Microbial immobilization method

Abstract

The invention discloses a microbial immobilization method, comprising immobilization for lactic acid bacteria and a continuous production process for Nisin. The microbial immobilization method comprises the following steps of: firstly, growing thalli in a reactor and adsorbing the thalli onto carrier materials; secondly, releasing the free thalli and adding fresh culture solution, and controlling a flow speed to enable the amount of the product Nisin to be the highest when fermentation solution just arrives at the bottom of the reactor and flows out by combining with the height-diameter ratio of the reactor; and finally, enabling the product to flow in a product collection tank, wherein the carriers used are reusable polyurethane foam carrier materials; the whole process is simple to operate; and because two restrictive factors influencing the growth and the production of lactic acid bacteria, namely, nutritional ingredient reduction and low pH caused by the product, are eliminated, continuous production for lactic acid bacteria under a high Nisin yield can be realized.

Description

technical field [0001] The invention relates to the immobilization technology of microbial cells, in particular to a novel process method for continuous production of immobilized lactic acid bacteria. Background technique [0002] Lactobacillus is a kind of antibacterial protein or processed polypeptide substance produced by the fermentation of lactic acid bacteria, which can inhibit or kill most Gram-positive pathogenic bacteria, and a few are effective against Gram-negative bacteria. Previous studies have found that although it cannot be used as an antibiotic, it can be used as a food preservative, and as a food preservative, it will not accumulate in the body and cause adverse reactions, can reduce the sterilization temperature, reduce heat treatment time and many other advantages . So far, the only commercialized lactobacillus is Nisin (a natural biologically active antimicrobial peptide of nisin). Nisin itself has the advantages of heat stability, acid resistance and l...

AI Technical Summary

Problems solved by technology

However, the current research on the immobilization of lactic acid bacteria is in the stage of laboratory exploration. The embedding method is mostly used, and the carrier materials are mostly natural organic carrier materials, such as alginate, carrageenan, cellulose and its derivatives, agar, etc. These materials Generally, the mechanical strength is low and the mass transfer is poor, which affects the supply of nutrients and the export of products; in addition, Nisin itself is a polypeptide with a molecular weight of 3510, so the diffusion in the gel may be greatly affected. It causes a higher concentration of Nisin to accumulate in the gel, thereby inhibiting the growth of lactic acid bacteria cells in the gel and continuing to synthesize Nisin, reducing the pH of the immobilized cell fermentation broth and reducing the Nisin titer, making the production mode of immobilized cells close to the level of free cell fermentation ; and the immobilized cell forming operation is cumbersome, easy to be contaminated with bacteria in the process, and continuous industrial production cannot be realized