Emerging green cell disruption techniques to obtain valuable compounds from macro and microalgae: a review.

In the modern era, macro-microalgae attract a strong interest across scientific disciplines, owing to the wide application of these cost-effective valuable bioresources in food, fuel, nutraceuticals, and pharmaceuticals etc. The practice of eco-friendly extraction techniques has led scientists to create alternative processes to the conventional methods, to enhance the extraction of the key valuable compounds from macro-microalgae. This review narrates the possible use of novel cell disruption techniques, including use of ionic liquid, deep eutectic solvent, surfactant, switchable solvents, high voltage electrical discharge, explosive decompression, compressional-puffing, plasma, and ozonation, which can enable the recovery of value added substances from macro-microalgae, complying with the principles of green chemistry and sustainability. The above-mentioned innovative techniques are reviewed with respect to their working principles, benefits, and possible applications for macro-microalgae bioactive compound recovery and biofuel. The benefits of these techniques compared to conventional extraction methods include shorter extraction time, improved yield, and reduced cost. Furthermore, various combinations of these innovative technologies are used for the extraction of thermolabile bioactive compounds. The challenges and prospects of the innovative extraction processes for the forthcoming improvement of environmentally and cost-effective macro-microalgal biorefineries are also explained in this review.

Opto-chemical treatment for enhanced high-level disinfection of mature bacterial biofilm in a Teflon-based endoscope model.

Medical societies and public health agencies rigorously emphasize the importance of adequate disinfection of flexible endoscopes. The aim of this work was to propose a novel opto-chemical disinfection treatment against Staphylococcus aureus grown in mature biofilm on Teflon-based endoscope channel models. Laser irradiation using near-infrared and blue wavelengths combined with a low concentration of chemical disinfectant induced both irreversible thermal denaturation and intercellular oxidative stress as a combined mechanism for an augmented antimicrobial effect. The opto-chemical method yielded a 6.7-log10 reduction of the mature Staphylococcus aureus biofilms (i.e., approximately 1.0-log10 higher than current requirement of standard treatment). The proposed technique may be a feasible disinfection method for mitigating the risk associated with infection transmission.

In vivo protective effect against ethanol metabolism and liver injury of oyster (Crassostrea Gigas) extracts obtained via subcritical water processing.

The present study assesses hepatoprotective effects of raw oyster lyophilized powder (OP) and subcritical water treated oyster powder (SOP) on D-galactosamine (D-GalN)-induced toxicity and acute ethanol intoxication in mice. High-performance liquid chromatography analysis revealed that four phenolic compounds and glucose were identified from the SOP. The levels of aspartate aminotransferase, alanine aminotransferase, and malondialdehyde were considerably lower for the oyster extracts and the levels of glutathione, γ-glutamylcysteinesynthetase, glutathione S-transferase, and glutathione reductase were higher in the D-GalN induced mice compared with those in the controls. Histology analysis suggested that SOP can protect against and heal the D-GalN toxified liver. For the acute ethanol intoxication study, the enzymatic activity of acetaldehyde dehydrogenase and SOP's alcohol dehydrogenase appeared better than that of OP. Overall, SOP may protect the liver from acute ethanol intoxication and D-GalN persuaded hepatitis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-00941-9.

Ultrasound-mediated fucoxanthin rich oil nanoemulsions stabilized by κ-carrageenan: Process optimization, bio-accessibility and cytotoxicity.

This work aims to produce and optimize a κ-carrageenan-based nanoemulsion (NE) to encapsulate seaweed oil, which is rich in fucoxanthin (FX), using ultrasound-assisted emulsification. κ-Carrageenan was produced using subcritical water, and seaweed oil was extracted using supercritical carbon dioxide with sunflower oil as the co-solvent. Response surface methodology (RSM) was used to understand the influence of several process parameters such as ultrasound amplitude, time, temperature, and duty cycle to produce an NE. The RSM factor was used to focus on droplet size, polydispersity index, zeta potential, viscosity, antioxidant, FX, encapsulation efficiency, and emulsion stability. Our outcomes suggested that the ultrasound process had a noteworthy influence on the NE. The best conditions to obtain an NE were an ultrasound amplitude of 87 µm, a sonication time of 394 s, a temperature of 60 °C, and a duty cycle of 50%. The resulting NE was studied by UV-Vis, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Moreover, the NE obtained from optimized conditions was checked for fatty acid content, color, oxidative stability, in vitro digestion, bioaccessibility of FX, and cytotoxicity. The results obtained suggest that lower droplet size of the emulsion can improve oxidative stability, in vitro digestion, bioaccessibility of FX, and good cell inhibition against a few cell lines. Therefore, a κ-carrageenan-stabilized NE can be used as a potential delivery system to endorse applications of seaweed oil, which is rich in FX, in functional foods, beverage systems, and pharmaceuticals.

Astaxanthin-alpha tocopherol nanoemulsion formulation by emulsification methods: Investigation on anticancer, wound healing, and antibacterial effects.

