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This work aimed to identify the influence of pH, molarity, w/v fraction, extraction time, agitation, and either a sodium (Na2HPO4·7H2O-NaH2PO4·H2O) or potassium buffer (K2HPO4-KH2PO4) used in the extraction of C-phycoerythrin (C-PE) from a thermotolerant strain of Potamosiphon sp. An experimental design (Minimum Run Resolution V Factorial Design) and a Central Composite Design (CCD) were used. According to the statistical results of the first design, the K-PO4 buffer, pH, molarity, and w/v fraction are vital factors that enhance the extractability of C-PE. The construction of a CCD design of the experiments suggests that the potassium phosphate buffer at pH 5.8, longer extraction times (50 min), and minimal extraction speed (1000 rpm) are ideal for maximizing C-PE concentration, while purity is unaffected by the design conditions. This optimization improves extraction yields and maintains the desired bright purple color of the phycobiliprotein. [ABSTRACT FROM AUTHOR]

This work aimed to identify the influence of pH, molarity, w/v fraction, extraction time, agitation, and either a sodium (Na2HPO4·7H2O-NaH2PO4·H2O) or potassium buffer (K2HPO4-KH2PO4) used in the extraction of C-phycoerythrin (C-PE) from a thermotolerant strain of Potamosiphon sp. An experimental design (Minimum Run Resolution V Factorial Design) and a Central Composite Design (CCD) were used. According to the statistical results of the first design, the K-PO4 buffer, pH, molarity, and w/v fraction are vital factors that enhance the extractability of C-PE. The construction of a CCD design of the experiments suggests that the potassium phosphate buffer at pH 5.8, longer extraction times (50 min), and minimal extraction speed (1000 rpm) are ideal for maximizing C-PE concentration, while purity is unaffected by the design conditions. This optimization improves extraction yields and maintains the desired bright purple color of the phycobiliprotein.

Drying the biomass produced is one of the critical steps to avoid cell degradation; however, its high energy cost is a significant technological barrier to improving this type of bioprocess's technical and economic feasibility. This work explores the impact of the biomass drying method of a strain of Potamosiphon sp. on the extraction efficiency of a phycoerythrin-rich protein extract. To achieve the above, the effect of time (12–24 h), temperature (40–70 °C), and drying method (convection oven and dehydrator) were determined using an I-best design with a response surface. According to the statistical results, the factors that most influence the extraction and purity of phycoerythrin are temperature and moisture removal by dehydration. The latter demonstrates that gentle drying of the biomass allows removing the most significant amount of moisture from the biomass without affecting the concentration or quality of temperature-sensitive proteins. [ABSTRACT FROM AUTHOR]

Drying the biomass produced is one of the critical steps to avoid cell degradation; however, its high energy cost is a significant technological barrier to improving this type of bioprocess’s technical and economic feasibility. This work explores the impact of the biomass drying method of a strain of Potamosiphon sp. on the extraction efficiency of a phycoerythrin-rich protein extract. To achieve the above, the effect of time (12–24 h), temperature (40–70 °C), and drying method (convection oven and dehydrator) were determined using an I-best design with a response surface. According to the statistical results, the factors that most influence the extraction and purity of phycoerythrin are temperature and moisture removal by dehydration. The latter demonstrates that gentle drying of the biomass allows removing the most significant amount of moisture from the biomass without affecting the concentration or quality of temperature-sensitive proteins.

Marine macroalgae waste, which results from the accumulation of drifted marine macroalgae at the beaches, was studied as an alternative source of natural pigments. For that, macroalgae waste was collected in a Northern Portugal beach, dehydrated using different procedures (freeze-drying, oven-drying and sun-drying), physiochemically characterized and after subjected to the chemical extraction of pigments. Six solvents and different amounts of biomass were studied, and the pigments quantification was made by UV spectrophotometry. Saccorhiza polyschides (brown algae) was the most represented species in the collected biomass. The differences found in the biomass characterization under different dehydrating conditions were not relevant. The obtained results showed marine macroalgae waste as a promising source of natural pigments and acetone was the best solvent for extraction, followed by methanol. Chlorophyll a was the predominant pigment found, regardless the dehydrating conditions employed. Freeze-dried biomass had significantly higher pigments concentrations (1685 μg chlorophyll a g−1; 174 μg carotenoids g−1; 252 μg fucoxanthin g−1) and there were no differences comparing the concentration of chlorophyll a from oven-dried and sun-dried biomass; however, between them, concentration of carotenoids was higher for oven-dried biomass (125 μg g−1), and fucoxanthin concentration was higher for sun-dried biomass (25 μg g−1). [ABSTRACT FROM AUTHOR]

