L-Alanine

L-Alanine - Names and Identifiers

Name	L-Alanine
Synonyms	Ala Alanine H-Ala-OH L-Alanine L-alanine-12C3 L-Alpha-Alanine 2-Aminopropanoicacid 2-Aminopropanoic acid Tenofovir Impurity 80 2-Aminopropanoic Acid 2-Amino-Propionic Acid (S)-2-Aminopropansαure (S)-2-Aminopropionsαure L-2-Aminopropionic acid (s)-2-aminopropanoicacid Aspartic Acid Impurity 6 (S)-2-Aminopropanoic acid
CAS	56-41-7
EINECS	200-273-8
InChI	InChI=1/C3H7NO2/c1-2(4)3(5)6/h2H,4H2,1H3,(H,5,6)/t2-/m0/s1
InChIKey	QNAYBMKLOCPYGJ-REOHCLBHSA-N

L-Alanine - Physico-chemical Properties

Molecular Formula	C3H7NO2
Molar Mass	89.09
Density	1,432 g/cm3
Melting Point	314.5 °C
Boling Point	212.9±23.0 °C(Predicted)
Specific Rotation(α)	14.5 º (c=10,6N HCl,dry sub.)
Water Solubility	166.5 g/L (25 ºC)
Solubility	Soluble in water (16.5%,25°C), insoluble in ether or acetone
Appearance	Crystalline powder
Color	White to almost white
Maximum wavelength(λmax)	['λ: 260 nm Amax: ≤0.03', , 'λ: 280 nm Amax: ≤0.02']
Merck	14,204
BRN	1720248
pKa	2.34(at 25℃)
PH	5.5-6.5 (100g/l, H2O, 20℃)
Storage Condition	2-8°C
Stability	Stable. Incompatible with strong oxidizing agents.
Refractive Index	1.4650 (estimate)
MDL	MFCD00064410
Physical and Chemical Properties	Colorless to white crystalline powder, odorless. Have a sweet taste, sweetness is about 70% of sucrose. Soluble in water, ethanol-soluble, insoluble in ether. It has optical rotation. Racemic (dl-) amino propionic acid melting point 295 C (decomposition),200 C sublimation. l-(l-)-2-aminopropionic acid melting point 297 ° C (decomposition); d-(d-) body melting point 295 ° C (decomposition). Levorotatory (l-) hydrochloride is prismatic Crystal, melting point 204 ℃ (decomposition); Levorotatory (l-) N-acetyl crystal melting point 116 ℃; the N-phenyl compound has a crystalline melting point of 152-154 °c.
Use	Food and beverage used as a preservative, flavor flavoring and amino acid low-alcohol wine, medicine for the synthesis of amino acid infusion

L-Alanine - Risk and Safety

Hazard Symbols	Xi - Irritant
Risk Codes	36/37/38 - Irritating to eyes, respiratory system and skin.
Safety Description	S24/25 - Avoid contact with skin and eyes. S36 - Wear suitable protective clothing. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
WGK Germany	3
RTECS	AY2990000
FLUKA BRAND F CODES	10
TSCA	Yes
HS Code	29224995
Hazard Class	IRRITANT

L-Alanine - Nature

Open Data Verified Data

white crystalline powder, odorless, has a special sweet taste, sweetness is about 70% of sucrose. Sublimation above 200 deg C. Soluble in water (17%,25 ° C), ethanol-soluble (0.2%,80% cold alcohol). Insoluble in ether. 5% aqueous solution pH 5.5-5.7. Chemical stability.

Last Update：2024-01-02 23:10:35

L-Alanine - Preparation Method

Open Data Verified Data

mainly L-aspartic acid as raw material, by decarboxylation, enzyme, decolorization, filtration, crystallization, centrifugation, washing, drying to get the finished product.

Last Update：2022-01-01 10:09:09

L-Alanine - Introduction

Alanine is a non-essential amino acid that plays a key role in the glucose-alanine cycle between muscle tissue and liver. In amino acid degradation tissues (such as muscle), the amino group is transferred to glutamic acid by transamination. The amino group of glutamic acid is transferred to pyruvate by alanine aminotransferase to form alanine and α-ketoglutarate. Alanine enters the bloodstream and is transported to the liver. This reaction is reversed in the liver, pyruvate is used in the gluconeogenesis pathway and forms glucose, which can be returned to other tissues through the circulatory system. Elevated alanine levels are associated with increased blood pressure, energy intake, cholesterol levels, and body mass index.

