title: Optimization of accessible catalase activity in polyacrylamide gel-immobilized Saccharomyces cerevisiae.
abstract: The permeabilization of Saccharomyces cerevisiae (baker's yeast), either before or after immobilization in polyacrylamide gel (PAG), has been examined as a means to increase the catalase activity of PAG-immobilized yeast cells. Prior permeabilization of the cells resulted in large losses of catalase activity during immobilization, but permeabilization after immobilization produced increases in the catalase activity of yeast/PAG particles. A dependence of the accessible catalase activity on the concentration of polyacrylamide in permeabilized yeast/PAG particles, and on the method of permeabilization of the immobilized cells, was observed. Optimal levels of stable catalase activity (1000-2000 IU/g PAG particles; ca. 5%-10% of total available activity) were obtained by immobilizing yeast cells (0.5 g wet cells/mL gel) in 10% (w/v) PAG, followed by permeabilization of the entrapped cells with either cetyltrimethylammonium bromide, Triton X-100 and one freeze-thaw, or five freeze-thaw cycles.
authors.affiliation: Central Research and Development, E.I. du Pont de Nemours & Co., Experimental Station, Wilmington, Delaware 19880-0328, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Seip
authors.forename: R
authors.initials: R
authors.lastname: Di Cosimo