Isolation and Identification of Lactobacillus Acidophilus Probiotic Bacteria from Traditional Tarkhineh Food and Their Ability to Lower Cholesterol and Triglyceride Levels in vitro

Isolation and identification of probiotic strains from native foods can lead to finding strains with unique capabilities. The aim of this study was to isolate, identify and evaluate the ability of Lactobacillus acidophilus bacteria isolated from traditional Tarkhineh food in lowering cholesterol and triglyceride levels in vitro. Native strains of Lactobacillus acidophilus were isolated from a local food called Tarkhineh using culture medium and identified based on phenotypic characteristics, standard biochemical tests and 16SrRNA sequencing. In the next step, the strains were examined for probiotic properties such as resistance to acid and bile and sensitivity to antibiotics. Cholesterol and triglyceride lowering activity of isolates in culture medium was also investigated by o-phthaldehyde method. The results showed that 16 strains of Lactobacillus acidophilus were isolated from Tarkhineh samples, among which four strains (S3, S12, S6, S5) showed 30 to 50% resistance, three strains (S7, S4, S10). had 50 to 75% resistance and 2 strains (S11, S1) had 75 to 100% growth in acidic MRS. In addition, strains S7 and S1 showed a growth rate of 0.3 to 0.5% and strains S4, S3, S11 grew at 0.7% bile salt in MRS medium. The highest cholesterol uptake was observed in S11 and S1 strains at 64± 0.23 and 60±0.18 (p<0.01) respectively. Strains S1 and S11 applied 72% ± 0.64 and 61 ± 0.25% triglyceride reduction respectively. The data of this study showed that the native strains of Lactobacillus acidophilus isolated from the local food of Tarkhineh had the potential to absorb and reduce cholesterol and triglycerides of the culture medium. These strains can be studied in laboratory animals as probiotics capable of absorbing and removing fat.