摘要：The microbial ecology of the flour fermentation is determined by ecological factors. Microbiological studies have revealed that more than 50 species of LAB, mostly species of the genus Lactobacillus, and more than 20 species of yeasts, especially species of the genera Saccharomyces and Candida, occur in this ecological niche. The flour microflora is composed of stable associations of lactobacilli and yeasts, in particular due to metabolic interactions. As shown for certain industrial flour processes, such microbial associations may endure for years, although the fermentation process runs under non-aseptic conditions. A reproducible and controlled composition and activity of the flour microflora is indispensable to achieve a constant quality of sourdough bread. Study on 4 natural flour types from various regions in Bulgaria – wheat flour from the villages of Okorsh, Dulovo and Melko, and rye flour from the village of Lilyak and the Archar mill. The isolates have been obtained through anaerobic cultivation on different media – MRS, mMRS 2% maltose, Eliker and mMRS 2% sucrose. The 10 isolates obtained have been analysed in terms of cell morphology, gas production on glucose, proteolytic activity and amylolytic activity. The species have been identified through molecular genetics methods, through 16S rRNA. The results indicate that the proteolytic and amylolytic activities are specific in terms of species and strains
