Evaluation of Streptococcus thermophilus effects on linoleic acid (c18: 2) under temperature and pH stress conditions Download PDF

Background and aim: Due to the beneficial physiological effects of conjugated linoleic acid (CLA), there has been a growing tendency to produce it as a functional lipid in recent years. In this study, optimization in lipid and linolenic acid production was investigated in as a Streptococcus thermophilus oleaginous Lactic Acid Bacteria. Material and method: In present study, we added linoleic acid (concentration 5µg mlˉ¹) in the medium of Streptococcus thermophilus in M17 media, under different pH and temperature stresses, and after 24 h of incubation, produced CLA was estimated by Spectrophotometric and Gas chromatographic techniques. Results: Our results indicated that Streptococcus thermophilus in M17 medium produces CLA in pH 7, but not in pH 4. This bacterium produces CLA at 37°C, but not at 45 °C. Conclusion: The findings indicated that transformed Streptococcus thermophilus can be used for CLA production in biocatalytic processes.