Purification Of Bacteriocins Producted By Lactobacillus Acidophlus

Bacteriocin (Bacteriocins) is synthesized in the metabolic process of bacteria and secreted into the environment of a class of the same species or species have close relationship with protein or peptide inhibition bactericidal substances, bacteriocins not only variety, but also in the nature the existence of widespread, almost every bacteria can produce bacteriocin. With the increasing problem of antibiotic resistance, bacteriocin in the prevention and treatment of human disease, animal healthcare and food preservation, etc. reflects the great potential.This paper studies the Lactobacillus acidophilus bacteriocin physical and chemical properties, through a single factor experiments and orthogonal experiments, culture medium and culture conditions to enhance the potency of bacteriocin and bacteriocin purification route, the details and results are as follows:(1) To find one pair of indicator bacteria strain better antibacterial.(2) Optimized medium formulation and culture conditions. Of medium glucose, peptone, beef extract, sodium chloride, calcium carbonate, MgSO4·7H2O, ammonium citrate, K2HPO4·3H2O, MnS04·H2O orthogonal test to optimize culture medium. The cultivation of bacteriocin temperature, fermentation time, inoculum size, medium pH, rotation speed for single factor experiments. Ultimately found that the optimal cell concentration increased by51.05×107cfu/ml, bacteriocin titer increased87.56AU/ml.(3) Physical and Chemical Properties of bacteria. Research shows that the bacteriocin is not only against Gram-positive bacteria inhibition, but also Gram-negative bacteria also have inhibitory effect; of protease-sensitive, indicating that the bacteriocin is a protein substance; its heat stability,120℃for30min to retain antimicrobial activity even after; in the larger context of the same pH to maintain a high antibacterial activity.(4) Groped a line of separation and purification:fermentation culture by centrifugation to remove bacteria, plaque supernatant using0.22μm filter after adding solid ammonium sulfate to a saturation of20%,4℃overnight.10000r/min centrifuged to precipitate dissolved in pure water. Adding solid ammonium sulfate to saturation from20%to80%,4℃overnight. Ammonium sulfate solution by overnight10000r/min centrifugation, precipitation was dissolved in pure water, collect sediment, water-soluble. Obtained after dialysis of crude extract of bacteriocin and then use SephadexG-50gel chromatography column and purified bacteriocin. Bacteriocin purified by Tricine-SDS-PAGE electrophoresis analysis, a single band with a molecular weight of about2.0KDa.