Method and system for producing lactic acid with high yield and high gloss pure lactide by using biological fermentation technology

A bio-fermentation and lactide technology, applied in the fields of fermentation biology and biodegradable materials, can solve the problems of many by-products, low reaction efficiency, low yield, etc., reduce the requirement of vacuum degree, ensure continuous production, The effect of improving the overall yield

Active Publication Date: 2020-09-08
COFCO NUTRITION & HEALTH RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the problems of low light purity and low yield of lactide prepared by the lactide production process in the prior art, and to provide a method for producing lactic acid with high yield and high light pure lactide by using biological fermentation technology. The method and system of ester, using the method and system of the present invention, can obtain high light pure lactide, and the yield is high
[0004] The inventors of the present invention have found that the reason why the yield and optical purity of lactide cannot be effectively improved in the prior art is that 1) in the prior art, lactic acid oligomers are usually obtained by one-step polycondensation, but the polymerization cannot be effectively obtained by one-step polycondensation lactic acid oligomers with a degree of 5-10, resulting in low efficiency of subsequent reactions and more by-products; 2) in the existing process, in order to obtain good reactivity, it is usually necessary to effectively dehydrate lactic acid (including the lactic acid carried by itself) water and the water generated by the polycondensation reaction), and the lactide product generated by the depolymerization reaction is evaporated in time, and in order to obtain a good effect of water and lactide evaporation, it is generally achieved by increasing the system temperature and reducing the system pressure However, many side reactions will occur under high temperature and low pressure, such as carbonization and oxidation of lactic acid oligomers, racemization and even decomposition of lactide, resulting in low lactide yield and optical purity

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  • Method and system for producing lactic acid with high yield and high gloss pure lactide by using biological fermentation technology
  • Method and system for producing lactic acid with high yield and high gloss pure lactide by using biological fermentation technology
  • Method and system for producing lactic acid with high yield and high gloss pure lactide by using biological fermentation technology

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preparation example Construction

[0066] In the present invention, preferably, the preparation method of the seed liquid comprises: picking a single colony of the Lactobacillus rhamnosus and inoculating it into a seed medium for seed culture to obtain the seed liquid.

[0067] In the present invention, in order to improve the yield of lactic acid, preferably, the inoculation amount of the seed liquid is 5-10 parts by volume relative to 100 parts by volume of the acidogenic fermentation medium.

[0068] In the present invention, the lactic acid in the obtained fermentation broth can be separated by a known method, for example, the cells in the fermentation broth are first removed, and then the fermentation broth after removing the cells is concentrated to crystallize the product, or an ion exchange layer is performed. Lactic acid is separated by methods such as analysis and the like.

[0069] In the present invention, lactic acid in the fermentation broth or lactic acid separated from the fermentation broth can...

Embodiment approach

[0082] According to a preferred embodiment of the present invention, the lactic acid is obtained by subjecting a lactic acid raw material with a water content of less than 10 wt % to a primary concentration in a primary concentration tower. Wherein, the first-level concentration tower includes a first-level atomization and rectification section, and the first-level atomization and rectification section is an empty barrel (a section of an empty barrel without packing or trays), and the first-level concentration Methods include:

[0083] (i) heating lactic acid feedstock with a water content of less than 10% by weight to 90-120°C, preferably 105-120°C;

[0084] (ii) introducing the heated lactic acid raw material in the form of mist droplets into the first-stage atomization and rectification section for flash evaporation, to obtain the first dehydrated lactic acid mist droplets and flash steam, wherein the flash steam contains water vapour and lactic acid vapour;

[0085] (iii)...

preparation example

[0172] A single colony of Lactobacillus rhamnosus strain CGMCC No. 19057 was picked and inoculated into MRS liquid medium, and cultured at 37°C and 150 rpm overnight to obtain OD 600 Seed solution for 12. Then, the above-mentioned seed solution was inoculated in the acidogenic fermentation medium at a ratio of 10% (v / v), and the strain was grown at 37 °C and 150 rpm for 6 hours, then the temperature was raised to 48 °C, and the culture was continued at 150 rpm for 42 hours. hours to obtain fermentation broth (total fermentation time 48 hours). First, the cells in the fermentation broth are removed, and then the lactic acid is separated and concentrated to obtain lactic acid with a water content of less than 10% by weight, and the optical purity of L-lactic acid is more than 95%.

[0173] (2) The system for producing lactide of the present invention, the system comprises:

[0174] A. Lactic acid concentration unit, described lactic acid concentration unit includes:

[0175] ...

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Abstract

The invention relates to the fields of fermentation biology and biodegradable materials, and in particular relates to a method and a system for preparing lactic acid by using a biological fermentationtechnology to produce high-yield and high-optical purity lactide. The method comprises the following steps: 1, inoculating lactic acid zymophyte (lactobacillus rhamnosus with the preservation numberof CGMCC No.19507) into a fermentation culture medium for lactic acid fermentation to obtain a lactic acid fermentation liquid, separating the lactic acid fermentation liquid to obtain an L-lactic acid raw material, and carrying out a pre-polycondensation reaction on lactic acid under a first polymerization condition to obtain a lactic acid prepolymer with a polymerization degree of less than 5 and a gas phase containing lactic acid; under a second polymerization condition, carrying out condensation polymerization on the lactic acid prepolymer in a falling-film reactor to obtain a lactic acidoligomer with a polymerization degree of 10 or below; and depolymerizing the lactic acid oligomer under the action of a catalyst to obtain a lactide-containing product. By utilizing the method and thesystem provided by the invention, the high-optical purity lactide can be obtained, and the yield is high.

Description

technical field [0001] The present invention relates to the field of fermentation biology and biodegradable materials, in particular to a method and system for producing lactide with high yield and high optical purity by utilizing biological fermentation technology to prepare lactic acid. Background technique [0002] In the context of global plastic restriction, new biodegradable polylactic acid materials have attracted more and more attention, and the annual consumption is increasing. Statistics from the European Bioplastics Association show that the production capacity of degradable materials is increasing at a rate of nearly 20% every year, but its demand is increasing at a rate of 30%, and the product has been in short supply for a long time. The synthesis of bio-based polylactic acid generally uses high DE value glucose as raw material, and generates high-purity lactic acid through biological fermentation. After dehydration and concentration, condensation recovery, pol...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12P7/56C07D319/12C12R1/225
CPCC07D319/12C12P7/56
Inventor 崔兆宁佟毅李义许克家杨凯周卫强
Owner COFCO NUTRITION & HEALTH RES INST
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