Last Update：2022-10-16 17:26:24

L-Alanine - Use

Open Data Verified Data

used as a flavor enhancer. Can increase the flavoring effect of condiment; Can also be used as a sour corrector, improve the sour taste of organic acids.

Last Update：2022-01-01 10:09:10

L-Alanine - Safety

Open Data Verified Data

This product is non-toxic.
the use of plastic bag jacket Kraft paper bag packaging, each bag of 25kg. In the storage and transportation of moisture, sun protection, fire prevention.

Last Update：2022-01-01 10:36:18

L-Alanine - Production method

1. the amination method of propionic acid uses propionic acid as raw material, and in the presence of 105 ℃ and 3% red phosphorus catalyst, liquid chlorine is introduced for chlorination to generate 2-chloropropionic acid, and then enters the ammonia solution, uses urotropine as catalyst, and ammoniates at 60 ℃ to generate 2-aminopropionic acid. Finally, the reactants are sent to methanol solution for crystallization, and the finished product of α-alanine is obtained by centrifugation and drying. 2.α-bromopropionic acid chlorination method mixes α-bromopropionic acid, ammonia water, and ammonium bicarbonate for 7 hours, then evaporates to dryness, then soaks in ethanol to wash away ammonium bromide, filters out crystals, and then after decolorization and filtration, Add ethanol to obtain crystals, filter and dry to obtain finished products. 3. Cyanohydrin acetaldehyde reacts with hydrocyanic acid to generate cyanohydrin, and then reacts with ammonia to obtain aminonitrile; then hydrolyze to generate sodium aminopropionate under alkaline conditions, and obtain α-alanine through ion exchange.

Last Update：2024-04-10 22:29:15

L-Alanine - Production method

The production process of L-alanine mainly adopts enzyme conversion method, which is simple and low cost, and is a competitive process route developed internationally.
L-aspartic acid was used as raw material by enzyme conversion method, and L-propane F was produced by decarboxylation reaction under the catalysis of aspartic acid-β-decarboxylase. Aspartic acid in L factory is produced by fumaric acid by E. coli ATCCll030 and pseudounicellular NX-1 fermentation. Aspartic acid-p decarboxylase solution was obtained by strain screening and two-stage strain culture. The conversion solution is enzymatic, decolorized, filtered, crystallized, centrifuged, washed and dried to obtain the finished product. The conversion rate of L aspartic acid is as high as 99%, and the total yield of the product is 80% of the theoretical yield.

production method	It is separated from the hydrolysis of proteins with more L-alanine content such as spun silk. It is obtained by enzymatic treatment with L-aspartic acid as raw material.
production method	with L-alanine rich protein such as silk protein, casein as raw materials, after acid hydrolysis separation, refined.
production method

Last Update：2024-04-10 22:29:15

L-Alanine - Nature

melting point	314.5 °C
specific rotation	14.5 ° (c=10,6N HCl,dry sub.)
boiling point	212.9±23.0 °C(Predicted)
density	1,432 g/cm3
FEMA	3818 \| DL-ALANINE
refractive index	1.4650 (estimate)
storage conditions	2-8°C
solubility	H2O: 100 mg/mL
acidity coefficient (pKa)	2.34(at 25℃)
morphology	powder
color	White to almost white
PH value	5.5-6.5 (100g/l, H2O, 20℃)
optical activity (optical activity)	[α]20/D +14.0±1°, c = 5% in 5 M HCl
water solubility	166.5 g/L (25 °C)
maximum wavelength (& lambda;max)	λ: 260 nm Amax: ≤0.03 λ: 280 nm Amax: ≤0.02
Merck	14,204
BRN	1720248
stability	Stable. Incompatible with strong oxidizing agents.
InChIKey	QNAYBMKLOCPYGJ-REOHCLBHSA-N
NIST chemical information	Alanine(56-41-7)
EPA chemical information	L-Alanine (56-41-7)

Last Update：2024-04-09 20:52:54

L-Alanine - Use

(1) can improve the nutritional value of food, in all kinds of food and beverages, such as bread, ice cakes, fruit tea, dairy products, carbonated drinks, sorbet, etc. Adding 0.1 ~ 1% alanine can obviously improve the protein utilization rate in food and beverage, and because alanine can be directly absorbed by cells, it can quickly recover fatigue and invigorate the spirit after drinking.

