Resin-based, in situ product removal (ISPR) was used to increase production of epsilon-poly-L-lysine (PL) by Streptomyces sp. GIM8. D152 resin was selected over Amberlite IRC-50, Amberlite IRC-76 and Amberlite IR-120 to develop ISPR using adsorption capacity and desorption ratio as bases. The yield of PL in response to external PL was unaffected in shake-flask culture; however, the production of PL increased to 2.9 from 0.8 g l(-1) shake-flasks using ISPR. In a 5 l fermentor, 23.4 g PL l(-1) was achieved compared to 3.76 g PL l(-1), in the controls by attaching two bags of D152 resin to the probes and baffles of the fermentor.