Microalgae growth using winery wastewater for energetic and environmental purposes

Winery wastewater (WWW), produced by winemaking activities (cleaning, transferring and storage operations), is an aqueous solution containing ethanol, organic acids, sugars, aldehydes, other microbial metabolites, soaps and detergents. Nowadays, innovative wastewater treatment processes are based on bacterial and yeast species while the role of microalgae is still unclear. Arthrospira (Spirulina) platensis and Chlorella vulgaris are unicellular prokaryotic and eukaryotic microorganisms, respectively, which can be easily grown even in non-optimal conditions. Several studies reported that the amount and quality of lipids contained in microalgal cells can differ as an outcome of changes in growth conditions or growth medium characteristics (concentration of carbon, nitrogen, phosphate, iron, etc.). In this study, we investigated the influence of different concentrations of WWW (20, 40 and 60 % v/v of the medium) on the growth and chemical composition of those photosynthetic microorganisms. Microalgae were grown into vertical glass bubblers (250 mL). The biomass concentration was quantified daily by measuring the optical density at 560 and 625 nm for A. platensis and C. vulgaris, respectively. Total Carbon and total Nitrogen concentrations, both in the media (mg/L) and in microalga biomass (g/100g), were monitored by a CHNS-O analyser. In order to quantify the influence of WWW-enrich media on the lipid concentration and composition, biomass was collected at the beginning of the stationary phase and the lipid fraction was extracted. Results suggested that the two tested microalgae can growth in media enriched with WWW and the total Nitrogen concentrations decreased up to 90 and 100 % for A. platensis and C. vulgaris, respectively. In conclusion, WWW could be successfully used for the growth of the tested microalgae, leading to a reduction of the environmental impact of this wastewater

Comparison of the Properties of a Random Copolymer and a Molten Blend PA6/PA6.9

This study compares the thermal and mechanical properties of two different materials, obtained via two diverse synthetic pathways. The first one is a mixed blend of PA6/PA6.9, while the second is a random copolymer (PA6.9-ran–PA6, obtained via copolymerization of its monomers, i.e., caprolactam, hexamethylenediamine and azelaic acid). Several tests are carried out according to the aforementioned pathways, varying the relative ratio between the two polymeric building blocks. The role of the synthetized plastic is to be coupled to polyamide material, such as PA6, to confer its better properties. The synthetized random copolymer, besides displaying ease of processability with respect to conventional methods, exhibits interesting features. It has a low melting point (135 °C, PA6.9-ran-PA6 50:50) and therefore it might be used as a hot-melt adhesive in composite material. Owing to its low crystallinity content, the material displays a rubber-like behavior and may be employed to confer elastomeric properties to PA6 matrix, in place of non-amidic material (for example elastomeric polyurethanes). This leads to a further advantage in terms of chemical recyclability of the end-of-life material, since the additive increases the percentage of PA6 in waste material and, consequently, the yield of caprolactam recovery

Olive leaves infuse and decoct production: Influence of leaves drying conditions and particle size

Taggiasca, a cultivar grown typically in western Liguria (Italy) and in the southern regions of France, is a tasty and sweet olive for table consumption and for the oil production. Olive oil production generates a huge amount a wastes. Besides the traditional olive mill wastewater and olive pomace, leaves of the trees are considered by-products and nowadays they are burned or used as animal feeds despite they have high content of bioactive compounds. Oleuropein, apigenin and vanillic acid are examples of polyphenols contained in olive leaves and their content changes depending on the cultivar, the region of growth and the harvesting time. The aim of this work is to valorise one of the by-products of the olive oil industry. The study aims to investigate the effect of the pre-treatment processes on the production of olive leaves infusion. Different drying techniques and particles size have been evaluated in order to produce an extract rich in phenolic compounds. Olive leaves (Taggiasca cultivar) were kindly provided by the Azienda Agricola Castellari company, Savona, Italy. Leaves were collected and immediately washed and dried at different temperatures (50, 60 and 70 \ub0C) in a ventilated oven. Moreover, an additional drying at 70 \ub0C was performed under nitrogen atmosphere. In order to evaluate the effect of the drying temperatures on total polyphenol (TP) and flavonoid (TF) yields and on antiradical power (ARP) of the extracts, samples were grinded (0.8-0.59 mm) using a laboratory mixer. Powders were then extracted using ethanol and analysed. Based on those results, the best drying condition was used to evaluate the influence of the matrix particle size on the extraction yield after ethanol extraction and teas production. Sieves (4, 9, 16, 20 and 30 Mesh) were used to obtain powder with particles distributed uniformly in the range 2.19 < A < 4.76, 1.19 < B < 2.19, 0.84 < C < 1.19 and 0.59 < D < 0.84 mm. Olive leaves teas were prepared as follow: 1) infusion, 200 ml of deionised boiling water were added to 2 g olive leaves powder and let them soak for 3 min without additional heating; 2) decoction, 200 ml cold water were added to 2 g of olive leaves powder and boiled for 15 min, waiting for 10 min after boiling before carrying on the analysis. After extracting with ethanol the dried matrix obtained at different temperatures, we found out that there was not statistical difference (p<0.05) in the TP (25.06\ub11.00 mgGAE/gDL) and TF (22.23\ub13.00 mgCE/gDL) content between samples obtained at 60, 70 \ub0C and 70 \ub0C under nitrogen flow. During the tea production, within each range of particles size (e.g. B), we found out that decoction is the process that allows to extract the highest quantity of total polyphenols (41.14\ub12.56 mgGAE/gDL) and total flavonoids (45.27\ub13.10 mgCE/gDL)