(2) improve the taste of synthetic sweeteners (saccharin sodium, licking chrysanthemum glycoside, sodium cyclamate, etc.), which can increase the sweetness and reduce the dosage. Adding 1 ~ 10% alanine to the compound sweetener can improve sweetness and ease the sweetness of artificial sweetener, just like natural sweetener, making it lasting. It is one of the raw materials for synthesizing alexame with high sweetness (Alitame,L-aspartyl-D-alanine amide, 600 times the sweetness of sucrose).

(3) Improve the sour taste of organic acids. 1-5% of the amount of organic acid mixed can improve the sour taste such as glacial acetic acid, succinic acid, fumaric acid, citric acid, tartaric acid, etc., so that the mixed sour taste is closer to the natural taste.

(4) Effect on pickled products. Adding 5-10% of salt can taste early and shorten the pickling time.

(5) after adding L-alanine to alcoholic beverages, it can make the taste mellow, prevent the aging of beer and sparkling wine, and reduce the smell of yeast. the addition amount is generally 1-3%.

(6) adding 1-3% L-alanine to mayonnaise can prevent oxidation.

(7) adding 2-3% to soybean meal products (such as soy sauce, etc.) can improve taste.

Last Update：2024-04-09 21:11:58

L-Alanine - Identification test, toxicity, use limit

identification test	content analysis and quality index analysis are the same as "01102,DL-alanine".
Toxicity	can be safely used in food (FDA,& sect;172.320,2000).
use limit	6.1% of total protein mass (by weight)(FDA & sect;172.320,2000). GB 2760-2001: The permitted use of food spices and seasonings is limited to GMP. FEMA is the same as "01102,DL-alanine".

Last Update：2024-04-09 20:45:29

L-Alanine - Use

use	food and beverage as preservatives, flavor seasonings and amino acid low-alcohol wine, medicine for the synthesis of amino acid infusion
use	used as food additive, feed, pharmaceutical intermediate
use	as a flavor enhancer, can increase the flavoring effect of chemical condiments; it can also be used as a sour taste correction agent to improve the sour taste of organic acids.
use	It is used for biochemical research and as an amino acid nutrition drug in medicine.
use	food additives, pharmaceutical raw materials, intermediates.
use	Nutritional supplements. It is a non-essential amino acid, which is the most abundant amino acid in blood and has important physiological functions. Flavor for flavoring. Used for unfermented products, synthetic sake, compound sweeteners, etc., it has obvious synergistic effect, and the dosage is generally 0.01% ~ 0.03%. Heating reaction with sugar (amino-carbonyl reaction) can produce special fragrance substances.
use	Biochemical research. Tissue culture. Liver function determination. It is a non-essential amino acid, which is the most abundant amino acid in blood and has important physiological functions.
use	Nutritional supplements. It is a non-essential amino acid, which is the most abundant amino acid in blood and has important physiological functions. Flavor for flavoring. Used for unfermented products, synthetic sake, compound sweeteners, etc., it has obvious synergistic effect, and the dosage is generally 0.01% ~ 0.03%. Heating reaction with sugar (amino-carbonyl reaction) can produce special fragrance substances.
use	This product is a raw material for the manufacture of vitamin B6, the synthesis of calcium pantothenate and other organic compounds. Adding to food can enhance the flavoring effect of chemical seasonings, improve the taste of sweeteners and the sour taste of organic acids, improve the quality of alcoholic beverages, prevent oil oxidation and improve the flavor of impregnated foods. It can also be used as a biochemical reagent for biochemical and microbial research.

