title: Differential dialysis culture for separation and concentration of a macromolecular product.
abstract: A differential dialysis flask, constructed with three chambers and two membranes of different porosity, was used to effect the separation and concentration of enterotoxin B produced extracellularly by a culture of Staphylococcus aureus. Variables were examined that affected the diffusion of glucose, as measured by half-equilibration time and permeability coefficient; the relative chamber volume, type of membrane, membrane masking, and mixing all exerted a substantial influence on diffusion rates. A number of membrane filters were tested for usefulness; one type, made with vinylidene fluoride, had desirable physical and diffusional properties, but neither it nor others consistently withheld the bacteria for more than a marginally useful period of about 50 hr. In ordinary two-chambered dialysis culture, the amount of enterotoxin reached 10 times that in control culture; in differential, three-chambered dialysis culture the comparable factor of increase was about 7, with about two-thirds of this amount being separated from cells in the product chamber of the flask.
mesh_terms: D003956:Dialysis / Q000295:instrumentation*; D004768:Enterotoxins / Q000096:biosynthesis; D005374:Filtration; D005947:Glucose; D013210:Staphylococcus / Q000254:growth & development
chemical_list: D004768:Enterotoxins; D005947:Glucose