Microplastics from agricultural mulch films: Biodegradation and ecotoxicity in freshwater systems.

The application of bio-based biodegradable mulch films in agriculture has raised environmental concerns regarding their potential impacts on adjacent freshwater ecosystems. This study investigated the biodegradation of microplastics derived from a bio-based biodegradable mulch (bio-MPs) and its acute and chronic ecotoxicity considering relevant scenarios (up to 200 and 250 mg/kg of sediment, using pristine and/or UV-aged particles), using the fungus Penicillium brevicompactum and the dipteran Chironomus riparius as model organisms, respectively, due to their ecological relevance in freshwater environments. Fourier-transform infrared spectroscopy analysis suggested changes in the fungus's carbohydrate reserves and bio-MP degradation through the appearance of low molecular weight esters throughout a 28 day biodegradation test. In a short-term exposure (48 h), C. riparius larvae exposed to pristine or UV-aged bio-MPs had up to 2 particles in their gut. Exposure to pristine bio-MPs decreased larval aerobic metabolism (<20 %) and increased neurotransmission (>15 %), whereas exposure to UV-aged bio-MPs activated larval aerobic metabolism (>20 %) and increased antioxidant defences (catalase activity by >30 % and glutathione-s-transferase by >20 %) and neurotransmission (>30 %). Longer-term (28-d) exposure to UV-aged bio-MPs did not affect larval survival and growth nor the dipteran's emergence but increased male numbers (>30 %) at higher concentrations. This study suggests that the selected agricultural bio-based mulch film is prone to biodegradation by a naturally occurring fungus. However, there is a potential for endocrine disruption in the case of prolonged exposures to UV-aged microplastics. This study emphasises the importance of further research to elucidate the potential ecological effects of these plastic products, to ensure effective management practices, and to establish new regulations governing their use.

Draft Genome Sequence of Zalerion maritima ATCC 34329, a (Micro)Plastic-Degrading Marine Fungus.

Zalerion maritima is a marine fungus that has been studied for the biodegradation of (micro)plastics. Here, we report the draft genome sequence of strain ATCC 34329, which was shown to have a size of 58.4 Mb, a GC content of 44.39%, and 10,802 predicted genes.

Sargassum muticum and Osmundea pinnatifida Enzymatic Extracts: Chemical, Structural, and Cytotoxic Characterization.

Seaweeds, which have been widely used for human consumption, are considered a potential source of biological compounds, where enzyme-assisted extraction can be an efficient method to obtain multifunctional extracts. Chemical characterization of Sargassum muticum and Osmundea pinnatifida extracts obtained by Alcalase and Viscozyme assisted extraction, respectively, showed an increment of macro/micro elements in comparison to the corresponding dry seaweeds, while the ratio of Na/K decreased in both extracts. Galactose, mannose, xylose, fucose, and glucuronic acid were the main monosaccharides (3.2-27.3 mg/glyophilized extract) present in variable molar ratios, whereas low free amino acids content and diversity (1.4-2.7 g/100gprotein) characterized both extracts. FTIR-ATR and 1H NMR spectra confirmed the presence of important polysaccharide structures in the extracts, namely fucoidans from S. muticum or agarans as sulfated polysaccharides from O. pinnatifida. No cytotoxicity against normal mammalian cells was observed from 0 to 4 mglyophilized extract/mL for both extracts. The comprehensive characterization of the composition and safety of these two extracts fulfils an important step towards their authorized application for nutritional and/or nutraceutical purposes.

Oxidation of benzoic acid from biomass burning in atmospheric waters.