Last Update：2024-04-09 21:21:28

L-Alanine - Production method

method 1. enzymatic method
Using enzyme engineering technology, using L-aspartic acid as raw material, L-alanine is produced under the action of β-deacidase of Pseudomonas de Akunha

Process:
L-aspartic acid [immobilized aspartic acid β-decarboxylase (decarboxylation)]& rarr;[37 ℃, pH6.0] decarboxylation [concentration, crystallization] & rarr;[decompression, 5 ℃] crystallization [refining] & rarr;[5 ℃] L-alanine crude
Strain culture of 68 different strains of Pseudomonas deakunha (Pseudomenas daconhae) were cultured in inclined medium and composed of peptone 0.25%, beef extract 0.52%, yeast extract 0.25%, NaCl 0.5%, pH7.0 and agar 2.0%. The seed culture medium is the same as the inclined culture medium, but without agar, and the culture medium in a 250mL triangular flask is 40mL. The shake flask culture medium is composed of archaeine 3.0%, peptone 0.9%, casein hydrolysate 0.5%, potassium dihydrogen phosphate 0.05%, MgSO4.7H2O 0.01%, the pH is adjusted to 7.2 with ammonia water, the culture medium in a 500ml triangular flask is 80ml, and the fresh inclined strain, vibration culture at 30 ℃ for 8h, then inoculated in shake flask medium, shaking culture at 30 ℃ for 24h, thus gradually expanded to 1000-2000ml culture tank culture. After the culture, adjust the pH to 4.75 with 1mol/L HCl and keep the temperature at 30 ℃ for 1h. Centrifuge with a rotary centrifuge and collect the bacteria for later use (containing L-aspartate-β-decarboxylase).
Cell fixation takes 20kg of the above wet bacteria, adds normal saline to stir evenly and dilute to 40L. In addition, 85L of 50g/L (5%) carrageenan solution dissolved in normal saline is taken, the two solutions are mixed at 45 ℃, cooled to 5 ℃ to form gel, soaked in 600L phosphate buffer solution containing 20g/L (2%) KCl, 0.2mol/L hexamethylenediamine 0.5mol/L and pH7.0, stirred at 5 ℃ for 10min, added glutaraldehyde to 0.6 mol/L, stir, after fully washing with 20g/L KCl solution, filter out the washing solution and prepare for later use.
Preparation of Bioreactor Immobilized Pseudomonas is loaded into a packed bed reactor (30cm × 180cm) with a pressure of 1.515 × 107 Pa for later use.
Decarboxylation takes L-aspartic acid solution (1mol/L) at 37 ℃, adds pyridoxal phosphate to 0.1 mmol/L concentration, sets pH6.0, sets pH6.0, keeps temperature at 37 ℃, flows into immobilized pseudomonas bioreactor at a certain spatial speed, carries out decarboxylation reaction, controls it to reach the maximum conversion rate (>95%), and collects decarboxylation solution to obtain crude L.
Refined, clear decarboxylation solution is taken, concentrated to half of the original volume under reduced pressure at 60-70 ℃, added with equal volume of methanol after cooling, crystallized at 5 ℃, left overnight, filtered to crystallize, washed with a small amount of cold methanol, drained, and vacuum dried at 80 ℃ to obtain crude L-alanine. Then add 3 times the volume of deionized water to the crude product, stir and dissolve at 80 ℃, add 5g/L (0.5%) activated carbon, stir and decolorize at 70 ℃ for 1h, filter to take filtrate, cool, add equal volume of methanol, crystallize at 5 ℃, filter to take crystallization, and dry at 80 ℃ in vacuum to obtain fine L-alanine.

Methods 2. immobilized enzyme
Using fumaric acid as raw material, it is first converted into L-aspartic acid with NH3 under the action of aspartic acid, and then, like the above enzymatic method, it is fixed in the β-decarboxylase of Pseudomonas deakunha Decarboxylation under the action of the enzyme to obtain L-alanine.

Technological process: fumaric acid [immobilized aspartase (conversion)]& rarr;[37 ℃, pH8.5] conversion solution [immobilized aspartate-β-decarboxylase] & rarr;[37 ℃, pH6.0] decarboxylation solution [concentration, crystallization] & rarr;[decompression, 5 ℃] crystallization [refining] & rarr; Aspartase immobilized cell seed culture, immobilization, preparation of bioreactor. See aspartase conversion process for details.
Immobilized aspartate-β-decarboxylase decarboxylation, refining with reference to the above enzymatic process.
Methods 3. chemical synthesis
Strecker method

Bucherer method

Then perform optical resolution to obtain L-alanine boutique.

