Method for preparing gamma-poly glutamic acid bioflocculant by bacillus licheniformis

Abstract

The invention discloses a method for preparing a gamma-poly glutamic acid bioflocculant by bacillus licheniformis, relates to a bioflocculant, and provides a method for preparing the gamma-poly glutamic acid bioflocculant by the bacillus licheniformis. The method comprises the steps of transferring the bacillus licheniformis to a slant culture medium to cultivate; choosing an activated strain by an inoculating loop; inoculating into a conical flask with seed culture medium to cultivate; inoculating into the conical flask with seed culture medium to cultivate; taking a secondary seed, inoculating into a fermentation culture medium to cultivate by 3% of inoculating quantity; centrifuging bioflocculant fermentation liquor, removing the sediment, collecting upper clear liquid; adding ethanol to the upper clear liquid and then stewing, centrifuging and removing the upper clear liquid; dissolving the sediment into deionized water; dialyzing by a dialysis bag; adding absolute ethyl alcohol to the dialyzed solution, evenly agitating, centrifuging and removing the upper clear liquid; freezing and drying the sediment in vacuum to obtain pure gamma-poly glutamic acid bioflocculant. The method is short in fermentation cycle, high in activity of synthetic flocculant, good in thermal stability, and large in industrial application potential.

Description

technical field [0001] The invention relates to a biological flocculant, in particular to a method for preparing a gamma-polyglutamic acid biological flocculant by using bacillus licheniformis. Background technique [0002] Bioflocculant (Bioflocculant) is a kind of special polymer metabolite produced by microorganisms that can aggregate and precipitate solid suspended particles, bacterial cells and colloidal particles that are not easy to degrade in liquid. Different microorganisms produce different types of flocculants under specific conditions. According to their chemical composition, most of the biological flocculants are polysaccharides and protein substances, and a small amount of them belong to other types such as lipids and DNA. [0003] Since Bovarnick et al. discovered that γ-PGA can be freely secreted into the culture medium as a polypeptide in 1942, it has been found that γ-PGA can accumulate extracellularly in various bacillus, such as: Bacillus.subtilis IFO3335...

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Problems solved by technology

[0018] The purpose of the present invention is to provide a method for preparing gamma-polyglutamic acid biological flocculants by Bacillus licheniformis for the problems of long fermentation period, low flocculant efficiency, poor thermal stability, and difficulty in popularization in the current production of biological flocculants. The method has the advantages of short fermentation period, high activity of the synthesized flocculant, good thermal stability, and great potential for industrial application

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