Fabrizio Fatichenti

Antagonistic activity of Debaryomyces hansenii towards Clostridium tyrobutyricum and Cl. butyricum

A study of the inhibitory action of Debaryomyces hansenii (31 strains) on Clostridium tyrobutyricum (5 strains) and Cl. butyricum (2 strains) on laboratory media showed that Deb. hansenii inhibited the growth of these organisms, and that this effect was due not only to competition for nutrients but also to the production of both extra- and intracellular antimicrobial metabolites. The inhibitory effect varied with strain and occurred whether the yeasts were grown aerobically or under reduced O2 tension.

A preliminary investigation into the effect of Saccharomyces cerevisiae on pesticide concentration during fermentation

SummaryThe experiment was set up to investigate whether degradation of residual pesticides during fermentation might be influenced by yeast action. Six products commonly used in viniculture were tested. After fermentation, 2 of the fungicides (Folpet and Metalaxyl) remained unaffected; the fungicide Vinclozolin and 2 of the insecticides (Carbaryl and Tetrachlorvinphos) suffered degradation not attributable to the yeast; the pyrethroid insecticide, Deltametrin, suffered complete degradation attributable to the yeast.

Malic acid production and consumption by selected of Saccharomyces cerevisiae under anaerobic and aerobic conditions

SummaryFermentation tests in clearly defined laboratory conditions were carried out with eight functionally selected strains of Saccharomyces cerevisiae. Analysis of the data showed that there were no significant differences in malic acid production between the strains when the acid was initially present. When it was initially absent, however, significant differences were observed two strains (Nos. 1141 and 1083) showing marked productive superiority. With malic acid as the sole C source, two strains (Nos. 1109 and 1141) showed less acid consumption.

The effect of Saccharomyces cerevisiae on concentration of dicarboxymide and acylanilide fungicides and pyrethroid insecticides during fermentation

SummaryContinuing the investigation into possible yeast influence on ferment degradation of residual pesticides, two dicarboxymide antibotrytic fungicides (Iprodione and Procymidone), three acylanilide antiperonosporic fungicides (Benalaxyl, Furalaxyl and Ofurace) and two pyrethroid insecticides (Permethrin and Fenvalerate) were tested.Only the pyrethroids were degraded completely during fermentation.

Yeast and pesticide interaction during aerobic fermentation

SummaryThe action of a yeast (Saccharomyces cerevisiae) upon the insecticides Carbaryl, Tetrachlorvinphos and Deltamethrin and the fungicides Quinomethionate, Triadimefon and Vinclozolin during aerobic fermentation was investigated. The yeast adsorbed all the pesticides, four of them completely and two (Carbaryl, 50%, and Triadimefon, 90%) partially. In the case of Deltamethrin and Quinomethionate, degradation also occurred.

A genetically improved wine yeast

SummaryMost of 31 hybrids, obtained by fusion between the petite mutant of a nonsporous strain ofSaccharomyces cerevisiae SS-1090 and a Kar mutant K1 killer ofS. cerevisiae adenine and uracil auxotrophic, proved to be enologically as useful as the parent strain, and in some cases more so. In addition, all of them possessed killer factor, rendering them potentially more competitive against wild yeasts. Most of them also proved to be highly sporous.

Temperature profile of Candida cacaoi SS-2566

SummaryCandida cacaoi SS-2566 was found to have a dissociative temperature profile and thermotolerant growth yield behaviour. With temperature-independent growth rates up to 42°C, its utilization at relatively high temperature for the production of cells (SCP, SCL) and/or metabolites may well be of interest, particularly in view of its hydrocarbon utilization.