This work evaluates the degradation of benzoic acid, a tracer from biomass burning, by different oxidation agents (Fe (III); H2O2; sunlight; and combinations of the previous ones) in model solutions and in real atmospheric waters. The extent of reactions was assessed by Ultraviolet-Visible and molecular fluorescence spectroscopies. The oxidation of benzoic acid occurred with the chemical oxidants Fe (III), H2O2, Fe (III) and H2O2 simultaneously in the presence of sunlight, and with Fe (III) and H2O2 simultaneously in the absence of light. The decrease of the pH value from neutral to acid for atmospheric waters generally increased the extent of oxidation. Sunlight was an important oxidation agent, and its combination with chemical oxidants increased the oxidation rate of benzoic acid, possibly due to the photogeneration of hydroxyl radicals. The results also suggested the occurrence of direct and indirect photolysis of benzoic acid in atmospheric waters. Moreover, the oxidation of benzoic acid produced new and more complex chromophoric compounds, which were then degraded. In addition, the nocturnal period is not sufficient for the full degradation of benzoic acid and of the intermediates formed by Fenton-like oxidation. The diurnal period may be enough for their full degradation through photo-Fenton-like oxidation, but this depends on the composition of the atmospheric waters, namely of the chromophoric content. Thus, this study highlights that benzoic acid from biomass burning, and its derivatives, may persist in atmospheric waters for periods of longer than one day, becoming available for other reactions, and may also affect the terrestrial and aquatic ecosystems through the wet depositions.

Microplastics in the environment: Challenges in analytical chemistry - A review.

Microplastics can be present in the environment as manufactured microplastics (known as primary microplastics) or resulting from the continuous weathering of plastic litter, which yields progressively smaller plastic fragments (known as secondary microplastics). Herein, we discuss the numerous issues associated with the analysis of microplastics, and to a less extent of nanoplastics, in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification. The analytical quality control and quality assurance associated with the validation of analytical methods and use of reference materials for the quantification of microplastics are also discussed, as well as the current challenges within this field of research and possible routes to overcome such limitations.

Recent Progress in Biosensors for Environmental Monitoring: A Review.

The environmental monitoring has been one of the priorities at the European and global scale due to the close relationship between the environmental pollution and the human health/socioeconomic development. In this field, the biosensors have been widely employed as cost-effective, fast, in situ, and real-time analytical techniques. The need of portable, rapid, and smart biosensing devices explains the recent development of biosensors with new transduction materials, obtained from nanotechnology, and for multiplexed pollutant detection, involving multidisciplinary experts. This review article provides an update on recent progress in biosensors for the monitoring of air, water, and soil pollutants in real conditions such as pesticides, potentially toxic elements, and small organic molecules including toxins and endocrine disrupting chemicals.

Biodegradation of polyethylene microplastics by the marine fungus Zalerion maritimum.

Plastic yearly production has surpassed the 300milliontons mark and recycling has all but failed in constituting a viable solution for the disposal of plastic waste. As these materials continue to accumulate in the environment, namely, in rivers and oceans, in the form of macro-, meso-, micro- and nanoplastics, it becomes of the utmost urgency to find new ways to curtail this environmental threat. Multiple efforts have been made to identify and isolate microorganisms capable of utilizing synthetic polymers and recent results point towards the viability of a solution for this problem based on the biodegradation of plastics resorting to selected microbial strains. Herein, the response of the fungus Zalerion maritimum to different times of exposition to polyethylene (PE) pellets, in a minimum growth medium, was evaluated, based on the quantified mass differences in both the fungus and the microplastic pellets used. Additionally, molecular changes were assessed through attenuated total reflectance Fourier transform Infrared Spectroscopy (FTIR-ATR) and Nuclear Magnetic Resonance (NMR). Results showed that, under the tested conditions, Z. maritimum is capable of utilizing PE, resulting in the decrease, in both mass and size, of the pellets. These results indicate that this naturally occurring fungus may actively contribute to the biodegradation of microplastics, requiring minimum nutrients.

Chemical and structural characterization of Pholiota nameko extracts with biological properties.

Edible mushrooms including Pholiota nameko are excellent sources of extractable bioactive compounds with much to explore. Enzymatic extractions with Cellulase and Viscozyme were responsible for highest extraction yields (67-77%). No strong antioxidant activity was observed although extracts were able to scavenge ABTS(+) and OH(+). Potential prebiotic activity was observed in all extracts, some increasing 1.4-2 Log cycles of Lactobacillus acidophilus La-5 and Bifidobacterium animalis BB12. 30-50% α-glucosidase inhibition was observed in ultrasound, Flavourzyme and Cellulase extracts. Flavourzyme and Cellulase extracts are richer in macro (Mg, K and P) and micro elements (Zn, Mn and Fe) in comparison to mushroom. Monosaccharides content and profile varied slightly among both extracts with predominance of glucose, galactose and mannose with no uronic acids detection; Flavourzyme extract reported higher free amino acids content. Presence of α and ß-glycosidic structures such as glucans and glucan-protein complexes are among the polysaccharides found in both extracts.