Last Update：2024-04-09 15:16:15

L-Alanine - Quality standard

[quality standard] AJI97 FCCV USP30
Project standard
Content 98.5% ~ 101.0%
Character white crystal or crystalline powder
specific rotation [α]D20 14.3 ° ~ 15.2 °
Acidity pH 5.5~7.0
Light transmittance ≥ 98.0%
Loss on drying ≤ 0.20%
Burning residue ≤ 0.10%
Heavy metal [Pb] ≤ 10ppm
Chloride [Cl-] ≤ 0.02%
Iron salt [Fe] ≤ 10ppm
Arsenic salt [As] ≤ 1ppm
Sulfate [SO42-] ≤ 0.02%
Ammonium salt [NH4 +] ≤ 0.02%
Other amino acids meet the requirements

Last Update：2024-04-09 19:04:54

L-Alanine - Reference Information

[quality standard] AJI97 FCCV USP30 project standard content 98.5% ~ 101.0% white crystal or crystalline powder specific optical rotation [α]D20 +14.3 ° ~ +15.2 ° acidity pH 5.5~7.0 transmittance ≥ 98.0% loss on drying ≤ 0.20% residue on ignition ≤ 0.10% heavy metal [Pb] ≤ 10ppm chloride [Cl-] ≤ 0.02% iron salt [Fe] ≤ 10ppm arsenic salt [As] ≤ 1ppm sulfate [SO42-] ≤ 0.02% ammonium salt [NH4 +] ≤ 0.02% Other amino acids

