CN117142683A

CN117142683A - Method for removing organic acid in amino acid fermentation liquor

Info

Publication number: CN117142683A
Application number: CN202310966798.4A
Authority: CN
Inventors: 田禾旺; 刘磊
Original assignee: Hefei Huaheng Biological Engineering Co ltd; Qinhuangdao Huaheng Bioengineering Co ltd; Anhui Huaheng Biotechnology Co Ltd
Current assignee: Hefei Huaheng Biological Engineering Co ltd; Qinhuangdao Huaheng Bioengineering Co ltd; Anhui Huaheng Biotechnology Co Ltd
Priority date: 2023-08-02
Filing date: 2023-08-02
Publication date: 2023-12-01

Abstract

The application relates to the technical field of amino acid production by a fermentation method, and discloses a method for removing organic acid in amino acid fermentation liquid, which comprises the following steps: (1) Adjusting the pH value of the amino acid fermentation liquor to be acidic to obtain an acidified amino acid fermentation liquor; (2) Extracting the acidified amino acid fermentation broth with a complex extractant; the composite extractant contains trioctyl phosphate, dodecane and trialkylphosphine oxide. The method for treating the amino acid fermentation liquor has good effect, the removal rate of formic acid, acetic acid and lactic acid is up to 90% or more, and the retention rate of amino acid is up to 99.5% or more.

Description

Method for removing organic acid in amino acid fermentation liquor

Technical Field

The application relates to the technical field of amino acid production by a fermentation method, in particular to a method for removing organic acid in amino acid fermentation liquor.

Background

Amino acids are widely used in industrial production, mainly in animal feed additives, human food condiments, cosmetics and medical products. Amino acids are constituent modules of proteins in organisms, and play a role in regulating metabolic pathways and metabolic modes of organisms, and are important components of living bodies. Currently, the production of amino acids in industry is mostly achieved by fermentation, in which sugars present in the substrate are converted into amino acids under aerobic or anaerobic conditions by means of one or several microorganisms, but by-products such as organic acids and heteroamino acids are produced during the fermentation conversion.

The byproducts such as organic acid generated in the process of producing amino acid by a fermentation method exist in a fermentation broth in the form of organic acid salt, and at present, an ion exchange method is generally adopted at home and abroad to remove impurities in the fermentation broth. Removing thalli from fermentation liquor, adjusting pH, performing ion exchange, adsorbing and saturating, eluting amino acid by ammonia water, and obtaining amino acid crystals by adopting a recrystallization mode. However, the conventional membrane filtration and decoloration treatment processes have poor removal effect on organic acid, in the subsequent evaporation process, the concentration of organic acid salt increases exponentially with the increase of evaporation concentration, wherein the high-boiling organic acid, such as lactic acid, increases the viscosity of materials, reduces the heat exchange efficiency, leads to the reduction of evaporation rate, and the low-boiling organic acid, such as formic acid and acetic acid, evaporates into water vapor, thereby corroding evaporation equipment and affecting the quality of condensed water, and meanwhile, the organic acid salt increases the solubility of amino acid in a solvent, leads to the increase of residual amino acid in a mother liquor, reduces the evaporation yield, and organic acid impurities in fermentation liquor also increase the amount of washing water, and affects the shape and color of products.

Thus, there is a need for a method for the rapid and efficient removal of organic acids from amino acid fermentation broths.

Disclosure of Invention

The application aims to solve the problem of low organic acid removal efficiency in amino acid fermentation liquid in the prior art, and provides a method for removing organic acid in amino acid fermentation liquid, which can efficiently remove most of organic acid byproducts generated in the fermentation process, so that the influence of the organic acid byproducts on a subsequent evaporation process is reduced.

In order to achieve the above object, the present application provides a method for removing organic acids from an amino acid fermentation broth, comprising the steps of:

(1) Adjusting the pH value of the amino acid fermentation liquor to be acidic to obtain an acidified amino acid fermentation liquor;

(2) Extracting the acidified amino acid fermentation broth with a complex extractant;

the composite extractant contains trioctyl phosphate, dodecane and trialkylphosphine oxide.

