Molecular identification and typing of lactobacillus delbrueckii subspecies bulgaricus and streptococcus thermophilus

Cebeci Aydın, Aysun
Lactic acid bacteria are associated with preservation of foods, including milk, meat and vegetables. Yoghurt is produced by the cooperative action of two starter bacteria; S. thermophilus and L. delbrueckii subsp. bulgaricus. In this study, identification and typing of yoghurt starter bacteria were aimed. Traditional home made yoghurts were collected from different areas of Turkey, identification of those isolates at species and subspecies level and typing at strain level were achieved using PCR based methods. In our study, identification of yogurt starter bacteria was studied using species specific primers and ARDRA. These methods were inefficient in identification of yoghurt starter bacteria, at species and subspecies level. Consequently, a reliable and quick method for accurate identification of yoghurt starter bacteria was developed. The new method focuses on amplification of methionine biosynthesis genes, for selective identification of yoghurt starter bacteria together with some cheese starters. Further discrimination by ARDRA enabled differentiation of yoghurt starter bacteria from cheese starters. Confirmation of the proposed method has been accomplished by partial sequencing of the 16S rRNA gene. After correct identification of starter bacteria had been achieved, the strains were typed at strain level using RAPD-PCR and MLST. RAPD-PCR with primer 1254 resulted better fingerprints, compared to primer M13 at strain level. Comparisons of the two typing methods showed that RAPD-PCR revealed strain diversity better than MLST, however MLST was a more robust and reliable method and resulted in clustering of the strains depending on the isolation source.


Release and characterization of beta-galactosidase from lactobacillus plantarum
Kara, Fırat; Gürakan, Candan; Department of Biotechnology (2004)
The enzyme, β-galactosidase (E.C. has been used for dairy industry for removing lactose from milk and milk by-products. In this study, three strains namely L. plantarum NCIMB 1193, L. plantarum DSM 20246 and L. plantarum E081 were used for β-galactosidase release by sonication method. The peak of the total enzyme activity was found to be corresponding to late logarithmic or early stationary phase of all strains. As a disruption method sonication was used for the release of β-galactosidase. Meanwhil...
Microbial inactivation and evaluation of furan formation in high hydrostatic pressure (HHP) treated vegetable-based infant food
Kultur, Gulcin; Mısra, N. N.; Barba, Francisco J.; Koubaa, Mohamed; Gökmen, Vural; Alpas, Hami (2017-11-01)
The inactivation of pathogenic and spoilage bacteria as well as the formation of food processing contaminants (e.g. acrylamide, furan, etc.) in infant foods is of utmost importance for industry, consumers as well as regulatory bodies. In this study, the potential of high hydrostatic pressure (HHP) for microorganism inactivation including total mesophilic aerobic bacteria (TMA) and total yeasts and molds (TYM) at equivalent processing conditions, as well as its effects on furan formation in vegetable-based i...
The use of microfluidization for the production of xanthan and citrus fiber-based gluten-free corn breads
OZTURK, Oguz Kaan; Mert, Behiç (2018-10-01)
Corn gluten meal is an underutilized byproduct due to its hydrophobic nature although it contains high amount of protein. The primary objectives of this study were to enhance the water holding capacity of this protein-rich byproduct with microfluidization technique and use it in bread-making formulations instead of gluten with the addition of different supplements. The increase in stability, surface area, and consequently water holding capacity with microfluidization resulted in the formation of compatible ...
Current applications of exopolysaccharides from lactic acid bacteria in the development of food active edible packaging
Moradi, Mehran; Guimarães, Jonas T; Şahin, Serpil (Elsevier BV, 2021-08-01)
The lactic acid bacteria (LAB) are usually recognized as safe for consumption and comprise several genera with different technological and health-promoting potential for food applications, including probiotic characteristics. Their exopolysaccharides (EPS) have interesting film-forming properties and may be used to produce edible packaging, as a structural enhancer, a bioactive agent or probiotic carrier in edible films and coatings. In these days, there is a specific demand for food products with reduced a...
Identification of serotype specific dna marker for salmonella typhimurium by rapd-pcr method
Aksoy, Ceren; Gültekin, Güzin Candan; Department of Biotechnology (2004)
This study was performed for the identification of specific DNA marker using RAPD-PCR (Random Amplified Polymorphic DNA) method for serotype Salmonella Typhimurium which is one of the most prevalent serotype causing food poisining all over the world. The Primer 3 (RAPD 9.1), 5̕-CGT GCA CGC-3ء, was used in RAPD-PCR with 35 different Salmonella isolates. 12 of them were serotype Salmonella Typhimurium and 23 of them were belonging to other six different serotypes. Accordingly, two different 300 bp and 700 bp ...
Citation Formats
A. Cebeci Aydın, “Molecular identification and typing of lactobacillus delbrueckii subspecies bulgaricus and streptococcus thermophilus,” Ph.D. - Doctoral Program, Middle East Technical University, 2008.