Screening of lactic acid bacteria isolated from traditional dairy products of Khorasan regarding extracellular folate production

Folate is a term used for a set of compounds with similar biological activities. Folate (polyglutamates) naturally contains all forms of vitamins in this family. In other words, folic acid is a form of folate that is oxidized, this compound is stable and can be absorbed by humans (monoglutamate)[1]. There are several methods for measuring folate, but due to the fact that in this study, the production of extracellular folate (Quatrofolate) was examined, so the microbial assay method was used as the main method. Lactobacillus. Rhamnosus (ATCC7469), which is used as a sensing organism. [2,3] This method can also measure all forms of folate. In this study, 47 medical strains isolated from traditional dairy products were Special Khorasan. traditional yogurt (12 strains of Streptococcus.thermophilus and 15 strains of Lactobacillus delbrueckii subsp. Bulgaricus, 13 strains of Lactobacillus delbrueckii subsp. Lactis, 3 strains of Lactobacillus helveticus) were studied. The results of this evaluation showed that both strains (25 and 26) of Lactobacillus delbrueckii subsp. Bulgaricus produced significant high folate concentrations (133.23 μg / mL and 102.34 μg / mL), as well as K73 strain of Streptococcus.thermophilus, strain 73 from the strains of  Lactobacillus delbrueckii subsp. Lactis and strain No.87 from the three strains of Lactobacillus helveticus (90.29 μg / mL, μg / mL39.71, μg / mL 17.94), were also able to produce high amounts of quatrofolate. According to this study, it was found that the examined previously isolated strains have a potential ability to produce extracellular folate, and the microbial assay method for measuring a sensitive vitamin such as folate in all its forms is considered an efficient and accurate method.