HMF synthesis typically requires high temperature and is carried out in aqueous solutions. In this work, the low-temperature dehydration of fructose to HMF in different deep eutectic solvents (DES) was investigated. We found a very active and selective reaction system consisting of the DES tetraethyl ammonium chloride as hydrogen bond acceptor (HBA) and levulinic acid as hydrogen bond donor (HBD) in a molar ratio of 1:2 leading to a maximum HMF yield of 68% after 120 h at 323 K. The DES still contained a low amount of water at the initial reaction, and water was also produced during the reaction. Considering the DES properties, neither the molar ratio in the DES nor the reaction temperature had a significant influence on the overall performance of the reaction system. However, the nature of the HBA as well as the acidity of the HBD play an important role for the maximum achievable HMF yield. This was validated by measured yields in a DES with different combinations of HBD (levulinic acid and lactic acid) and HBA (choline chloride and tetra-n-alkyl ammonium chlorides). Moreover, addition of vanadium containing catalysts, especially the polyoxometalate HPA-5 (H8PV5Mo7O40) leads to drastically increased reaction kinetics. Using HPA-5 and the DES tetraethyl ammonium chloride—levulinic acid we could reach a maximum HMF yield of 57% after only 5 h reaction time without decreasing the very high product selectivity.

• Efficient dehydration of N -(2-hydroxyethyl)-2-pyrrolidone by Na 2 O/SiO 2 (Y > 90%). • Volcano trend in catalyst productivity with increasing sodium content. • Underlying balance of basic sites and silanols; highlighted by FTIR and TPD. • Derivation of catalyst surface model and bifunctional reaction mechanism. • Catalyst transfer to structure-similar, bio-derived educts possible. The gas-phase dehydration of biomass-derived N -(2-hydroxyethyl)-2-pyrrolidone by Na 2 O/SiO 2 -type catalysts propounds a promising route to polyvinylpyrrolidone, a high-value polymer. Thus, an optimization of said catalysts via variations of the silica parent, sodium precursor and sodium loading was performed. The combination of resulting performance data with in-depth characterization via FTIR spectroscopy, CO 2 -TPD and physisorption techniques leads to a clear structure-activity correlation. Most importantly, catalyst activity is promoted by a balance between weak basic sites (Si-ONa) and surface hydroxyls (Si-OH), which comes about through ion exchanging a fraction of the initial silanol in mild conditions. The optimal synthesis procedure and recipe are thus a function of the type of parent silica. With this renewed molecular understanding of the reaction, the scope of application of the Na 2 O/SiO 2 materials was expanded to the dehydration of other biomass-derived chemicals of interest in the polymer industry. [ABSTRACT FROM AUTHOR]

HMF synthesis typically requires high temperature and is carried out in aqueous solutions. In this work, the low-temperature dehydration of fructose to HMF in different deep eutectic solvents (DES) was investigated. We found a very active and selective reaction system consisting of the DES tetraethyl ammonium chloride as hydrogen bond acceptor (HBA) and levulinic acid as hydrogen bond donor (HBD) in a molar ratio of 1:2 leading to a maximum HMF yield of 68% after 120 h at 323 K. The DES still contained a low amount of water at the initial reaction, and water was also produced during the reaction. Considering the DES properties, neither the molar ratio in the DES nor the reaction temperature had a significant influence on the overall performance of the reaction system. However, the nature of the HBA as well as the acidity of the HBD play an important role for the maximum achievable HMF yield. This was validated by measured yields in a DES with different combinations of HBD (levulinic acid and lactic acid) and HBA (choline chloride and tetra-n-alkyl ammonium chlorides). Moreover, addition of vanadium containing catalysts, especially the polyoxometalate HPA-5 (H8PV5Mo7O40) leads to drastically increased reaction kinetics. Using HPA-5 and the DES tetraethyl ammonium chloride-levulinic acid we could reach a maximum HMF yield of 57% after only 5 h reaction time without decreasing the very high product selectivity., (Copyright © 2019 Körner, Albert and Held.)