2.3.2. Purification in physiological conditionsThe same chromatographic techniques were used with pH 7 buffers. The culture filtrate was neutralized by adding K2HPO4 0.2 M. The two buffers used for RPC were Buffer C: KHPO4 10mM pH 7 and Buffer D: id + 70% acetonitrile. No neutralization was required before bioassays but the samples were still slightly evaporated (to half of the initial volume) to eliminate the acetonitrile. The gradient used for capture was a linear gradient (20 column volumes) from buffer C to D.