Abstract:

The high-yield ε-poly-L-lysine-producing Streptomyces violaceusniger strain isolated and preserved in our laboratory was cultured to produceε-poly-L-lysine in this study. The mycelia-free supernatant obtained after the centrifugal separation of the fermentation broth was ultrafiltrated through 5 kD (larger than the molecular weight of ε-poly-L-lysine) polysulfone membrane and the filtrate was collected. The static adsorption and desorption characteristics of the filtrate on three different types of ion exchange resins were compared, and the dynamic adsorption and desorption of the filtrate on the selected resin were studied with respect to the effect of operation conditions on adsorption quantity and recovery. Based on the results from static adsorption and desorption, weakly acidic cation exchange resin HD-2 had excellent separation performance onε-poly-L-lysine. The best purification process forε-poly-L-lysine was that the sample to be separated was applied to a 22 mm×300 mm HD-2 column with a flow rate of 3 mL/min, followed by 0.1 mol/L NaCl elution with the same flow rate. Aε-poly-L-lysine recovery of 92.0% was achieved using the optimized purification process.

Key words: ε-poly-L-lysine, fermentation broth, separation and purification, cation exchange resin