Preferably, in the step (1), the pH of the amino acid fermentation broth is adjusted to 2 to 4.

Preferably, the pH of the amino acid broth is adjusted using a mineral acid; the inorganic acid is selected from sulfuric acid, nitric acid or phosphoric acid.

Preferably, in step (1), the acidified amino acid broth contains formic acid, acetic acid and lactic acid.

Preferably, in the step (2), the volume ratio of the trioctyl phosphate, the dodecane and the trialkylphosphine oxide in the composite extractant is 2.5-7: 2 to 4:10.

preferably, in the step (2), the volume ratio of the usage amount of the acidified amino acid fermentation broth to the usage amount of the compound extractant is 1:1 to 2.5.

Preferably, in the step (2), the extraction is multistage extraction, and the stage number is 5-6.

Preferably, the multistage extraction is performed using a centrifugal extractor.

Preferably, the amino acid broth is selected from the group consisting of an L-alanine broth, a valine broth, an isoleucine broth, an arginine broth, and an ornithine broth.

Preferably, the method further comprises: separating and removing thalli from the amino acid fermentation liquor and performing ultrafiltration treatment.

Preferably, the method for separating and removing the bacterial cells is ceramic membrane filtration.

Preferably, the pore diameter of the ceramic membrane is 10-200 nm.

Preferably, the ultrafiltration treatment mode is ultrafiltration membrane filtration, wherein the molecular weight cut-off of the ultrafiltration membrane is 1000-2000D.

Preferably, the filtration pressure of the ultrafiltration membrane filtration is 0.8-1 Mpa.

Compared with the prior art, the technical scheme of the application has the following advantages:

(1) By adopting the method to treat the amino acid fermentation liquor, the byproducts such as formic acid, acetic acid, lactic acid and the like in the amino acid fermentation liquor can be removed, the removal rate is up to 90% or more, and the retention rate of amino acid in the product is up to 99.5% or more. Based on the method, the risk of corroding evaporation equipment in the subsequent evaporation process of the amino acid fermentation broth is reduced, and the evaporation efficiency is improved.

(2) The method for removing the organic acid in the amino acid fermentation broth has the advantages of simple and convenient operation, simple steps, no need of using large-scale expensive equipment, and environment friendliness, and simultaneously greatly reduces the consumption of washing water.

(3) The method has excellent removal effect on low-concentration organic acid in the amino acid fermentation broth, and meanwhile, can obtain products with good morphology and color.

Drawings

FIG. 1 is a flow chart of a method of treating an amino acid broth according to one particular embodiment of the application.

Detailed Description

The following describes specific embodiments of the present application in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the application, are not intended to limit the application.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

In the description of the present application, "multistage" means two or more stages. The terms "comprises," "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that one or more other features, integers, steps, operations, elements, components, and/or groups thereof may be present or added.

The application provides a method for removing organic acid in amino acid fermentation liquor, which comprises the following steps:

In the method, the composite extractant containing trioctyl phosphate, dodecane and trialkylphosphine oxide is used for extracting the acidified amino acid fermentation broth, so that low-concentration organic acids (such as formic acid, acetic acid and lactic acid) in the acidified amino acid fermentation broth can be effectively extracted, and the adverse effect caused by the existence of the organic acids in the subsequent evaporation stage is further reduced.

In the method, the pH of the amino acid fermentation liquor is regulated to be acidic, so that the organic acid salt can be completely converted into organic acid molecules, and the removal of the organic acid is facilitated.

In a preferred embodiment, in step (1), the pH of the amino acid fermentation broth is adjusted to 2 to 4.

In a preferred embodiment, the pH of the amino acid broth is adjusted using a mineral acid selected from sulfuric acid, nitric acid or phosphoric acid.