Immunosensors in Clinical Laboratory Diagnostics.

The application of simple, cost-effective, rapid, and accurate diagnostic technologies for detection and identification of cardiac and cancer biomarkers has been a central point in the clinical area. Biosensors have been recognized as efficient alternatives for the diagnostics of various diseases due to their specificity and potential for application on real samples. The role of nanotechnology in the construction of immunological biosensors, that is, immunosensors, has contributed to the improvement of sensitivity, since they are based in the affinity between antibody and antigen. Other analytes than biomarkers such as hormones, pathogenic bacteria, and virus have also been detected by immunosensors for clinical point-of-care applications. In this chapter, we first introduced the various types of immunosensors and discussed their applications in clinical diagnostics over the recent 6 years, mainly as point-of-care technologies for the determination of cardiac and cancer biomarkers, hormones, pathogenic bacteria, and virus. The future perspectives of these devices in the field of clinical diagnostics are also evaluated.

Critical overview on the application of sensors and biosensors for clinical analysis.

Sensors and biosensors have been increasingly used for clinical analysis due to their miniaturization and portability, allowing the construction of diagnostic devices for point-of-care testing. This paper presents an up-to-date overview and comparison of the analytical performance of sensors and biosensors recently used in clinical analysis. This includes cancer and cardiac biomarkers, hormones, biomolecules, neurotransmitters, bacteria, virus and cancer cells, along with related significant advances since 2011. Some methods of enhancing the analytical performance of sensors and biosensors through their figures of merit are also discussed.

Chemical composition of red, brown and green macroalgae from Buarcos bay in Central West Coast of Portugal.

Six representative edible seaweeds from the Central West Portuguese Coast, including the less studied Osmundea pinnatifida, were harvested from Buarcos bay, Portugal and their chemical characterization determined. Protein content, total sugar and fat contents ranged between 14.4% and 23.8%, 32.4% and 49.3% and 0.6-3.6%. Highest total phenolic content was observed in Codium tomentosum followed by Sargassum muticum and O. pinnatifida. Fatty acid (FA) composition covered the branched chain C13ai to C22:5 n3 with variable content in n6 and n3 FA; low n6:n3 ratios were observed in O. pinnatifida, Grateloupia turuturu and C. tomentosum. Some seaweed species may be seen as good sources of Ca, K, Mg and Fe, corroborating their good nutritional value. According to FTIR-ATR spectra, G. turuturu was associated with carrageenan seaweed producers whereas Gracilaria gracilis and O. pinnatifida were mostly agar producers. In the brown algae, S. muticum and Saccorhiza polyschides, alginates and fucoidans were the main polysaccharides found.

Impact of enzyme- and ultrasound-assisted extraction methods on biological properties of red, brown, and green seaweeds from the central west coast of Portugal.

Seaweeds are an excellent source of bioactive compounds, and therefore the use of sustainable and food compatible extraction methods such as enzyme-assisted (EAE) and ultrasound-assisted extraction were applied on Sargassum muticum, Osmundea pinnatifida, and Codium tomentosum. Extracts were evaluated for proximate characterization and biological properties. Higher extraction yields were observed for C. tomentosum EAE (48-62%; p < 0.05 for Cellulase and Viscozyme), followed by O. pinnatifida (49-55%; p < 0.05 except Alcalase) and S. muticum (26-31%; p < 0.05). S. muticum extracts presented the highest nitrogen (25 ± 2 mg/glyoph extract) and total phenolics (261 ± 37 µgcatechol equiv/glyoph extract) contents, whereas higher sugars (78 ± 14 mgglucose equiv/glyoph extract) including sulfated polysaccharide (44 ± 8 mgNa2SO4 acid/glyoph extract) contents characterized O. pinnatifida extracts. A higher effect on hydroxyl-radical scavenging activity (35-50%) was observed for all extracts, whereas S. muticum Alcalase and C. tomentosum Cellulase extracts exhibited higher prebiotic activity than fructooligosaccharides. O. pinnatifida and C. tomentosum EAE showed inhibitory potential against α-glucosidase (38-49%).

Assessment of cardiovascular disease risk using immunosensors for determination of C-reactive protein levels in serum and saliva: a pilot study.

