الفهرس 
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Abstract
In this study, sixteen isolated lactic acid bacteria from Egyptian food and Streptococcus thermophillus and Lactobacillus bulgaricus,were used. Investigated bacteria were screened for production of antifungal substances using well agar diffusion method against Candida albicans. The most potent bacterial producers were characterized morphologically, biochemically, genetically by 16S rRNA gene sequencing and identified as Enterococcus hirae and Enterococcus faecium. Some physiological factors affecting the production of the antifungal substances (temperature, pH, carbon sources, nitrogen sources and different media) were studied. The sensitivity of the extracted substances against proteolytic enzymes were examined to confirm their proteinaceous nature. The effect of heat, pH and some surfactants were examined to observe the stability of the antifungal substances. The protein active substance produced by E.hirae had high potency against number of pathogenic fungi like Trichophyton mentagrophytes, Microsporum gypseum, Microsporum nanum, Microsporum canis, Aspergillus niger and Fusarium oxysporum. Also, the protein active substance of E. faecium was active against some of them. The antifungal substances were precipitated by ammonium sulphate from culture supernatants of the two bacteria. The active substances produced by E. hirae and E. faecium were composed of four and five proteinaceous subunits respectively, with different molecular weights estimated on SDS polyacrylamide gel electrophoresis. The amino acid content was estimated for antifungal substances of E. hirae and E. faecium strains and of amino acids respectively. The broad-spectrum of activity of these substances can be used as a potent natural antifungal agents to reduce using chemical antifungal substances.