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The influence of solvents on enzymatic activity and stability was investigated. As a model reaction the α-chymotrypsin-catalyzed esterification of N-acetyl-l-phenylalanine with ethanol was used. The enzyme was adsorbed on porous glass beads and used in various solvents. Small amounts of water were added to increase the enzymatic activity. These enzyme preparations obeyed. Michaelis-Menten kinetics

Coimmobilization of biocatalyst and substrate was studied as a method to increase the conversion rate in systems with substrates of extremely low solubility in water. The system studied was the conversion of hydrocortisone to prednisolone by Arthrobacter simplex. As a matrix for coimmobilization, alginate turned out to be superior to agar and agarose. After the reaction was complete, the beads wer

Theoretical calculations of reaction kinetics were done for one‐step reactions catalyzed by cells immobilized in spherical beads. The reactions catalyzed by free cells were assumed to obey Michaelis–Menten kinetics for a one‐substrate reaction. Both external (outside the beads) and internal (inside the beads) mass transfer of the substrate were considered for the immobilized preparations. The theo

Gluconobacter oxydans cells were immobilized in calcium alginate and the preparation was used for the oxidation of glycerol to dihydroxyacetone. The characterization was done according to the guidelines given by the Working Party on Immobilized Biocatalysts of the European Federation of Biotechnology. The pH optimum of the preparation was found to be 5.0 and the temperature optimum was 40°C. Howev

Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. In this study p-benzoquinone is used as a substitute for oxygen in the oxidation of glycerol to dihydroxyacetone by immobilized Gluconobacter oxydans cells. The reaction rate was much higher when p-benzoquinone was used compared to when oxygen was used. In an experiment with free cells

Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. This report concerns the use of hemoglobin or emulsions of perfluorochemicals (completely fluorinated organic compounds) to carry oxygen to immobilized cells. Both methods work well and do not seem to harm the cells. The perfluorochemical method of improving oxygen supply showed a high

The stability of biocatalysis in systems containing organic solvents is reviewed. Among the examples presented are homogeneous mixtures of water and water-miscible organic solvents, aqueous/organic two-phase systems, solid biocatalysts suspended in organic solvents, enzymes in reverse micelles and modified enzymes soluble in water immiscible solvents. The stability of biocatalysts in organic solve

#105. Elonei Mamre, for cello

This score is a 100% recomposition of my earlier piece illusions (#74/2006). As before, this music references and is inspired by a report titled, “Demonstrations of Auditory Illusions and Tricks” by Yoshitaka Nakajima, Takayuki Sasaki & Gert ten Hoopen.This piece is based on five classes of auditory illusions that were reported by Yoshitaka Nakajima, Takayuki Sasaki, & Gert ten Hoopen.

#104_loga, a nonlinear scale of time, for tpt, tbn. “loga, a nonlinear scale of time” refers to the illusion of nonlinear time perception. This idea suggests that our estimation of time intervals whether on a small (milliseconds) or large (decades) scale should be logarithmic, giving us a subjective experience very different from clock or calendar. Of course, our perception of time is influenced b

#103, Linda Kurba Leskinaine is the second part of a planned trilogy (the first part being Kalevi Matus from 2000). Both pieces are based on an episode of the Estonian national epic, the Kalevipoeg, written by Friedrich Reinhold Kreutzwald (1862, Kuopio (Finland)).

This article examines the schemes of informal payment of wages by individual employers with the aim to avoid taxation. It will also analyze the causes and consequences of this phenomenon and the effect of the “colour” of income on the well-being of an employee, an employer and the state as a whole. It also discusses legal consequences that employers and employee face when engaging in hidden scheme