Showing papers by "Milena Sinigaglia published in 1993"
TL;DR: The ability of the cells to form a floating film seems to be an implicit strain character associated with an elevated unsaturation level and a mean chain length of fatty acid residues, as well as cellular hydrophobicities higher than those shown by non‐film‐forming strains belonging to the same species.
Abstract: Eleven strains belonging to two physiological races of Saccharomyces cerevisiae endowed with different abilities of forming films at air-liquid interfaces were analysed in relation to cell fatty acid composition and cell hydrophobicity. Extensive individual differences in fatty acid profiles were observed both in the film and in the non-film phase. The ability of the cells to form a floating film seems to be an implicit strain character associated with an elevated unsaturation level and a mean chain length of fatty acid residues, as well as cellular hydrophobicities higher than those shown by non-film-forming strains belonging to the same species.
21 citations
TL;DR: The modelling of fermentation rate in relation to certain variables indicated that the fermentative performance at superoptimal temperatures, and particularly the optimal temperature and maximal temperature of the strain displaying a dissociative profile, could be increased by acting on medium composition.
Abstract: Two Saccharomyces cerevisiae strains, one specifically of S. cerevisiae and another belonging to the physiological race S. uvarum, exhibited associative and dissociate thermal profiles, respectively. The S. cerevisiae subsp. uvarum strain, which displayed the dissociative profile, was characterized by a higher aptitude for fermenting glucose in a superoptimal temperature range as well as by a lower fatty acid unsaturation degree. On the other hand, both strains exhibited a similar fatty acid composition modulation pattern with regard to temperature: the unsaturation level presented two relative maxima at 15 and 40° C. However, on the basis of Central Composite Design results, supplementation with an oleic acid source under semi-anaerobic conditions did not improve the fermentative performances in either strain. the modelling of fermentation rate in relation to certain variables indicated that the fermentative performance at superoptimal temperatures, and particularly the optimal temperature (Topt) and maximal temperature (Tmax) of the strain displaying a dissociative profile, could be increased by acting on medium composition.
20 citations
TL;DR: The physiological properties and fatty acid content of 59 strains of Saccharomyces cerevisiae isolated from soft-drink factories, a fruit puree factory, a fuel-alcohol distillery and a winery were compared.
Abstract: The physiological properties and fatty acid content of 59 strains of Saccharomyces cerevisiae isolated from soft-drink factories, a fruit puree factory, a fuel-alcohol distillery and a winery were compared. Discriminant analysis of the results allocated the strains to four groups according to their source. Resistance to preservatives and temperature stress were correlated with differences in fatty acid composition. The fatty acid C18: 1 delta 11, growth at pH 2 and in the presence of 200-600 mg l-1 benzoate or sorbate, and maximal growth rate at 42 degrees C were characteristics associated with yeasts from particular environments. However, tolerance of thermal stress and content of the C18: 2 fatty acid were associated with subspecies: the former species S. capensis, S. chevalieri, etc. The relative content of C10: 0, C12: 0 and C18: 0 acids varied according to both isolation source and subspecies.
8 citations