FEMA	3818 \| DL-ALANINE
NIST chemical information	information provided by: webbook.nist.gov (external link)
EPA chemical substance information	information provided by: ofmpeb.epa.gov (external link)
Food additives	(1) can improve the nutritional value of food, in all kinds of food and beverage, such as: bread, ice cakes, fruit tea, dairy products, carbonated drinks, ice creams, etc. Adding 0.1~1% of alanine can significantly improve the utilization rate of protein in food and beverage, and because alanine can be directly absorbed by cells, it can quickly recover fatigue after drinking, high spirit. (2) to improve the taste of artificial synthetic sweeteners (saccharin sodium, licking chrysanthemum glycoside, sodium cyclamate, etc.), can make the sweetness efficiency, reduce the amount. Adding 1 ~ 10% of alanine in the compound sweetener can improve the sweetness and ease the sweetness of the artificial sweetener, like the natural sweetener, making the aftertaste lasting. It is one of the raw materials for the synthesis of Alitame (L-aspartyl-D-alanine amide, 600 times the sweetness of sucrose) with high sweetness. (3) improve the sour taste of organic acids. The addition of 1-5% of the amount of organic acid can improve the sour taste such as glacial acetic acid, succinic acid, fumaric acid, citric acid, tartaric acid and the like, so that the mixed sour taste is closer to the natural taste. (4) the effect of curing products. Add 5-10% of the amount of salt can taste early, shorten the curing time. (5) after L-alanine is added to the alcoholic beverage, it can make the taste thick, and can prevent the aging of beer and bubble wine, reduce the smell of yeast, and the addition amount is generally 1-3%. (6) the oxidation can be prevented by adding 1-3% of L-alanine to the mayonnaise. (7) in soybean meal products (such as soy sauce, etc.) add 2-3% can improve the taste.
reference quality standard
identification test	the content analysis and quality index analysis were the same as those of "01102,DL-alanine".
toxicity	can be used safely in foods (FDA,§ 172.320,2000).
usage limit	accounts for 6.1% by weight of the total protein mass (FDA § 172.320,2000). GB 2760-2001: permitted use of food spices and seasoning, are limited to GMP. FEMA is the same as 01102,DL-alanine ".
Use	used in food and beverage as a preservative, flavor flavoring and amino acid low-alcohol wine, medicine for the synthesis of amino acid infusion used as food additives, feed, pharmaceutical intermediates as a flavor enhancer, can increase the effect of chemical seasoning; Can also be used as a sour corrector, improves the sour taste of organic acids. used in biochemical research, used as amino acid nutrition medicine. food additives, pharmaceutical raw materials, intermediates. nutritional supplements. Belongs to non-essential amino acids, is the most abundant in the blood of a kind of amino acid, has an important physiological role. Flavoring agent. For non-fermented products, synthetic sake, compound sweeteners, etc., have obvious synergistic effect, the dosage is generally 0.01% ~ 0.03%. Heat reaction with sugar (amino-carbonyl reaction), can produce special flavor substances. biochemical study. Tissue culture. Liver function was measured. Belongs to non-essential amino acids, is the most abundant in the blood of a kind of amino acid, has an important physiological role. nutritional supplements. Belongs to non-essential amino acids, is the most abundant in the blood of a kind of amino acid, has an important physiological role. Flavoring agent. For non-fermented products, synthetic sake, compound sweeteners, etc., have obvious synergistic effect, the dosage is generally 0.01% ~ 0.03%. Heat reaction with sugar (amino-carbonyl reaction), can produce special flavor substances. This product is a raw material for the manufacture of vitamin B6, synthetic calcium pantothenate and other organic compounds. Added in food can enhance the flavoring effect of chemical seasoning, improve the taste of sweeteners and the sour taste of organic acids, improve the quality of alcoholic beverages, Prevent oil oxidation and improve the flavor of impregnated food. It can also be used as a Biochemical reagent for biochemical and microbiological research.
production method	1. Propionic acid ammonium chloride method from propionic acid as raw material, in the presence of 105 ℃ temperature and 3% red phosphorus catalyst, into the liquid chlorine for chlorination, generating 2-chloropropionic acid, and then into the ammonia solution, using urotropine as catalyst, ammoniation was carried out at 60 ℃ to produce 2-aminopropionic acid. Finally, the reactant is sent to a methanol solution for crystallization, and then centrifuged and dried to obtain a final α-alanine. 2. Α-Bromo propionic acid chloride method the α-Bromo propionic acid, ammonia water, ammonium bicarbonate were mixed and refluxed for 7H, then evaporated to dryness, and then washed with ethanol to soak ammonium bromide, filtered out the crystals, and then decolorized and filtered, added ethanol to obtain crystals, the final product was obtained by filtration and drying. 