In a preferred embodiment, the mineral acid is provided in the form of an aqueous mineral acid solution, which may be added dropwise.

In order to further increase the removal rate of the organic acid, in a preferred embodiment, in step (1), the pH of the amino acid fermentation broth is adjusted to 2 to 4; in particular, the pH may be 2, 2.1, 2.5, 2.8, 3, 3.5 or 4.

In a preferred embodiment, in step (1), the acidified amino acid broth contains formic acid, acetic acid and lactic acid.

In a further preferred embodiment, in step (1), the concentration of formic acid in the acidified amino acid broth is from 0.5 to 5g/L, the concentration of acetic acid is from 1 to 10g/L, and the concentration of lactic acid is from 0.5 to 5g/L.

In order to further improve the extraction effect of the composite extractant, the composite extractant also has a good removal effect on the amino acid fermentation broth with lower organic acid concentration, and in the preferred embodiment, in the step (2), the volume ratio of the trioctyl phosphate, the dodecane and the trialkylphosphine oxide in the composite extractant is 2.5-7: 2 to 4:10; specifically, the volume ratio of the three can be 2.5:2: 10. 3:2: 10. 4:2: 10. 5:2: 10. 6:2: 10. 7:2: 10. 3:2.5: 10. 2.5:3: 10. 3:3: 10. 4:3: 10. 5:3: 10. 6:3: 10. 7:3: 10. 6:3.5: 10. 2.5:4: 10. 3:4: 10. 4:4: 10. 5:4: 10. 6:4:10 or 7:4:10.

in a specific embodiment, in the step (2), the compound extractant is formed by mixing trioctyl phosphate, dodecane and trialkylphosphine oxide.

In order to improve the removal rate of the organic acid, in a preferred embodiment, in the step (2), the volume ratio of the usage amount of the acidified amino acid fermentation broth to the usage amount of the complex extractant is 1:1 to 2.5; specifically, the volume ratio of the two dosages can be 1:1. 1:1.5, 1:2 or 1:2.5.

in the preferred case, in the step (2), the extraction is a multistage extraction with a stage number of 5 to 6; specifically, the number of stages may be 5 stages or 6 stages.

In a specific embodiment, the multistage extraction is performed using a centrifugal extractor.

In a preferred embodiment, the amino acid broth is selected from the group consisting of L-alanine broth, valine broth, isoleucine broth, arginine broth, or ornithine broth.

In order to further increase the removal efficiency of the organic acid, the method preferably further comprises: separating and removing thalli from the amino acid fermentation liquor and performing ultrafiltration treatment.

Further preferably, the inactivated amino acid fermentation broth is subjected to separation to remove bacterial cells and ultrafiltration before the pH of the amino acid fermentation broth is adjusted to be acidic.

In a preferred embodiment, the inactivation treatment is a high temperature inactivation treatment, the conditions of the inactivation treatment comprising: the temperature is 85-90 ℃ and the time is 20-30 min; specifically, the temperature may be 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃ or 90 ℃; the time may be 20min, 22min, 24min, 26min, 28min or 30min.

In a preferred embodiment, the means for separating and removing the cells is ceramic membrane filtration.

Preferably, the pore diameter of the ceramic membrane is 10-200 nm; in particular, the pore size of the ceramic membrane may be 10nm, 15nm, 20nm, 30nm, 50nm, 80nm, 100nm, 120nm, 150nm, 180nm or 200nm.

Further preferably, the pressure of the ceramic membrane filtration is 0.3-0.4 Mpa; specifically, the pressure of filtration may be 0.3Mpa, 0.32Mpa, 0.34Mpa, 0.36Mpa, 0.38Mpa or 0.4Mpa.

Preferably, the ultrafiltration treatment mode is ultrafiltration membrane filtration, wherein the molecular weight cut-off of the ultrafiltration membrane is 1000-2000D; in particular, the ultrafiltration membrane may have a molecular weight cut-off of 1000D, 1500D or 2000D.

