Process-intensified extraction of phycocyanin followed by β-carotene from Spirulina platensis using ultrasound-assisted extraction

Green and sustainable technologies for extraction of carotenoids from natural sources: a comprehensive review

In recent years, driven by increasing consumer demand for natural and healthy convenient foods, the food industry has been shifting from synthetic to natural products. This shift is also reflected in the growing popularity of non-conventional extraction methods for pigments, which are favored for sustainability and environment-friendliness compared to conventional processes. This review aims to investigate the extraction of carotenoids from a variety of natural sources, including marine sources like fungus, microalgae, and crustaceans, as well as widely studied plants like tomatoes and carrots. Additionally, it delves into the recovery of valuable carotenoids from waste products like pomace and peels, highlighting the nutritional and environmental benefits. The review also emphasizes the role of green solvents such limonene, vegetable oils, ionic liquids, supercritical fluids, and natural deep eutectic solvents in effective and ecologically friendly carotenoid extraction. These technologies support the ideas of a circular and sustainable economy in addition to having a smaller negative impact on the environment. Overall, the present study highlights the crucial importance of green extraction technologies in achieving the dual goals of sustainability and public safety.

Exploring the ignored role of escaped algae in a pilot-scale DWDS: Disinfectant consumption, DBP yield and risk formation

Insufficient treatments during bloom-forming seasons allow algae to enter the subsequent drinking water distribution system (DWDS). Yet, scarce information is available regarding the role escaped algae to play in the DWDS, and how they interact with the system. Thus, three scenarios were conducted: a pilot DWDS with algae (a), pipe water (b), and pipe water with algae (c). Experimental results showed that, compared to biofilm and bulk water, escaped algae required fewer disinfectants. Competition for disinfectants varied with algal strains (Microcystis aeruginosa, MA; Pseudanabaena sp., PS) and disinfectant types (chlorine, Cl2; chloriamine, NH2Cl). Algae in the MA-Cl2 group showed the highest demand (6.25%-36.02%). However, the low-concentration disinfectants distributed to algae could trigger distinct algal status alternations. Cl2 diffused into intact MA cells and reacted with intracellular compositions. Damaged PS cells reached 100% within 2 h. Typical disinfection byproducts (DBPs), including trihalomethanes (THMs), haloacetic acids and halogenated acetonitriles were examined. Disinfectant types and algal strains affected DBP yield and distribution. Although disinfectants consumed by algae might not promote dissolved DBP formation, especially for THMs. DBP formation of the other components was affected by escaped algae via changing disinfectant assignment (reduced by 45.45% for MA-Cl2) and transformation efficiency (by 34.52%). The cytotoxicity risks were estimated. Dissolved DBP-induced risks were not added when escaped algae occurred, whereas disruption and release of intracellular substances increased risks; the maximum cytotoxicity did not occur at 12 h rather than at the end (24 h). Overall, this study provided an innovative perspective on algal-related water quality issues in water systems.

Valuable pigments from microalgae: phycobiliproteins, primary carotenoids, and fucoxanthin

Phycobiliproteins, carotenoids and fucoxanthin are photosynthetic pigments extracted from microalgae and cyanobacteria with great potential biotechnological applications, as healthy food colorants and cosmetics. Phycocyanin possesses a brilliant blue color, with fluorescent properties making it useful as a reagent for immunological essays. The most important source of phycocyanin is the cyanobacterium Arthrospira platensis, however, recently, the Rhodophyta Galdieria sulphuraria has also been identified as such. The main obstacle to the commercialization of phycocyanin is represented by its chemical instability, strongly reducing its shelf-life. Moreover, the high level of purity needed for pharmaceutical applications requires several steps which increase both the production time and cost. Microalgae (Chlorella, Dunaliella, Nannochloropsis, Scenedesmus) produce several light harvesting carotenoids, and are able to manage with oxidative stress, due to their free radical scavenging properties, which makes them suitable for use as source of natural antioxidants. Many studies focused on the selection of the most promising strains producing valuable carotenoids and on their extraction and purification. Among carotenoids produced by marine microalgae, fucoxanthin is the most abundant, representing more than 10% of total carotenoids. Despite the abundance and diversity of fucoxanthin producing microalgae only a few species have been studied for commercial production, the most relevant being Phaeodactylum tricornutum. Due to its antioxidant activity, fucoxanthin can bring various potential benefits to the prevention and treatment of lifestyle-related diseases. In this review, we update the main results achieved in the production, extraction, purification, and commercialization of these important pigments, motivating the cultivation of microalgae as a source of natural pigments.

High Purity Grade Phycocyanin Recovery by Decupling Cell Lysis from the Pigment Extraction: an Innovative Approach

Phycocyanin, a phycobiliprotein, is one of the few natural blue pigments available as food colourant, and it is largely used in food industry. We have devised an innovative two-step extraction process which allowed to obtain bright blue phycocyanin crude extracts with high purity grade P (within 2.5 and 3.5) directly from fresh biomass of Arthrospira platensis Gomont 1892 (commonly named Spirulina). We found out and for the first time exploited ammonium sulphate capability to minimize the release of water soluble phycobiliproteins in aqueous medium during ultrasound-assisted cell lysis/purification phase. The conventional sequence which is, extraction followed by purification, was reversed. The extraction phase was decoupled from biomass cell lysis. Cell lysis, accomplished by ultrasonication in ammonium sulphate solution, was merged with purification in a single step, before the pigment extraction/recovering phase. The process was entirely carried out in aqueous solutions. No downstream purification was required to obtain products suitable for the most common phycocyanin applications (i.e. foods, nutraceuticals). Production time, hours instead of days, was reduced to the advantage of the product quality. The process has the great advantages of (1) direct use of extracting solutions that cannot be used in the ordinary ultrasound-assisted extraction of phycocyanin (because of the extensive simultaneous extraction of contaminant molecules), (2) gain of high commercial value phycocyanin due to the elevated purity grade and (3) direct production of highly concentrated bright blue pigment crude extracts (up to about 5 mg mL−1) immediately in hand to the market.

Graphical Abstract