Extraction of polar lipids from bifidobacteria by supercritical carbon dioxide (scCO2)

This study describes an efficient isolation procedure for the extraction of polar lipids from two strains of bifidobacteria – Bifidobacterium longum and Bifidobacterium angulatum. We first compared the lipid profiles of two strains of bifidobacteria and showed that the strains of the same genus may differ by lipid composition of cell walls. The polar lipids were isolated using the following conditions: pressure 250 bar, temperature 45 °C, CO2 flow rate 5 g/min, hydromethanolic co-solvent concentration 10% (v/v). In the lipid extracts the carbohydrate moiety of glycolipids and in phospholipids phosphorus moiety were quantified and compared to the reference material isolated by classical extraction. Thrice the amount of glycolipids and phospholipids in comparison with classical method was found in the lipid extract from B. longum obtained with scCO2, and twice the amount of more – from B. angulatum. By TLC were identified different glycolipid profiles of these strains, four glycolipids were detected from B. longum and seven glycolipids from B. angulatum. From 5 g of biomass during prolonged fractionated extraction (12 h) 2.80 and 3.11 mg of glycolipids, 1.86 and 1.88 mg of phospholipids from B. longum and B. angulatum was obtained, respectively.