BACKGROUND: Disposable immunosensors based on field effect transistors with single-walled carbon nanotubes (NTFET) were applied for the first time to clinical samples of undiluted blood serum and saliva for the determination of C-reactive protein (CRP), and validated by comparison with ELISA. RESULTS: The NTFET showed comparable analytical performance with the ELISA when applied to clinical samples, which means that NTFET can be used as an alternative to ELISA. Also, a high correlation between the serum and salivary CRP levels was found with the NTFET, which means that saliva could be used based on a noninvasive sampling as an alternative fluid to blood serum. The establishment of a new range of CRP levels based on saliva was also found. CONCLUSION: The monitoring of CRP in saliva samples by disposable immunosensors could be a valuable approach for the improvement of healthcare services, considering the worldwide increased incidence of cardiovascular diseases.

The impact of uranium mine contamination of soils on plant litter decomposition.

As part of a tier 3 risk assessment performed for a uranium mining area, the ability of soils with different degrees of metal contamination to degrade organic matter was assessed using litter bags filled with leaves of Quercus robur, Pinus pinaster, Salix atrocinerea, or a mixture of the three species. Litter bags were exposed at different sites within the mine area and at a reference area for 3, 6, 9, and 12 months. Biomass loss, nitrogen (N), phosphorus (P), carbon (C) and total fatty acid, total phenolic, and ergosterol contents were assessed for each litter bag retrieved from the field. The decomposition of litter at each site seemed to be governed by a complex interaction of many different factors. After 12 months of exposure, leaves from the most contaminated sites were distinguishable from those from the reference site. In the reference site, the greatest percentages of biomass loss were attained by Q. robur and P. pinaster leaves. These species displayed the second highest and the lowest C-to-N ratios, respectively. In addition, the high P content of the litter from these two species may have favored microbial colonization. The results suggest that the decomposition of P. pinaster and Q. robur leaves may have been favored at the reference site by the high abundance of both species at this site and the subsequent adaptation of the microbial community to their litter. Our study shows that different species of leaf litter should be used to discriminate between contaminated sites with different levels of contamination.

Strategies based on silica monoliths for removing pollutants from wastewater effluents: a review.

Silica monoliths have been used for more than half a century in a wide variety of applications, such as stationary phases for microextraction fibers, capillary columns for chromatography, in the encapsulation of biomolecules for affinity chromatography and for microfluidic or microarray chips and, more recently, and less well known for wastewater treatment. The main objective of this review article is to specifically overview the strategies that use silica monoliths for the removal of chemical pollutants from wastewater effluents or prepared solutions. The discussion of advantages and drawbacks of such strategies will be supported with the main studies carried out so far which have been performed in laboratory environment only. The application and potential research interest in several strategies using composites and biocomposites based silica monoliths as cleaning systems are also discussed.

Disposable immunosensors for C-reactive protein based on carbon nanotubes field effect transistors.

Label-free immunosensors based on single-walled carbon nanotubes field effect transistor (NTFET) devices were developed for the detection of C-reactive protein (CRP) which is currently the best validated inflammatory biomarker associated with cardiovascular diseases. The immunoreaction principle consists in the direct adsorption of CRP specific antibodies (anti-CRP) to single-walled carbon nanotubes (SWCNTs) networks. Such anti-CRP are the molecular receptors of CRP antigens which, in turn, can be detected by the developed NTFET devices in a linear dynamic range of 10(-4)-10(2) µg/mL. Thus, typical values of CRP (in blood serum) for healthy persons (<1 µg/mL), and higher levels (>5 µg/mL) corresponding to pathological states, can be both detected with the NTFET immunosensors, becoming an advantageous alternative as the basis for the development of analytical instrumentation for assessment of risk of occurrence of cardiovascular diseases. A log-log linear regression was applied to the experimental data with a correlation coefficient of r=0.9962 (p<0.001), and there is no statistical difference (from ANOVA) between individual NTFET devices (p=0.9582), demonstrating acceptable reproducibility. According to the experimental results, the estimate of detection limit (LOD, 10(-4)µg/mL) is 3-fold lower than that of some conventional immunoassay techniques for blood serum (e.g., LOD of 0.2 µg/mL for high-sensitivity enzyme-linked immunosorbent assay), and the dynamic range (10(-4)-10(2)µg/mL) is about 6-fold higher. Furthermore, this simple and low-cost methodology allows the use of sample volumes as low as 1 µL for the label-free detection of CRP.

