Production method of lactic acid and polylactic acid

A manufacturing method, a technology for polylactic acid, applied in the directions of organic chemistry methods, chemical instruments and methods, separation/purification of carboxylic acid compounds, etc., can solve the problems of undisclosed impurities, thermal stability, mechanical strength, influence of color tone, high price, Huge cost and other issues, to achieve the effects of excellent thermal stability, improved productivity, and easy operation

Inactive Publication Date: 2011-11-30
TORAY IND INC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Then, by adding an acidic substance (for example, sulfuric acid) to the culture solution after the cultivation is completed, a free lactic acid solution can be obtained, but it leads to the generation of a calcium salt by-product (for example, calcium sulfate) as an impurity
[0006] As a method of removing the generated calcium salt by-products and separating lactic acid, when calcium salts such as calcium sulfate are poorly soluble and precipitate, a method of removing them by filtration using qualitative filter paper, etc., may be used, but it may cause dissolution in the solution Trace amounts of calcium salts cannot be removed and remain in solutions containing lactic acid
Therefore, there is a problem that, for example, when the lactic acid-containing filtrate is concentrated in the subsequent refining process, calcium salts or soluble inorganic salts other than calcium salts are precipitated again in the solution containing free lactic acid ( precipitation)
In addition, the regeneration of ion exchange resins has the following problems: a large amount of sodium hydroxide aqueous solution and hydrochloric acid aqueous solution is used, and a large amount of waste liquid is discharged along with the regeneration, and huge costs are required for waste liquid treatment.
However, the bipolar membrane used in this method is not only expensive, but also has the problem that the removal efficiency of inorganic salts such as calcium salts is not necessarily high.
[0009] In addition, a method for removing inorganic salts from a solution containing lactic acid using a nanofiltration membrane is disclosed (for example, refer to Patent Documents 4 to 6), but the process of recovering lactic acid by distillation and the impact of distillation on the yield of lactic acid are not disclosed. influence, and it is not disclosed whether the obtained lactic acid can be applied to the manufacture of polylactic acid utilizing the direct polymerization method at an industrial level
[0010] In addition, although Patent Documents 7 to 10 disclose that when high-molecular-weight polylactic acid is obtained by direct dehydration polycondensation of lactic acid, specific impurities need to be kept below a specific amount, but do not disclose the effects of impurities on thermal stability, mechanical strength, and color tone. influence, they are important factors in the processability of polylactic acid

Method used

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  • Production method of lactic acid and polylactic acid
  • Production method of lactic acid and polylactic acid
  • Production method of lactic acid and polylactic acid

Examples

Experimental program
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Embodiment

[0181] Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to the following examples.

[0182] In this example, as a microorganism having an L-lactic acid fermenting ability, an Xenopus laevis-derived L-lactate dehydrogenase gene (L-LDH gene) having the base sequence shown in SEQ ID NO: 1 was used. Saccharomyces cerevisiae in Saccharomyces cerevisiae.

reference example 1

[0183] (Reference Example 1) Preparation of Yeast Strain Having L-lactic Acid Fermentation Ability

[0184] A strain obtained by breeding the B3 strain described in JP-A-2008-029329 in a culture medium was used as a yeast strain having L-lactic acid fermentation ability. The breeding method is as follows.

[0185] First, in the B3 strain, the L-LDH gene described in SEQ ID NO: 1 was introduced into the SED1 locus. The introduction into the SED1 locus is carried out as follows: using pTRS102 described in JP-A-2008-029329 as an amplification template, using PCR using oligonucleotides (SEQ ID NO: 2, 3) as a primer set, for the gene containing The PCR fragment of 1.3kb of L-LDH gene and TDH3 terminator sequence of Xenopus laevis was amplified. Here, SEQ ID NO: 2 is designed to add a sequence equivalent to 60 bp upstream from the initiation codon of the SED1 gene.

[0186] Next, using plasmid pRS423 as an amplification template, a PCR fragment of about 1.3 kb including the HIS3 ...

reference example 2

[0211] (Reference Example 2) Production of L-lactic acid by batch fermentation

[0212] Using the HI003 strain prepared in Reference Example 1, a batch fermentation test was performed using a raw material sugar medium (70 g / L saccharin (manufactured by Muso Co., Ltd.), 1.5 g / L ammonium sulfate). This medium was used after autoclaving (121°C, 15 minutes). The concentration of lactic acid as a product was evaluated using HPLC shown in Reference Example 1, and the glucose concentration was measured using Glucose test Wako C (manufactured by Wako Pure Chemical Industries, Ltd.). The operating conditions of the batch fermentation apparatus of Reference Example 2 are shown below.

[0213] Reaction tank capacity (amount of lactic acid fermentation medium): 2 (L), temperature adjustment: 32 (°C), reaction tank ventilation: 0.1 (L / min), reaction tank stirring speed: 200 (rpm), pH adjustment: use 1N calcium hydroxide to adjust to pH5.

[0214] First, the HI003 strain was cultured ove...

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Abstract

Lactic acid obtained by a method for producing lactic acid, the method comprising: (A) a step of continuous fermentation wherein a fermentation culture medium of a microorganism having an ability of lactic acid fermentation is filtered through a porous membrane having an average pore size of not less than 0.01 µm and less than 1 µm with a transmembrane pressure difference within the range of 0.1 to 20 kPa, and the permeate is collected, while retaining the non-permeated liquid in or returning the non-permeated liquid to the culture, and adding a fermentation feedstock to the culture; (B) a step of filtering the permeate obtained in Step (A) through a nanofiltration membrane; and (C) a step of distilling the permeate obtained in Step (B) under a pressure of not less than 1 Pa and not more than atmospheric pressure, at 25°C to 200°C to recover lactic acid; comprises only small amounts of impurities, and a polylactic acid obtained using the lactic acid as a raw material has excellent thermal stability, mechanical strength and hue.

Description

technical field [0001] The present invention relates to a method for producing lactic acid, a method for producing polylactic acid using lactic acid obtained by the method for producing lactic acid as a raw material, and lactic acid and polylactic acid respectively obtained by these methods, wherein the method for producing lactic acid is obtained by culturing Lactic acid produced in a fermentation broth obtained from a microorganism capable of producing lactic acid is separated to produce lactic acid. Background technique [0002] Lactic acid is widely used in industrial applications as a monomer raw material for polylactic acid (which is a biodegradable plastic) in addition to uses for food and medicine, and its demand is increasing. Lactic acid is known to be produced by fermentation using microorganisms that convert a substrate containing carbohydrates represented by glucose into lactic acid. [0003] In order to obtain lactic acid as a raw material of polylactic acid, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P7/56C07C59/08C08G63/06C08G63/08C12N15/09
CPCB01D61/027B01D71/56C08G63/06C07C51/42C12P7/56B01D2311/2688B01D71/64B01D2311/2669C07C59/08B01D2311/06B01D2311/04C07B2200/07B01D2311/18C07D319/12C08G63/08
Inventor 泽井健司泽井秀树耳塚孝伊藤正照山田胜成河村健司峰岸进一中川泉长野达也
Owner TORAY IND INC
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