Frozen and thermal treatment on ε-polylysine fermentation broth to remove protein

Removal of protein in e-polylysine(e-PL)fermentation broth is an important step before the extraction of e-PL.With the relative quality contents of e-PL and protein as the measurement indexes,the research carried out a comparision between frozen processing and thermal treatment to remove protein and the result indicated that the latter was preferred.Then the thermal treatment conditions were optimized as pH6.0,temperature 80℃ and treat time 15min.Under this optimal conditions,removal rate of protein and retention rate of e-PL reached 83% and almost 100% respectively.SDS-PAGE was employed to evaluate the effect of protein removal and the result showed that the molecular weight of protein in e-PL fermentation broth distributed below 66400,only those whose weight below 14300 were hard to be removed by thermal treatment.Research on thermal treatment of e-polylysine fermentation broth derived some significance.