Isolation of Laurus nobilis Leaf Polyphenols: A Review on Current Techniques and Future Perspectives

In recent years, the market demand for products enhanced with ingredients derived from natural products, such as polyphenols, is rapidly increasing. Laurus nobilis L., known as bay, sweet bay, bay laurel, Roman laurel or daphne is an evergreen Mediterranean shrub whose leaves have traditionally been used in cuisines and folk medicine due to their beneficial health effects, which can nowadays be scientifically explained by various biological activities of the leaf extracts. Many of these activities can be attributed to phenolic compounds present in L. nobilis leaves which include flavonoids, phenolic acids, tannins (proanthocyanidins) and lignans. In order to enable efficient industrial utilization of these valuable compounds, it is crucial to establish optimal extraction procedures resulting in the highest yields and quality of the extracts. This paper offers the first systematic review of current literature on the influence of conventional and advanced extraction techniques, including microwave-assisted, ultrasound-assisted, enzyme-assisted, supercritical-CO2 and mechanochemical-assisted extraction on the phenolic content of L. nobilis leaf extracts, allowing more efficient planning of further research and simplifying the steps towards industrial utilization of this plant.

Insights into cell wall disintegration of Chlorella vulgaris

With their ability of CO2 fixation using sunlight as an energy source, algae and especially microalgae are moving into the focus for the production of proteins and other valuable compounds. However, the valorization of algal biomass depends on the effective disruption of the recalcitrant microalgal cell wall. Especially cell walls of Chlorella species proved to be very robust. The wall structures that are responsible for this robustness have been studied less so far. Here, we evaluate different common methods to break up the algal cell wall effectively and measure the success by protein and carbohydrate release. Subsequently, we investigate algal cell wall features playing a role in the wall’s recalcitrance towards disruption. Using different mechanical and chemical technologies, alkali catalyzed hydrolysis of the Chlorella vulgaris cells proved to be especially effective in solubilizing up to 56 wt% protein and 14 wt% carbohydrates of the total biomass. The stepwise degradation of C. vulgaris cell walls using a series of chemicals with increasingly strong conditions revealed that each fraction released different ratios of proteins and carbohydrates. A detailed analysis of the monosaccharide composition of the cell wall extracted in each step identified possible factors for the robustness of the cell wall. In particular, the presence of chitin or chitin-like polymers was indicated by glucosamine found in strong alkali extracts. The presence of highly ordered starch or cellulose was indicated by glucose detected in strong acidic extracts. Our results might help to tailor more specific efforts to disrupt Chlorella cell walls and help to valorize microalgae biomass.

A Review On The Potential Of Spirulina And Its Application In Nutraceuticals And Pharmaceuticals

Microalgae and lactic acid bacteria have become an innovative and promising resource of nutritional supplements as they are commercially cultivated to produce valuable compounds, including protein, pigments, lipids, essential amino acids, monounsaturated and polyunsaturated fatty acids, carotenoids, steroids and vitamins. The pharmacological actions, such as nutraceutical improvements, lowering LDL cholesterol levels, anti-inflammation, antioxidation, antitumor, immunological enhancement, and hepatorenal protection from Spirulina spp and Lactic acid Bacillus have been reported recently. Based on the therapeutic potential of spriulina fermentation based lactic acid bacteria, different application studies such as, determining the effect of Spirulina fermentation with Lactic acid bacteria (FSL) on enhancing the Nutraceutical properties of Spirulina species, investigating the effect of Spirulina fermentation with Lactic acid bacteria (FSL) on lowering the LDL cholesterol and increasing HDL cholesterol, and evaluating the cytotoxic effect and influence of FSL on human cancer cell line was reviewed in the current article.

Hydroelementation of diynes

This comprehensive review highlights the hydroelementation reactions of conjugated and separated diynes to various products including enynes, dienes, allenes, polymers or cyclic compounds, and their further transformation to valuable compounds.

A Novel Recycling Route for Spent Li-Ion Batteries

In this work, a recycling route for spent Li-ion batteries (LIBs) was developed. For this, the recovery of the metal content in both electrodes (anode and cathode) was investigated. Based on these results, an economic analysis of this recycling process was carried out. The obtained results showed that more than 90% of the material contained in both electrodes was recycled. The dissolution with acetic acid of the metals present in the active cathodic material is thermodynamically viable and the addition of a reducing agent such as hydrogen peroxide improved the spontaneity of the reaction. Dissolutions close to 100% for Li and Co were obtained. In addition, it was determined that the synthesis of lithium and cobalt valuable compounds was viable from the leach liquor, recovering approximately 90% of Co as cobalt oxalate, and 92% of Li as lithium carbonate. Furthermore, carbon graphite and Cu were fully recovered (100%) from the anodes. Finally, the results of the economic analysis showed that the recovered products have a high commercial value and industrial interest, providing an environmentally and economically viable process.