3. Cyanohydrin acetaldehyde reacts with hydrocyanic acid to generate cyanohydrin, and then reacts with ammonia to obtain aminonitrile; Then hydrolyzes under alkaline conditions to generate sodium aminopropionate, and obtains α-alanine by ion exchange. obtained by separation after hydrolysis of a protein having a high content of L-alanine such as spun silk. From L-aspartic acid as raw material by enzyme treatment. with L-alanine rich protein such as silk protein, casein as raw material, after acid hydrolysis separation, refined and obtained. The production process of L-alanine mainly adopts enzyme conversion method, which is a simple process and low cost, and is an international competitive development process route. L-alanine was produced by decarboxylation of L-aspartate catalyzed by aspartate-β-decarboxylase; L plant aspartic acid by fumaric acid by Escherichia coli ATCCll030 and false single cell NX-1 fermentation production; Aspartic acid A p decarboxylase liquid by strain screening, two levels of strain culture obtained. The conversion solution is subjected to enzyme killing, decolorization, filtration, crystallization, centrifugation, washing and drying to obtain a finished product, The conversion of L-aspartic acid was as high as 99%, and the overall yield of the product was 80% of the theoretical yield. method 1. Enzymatic application of enzyme engineering technology, with L-aspartic acid as raw material, under the action of β-deacidification enzyme of Pseudomonas deakun: L-aspartic acid [immobilized aspartate β-decarboxylase (decarboxylation)]→[37 ℃, pH6.0] decarboxylation [concentration, crystallization] → [decompression, 5 ℃] crystallization [refined] →[5 ℃] L-alanine crude strain culture Pseudomonas decumenata (Pseudomonas dconhae) 68 kinds of different strains culture, using slant medium, the composition was peptone 0.25%, beef extract 0.52%, yeast extract 0.25%, NaCl 0.5%, ph 2.0%, Agar. The seed medium was the same as the slant medium, but without the addition of Agar, and the volume of the medium in the 250ml Erlenmeyer flask was 40ml. The composition of the shake flask culture medium was 3.0%, 0.9%, casein hydrolysate 0.5%, potassium dihydrogen phosphate 0.05%, MgSO4.7H2O 0.01%, Adjust pH to 7 with ammonia. The volume of culture medium in 2, 500ml flask was 80ml. The fresh inclined surface strain cultured for 24h was inoculated into the seed medium, and the culture was shaken for 8H at 30 ℃, and then inoculated into the shake flask medium, the culture was carried out at 30 ° C. For 24 hours with shaking, and the culture was gradually expanded to a culture tank of 1000-2000ml. At the end of the culture, the pH was adjusted to 4.75 with 1mol/L HCl and incubated at 30 °c for 1H. The cells were collected by centrifugation in a rotary centrifuge for use (containing L-aspartic acid-β-decarboxylase). The cells were fixed and 20kg of the above-mentioned wet cells were taken, stirred with physiological saline and diluted to 40L. Another 50g/L (5%) Carrageenan solution (85L) dissolved in physiological saline was added, and the two solutions were heated at 45 ℃ and then mixed, cooled to 5 ℃ to form glue, soak in 600L phosphate buffer containing 20g/L (2 %), 0.2mol/L hexamethylene diamine 0.5mol/L, pH7.0, stir at 5 ℃ for 10min, add glutaraldehyde to 0.6 mol/L, stir at 5 ℃ for 30 min, take out and cut into 3-5mm3 small pieces, After sufficiently washing with 20g/L KCl solution, the washing solution is filtered off and ready for use. Preparation of bioreactor the immobilized Pseudomonas was loaded into a packed bed reactor (30 × 1.515) at a pressure of 107 × 180, ready for use. Decarboxylation L-aspartic acid solution (1mol/L) was taken at 37 ℃, pyridoxal phosphate was added to 0.1 mmol/L concentration, pH was adjusted to 6.0, pH was adjusted to 6.0, and the temperature was maintained at 37 ℃, according to a certain space velocity into the immobilized Pseudomonas bioreactor, decarboxylation reaction, control it to reach the maximum conversion rate (>95%), the collection of decarboxylation solution to obtain crude L-alanine solution. Refine the clear decarboxylation solution, concentrate it to half of the original volume under reduced pressure at 60-70 ℃, add equal volume of methanol after cooling, crystallize at 5 ℃, place it overnight, filter to take the crystal, wash with a small amount of cold methanol, draw dry, vacuum drying at 80 deg C, The crude L-alanine was obtained. The crude product was added to 3 times the volume of deionized water, stirred and dissolved at 80 ℃, 5g/L (0.5%) activated carbon was added, stirred and decolorized at 70 ℃ for 1H, the filtrate was filtered and cooled, equal volume of methanol was added, and the crystals were crystallized at 5 ° C., filtered and dried under vacuum at 80 ° C. To obtain fine L-alanine. Method two, Immobilized enzyme with fumaric acid as raw material, first with NH3 in the role of aspartic acid into L-aspartic acid, L-alanine is obtained by decarboxylation under the action of β-decarboxylase of immobilized Pseudomonas deakenha. Process: fumaric acid [immobilized aspartate enzyme (conversion)]→[37 ℃, pH8.5] conversion solution [immobilized aspartate-β-decarboxylase] →[37 ℃, PH 6.0] decarboxylation solution [concentration, crystallization] → [reduced pressure, 5 ℃] crystallization [purification] →[5 ℃]L-alanine aspartate enzyme immobilized cell seed culture, immobilization, preparation of a bioreactor. See aspartate enzyme conversion process for details. The immobilized aspartic acid-β-decarboxylase was decarboxylated and refined with reference to the above enzymatic process. Method Three, chemical synthesis method Strecker method Bucherer method and then optical resolution, that is, L-alanine quality.
toxic substance data	information provided by: pubchem.ncbi.nlm.nih.gov (external link)