The Primary Study On Extraction Technology Of The Biological Preservative ε-Poly-L-Lysine From Fermentation Liquid

ε -Poly-L-Lysine is comprised of lysine linked by amide bond through microbial fermentation. It has excellent antibacterial activity against Gram-positive and Gram-negative bacteria, yeast and some kinds of viruses. In additional ε -Poly-L-Lysine is soluble and attractive heat stable. At present ε -Poly-L-Lysine have been used as natural food preservative mainly, degradable biological matreria, coat of drug, carrier of garget drug and medical research.The separation and extraction of ε -Poly-L-Lysine from fermentation liquid by using weak acid anion-exchange resin D152 was studied. The culture broth(pH3.2) was filtered and the filtrate was adjusted to Ph8.5. Then, the precipitate formed was removed by filtration. The filtrate was applied on a column of Amberlite IRC-50(H+-from) and washed with 0.2N acetic acid and water, successively. The substance was eluted with 0.1N hydrochloric acid. The eluate was neutralized with 1N sodium hydroxide and decolorized with active charcoal, and then evaporated to a small volume. The D.P. substance was precipitated as a white powder by addition of an ethanol and ether (2:1)mixture. The substance was further purified by column chromatography on SephadexG-25.Through static exchange experiments, static exchange parameters of ε -Poly-L-Lysine on D152 resin is discussed. Through dynamic exchange experiment, the technical process using Hcl as eluent and Hcl as regenerative agent is studied, and main technical parameters are determined.