Summary of the invention
The objective of the invention is to overcome the defective of prior art, improve the production efficiency of L-citrulline, reduce the production cost of L-citrulline; Utilize enterococcus faecalis immobilized cell packed column for the synthetic L-citrulline of reactor catalysis, improved degree of purity of production, increased productive rate, shortened the production cycle, greatly reduce production cost, make large scale continuous prod L-citrulline become possibility.Wherein immobilized cell promptly adopts the sodium alginate to embed method that enterococcus faecalis CGMCC NO.1866 is carried out immobilization, and the good cell of immobilization is filled in the packed column, allows then contain the arginic phosphate buffer solution of L-with certain flow velocity packed column of flowing through.This preparation method carries out immobilization by selecting suitable fixing condition for use to enterococcus faecalis CGMCC NO.1866, immobilized cell is filled in the packed column of certain aspect ratio, again with this packed column as catalyzer, allow and contain the arginic phosphoric acid buffer of L-, the synthetic L-citrulline of catalysis under optimum reaction condition with certain flow velocity this packed column of flowing through.This method has that fixation cell cytoactive height, good stability, life-span are long, and impurity in products is few, but serialization with short production cycle, advantage such as technological operation is simple, production cost is low.
Overall technology design of the present invention is:
1, the method for immobilized cell continuously producing L-carbamyl ornithine, production process comprises following process steps:
(1) seed liquor cultivation and fermentor cultivation prepare enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell;
(2) preparation of immobilization enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell;
(3) immobilized cell is filled in the packed column;
(4) containing the arginic phosphate buffer solution of the L-packed column of flowing through, the L-citrulline is synthesized in catalysis;
(5) separation and purification of product.
Concrete processing step of the present invention and processing condition are:
The preparation of enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell in the step (1):
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 25-40 ℃, the 170r/min shaking table gets primary seed solution after cultivating 24-48h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 25-40 ℃, the 170r/min shaking table is cultivated 24-48h and is got secondary seed solution again; With 10-15% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
Glucose 20-60 part, peptone 50-100 part, extractum carnis 50-100 part, (NH
4)
2SO
42-8 part, sal epsom 0.5-2 part, sodium-chlor 1-2 part, L-arginase 12-5 part, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 1000 parts in 0.002 part and water;
The processing condition of fermentation are 10-15% for the fermented liquid inoculum size, and the pH value is 6.0-8.0, and culture temperature is 25-40 ℃, and ventilation is 0.6-1.0vvm, and mixing speed is 120-160r/min, and fermentation time is 48-72h.
Enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell fixation in the step (2):
With mass percent concentration is that the sodium alginate adding distil water of 3-9% boils dissolving, the cooling back is the bacteria suspension mixing of 50-100g/L with the equal-volume cell concn, get the emulsion tube of the suitable 4mm * 6mm of length, at one end adopt the water dropper of the about 1.0mm-4.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 50-100drop/min.Under agitation condition, mixed solution is dropwise splashed into 0.1-1.0mol/L boric acid and 0.5-2.0mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 5-15h, and making diameter is the 2-5mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
Step is filled into immobilized cell in the packed column in (3):
Packed column is that aspect ratio is the synthetic glass post of 15-35, fills packed column with immobilized cell.
Step (4) is containing the arginic phosphate buffer solution of the L-packed column of flowing through, and the L-citrulline is synthesized in catalysis:
The arginic amount concentration of L-is 0.65-1.0mol/l, and the amount concentration of phosphate buffer solution (pH6.0) is 0.2-0.4mol/l, and the catalyzed reaction temperature is 30-55 ℃, and the buffered soln flow velocity is 0.3-0.5BV/h.Under this reaction conditions, the arginic transformation efficiency of L-is 95-99%, contains L-citrulline 112-165g in every liter of fermented liquid, and after immobilized cell transformed 480-960h, the cell catalysis vigor was still stable, and promptly be 480-960h the work-ing life of immobilized cell.
The separation and purification of step (5) L-citrulline comprises following three steps:
A, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.
Used enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 of the present invention is in China Committee for Culture Collection of Microorganisms's common micro-organisms center preservation, preserving number is enterococcus faecalis CGMCC NO.1866, and the preservation time is on November 22nd, 2006.