Removal of the organic content from a bleached kraft pulp mill effluent by a treatment with silica-alginate-fungi biocomposites.

This study attempts a treatment strategy of a bleached kraft pulp mill effluent with Rhizopus oryzae or Pleurotus sajor caju encapsulated on silica-alginate (biocomposite of silica-alginate-fungi, with the purpose of reducing its potential impact in the environment. Active (alive) or inactive (death by sterilization) Rhizopus oryzae or Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the bleached kraft pulp mill effluent. The treatment of bleached kraft pulp mill effluent by active and inactive biocomposites was performed throughout 29 days at 28°C. The efficiency of treatment was evaluated by measuring the removal of organic compounds, chemical oxygen demand and the relative absorbance ratio over time. Both fungi species showed potential for removal of organic compounds, colour and chemical oxygen demand. Maximum values of reduction in terms of colour (56%), chemical oxygen demand (65%) and organic compounds (72-79%) were attained after 29 days of treatment of bleached kraft pulp mill effluent by active Rhizopus oryzae biocomposites. The immobilization of fungi, the need for low fungal biomass, and the possibility of reutlization of the biocomposites clearly demonstrate the industrial and environmental interest in bleached kraft pulp mill effluent treatment by silica-alginate-fungi biocomposites.

Strategies for enhancing the analytical performance of nanomaterial-based sensors.

We provide a state-of-the-art review of the main strategies for the enhancement of analytical performance of sensors using nanomaterials, particularly nanowires and carbon-based materials. We emphasize the way to overcome the problem of device-to-device variation. We discuss the study of the influence of nanomaterial characteristics, sensor dimensions and operational conditions on sensing performance, and the application of appropriate calibration models.

Excreted thiocyanate detects live reef fishes illegally collected using cyanide--a non-invasive and non-destructive testing approach.

Cyanide fishing is a method employed to capture marine fish alive on coral reefs. They are shipped to markets for human consumption in Southeast Asia, as well as to supply the marine aquarium trade worldwide. Although several techniques can be used to detect cyanide in reef fish, there is still no testing method that can be used to survey the whole supply chain. Most methods for cyanide detection are time-consuming and require the sacrifice of the sampled fish. Thiocyanate anion (SCN(-)) is a metabolite produced by the main metabolic pathway for cyanide anion (CN(-)) detoxification. Our study employed an optical fiber (OF) methodology (analytical time <6 min) to detect SCN(-) in a non-invasive and non-destructive manner. Our OF methodology is able to detect trace levels (>3.16 µg L(-1)) of SCN(-) in seawater. Given that marine fish exposed to cyanide excrete SCN(-) in the urine, elevated levels of SCN(-) present in the seawater holding live reef fish indicate that the surveyed specimens were likely exposed to cyanide. In our study, captive-bred clownfish (Amphiprion clarkii) pulse exposed for 60 s to either 12.5 or 25 mg L(-1) of CN(-) excreted up to 6.96±0.03 and 9.84±0.03 µg L(-1) of SCN(-), respectively, during the 28 days following exposure. No detectable levels of SCN(-) were recorded in the water holding control organisms not exposed to CN(-), or in synthetic seawater lacking fish. While further research is necessary, our methodology can allow a rapid detection of SCN(-) in the holding water and can be used as a screening tool to indicate if live reef fish were collected with cyanide.

Marine biotechnology advances towards applications in new functional foods.

The marine ecosystem is still an untapped reservoir of biologically active compounds, which have considerable potential to supply food ingredients towards development of new functional foods. With the goal of increasing the availability and chemical diversity of functional marine ingredients, much research has been developed using biotechnological tools to discover and produce new compounds. This review summarizes the advances in biotechnological tools for production of functional ingredients, including enzymes, for the food industry. Tools involving biotechnological processes (bioreactors, fermentations, bioprocessing) and those involving genetic research designated as molecular biotechnology are discussed highlighting how they can be used in the controlled manipulation and utilization of marine organisms as sources of food ingredients, as well as discussing the most relevant shortcomings towards applications in new functional foods.