby the catalytic triad, showed a degradation activity increased by 3.3-fold in comparison to the wild-type enzyme. Importantly, this structural modification favoured the function of the enzyme in breaking down highly crystallized (~31%) PET, which is found in commercial soft drink bottles. In addition, microscopical analysis of enzyme-treated PET samples showed that IsPETase acts better when the smooth surface of highly crystalline PET is altered by mechanical stress. These results represent important progress in the accomplishment of a sustainable and complete degradation of PET pollution.

Polymer flooding consists of injecting polymer-augmented water into the reservoir to control the water-oil mobility ratio, resulting in an increase in the volumetric sweep efficiency compared to water flooding. Synthetic polymers (polyacrylamides) and biopolymers (scleroglucan, xanthan gum, schizophyllan) are the two families of polymers usually evaluated for enhanced oil recovery (EOR). Scleroglucan (SG) is resistant to electrolytes, hydrolysis, pH (3-10) and temperature (30-100°C) and has remarkable rheological properties, but it is quite susceptible to microbiological degradation. The primary objective of this study was to evaluate the biodegradation of SG in the injection and production processes and its aquatic toxicity. The anaerobic biodegradation of the SG solutions was determined through the viscosity changes of the solutions, while the aerobic biodegradation was calculated with the changes in the SG concentration. It was observed that the viscosity reduction of the SG solution was 30% and the SG concentration decreased from 100 ppm to 52 ppm because bacteria can metabolize the biopolymer. Daphnia pulex, Scenedesmus acutus and Oreochromis sp. were the organisms used in the ecotoxicological assays of the SG solutions. The acute ecotoxicological bioassays showed that there was no evidence of acute deleterious effects of SG on any of the three organisms. From the chronic ecotoxicological bioassays, it was concluded that there was no effect of SG on the mortality of Daphnia pulex, regardless of the tested SG concentration. RESUMEN La inyección de polímeros en el yacimiento es usada para incrementar la viscosidad del agua para controlar la relación de movilidad agua-petróleo, lo que resulta en un aumento en la eficiencia de barrido volumétrico, en comparación con el proceso de inyección de agua. Los polímeros sintéticos (poliacrilamidas) y biopolímeros (escleroglucano, goma xantana, esquizofilano) son las dos familias de polímeros más usadas para la recuperación mejorada de petróleo (EOR). El escleroglucano (SG) es resistente a electrolitos, hidrólisis, pH (3- 10) y temperatura (30-100°C) y tiene excelentes propiedades reológicas, pero es susceptible a la degradación microbiana. El objetivo principal de este estudio fue evaluar la biodegradación de SG durante su inyección y producción y su toxicidad acuática. La biodegradación anaeróbica de las soluciones SG se determinó a través de los cambios de viscosidad de las soluciones, mientras que la biodegradación aeróbica fue calculada por los cambios en la concentración de SG. Se observó que la reducción de la viscosidad de la solución SG fue del 30% y que la concentración de SG disminuyó de 100 a 52 ppm, porque las bacterias pueden metabolizar el biopolímero. Daphnia pulex, Scenedesmus acutus y Oreochromis sp. fueron los organismos utilizados en los ensayos ecotoxicológicos de las soluciones SG. Los bioensayos ecotoxicológicos agudos mostraron que no hay evidencia de efectos nocivos agudos del SG en ninguno de los tres organismos. A partir de los bioensayos ecotoxicológicos crónicos se concluyó que no hay efecto del SG en la mortalidad de Daphnia pulex, a las concentraciones de SG evaluadas.

The efficient remediation of heavy metal complexes in water has become a difficult and challenging task owing to their high stability and strong mobility. In this study, a novel strategy was employed for highly efficient removal of Cu-citrate by using intimately coupled photocatalysis and biodegradation (ICPB) system with non-woven cotton fabric as a carrier. Experimental results showed that the ICPB system caused 94% Cu removal, which was higher than those of single photocatalysis. After 5 cycles, Cu removal efficiency could still reach 78% within 5 h. The existence of 0-40 mg/L citrate had negligible influence, whereas the presence of 60-100 mg/L citrate exhibited a limited adverse effect on Cu removal (∼70%). The decomplexation of Cu-citrate was realized via the function of free radicals and microorganisms. Two main processes, such as bio-adsorption of Cu2+ by microorganisms, deposition of Cu0 on the surface of material, played important role in Cu removal from aqueous solution. The dominant microorganisms in the system were Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Chlorophyta, Planctomycetes, and Verrucomicrobia. Furthermore, the performance of ICPB system was also validated through treatment of other heavy metal complexes. This study provided a feasible strategy for the decontamination of heavy metal complexes in wastewater.