الفهرس 
NTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Benefit yeasts, especially S. cerevisiae is very important for the economy. It is responsible for most fermentations in food industries. It is very important as food supplement whether in human or animal feeding. S. cerevisiae also is used in the enzymes, vitamins, bio-ethanol production and many other industries.
This study was conducted with the following aims:
I. Isolating many strains of Saccharomyces species from different rich sugar food sources by using three different fungi media.
II. Pre-identifying of the most promising isolates by using morphological, physiological, technological characterization methods and determination of the antimicrobial activity against pathogens.
III. Genetic identification of the selected isolate using18S method.
IV. Isolation of the intracellular and extracellular bioactive polypeptides according to their antimicrobial activity.
V. Studying the production optimization condition of bioactive polypeptides.
VI. Using the purification, characterization and pre-identification methods and techniques of the most promising bioactive polypeptides to be used in other future industrial applications.
VII. Using the identified isolated S. cerevisiae for the production of Egyptian pan bread fortification to enhance the nutritional quality.
VIII. Evaluating the quality attributes of fortified pan bread by determining the proximate chemical composition, Vitamin B complex, minerals, amino acid profile and sensory evaluation.
The main results of this study can be summarized in the following points
1. 150 yeast strains were isolated from grapes, figs, dates, molasses and honey under the same conditions of temperature and pH having approximately the same number. Thus we can conclude that Saccharomyces yeast can be developed on rich sugar food waste industry.
2. Optimization of growth conditions showed that optimum growth was at pH 6.5 and 25-30℃ incubation for 72h.
3. The sixteen strains of yeasts isolates were able to produce good flavor it can be used as a starter culture.
4. few strains were able to grow weakly at 20℃ and 37℃ but most of them were able to grow strongly at 25℃, 30℃ and35℃ and there are no strains can grow at 40℃.
5. few strains were able to grow weakly in 3.3, 4.5, 5.5, 7.5 and 8.0 pH values but most of them were able to grow strongly in 6.0, 6.5 and 7.0 pH values.
6. YHS1 2, YGS1, YHS1 1, YFS1, YHS2 isolates were the most developer of acidity, which indicate how much strong and fast of these isolates.