Further preferably, the pressure of the ultrafiltration membrane during filtration is 0.8-1 Mpa; specifically, the pressure of filtration may be 0.8Mpa, 0.85Mpa, 0.9Mpa, 0.95Mpa or 1Mpa.

In the present application, "filtered pressure" means inlet pressure at the time of filtration, expressed as relative pressure.

According to some embodiments of the application, the method according to the application comprises in particular the following steps:

(1) Inactivating the amino acid fermentation liquor, filtering by a ceramic membrane and an ultrafiltration membrane to obtain filtrate, and regulating the pH value of the filtrate to 2-4 by using inorganic acid to obtain acidified amino acid fermentation liquor;

Referring to fig. 1 in combination, the method of the present application further includes: and (3) back-extracting the acid-containing organic phase obtained by extraction in the step (2) by using water to obtain an acid-containing aqueous phase and an organic phase. The obtained organic phase can be used as a composite extractant for repeated use, so that the cost can be saved and the pollution can be reduced.

Further preferably, the method of the present application further comprises: the pH value of the acid-containing aqueous phase is adjusted to 7.5-8.5, and then the acid-containing aqueous phase is treated by a Reverse Osmosis (RO) membrane. The water obtained by reverse osmosis membrane treatment can be reused as a stripping agent.

In a specific embodiment, the pH of the acid-containing aqueous phase may be adjusted to a pH of 7.5 to 8.5 using a caustic soda flake.

In a preferred embodiment, referring to FIG. 1 in combination, the method for removing organic acids from an amino acid broth comprises:

(2) Extracting the acidified amino acid fermentation broth by using a composite extractant to obtain an amino acid aqueous phase and an acid-containing organic phase; wherein the composite extractant contains trioctyl phosphate, dodecane and trialkylphosphine oxide;

(3) Back extracting the acid-containing organic phase by using water to obtain an acid-containing aqueous phase and an organic phase;

(4) And regulating the pH value of the acid-containing water phase to 7.5-8.5, and then treating by a reverse osmosis membrane.

A method for removing organic acids from an amino acid broth according to the present application is further described by way of example. The embodiment is implemented on the premise of the technical scheme of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiment.

The experimental methods in the following examples and comparative examples, unless otherwise specified, are conventional in the art. The L-alanine fermentation broth used in the following examples and comparative examples was obtained from Hua Heng Biotech Co., ltd. And other experimental materials, unless otherwise specified, were commercially available.

Example 1

(1) Taking 25L of L-alanine fermentation liquor, carrying out high-temperature inactivation treatment on the L-alanine fermentation liquor at the temperature of 85 ℃ for 30min, filtering the L-alanine fermentation liquor after the high-temperature inactivation treatment by a ceramic membrane, wherein the pore diameter of the ceramic membrane is 50nm, the inlet pressure during filtration is 0.3Mpa, and then filtering the L-alanine fermentation liquor by an ultrafiltration membrane, the molecular weight cut-off of the ultrafiltration membrane is 1000D, and the inlet pressure during filtration is 1Mpa, thus obtaining filtrate B1; dropwise adding sulfuric acid aqueous solution into the filtrate B1, and regulating the pH value of the filtrate B1 to 2.5 to obtain acidified L-alanine fermentation broth C1 (with the amino acid content of 127.1g/L, the formic acid content of 1.178g/L, the acetic acid content of 1.569g/L and the lactic acid content of 0.883 g/L);

(2) Extracting the acidified L-alanine fermentation broth C1 by using a composite extractant, and introducing the acidified L-alanine fermentation broth C1 and the composite extractant into a 5-stage centrifugal extractor for treatment, wherein the composite extractant is formed by mixing trioctyl phosphate, dodecane and trialkylphosphine oxide, and the volume ratio of the three is 3:2.5:10, the volume ratio of the dosage of the acidified L-alanine fermentation broth C1 to the dosage of the compound extractant is 1:2.

