Method for producing L-lactic acid by simultaneous saccharification and fermentation

A simultaneous saccharification and fermentation, lactic acid technology, applied in the direction of microorganism-based methods, biochemical equipment and methods, fermentation, etc., can solve the problems of low fermentation temperature of strains, increased dosage of feedback inhibition enzymes, increased production costs, etc., to reduce fermentation cost, reduction in the amount of enzyme used, and low cost of raw materials

Active Publication Date: 2021-04-30
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this process, fermentation and enzymatic hydrolysis cannot be carried out simultaneously, and the fermentation temperature is 32°C-34°C, which is relatively low and prone to bacterial contamination, and cannot solve the problem of feedback inhibition of enzymatic hydrolysis products
[0009] Therefore, in the existing L-lactic acid fermentation technology, there are problems such as low strain fermentation temperature, low synchronous saccharification and fermentation efficiency, and feedback inhibition of enzymatic hydrolysis products resulting in increased enzyme dosage, resulting in increased production costs.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) Take 1 kg of corn stalks, crush them into particles of about 5 mm, add 5 kg of NaOH solution with a mass concentration of 1%, treat at 105°C for 10 minutes, and separate solid and liquid by pressure filtration to obtain corn stalk residue I and liquid II .

[0034] (2) Preparation of Enterococcus faecalis fermented seed liquid: Add 15 mL of MRS medium to the test tube, inoculate the Enterococcus faecalis in the glycerol storage tube into the test tube medium, and culture at 45°C for 20 hours to obtain the first-grade seed liquid; Add 135mL of MRS medium into a 250mL shake flask, insert 15mL of primary seed liquid, and culture at 45°C for 8 hours to obtain secondary seed liquid.

[0035] (3) Add 1.5L sugar-free MRS medium to a 2.5L fermenter, add corn stalk residue I, make the cellulose concentration in the fermentation broth 70g / L, add cellulase (Celluclast 1.5L, purchased from Sigma Company), and 150mL of the secondary seed solution was added at the same time, at ...

Embodiment 2

[0038] (1) Take 2 kg of corn stalks, crush them into particles of about 4 mm, add 10 kg of NaOH solution with a mass concentration of 2%, treat at 105°C for 10 minutes, and separate the solid and liquid by pressure filtration to obtain corn stalk residue I and liquid II .

[0039] (2) Preparation of Enterococcus faecalis fermented seed liquid: add 35mL MRS medium to the test tube, inoculate the Enterococcus faecalis in the glycerin storage tube into the test tube medium, and culture at 50°C for 20 hours to obtain the first-grade seed liquid; Add 315mL of MRS medium into a 500mL shake flask, add 35mL of primary seed liquid, and culture at 50°C for 8 hours to obtain secondary seed liquid.

[0040] (3) Add 3.5L sugar-free MRS medium to a 5L fermenter, add corn stalk residue I, make the cellulose concentration in the fermentation liquid 170g / L, add cellulase (Celluclast 1.5 L, purchased from Sigma Company), while adding 350mL of secondary seed liquid, at a temperature of 50°C, wi...

Embodiment 3

[0043] (1) Take 1.5 kg of corn stalks, crush them into particles of about 2 mm, add 10 kg of NaOH solution with a mass concentration of 2%, treat at 105°C for 10 minutes, and separate solid and liquid by pressure filtration to obtain corn stalk residue I and liquid II.

[0044] (2) Preparation of Enterococcus faecalis fermented seed liquid: add 35mL MRS medium to the test tube, inoculate the Enterococcus faecalis in the glycerin storage tube into the test tube medium, and culture at 50°C for 20 hours to obtain the first-grade seed liquid; Add 315mL of MRS medium into a 500mL shake flask, add 35mL of primary seed liquid, and culture at 50°C for 8 hours to obtain secondary seed liquid.

[0045] (3) Add 3.5L sugar-free MRS medium into a 5L fermenter, add corn stalk residue I, make the cellulose concentration in the medium 120g / L, add cellulase (Celluclast 1.5 L, purchased from Sigma Company), and 350 mL of secondary seed solution was added at the same time, and the temperature w...

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Abstract

The invention relates to a method for producing L-lactic acid by simultaneous saccharification and fermentation, which comprises the following steps: by using lignocellulose as a raw material, carrying out simultaneous saccharification and fermentation in the presence of an enterococcus faecalis DLY-FLYC seed solution and cellulase under enzymolysis conditions. The newly separated and screened enterococcus faecalis DLY-LFYC can be used for synchronous saccharification and fermentation at a high temperature, the concentration and optical purity of the L-lactic acid produced by fermentation are high, particularly, cellobiose can be used as a strain, the feedback inhibition effect is small, and the lactic acid fermentation effect is improved.

Description

technical field [0001] The invention belongs to the field of biochemical industry, and in particular relates to a method for producing L-lactic acid by synchronous saccharification and fermentation. Background technique [0002] Lactic acid is one of the three major organic acids recognized in the world. It has optical isomers and is divided into D-lactic acid, L-lactic acid and DL-lactic acid. Among them, L-lactic acid is L-lactic acid, which is the only one that can be decomposed and utilized by the human body. Lactic acid type. L-lactic acid is widely used in food, medicine, agriculture, cosmetics and many other fields, especially L-lactic acid with high optical purity, because it can be used as the precursor of biodegradable material L-polylactic acid, the market demand is huge. It is estimated that the demand for food-grade L-lactic acid is growing at a rate of 5%-8% per year, far exceeding the current supply capacity. [0003] Currently, most of the production of lac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P7/56C12N1/20C12R1/01
CPCC12P7/56C12P2201/00C12P2203/00Y02E50/10
Inventor 樊亚超张霖师文静
Owner CHINA PETROLEUM & CHEM CORP
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