High-glutathione containing yeast Saccharomyces cerevisiae: optimization of production.

Experimental design procedure was used to search for optimal medium composition for maximization of glutathione yield using a high-glutathione containing yeast S. cerevisiae S-8H. The effects of the chosen factors (glucose, peptone, KN2PO4, biotin and cysteine) on the relationship between yeast biomass formation and the content of intracellular glutathione were examined. Results obtained showed that glucose and peptone had significant first- and second-order effects, as well as different interactive effects on these overall parameters. On the other hand, cysteine showed only second-order effect for glutathione content and interactive effects for both glutathione content and yield. Its presence had a marked positive effect on the content of glutathione, but reduced the biomass formation. The optimal levels of these factors found were in the range of 2.5%, 4%, 0.027%, 10 micrograms/cm3 and 0.08%, respectively. The average yield obtained at this optimium was 160.1 mg glutathione/dm3 and a glutathione content of 17 mg/g dry biomass.

Physiological suppression of superoxide dismutase deficiency in yeast Saccharomyces cerevisiae.

Deficiency in superoxide dismutases results in pleiotropic effects including hypersensitivity to oxygen and amino acid auxotrophy. Various types of physiological suppressors of deficiency in cytosolic superoxide dismutase were isolated, whereas attempts to isolate suppressors of mitochondrial enzyme deficiency proved a failure. General characteristics of isolated suppressors are presented.

Biosynthesis of cellulolytic enzymes in semi-continuous cultures.

The aim of the research was to check the possibility of the semicontinuous cultivation of two Fusarium sp. strains producing cellulolytic enzymes. The cultures were grown in 5 1 fermentor on the mineral medium with addition of 1% cellulose cotton. In these cultures lasting 9 to 16 days the total activity was about 13 mg of reducing sugar/ml culture filtrate/hour. The comparison of the results of semi-continuous and periodic cultures pointed to the productivity of cellulolytic enzymes which was 1.2 to 2 times higher during one hour in semi-continuous cultures.

Mixed cultures of different yeasts species and yeasts with filamentous fungi in the SCP production. I. Production of single cell protein by mixed cultures Candida lipolytica and Candida tropicalis.

The aim of this study was to determine the application of mixed cultures Candida lipolytica and Candida tropicalis in the SCP production. N-paraffin fraction of crude oil and individual n-alkanes C:7--C:17 and glucose were used as carbon sources. The cultures were grown on laboratory scale in shaking flasks and in a 7 1 fermentor. It was found that the mixed cultures gave about 18% higher yield of biomass than the individual cultures.