A significant amount of investigation has already taken place into alginate spherical hydrogels' attractiveness for application as drug delivery carriers.One of their weaknesses is, however, their short lives within dry airconditions. In this study we used a multi-step sol-gel process for generating dry and stable complex alginate aerogels with multi-membranes. Firstly, the formation was performed of spherical hydrogels within a CaCl2 solution. These cores were further immersed in alginate solution, filtered through a sieve, and dropped into the salt solution again. Different multi-membrane hydrogels were obtained by repeating the above process. They were further converted into aerogels by supercritical drying. The effect of the membranes' numbers was investigated regarding the model drug nicotinic acid's loading and release. The drug loading increased and the drug release was prolonged by adding more membranes around the core. By increasing the amount of drug inside the multi-membrane spheres, the burst drug release was even further inhibited compared to the lower drug-loaded samples.
Due to the rise in global biodiesel production, the amount of crude glycerol, the main byproduct, has increased steadily. Identification of high value addedoutlets for crude glycerol has been explored in detail to increase the overall economics of the biodiesel process. Examples are the use of glycerol for the synthesis of green biobased chemicals and the conversion to hydrogen and/or syngas. Supercritical water has received considerable attention as reaction medium for glycerol reforming because it allows the processing of streams with high moisture content and the production of clean gas at high pressure, being attractive from an environmental point of view. The recent interest in supercritical water reforming of biomass, especially glycerol, hascreated the need for the available data in this specific field to be collected and compared. This review, the first to deal exclusively with glycerol processing, focuses on the production of gas and of organic components in supercritical water. Both catalytic and non-catalytic reforming of glycerol is considered and thermodynamics are addressed. The results suggest that the process conditions during supercritical water reforming of glycerol should depend on the aimed products. Low temperatures, high pressures, concentrated feed solutions and acidic catalyst will generate liquid products, with acrolein as the main compound. For gasification, high temperatures, lower pressures, dilute feed solutions and alkali or metal catalysts should be used.
The aim of the research was to break the cell walls and membranes of Hortaea werneckii using SC CO2 and consecutively to release enzymes from cells with their unchanged activity after treatment. The suspension culture of H. werneckii, which belongs to the black yeasts, was incubated in supercritical carbon dioxide (SC CO2) in order to use the enzymes from these fungi for biotransformations and compare their activity with the activity of purified commercial enzymes at the same conditions. H. werneckii cell suspension was treated in SC CO2 at different pressure and fixed temperature (35 °C). The viability of H. werneckii cells was determined by measuring the optical density of the cell suspension at 600 nm. The total protein concentration and absorbance of nucleic acids in the suspension was determined on UV-Vis spectrophotometer at 595 nm and at 260 nm, respectively. The activity of intracellular enzyme eliminated from H. werneckii cells and that of extracellular enzyme after the treatment of the cells with SC CO2 was compared with the activity of α-amylase from Aspergillus oryzae and cellulase from Trichoderma reesei, Cellusoft L.
Hydrothermal (HT) reactions of agricultural and food-processing waste have been proposed as an alternative to conventional waste treatment technologies due to allowing several improvements in terms of process performance and energy and economical advantages, especially due to their great ability to process high moisture content biomass waste without prior dewatering. Complex structures of wastes and unique properties of water at higher temperatures andpressures enable a variety of physical-chemical reactions and a wide spectra of products. This paperʼs aim is to give extensive information about the fundamentals and mechanisms of HT reactions and provide state of the research of agri-food waste HT conversion.
Research results of how threshold inhibitors influence on water scale precipitation and morphology are presented. The inhibitory effect was evaluated with two experiments where water scale precipitation was observed. The first experiment was done on heaters from boiler for hot water and outflow pipes. The second experiment was done on washing machine heaters. In both cases, tap water was used that contained Mg2+ and Zn2+ ions. In all samples hard, compact water scale was in a shape of aragonite.