The screening of enterococcus faecalis CGMCC NO.1866, form by following process steps:
(1) ampere night soil management enterococcal species inoculation inclined-plane is made slant strains;
(2) with bacterial classification spread plate after the rejuvenation;
(3) flat-plate bacterial colony is inoculated shake flask fermentation and cultivated, carry out primary dcreening operation and multiple sieve;
(4) bacterial strain after will sieving again carries out complex mutation.
Plate culture medium in the step (1) in slant medium and the step (2) is made up of following parts by weight of component:
Glucose 10-40 part, peptone 50-100 part, extractum carnis 50-100 part, (NH
4)
2SO
42-8 part, sal epsom 0.5-2 part, sodium-chlor 1-2 part, L-arginase 12-5 part, CaCl
22H
20.05 part of O, FeCl
24H
21000 parts in 0.1 part of O and water;
Preparation slant strains and dull and stereotyped processing condition are that the pH value is that 6.0-8.0, temperature 25-45 ℃, incubation time are 24-48 hour.
Fermented liquid is made up of following parts by weight of component in the step (3):
Glucose 20-60 part, peptone 50-100 part, extractum carnis 50-100 part, (NH
4)
2SO
42-8 part, sal epsom 0.5-2 part, sodium-chlor 1-2 part, L-arginase 12-5 part, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 1000 parts in 0.002 part and water;
The processing condition of fermentation are: the pH value is 6.0-8.0, and culture temperature is 25-35 ℃, and mixing speed is 120-160 rev/min, and fermentation time is 24-48 hour.
Mutagenesis comprises the preparation of seed bacteria suspension successively in the step (4), and the add-on of mutagenic compound is during uv irradiating.
Slant strains is inoculated into contains in the 5ml physiological saline test tube, adding volume percent in the test tube is the ethyl sulfate mutagenic compound of 0.5%-2.0%, 1-2min vibrates on the vortex oscillation device, get this bacteria suspension spread plate of 0.5ml, flat board is placed on ultra violet lamp 20-60s, then flat board is secretly cultivated.Culture condition is: culture temperature 25-35 ℃, incubation time is 48-72 hour.
At last, obtain enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866.
The method of utilizing enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 immobilized cell continuously producing L-carbamyl ornithine provided by the invention is applicable to that with sodium alginate, alginate calcium, gelatin, polyvinyl alcohol (PVA) gel, agar, urethane, light-hardening resin or carbopol gel etc. be the synthetic L-citrulline of entrapment media immobilization enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell catalysis.
The method of utilizing enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 immobilized cell continuously producing L-carbamyl ornithine provided by the invention is applicable to the packed column as immobilized cell such as synthetic glass post, plastic column, stainless steel column or glass column.
The obtained technical progress of the present invention is:
The first, used enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial classification of the present invention has higher enzyme life-span and easier immobilization alive, longer than existing bacterial classification such as streptococcus faecium, the false monospore bacillus of stink, the false monospore bacillus of verdigris color, viridans streptococci, Clostridium perfringens or the yeast that can produce the L-citrulline.Fermented liquid L-citrulline concentration is 1.89 times of existing enzyme the highest bacterial classification alive (streptococcus faecium fermented liquid L-citrulline concentration is 87.5g/L) up to 165g/L; Every batch of thalline reaches 960h work-ing life, is 1.90 times of the longest bacterial classification in existing work-ing life (the false monospore bacillus of stink work-ing life be 504h); Enzyme after the somatic cells immobilization is lived and is 99% of immobilized thallus not, be the false monospore bacillus of stink (enzyme after the somatic cells immobilization only live for immobilized thallus not 56%) 1.77 times.
The second, the present invention is by enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell is carried out immobilization, and as reactor, the L-citrulline is synthesized in catalysis with the immobilized cell packed column.The obtained progress of the present invention is mainly reflected in following several respects:
(1) immobilized cell long service life, with the immobilized cell packed column is catalyzer, can reach 480-960h by the synthetic L-citrulline of continuous catalysis, be free cell (be 24h work-ing life) 20-40 doubly, this has not only reduced raw material consumption, and saved energy consumption, greatly reduce production cost.
(2) immobilized cell has strengthened the tolerance level of thalline to environment, optimum temperuture such as the synthetic L-citrulline of free cell catalysis is 37 ℃, optimum pH is 6.0, and immobilized cell is 30-55 ℃ in temperature, the pH value all has maximum enzyme to live when 5.0-7.0, so immobilized cell easy realization of large-scale production more.
