title: Effects of solvent molecular toxicity and microenvironment composition on the Delta(1) dehydrogenataon activity of Arthrobacter simplex cells.
abstract: Solvent selection tests were carried out for the Delta(1) dehydrogenation of 6-alpha-methylhydrocortisone-21-acetate by Arthrobacter simplex cells in the presence of organic solvents. Solubility limits were determined for substrate and product in dry and water-saturated solvents and solvent mixtures. Molecular toxicity levels were estimated by measuring the dehydrogenation activity decay of freely suspended cells incubated in solvent-saturated aqueous media. Chloroform and n-decan-1-ol were the best choice of solvent, for both solubility and catalytic stability. High concentrations of water-soluble additives, such as monosodium glutamate, were found to greatly improve the retention of activity in chloroform-saturated media.
authors.affiliation: Laboratório de Engenharia Bioquímica, Instituto Superior Técnico, 1000 Lisbon, Portugal.
authors.forename: H M
authors.initials: HM
authors.lastname: Pinheiro
authors.forename: J M
authors.initials: JM
authors.lastname: Cabral