Emulsion-based delivery systems have been fabricated and developed to increase the bioavailability of astaxanthin and alpha-tocopherol as active compounds for various biomedical applications. Astaxanthin-alpha tocopherol nanoemulsion (ATNE) is well known for its potential 6.-6.30 effect. The current study investigated ATNE by spontaneous (SENE) and ultrasonication emulsification (USNE) methods to optimally fabricate oil/water nanoemulsion characterized for biomedical applications. The two methods were compared by using a response surface method of 3-level Box-Behnken design (BBD) with significant factors. Transmission electron microscopy (TEM) confirmed spherical-shaped nanoemulsion from SENE and USNE methods and dynamic light scattering (DLS) proved the good stability of the fabricated nanoemulsion. Cytotoxicity studies on three different cancer cells confirmed that the nanoemulsion at higher concentrations was more toxic than one at lower concentrations by accompanying a significant decrease in the cellular viability after 24 and 48 h of exposure. The wound-healing potential using scratch assay evidenced faster healing effect of the nanoemulsion. Both minimal inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) methods confirmed significant antibacterial activity to disrupt the integrity of the bacterial cell membrane. The current results suggested that ATNE act as effectively targeted drug delivery vehicles in the future for cancer treatment applications due to its significant results of anticancer, wound healing, and antimicrobial effects.

Hydrothermal degradation of seaweed polysaccharide: Characterization and biological activities.

Fucoidan is a marine sulfated polysaccharide that possesses various biological activities. To enhance the functional properties of fucoidan, it was depolymerized using a green technique viz. subcritical water treatment (SCW) to produce a low molecular weight fucoidan. In this study, response surface methodology (RSM) was used to study the influence of different influences for instance temperature, pressure, liquid to solid ratio, and agitation speed to depolymerize fucoidan. RSM was used to focus on the antioxidant activity and chemical composition of SCW-treated fucoidan. Further, resulting SCW-treated fucoidan was investigated by UV-Vis, FT-IR, Thermal gravimetric analysis (TGA), DSC, Elemental analysis, and ESI-MS. Moreover, the optimized SCW-treated fucoidan was checked for cytotoxicity, antimicrobial, antidiabetic, and anticoagulant activity compared with the untreated fucoidan. The obtained values displayed that SCW treatment breakdowns polymer chain and so it produces low molecular weight fucoidan. Biological activities were improved as the molecular weight was reduced.

Fabrication of multifunctional chitosan-based nanocomposite film with rapid healing and antibacterial effect for wound management.

A nanocomposite film, chitosan (CS)-polyvinylpyrrolidone (PVP)-bentonite (BN) was fabricated to enhance wound healing processes as a new nanoplatform for wound dressing. Both physical properties and antibacterial activity of the proposed film were examined to validate its applicability and inhibitory effect for wound management. In vitro cytotoxicity was evaluated by using MTT assay on L929 and NIH3T3 cells to identify the toxicity level of the film. In vivo wound healing test assessed the wound healing performance in animal models. The results confirmed a strong interaction between surface functional groups among CS, PVP and BN with suitable surface morphology and high thermal stability. The CS-PVP-BN film improved various material features such as including mechanical property, tensile strength, pH and porosity, inhibitory activity on bacterial organisms, and collagen deposition. The animal study confirmed that the fabricated film yielded a rapid healing rate of 97%, less scarring, thick granulation at the 11th day, regeneration of epidermis at the 16th day, and abundant deposition of collagen and fibroblast, compared with control. The non-toxic nanocomposite film can be a promising antibacterial wound dressing with rapid wound healing effects in wound care management.

Deep eutectic solvent-based extraction and fabrication of chitin films from crustacean waste.

In this study, chitin was exclusively extracted from shrimp shells (Marsupenaeus japonicas) through a green solvent called deep eutectic solvent (DES), and various types of DES were utilized to extract chitin. The physicochemical properties of the obtained chitin were compared with the conventional method. A high purity of chitin was obtained while using DES-8 (choline chloride-malonic acid) with a yield of 19.41% ±â€¯1.35%, and purity was confirmed using 13C nuclear magnetic resonance. The DES-produced chitin was utilized to produce chitin films and was compared with standard chitin films. The obtained films were characterized by SEM, AFM, TGA, DSC, FTIR, mechanical properties, moisture sorption, swelling behavior, and biodegradation. The DES film showed similar properties to the standard film, while the mechanical properties, swelling behavior, and biodegradation of the DES chitin films proved to be similar to standard chitin film. These chitin films can be used as wound healing resources.

Structural, antioxidant, and emulsifying activities of fucoidan from Saccharina japonica using pressurized liquid extraction.

Pressurized liquid extraction (PLE) was utilized to extract sulfated polysaccharides (fucoidan) from brown seaweed Saccharina japonica. Various conditions of temperature (80-200°C), pressure (5-100bar), and solvents (water, 0.1% sodium hydroxide, 0.1% formic acid, 70% ethanol, 50% ethanol, and 25% ethanol) were assessed; the best crude fucoidan (CF) yield was 8.23%, obtained from 140°C and 50bar (sodium hydroxide). Compositional analysis, FT-IR, molecular weight, monosaccharides, TGA, UV-vis, XRD, and elemental analysis confirm that extracted polysaccharides revealed the features of fucoidan. Fucose was the main monosaccharide present in CF obtained by various solvent systems. All CF showed antioxidant activities as measured by DPPH radical and ABTS(+) radical scavenging. CF demonstrates good emulsion-stabilizing capacities, especially with vegetable oils. This study demonstrates that PLE is an efficacious method for enhancing the yield of polysaccharides from S. japonica and that it could be a potential source of natural antioxidants and emulsifiers.