An alternative method for the decoloration of ɛ-poly-l-lysine eluate by macroporous resin in the separation and purification of ɛ-poly-l-lysine from fermentation broth

•Macroporous resin was firstly proposed to the decoloration of the ɛ-PL eluate.•The conditions of the decoloration by SX-8 resin were optimized.•SX-8 resin carried out the high decoloration and ɛ-PL recovery ratios.•Pigments with absorption at 300–900 nm were effectively removed.•This method is promising for the scale-up production of ɛ-PL.

To develop an efficient strategy for the decoloration of ɛ-poly-l-lysine (ɛ-PL) produced by microbial fermentation with Streptomyces, macroporous resin was firstly investigated on the removal of pigments in ɛ-PL ion exchange eluate here. SX-8 resin was found to be the best through static and dynamic comparison tests, which adsorbed the most pigments and the least ɛ-PL. Under the optimized dynamic adsorption conditions, i.e. pH 7.0, 30° C, 1 BV/h uploading rate, 7 g/L ɛ-PL concentration, SX-8 resin was employed to the treatment of 100 mL (10 BV) ɛ-PL ion exchange eluate, and the resulting decoloration ratio was 83.9% with a recovery ratio of ɛ-PL 97.3%. Further spectrum analysis showed that pigments with absorption wavelength between 300 and 900 nm were effectively removed after treatment by SX-8 resin. The results presented reveal that SX-8 resin is promising for scale-up ɛ-PL extraction and purification from fermentation broth.