No abstract

Exopolysaccharides are high molecular weight polymers of repeated sugar units with diverse chemical structure and unique properties and produced by microorganisms. Lactic acid bacteria are important exopolysaccharide producers. Lactic acid bacteria derived exopolysaccharides, one of the postbiotics, are known to have technological properties such as stabilizing, thickening, emulsifing and also biological activities. Lactic acid bacteria can synthesis exopolysaccharides with large structural variability and this diversity brings these polymers to possess several bioactivities. Bioactivities such as immunomodulatory, antiinflammatory, antitumor and antimutagenicity, antioxidant, antibacterial and antiviral, cholesterol-lowering, antihypertensive activity and gastro-protective activity bring these biopolymers commercial value in the global market and potential to be used in biomedical and pharmaceutical applications. Therefore, to evaluate the availability of these natural exopolysaccharides for new applications extensive understanding of the structure-function relationships will be required. In this review, it is presented a comprehensive overview for the most recent reports on the health benefits of postbiotic lactic acid bacterial exopolysaccharides.

Lactic acid bacteria are the substantial source for producing polysaccharides used in technological applications as thickeners and viscosifiers in the food industry. A broad variety of lactic acid bacteria species secrete structurally diverse exopolysaccharides that contribute to their surface attachment, protection against abiotic or biotic stress factors and nutrient uptake. The exopolysaccharides are produced naturally during fermentation process by living lactic acid bacteria cells and accepted as postbiotic for these metabolites having various physiological health-promoting effects. Exopolysaccharide producer lactic acid bacteria encode a great number of enzymes and regulatory proteins involved exopolysaccharide biosynthesis process. This process is a complex and occurs through presence of multiple genes. However, it is crucial the understanding of structure, composition, function, chemical, and physical properties of exopolysaccharides which vary from one type of bacteria to another via chemical analysis methods. In this review, the use of lactic acid bacteria exopolysaccharides, their structures, genetic modules and biosynthesis, and the use of exopolysaccharides derived from lactic acid bacteria in the food industry are described, discussed and focused on recent developments.

Laktik asit bakterileri (LAB); doğada fermentatif, fakültatif, anaerob ve aerotolerant özelliklere sahip geniş bir mikroorganizma grubudur. LAB’ların çeşitli fermentasyonlar açısından önemli bir yere sahip oldukları bilinmektedir. LAB’ lar antibiyotiklere maruz kalma durumlarında gıda tüketimi ile tüketicilerde antibiyotik direnç belirleyicilerin yayılımı açısından önem arz etmektedirler. Bu çalışmada Tulum peynirlerinden izole edilen ve Lactobacillus plantarum (9) ve Lactobacillus paracasei (6) olarak PCR yöntemi ile tanımlanan izolatların antibiyotik dirençlilikleri fenotipik yöntemlerle belirlenmiştir. LAB izolatlarının göstermiş olduğu en yüksek direncin (%100) kanamisin, streptomisin ve ampisilin antibiyotiklerine karşı olduğu tespit edilmiştir. Ayrıca eritromisin (% 86,6), rifampisin ve tetrasiklin (%73,3), gentamisin ve vankomisin (% 80), kloramfenikol (% 60), penisilin (% 53,3) antibiyotiklerine karşı da önemli oranlarda dirençlilik tespit edilmiştir.