(3) product purity height utilizes the catalysis of immobilized cell packed column to synthesize the L-citrulline, can avoid on the one hand free cell in catalytic process because of broken, the dead albumen that produces and other amino acid impurity; On the other hand, can avoid cell directly to mix, bring difficulty for the subsequent products separation and purification with reaction solution.
(4) cycle weak point, the production cycle of utilizing immobilized cell to produce the L-citrulline is 3-5h, and free cell is 24h, production efficiency has improved 5-8 doubly.
(5) but produce serialization, packed column reactor of the present invention, reaction solution is from an end of the post the other end of flowing through, the reaction solution that comes out is product L-citrulline, whole process can continuous production, has simplified reactions steps, has improved production efficiency greatly.
In sum, the present invention adopts immobilized cell continuously producing L-carbamyl ornithine, the highest 165g L-citrulline that contains in every liter of fermented liquid, and immobilized cell work-ing life is 960 hours, has great industrialization meaning.
Embodiment: the present invention is described further below in conjunction with embodiment.
Embodiment 1
(1) preparation of somatic cells:
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 25 ℃, the 170r/min shaking table gets primary seed solution after cultivating 48h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 25 ℃, the 170r/min shaking table is cultivated 36h and is got secondary seed solution again; With 10% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
20 parts of glucose, 100 parts of peptones, 50 parts of extractum carniss, (NH
4)
2SO
42 parts, 0.5 part in sal epsom, 2 parts in sodium-chlor, L-arginase 12 part, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 0.002 part, 1000 parts in pH7.0 and water;
The processing condition of fermentation are 10% for the fermented liquid inoculum size, and the pH value is 6.0, and culture temperature is 25 ℃, and ventilation is 0.6vvm, and mixing speed is 120r/min, and fermentation time is 72h.
(2) immobilization of somatic cells:
With mass percent concentration is that 9% sodium alginate adding distil water boils dissolving, and the cooling back is the bacteria suspension mixing of 100g/L with the equal-volume cell concn, gets the emulsion tube of the suitable 4mm * 6mm of length, at one end adopts the water dropper of the about 4.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 100drop/min.Under agitation condition, mixed solution is dropwise splashed into 0.1mol/L boric acid and 1.0mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 15h, and making diameter is the 5mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
(3) immobilized cell is filled in the packed column:
Get an aspect ratio and be 15 synthetic glass post as packed column, immobilized cell is packed in the packed column.
(4) the synthetic L-citrulline of immobilized cell packed column catalysis:
(0.2mol/l pH6.0), is under 30 ℃ of conditions in temperature, is the 0.3BV/h packed column of flowing through with the flow velocity with the arginic amount concentration phosphate buffer solution that is 0.85mol/l.Under this reaction conditions, the arginic transformation efficiency of L-is 97.5%, contains L-citrulline 144.4g in every liter of fermented liquid, and after immobilized cell transformed 800h, the cell catalysis vigor was still stable, and promptly be 800h the work-ing life of immobilized cell.
(5) separation and purification of L-citrulline comprises following three steps:
A, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.
Embodiment 2
(1) preparation of somatic cells:
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 30 ℃, the 170r/min shaking table gets primary seed solution after cultivating 36h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 30 ℃, the 170r/min shaking table is cultivated 36h and is got secondary seed solution again; With 10% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
40 parts of glucose, 75 parts of peptones, 75 parts of extractum carniss, (NH
4)
2SO
46 parts, 1 part in sal epsom, 1 part in sodium-chlor, 3 parts of L-arginine, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 0.002 part, 1000 parts in pH7.0 and water;
The processing condition of fermentation are 10% for the fermented liquid inoculum size, and the pH value is 7.0, and culture temperature is 30 ℃, and ventilation is 0.8vvm, and mixing speed is 140r/min, and fermentation time is 56h.
(2) immobilization of somatic cells:
With mass percent concentration is that 5% sodium alginate adding distil water boils dissolving, and the cooling back is the bacteria suspension mixing of 90g/L with the equal-volume cell concn, gets the emulsion tube of the suitable 4mm * 6mm of length, at one end adopts the water dropper of the about 4.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 80drop/min.Under agitation condition, mixed solution is dropwise splashed into 0.3mol/L boric acid and 1.0mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 10h, and making diameter is the 3mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
(3) immobilized cell is filled in the packed column:
Get an aspect ratio and be 25 synthetic glass post as packed column, immobilized cell is packed in the packed column.