example 2

(1) Taking 25L of L-alanine fermentation liquor, carrying out high-temperature inactivation treatment on the L-alanine fermentation liquor at the temperature of 85 ℃ for 30min, filtering the L-alanine fermentation liquor after the high-temperature inactivation treatment by a ceramic membrane, wherein the pore diameter of the ceramic membrane is 50nm, the inlet pressure during filtration is 0.36Mpa, and then filtering the L-alanine fermentation liquor by an ultrafiltration membrane, the molecular weight cut-off of the ultrafiltration membrane is 2000D, and the inlet pressure during filtration is 1Mpa, thus obtaining filtrate B2; dropwise adding sulfuric acid aqueous solution into the filtrate B2, and regulating the pH value of the filtrate B2 to 2.8 to obtain acidified L-alanine fermentation broth C2 (the amino acid concentration is 125.7g/L, the formic acid concentration is 1.164g/L, the acetic acid concentration is 2.037g/L, and the lactic acid concentration is 1.021 g/L);

(2) Extracting the acidified L-alanine fermentation broth C2 by using a composite extractant, and introducing the acidified L-alanine fermentation broth C2 and the composite extractant into a 5-stage centrifugal extractor for treatment, wherein the composite extractant is formed by mixing trioctyl phosphate, dodecane and trialkylphosphine oxide, and the volume ratio of the three is 5:3:10, the volume ratio of the dosage of the acidified L-alanine fermentation broth C2 to the dosage of the compound extractant is 1:2.

example 3

(1) Taking 25L of L-alanine fermentation liquor, carrying out high-temperature inactivation treatment on the L-alanine fermentation liquor at the temperature of 85 ℃ for 30min, filtering the L-alanine fermentation liquor after the high-temperature inactivation treatment by a ceramic membrane, wherein the pore diameter of the ceramic membrane is 50nm, the inlet pressure during filtration is 0.4Mpa, and then filtering the L-alanine fermentation liquor by an ultrafiltration membrane, the molecular weight cut-off of the ultrafiltration membrane is 1000D, and the inlet pressure during filtration is 1Mpa, thus obtaining filtrate B3; dropwise adding sulfuric acid aqueous solution into the filtrate B3, and regulating the pH value of the filtrate B3 to 2.1 to obtain acidified L-alanine fermentation broth C3 (the amino acid concentration is 123.2g/L, the formic acid concentration is 1.078g/L, the acetic acid concentration is 1.443g/L, and the lactic acid concentration is 0.951 g/L);

(2) Extracting the acidified L-alanine fermentation broth C3 by using a composite extractant, and introducing the acidified L-alanine fermentation broth C3 and the composite extractant into a 5-stage centrifugal extractor for treatment, wherein the composite extractant is formed by mixing trioctyl phosphate, dodecane and trialkylphosphine oxide, and the volume ratio of the three is 6:3.5:10, the volume ratio of the dosage of the acidified L-alanine fermentation broth C3 to the dosage of the compound extractant is 1:2.

comparative example 1

The procedure of example 1 was followed, except that the complex extractant was mixed with trioctyl phosphate and dodecane in a volume ratio of 3:2.5.

comparative example 2

The procedure of example 1 was followed, except that the complex extractant was mixed with dodecane and trialkylphosphine oxide in a volume ratio of 2.5:10.

comparative example 3

The procedure of example 1 was followed, except that the complex extractant was mixed with trioctyl phosphate and trialkylphosphine oxide in a volume ratio of 3:10.

test case

1. Detecting the extracted amino acid aqueous phases of the examples 1-3 and the comparative examples 1-3 by adopting a high performance liquid chromatography, wherein the detection indexes are the concentrations of organic acid (formic acid, acetic acid and lactic acid) and amino acid, the mobile phase of the amino acid detection high performance liquid chromatography is a copper sulfate aqueous solution with the concentration of 0.4998g/L, the mobile phase of the organic acid detection high performance liquid chromatography is an aqueous solution added with 0.15 wt%sulfuric acid, and the organic acid detection high performance liquid chromatography is recorded by adopting a differential detector, wherein the formic acid peak-off time is about 17min, the acetic acid peak-off time is about 19min, the lactic acid peak-off time is about 15min, and the amino acid peak-off time is about 7 min; the test results are shown in Table 1.

