Biosorption of heavy metals.

Only within the past decade has the potential of metal biosorption by biomass materials been well established. For economic reasons, of particular interest are abundant biomass types generated as a waste byproduct of large-scale industrial fermentations or certain metal-binding algae found in large quantities in the sea. These biomass types serve as a basis for newly developed metal biosorption processes foreseen particularly as a very competitive means for the detoxification of metal-bearing industrial effluents.

Biosorption of lead and nickel by biomass of marine algae.

Screening tests of different marine algae biomas types revealed a high passive biosorptive uptake of lead up to 270 mg Pb/g of biomass in some brown marine algae. Members of the order Fucales perfomed particularly well in this descending sequence: Fucus > Ascophyllum > Sargassum. Although decreasing the swelling of wetted biomass particles, their reinforcement by crosslinking may significantly affect the biosorption performance.

Cadmium biosorption by Saccharomyces cerevisiae.

Cadmium uptake by nonliving and resting cells of Saccharomyces cerevisiae obtained from aerobic or anaerobic cultures from pure cadmium-bearing solutions was examined. The highest cadmium uptake exceeding 70 mg Cd/g was observed with aerobic baker's yeast biomass from the exponential growth phase. Nearly linear sorption isotherms featured by higher sorbing resting cells together with metal deposits localized exclusively in vacuoles indicate the possibility of a different metal-sequestering mechanism when compared to dry nonliving yeasts which did not usually accumulate more than 20 mg Cd/g.

Biosorption of cadmium by biomass of marine algae.

Biomass of nonliving, dried brown marine algae Sargassum natans, Fucus vesiculosus, and Ascophyllum nodosum demonstrated high equilibrium uptake of cadmium from aqueous solutions. The metal uptake of cadmium from aqueous solutions. The metal uptake by these materials was quantitatively evaluated using sorption isotherms.

Tumor necrosis factor and its induction by bacterial endotoxins.

Using suitable immunomodulators (Corynebacterium parvum vaccine, Zymosan or muramyl dipeptide), lipopolysaccharides (LPS) from various members of the family Enterobacteriaceae (Escherichia, Salmonella, Serratia, Shigella) were tested on rabbits in relation to the production of tumor necrosis factor (TNF). TNF was determined by means of the serum titration of L-929 cell cultures in the presence of Actinomycin D, this with resulting titres of 3.2 x 10(3) to 5.

Preparation of zymosan from yeast cell walls.

Cell walls of the yeast Saccharomyces cerevisiae after disintegration and protoplasm removal by centrifugation and repeated washing were suspended in 0.5 M Na2HPO4, pH 7.8-8.

Cytological and chemical changes in cell walls of Rhodotorula gracilis. III. Characteristics and life cycle of the yeast.

The phenotype and genotype of six strains of the genus Rhodotorula Harrison and of one strain of the genus Cryptococcus Phaff et Fell, with anomalous thickening of cell walls were investigated. The present studies showed that the strains investigated represent different stages of the life cycles of the genus Rhodosporidium Banno. The anomalous thickening of the cell walls can be explained by extreme conditions resulting in the formation of surviving forms (teliospores, chlamydospores).

The chitin-glucan complex of Saccharomyces cerevisiae. III. Electron-microscopic study of the prebudding stage.

Differentiation of the cell wall of Saccharomyces cerevisiae at the site of the future bud was followed. A lentil-like structure originates on the inner side of the cell wall during the first phase. At the same time, an electron-dense layer occurs at the boundary between the inner layer of the cell wall and the lentil-like structure.