Lactobacillus casei and application of lactobacillus casei in ferment production of L-lactic acid

Abstract

The invention relates to lactobacillus casei for producing L-lactic acid and application thereof. A strain is lactobacillus casei FY-04 and was collected in China General Microbiological Culture Collection Center (CGMCC) on September 11th, 2009, and the collection number is CGMCC No.3269. The strain is negative in Gram staining, and is facultative and aerobic. When the strain is used for fermenting starch for producing the L-lactic acid, air is introduced in the process of fermentation, a trace amount of oxygen can promote thalli to proliferate, and by introducing oxygen, carbon dioxide can be carried out of a fermentation system, which ensures that the pH value in the fermentation system is stable and the fermentation system is favorable for the growth of the strain. Compared with the anaerobic strain fermentation process, the fermentation process has stable pH value and high acid producing efficiency.

Description

technical field [0001] The invention belongs to the technical field of organic acid fermentation, and in particular relates to a method for producing Lactobacillus casei and L-lactic acid or a salt thereof. Background technique [0002] Lactic acid, also known as a-hydroxypropionic acid (a-hydrxy-propioric acid), molecular formula: C 2 h 5 OCOOH, with a relative molecular weight of 90.08, is a simple hydroxy acid. There is an asymmetric carbon atom in the molecule, which is optically active, so there are two optical isomers of L-lactic acid and D-lactic acid. L-lactic acid is right-handed, D-lactic acid is left-handed, and DL-lactic acid is racemic. The physical and chemical properties are basically the same except for optical rotation. [0003] Lactic acid is one of the important multipurpose organic acids, which widely exists in the human body, animals, plants and microorganisms. L-lactic acid and its salts are widely used in food, medicine, agriculture, chemical indus...

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Problems solved by technology

[0006] Purac Biochemical Company proposed in CN03814886.2 to use Bacillus coagulans, Bacillus amylophagosus, Bacillus schtzeri, Geobacillus stearothermophilus or their mixtures, and use starch to simultaneously saccharify and ferment under optimal pH conditions of 5.50 to 5.60 to produce Lactic acid or its salts, the enantiomeric purity of the obtained product is greater than 99%, and the residual sugar is less than 2g / L. At the same time, it is believed that lactic acid bacteria such as Lactobacillus affect the enantiomeric purity of lactic acid at their growth temperature of 30-50 ° C, which is not suitable for the lactic acid industry. production, and the growth temperature range of these microorganisms is not suitable for simultaneous saccharification and fermentation

[0007] Shanghai Xinli Industrial Microbiology Technology Co., Ltd. proposed in CN02145142.7 a method for producing L-lactic acid by parallel anaerobic fermentation of Lactobacillus thermophiles, performing anaerobic fermentation at a pH of 5.0 to 6.5 and a temperature of 45 to 55°C, adding inorganic and organic nitrogen sources provide nutrients to the strains, increasing the cost of fermentation, and the addition of these nitrogen sources makes the product extraction process more complicated

[0008] Jilin University proposes in CN200510119041.3 the method for anaerobic production of L-lactic acid with Lactobacillus casei. The raw materials used are monosaccharides such as glucose or lactose, and the nitrogen source is inorganic and organic nitrogen. It is well known that the price of glucose or lactose is much higher than that of starch-containing substances, will inevitably increase the cost of fermentation and extraction

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