Extraction method and application of lactobacillus extracellular protein

Abstract

The invention discloses an extraction method and an application of lactobacillus extracellular protein. The method can be used for obtaining extracellular protein secreted by lactobacillus at a relatively high level and is simple in a preparation process, low in cost and applicable to large-scale production. The method comprises the following steps: inoculating the lactobacillus in an improved tomato juice culture medium and culturing at the temperature of 37 DEG C under an anaerobic condition; scraping off cultured lactobacillus lawn, transferring to a phosphate buffer solution of which the pH value is 7.2-7.4, re-suspending, afterwards shaking, centrifuging to remove thallus and collecting liquid supernatant; desalting by means of dialysis and concentrating to obtain a crude extract solution of the lactobacillus extracellular protein; performing SephadexG-100 dextran gel chromatography on the crude extract solution of the lactobacillus extracellular protein, and collecting a protein solution having a protein peak to obtain purified lactobacillus extracellular protein. Identification on molecular weight of the lactobacillus extracellular protein shows that the molecular weight is 67KD and 37KD. Application tests of two types of lactobacillus acidophilus extracellular protein show that the 67KD and 37KD extracellular protein has different inhibition effects on growth of HT-29 cells.

Description

technical field [0001] The invention belongs to the technical field of microorganisms, in particular to a method for extracting extracellular proteins secreted by probiotics and the application of the extracellular proteins of Lactobacillus acidophilus. Background technique [0002] For a long time, probiotics have been considered "generally safer", but probiotic strains selected for therapeutic purposes usually have better adhesion to intestinal epithelial cells, and this characteristic also increases the possibility of bacterial translocation . Probiotics have been clinically reported to cause bacteremia, infective endocarditis, and liver abscess in some immunocompromised individuals. Therefore, although probiotics have entered clinical application, many issues such as dosage, timing, course of treatment, and safety of medication still need to be clarified. [0003] Lactobacillus acidophilus is an important microorganism in the human gut. Since the mid-1980s, with repor...

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Problems solved by technology

The actual level of research is due to the differences in the extracellular proteins secreted by different bacterial species in different culture media, mainly because the level of s

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