The'843 patent teaches that this method improves the final purity from about 80% to about 93% and increases the yield from about 5% to about 35% ; however, the '843 patent does not disclose the type of impurities present in the daptomycin preparation. United States Patent 5, 912, 226 describes the identification and isolation of two impurities produced during the manufacture of daptomycin.