Optimisation of blueberry (Vaccinium corymbosum L.) press residue extraction using a combination of pectolytic enzyme and ultrasound treatments

Blueberries are one of the most popular and widely consumed berries, they are usually consumed fresh, dried or processed into juice. During the production of juices large quantities of berry press residues are generated, which are an industrial by-product and they accumulate as food waste. Optimal management of this industrial fruit by-product could help in utilising berry press residues with the purpose to valorise and add economic value. Blueberry press residues consist of skins and seeds which hold valuable compounds with antioxidant activity –polyphenolics. To facilitate the objective of bioactive compound release, the cell walls must rupture. Pectolytic enzymes could be used to degrade the structural polysaccharides of the berry skin cell wall, thus releasing the contents of the cells into the extraction medium. The physical characteristics of berry skins allows the use of pectolytic enzymes for the disruption of cells; however, the effects of enzymatic hydrolysis could be further improved using ultrasound. In this study the combined effects of enzyme and ultrasonic treatments were evaluated and optimised using the Response Surface Methodology approach in order to increase the release of polyphenolic compounds (especially anthocyanins). The optimised method was further tested to evaluate the application potential of enzyme and ultrasound treatment to prepare blueberry or lingonberry juice with increased antioxidant activity and more vibrant colour. The obtained results provide an optional method of berry press residue valorisation to produce higher quality juice or extract bioactive compounds from this type of food-waste.

Phenological traits of red amaranth varieties with a high content of amaranthine cultivated in open fields of Moscow region

The article focuses on phenological features of amaranth varieties grown in open fields as a reaction to variability of weather conditions in the Moscow region. Amaranthine is one of the promising compounds found in red-colored amaranths. It refers to a class of betalain pigments. The study revealed growth stages defined by the highest content of amarantine per plant and analyzed accumulation of the pigment in amaranth leaves and inflorescences. Phenological observations of introduced plant species under new conditions are important and determine their resistance to adverse environmental factors, ability to produce high quality fruits and seeds, and potential for cultivation. During the introduction of new amaranth varieties, the most adapted forms were selected for the conditions of the Non-Chernozem zone of the Russian Federation in 2013-2016. The studied Russian and Ecuador varieties were divided into 4 groups depending on the growth period (from germination to seed maturity). Analysis of phenological traits of plants confirmed that period of amaranth development did not depend on the variety, except the fourth stage of late-ripening cultivars - Don Pedro and Eku 17020, dependent on weather conditions. Being dependent on weather conditions, the vegetative growth period turned to be the most stable. Late cv. Eku 17020 did not form mature seeds in open ground conditions, which is explained by its origin (Ecuador). In the present study we identified growth stages when plant raw materials had the highest dye content in red-leaved amaranth varieties (Valentina, Don Pedro and Fakel). We also considered the perspective of cultivation of green-leaved varieties with red inflorescences - Pamyati Kovasa and Eku-17020 - as sources of biologically valuable compounds in the Moscow region.

Marine Health-Promoting Compounds: Recent Trends for Their Characterization and Human Applications

Seaweeds represent a rich source of biologically active compounds with several applications, especially in the food, cosmetics, and medical fields. The beneficial effects of marine compounds on health have been increasingly explored, making them an excellent choice for the design of functional foods. When studying marine compounds, several aspects must be considered: extraction, identification and quantification methods, purification steps, and processes to increase their stability. Advanced green techniques have been used to extract these valuable compounds, and chromatographic methods have been developed to identify and quantify them. However, apart from the beneficial effects of seaweeds for human health, these natural sources of bioactive compounds can also accumulate undesirable toxic elements with potential health risks. Applying purification techniques of extracts from seaweeds may mitigate the amount of excessive toxic components, ensuring healthy and safer products for commercialization. Furthermore, limitations such as stability and bioavailability problems, chemical degradation reactions during storage, and sensitivity to oxidation and photo-oxidation, need to be overcome using, for example, nanoencapsulation techniques. Here we summarize recent advances in all steps of marine products identification and purification and highlight selected human applications, including food and feed applications, cosmetic, human health, and fertilizers, among others.

Microalgal Systems for Wastewater Treatment: Technological Trends and Challenges towards Waste Recovery

Wastewater (WW) treatment using microalgae has become a growing trend due the economic and environmental benefits of the process. As microalgae need CO2, nitrogen, and phosphorus to grow, they remove these potential pollutants from wastewaters, making them able to replace energetically expensive treatment steps in conventional WW treatment. Unlike traditional sludge, biomass can be used to produce biofuels, biofertilizers, high value chemicals, and even next-generation growth media for “organically” grown microalgal biomass targeting zero-waste policies and contributing to a more sustainable circular bioeconomy. The main challenge in this technology is the techno-economic feasibility of the system. Alternatives such as the isolation of novel strains, the use of native consortia, and the design of new bioreactors have been studied to overcome this and aid the scale-up of microalgal systems. This review focuses on the treatment of urban, industrial, and agricultural wastewaters by microalgae and their ability to not only remove, but also promote the reuse, of those pollutants. Opportunities and future prospects are discussed, including the upgrading of the produced biomass into valuable compounds, mainly biofuels.