2. The calculation formula of the organic acid removal rate is as follows: [ (concentration of organic acid in amino acid broth before extraction-concentration of organic acid in amino acid broth after extraction)/concentration of organic acid in amino acid broth before extraction ] ×100%;

the amino acid retention was calculated as: (concentration of amino acid in amino acid broth after extraction/concentration of amino acid in amino acid broth before extraction) ×100%; the calculation results are shown in Table 2.

TABLE 1

Numbering device	Formic acid concentration (g/L)	Acetic acid concentration (g/L)	Lactic acid concentration (g/L)	Amino acid concentration (g/L)
					Example 1	0.1084	0.1381	0.071	126.6
Example 2	0.1152	0.1956	0.0888	125.2
					Example 3	0.0916	0.1126	0.0685	122.8
Comparative example 1	0.172	0.2699	0.2633	126.5
					Comparative example 2	0.245	0.306	0.11	126.6
Comparative example 3	0.4394	0.4895	0.1024	126.6

TABLE 2

Numbering device	Formic acid removal Rate (%)	Acetic acid removal rate (%)	Lactic acid removal Rate (%)	Amino acid retention (%)
					Example 1	90.8	91.2	92	99.6
Example 2	90.1	90.4	91.3	99.6
					Example 3	91.5	92.2	92.8	99.7
Comparative example 1	85.4	82.8	70.3	99.5
					Comparative example 2	79.2	80.5	87.1	99.6
Comparative example 3	62.7	68.8	88.4	99.6

As can be seen from the data in tables 1 and 2, the method for treating the amino acid fermentation broth has good effect, the removal rate of formic acid, acetic acid and lactic acid is up to 90% or more, and the retention rate of amino acid is up to 99.5% or more.

The preferred embodiments of the present application have been described in detail above, but the present application is not limited thereto. Within the scope of the technical idea of the application, a number of simple variants of the technical solution of the application are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the application, all falling within the scope of protection of the application.

Claims

1. A method for removing organic acids from an amino acid broth, comprising the steps of:

2. The method according to claim 1, wherein in step (1), the pH of the amino acid broth is adjusted to 2 to 4;

3. The method according to claim 1 or 2, wherein in step (1) the acidified amino acid broth comprises formic acid, acetic acid and lactic acid.

4. The method according to claim 1, wherein in the step (2), the compound extractant comprises trioctyl phosphate, dodecane and trialkylphosphine oxide in an amount of 2.5 to 7 by volume: 2 to 4:10.

5. the method of claim 1, wherein in step (2), the acidified amino acid broth and the complex extractant are used in a volume ratio of 1:1 to 2.5.

6. The method according to claim 1, wherein in the step (2), the extraction is a multistage extraction with a stage number of 5 to 6;

7. The method according to any one of claims 1-6, wherein the amino acid broth is selected from the group consisting of L-alanine broth, valine broth, isoleucine broth, arginine broth, and ornithine broth.

8. The method according to any one of claims 1-7, further comprising: separating and removing thalli from the amino acid fermentation liquor and performing ultrafiltration treatment.

9. The method according to claim 8, wherein the means for separating and removing the cells is ceramic membrane filtration;

preferably, the pore diameter of the ceramic membrane is 10-200 nm.

10. The method according to claim 8, wherein the ultrafiltration treatment is performed by ultrafiltration membrane filtration, wherein the ultrafiltration membrane has a molecular weight cut-off of 1000 to 2000D;