Production of conjugated linoleic acid by permeabilized Lactobacillus acidophilus cells

To overcome the problem of enzyme extraction and poor permeability of cell to linoleic acid (LA), experiments were carried out to permeabilize Lactobacillus acidophilus cells for their subsequent use for the production of conjugated linoleic acid (CLA) from LA through catalysis of linoleate isomerase in the cells. The reagents, reagent dosage and time of cell permeabilization treatment were investigated. The results indicated that the maximum activity of CLA biosynthesis was obtained after the cells were treated with 2% (w/v) of Cetyltrimethylammoniumbromide (CTAB) at 37 °C for 40 min. Reaction conditions for producing CLA by permeabilized cells were optimized. The conversion yield of LA to CLA was up to 86.4% with 8 × 1010 CFU/ml permeabilized L. acidophilus cells in 0.1 mol/l phosphate–citrate buffer (pH 4.0) including 2 mg/ml LA at 45 °C under shaking condition (120 rpm) after 6 h reaction. Batch reactions showed that the permeabilized cells could be reused for 10 cycles at least in the biosynthesis reaction. The total CLA yield was up to 1.52 g/g wet permeabilized cells. Development of permeabilized cells provides a new alternative technology for CLA production.