Influence of TiO 2 Nanoparticles on Growth and Phenolic Compounds Production in Photosynthetic Microorganisms

The influence of titanium dioxide nanoparticles (pure anatase and 15% N doped anatase) on the growth of Chlorella vulgaris, Haematococcus pluvialis, and Arthrospira platensis was investigated. Results showed that pure anatase can lead to a significant growth inhibition of C. vulgaris and A. platensis (17.0 and 74.1%, resp.), while for H. pluvialis the nanoparticles do not cause a significant inhibition. Since in these stress conditions photosynthetic microorganisms can produce antioxidant compounds in order to prevent cell damages, we evaluated the polyphenols content either inside the cells or released in the medium. Although results did not show a significant difference in C. vulgaris, the phenolic concentrations of two other microorganisms were statistically affected by the presence of titanium dioxide. In particular, 15% N doped anatase resulted in a higher production of extracellular antioxidant compounds, reaching the concentration of 65.2 and 68.0 mg gDB-1 for H. pluvialis and A. platensis, respectively

Dermal Patch with Integrated Flexible Heater for on Demand Drug Delivery

Topical administration of drugs and growth factors in a controlled fashion can improve the healing process during skin disorders and chronic wounds. To achieve this goal, a dermal patch is engineered that utilizes thermoresponsive drug microcarriers encapsulated within a hydrogel layer attached to a flexible heater with integrated electronic heater control circuitry. The engineered patch conformally covers the wound area and enables controlled drug delivery by electronically adjusting the temperature of the hydrogel layer. The drugs are encapsulated inside microparticles in order to control their release rates. These monodisperse thermoresponsive microparticles containing active molecules are fabricated using a microfluidic device. The system is used to release two different active molecules with molecular weights similar to drugs and growth factors and their release profiles are characterized. This platform is a key step towards engineering smart and closed loop systems for topical applications

Breathable hydrogel dressings containing natural antioxidants for management of skin disorders.

Traditional wound dressings are not effective enough to regulate the moisture content and remove excessive exudate from the environment. Wet wound dressings formed from hydrogels such as alginate are widely used in clinical practice for treatment of skin disorders. Here, we functionalize alginate dressings with natural antioxidants such as curcumin and t-resveratrol to render them both anti-inflammatory and antibacterial. The hydrogel maintains excellent mechanical properties and oxygen permeability over time. The release rate of the compounds from the hydrogels is assessed and their impact on bacterial and cellular growth is evaluated. The antioxidant compounds act as bactericidal agents and improve cell viability. The optimal concentration of active compounds in the engineered alginate-based dressings is determined

Flexible pH-Sensing Hydrogel Fibers for Epidermal Applications

Epidermal pH is an indication of the skin’s physiological condition. For example, pH of wound can be correlated to angiogenesis, protease activity, bacterial infection, etc. Chronic non-healing wounds are known to have an elevated alkaline environment, while healing process occurs more readily in an acidic environment. Thus, dermal patches capable of continuous monitoring of pH can be used as point-of-care systems for monitoring skin disorder and the wound healing process. Here, we present pH-responsive hydrogel fibers that can be used for long-term monitoring of epidermal wound condition. We load pH-responsive dyes into mesoporous microparticles and incorporate them into hydrogel fibers developed through microfluidic spinning. The fabricated pH-responsive microfibers are flexible and can create conformal contact with skin. The response of pH-sensitive fibers with different compositions and thicknesses are characterized. The suggested technique is scalable and can be used to fabricate hydrogel based wound dressing with a wide range of sizes. Images of the pH-sensing fibers during real-time pH measurement can be captured with a smart phone camera for convenient readout on-site. Through image processing, a quantitative pH map of the hydrogel fibers and the underlying tissue can be extracted. The developed skin dressing can act as a point-of-care device for monitoring the wound healing process