(4) the synthetic L-citrulline of immobilized cell packed column catalysis:
(0.2mol/l pH6.0), is under 40 ℃ of conditions in temperature, is the 0.4BV/h packed column of flowing through with the flow velocity with the arginic amount concentration phosphate buffer solution that is 0.8mol/l.Under this reaction conditions, the arginic transformation efficiency of L-is 98.5%, contains L-citrulline 137.3g in every liter of fermented liquid, and after immobilized cell transformed 720h, the cell catalysis vigor was still stable, and promptly be 720h the work-ing life of immobilized cell.
(5) separation and purification of L-citrulline comprises following three steps:
B, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.
Embodiment 3
(1) preparation of somatic cells:
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 30 ℃, the 170r/min shaking table gets primary seed solution after cultivating 36h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 30 ℃, the 170r/min shaking table is cultivated 36h and is got secondary seed solution again; With 12% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
40 parts of glucose, 75 parts of peptones, 75 parts of extractum carniss, (NH
4)
2SO
46 parts, 1 part in sal epsom, 1.0 parts in sodium-chlor, 3 parts of L-arginine, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 0.002 part, 1000 parts in pH7.0 and water;
The processing condition of fermentation are 12% for the fermented liquid inoculum size, and the pH value is 7.0, and culture temperature is 30 ℃, and ventilation is 0.9vvm, and mixing speed is 160r/min, and fermentation time is 48h.
(2) immobilization of somatic cells:
With mass percent concentration is that 6% sodium alginate adding distil water boils dissolving, and the cooling back is the bacteria suspension mixing of 90g/L with the equal-volume cell concn, gets the emulsion tube of the suitable 4mm * 6mm of length, at one end adopts the water dropper of the about 2.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 100drop/min.Under agitation condition, mixed solution is dropwise splashed into 0.1mol/L boric acid and 2.0mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 10h, and making diameter is the 2mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
(3) immobilized cell is filled in the packed column:
Get an aspect ratio and be 30 synthetic glass post as packed column, immobilized cell is packed in the packed column.
(4) the synthetic L-citrulline of immobilized cell packed column catalysis:
(0.3mol/l pH6.0), is under 40 ℃ of conditions in temperature, is the 0.5BV/h packed column of flowing through with the flow velocity with the arginic amount concentration phosphate buffer solution that is 0.65mol/l.Under this reaction conditions, the arginic transformation efficiency of L-is 99%, contains L-citrulline 112.1g in every liter of fermented liquid, and after immobilized cell transformed 960h, the cell catalysis vigor was still stable, and promptly be 960h the work-ing life of immobilized cell.
(5) separation and purification of L-citrulline comprises following three steps:
C, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.
Embodiment 4
(1) preparation of somatic cells:
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 30 ℃, the 170r/min shaking table gets primary seed solution after cultivating 36h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 30 ℃, the 170r/min shaking table is cultivated 36h and is got secondary seed solution again; With 15% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
40 parts of glucose, 75 parts of peptones, 75 parts of extractum carniss, (NH
4)
2SO
46 parts, 1 part in sal epsom, 1 part in sodium-chlor, 3 parts of L-arginine, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 0.002 part, 1000 parts in pH7.0 and water;
The processing condition of fermentation are 15% for the fermented liquid inoculum size, and the pH value is 7.0, and culture temperature is 30 ℃, and ventilation is 1.0vvm, and mixing speed is 160r/min, and fermentation time is 48h.
(2) immobilization of somatic cells:
With mass percent concentration is that 8% sodium alginate adding distil water boils dissolving, and the cooling back is the bacteria suspension mixing of 75g/L with the equal-volume cell concn, gets the emulsion tube of the suitable 4mm * 6mm of length, at one end adopts the water dropper of the about 4.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 75drop/min.Under agitation condition, mixed solution is dropwise splashed into 1.0mol/L boric acid and 0.5mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 12h, and making diameter is the 5mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
(3) immobilized cell is filled in the packed column:
Get an aspect ratio and be 30 synthetic glass post as packed column, immobilized cell is packed in the packed column.
(4) the synthetic L-citrulline of immobilized cell packed column catalysis:
(0.4mol/l pH6.0), is under 55 ℃ of conditions in temperature, is the 0.3BV/h packed column of flowing through with the flow velocity with the arginic amount concentration phosphate buffer solution that is 1.0mol/l.Under this reaction conditions, the arginic transformation efficiency of L-is 95%, contains L-citrulline 165.5g in every liter of fermented liquid, and after immobilized cell transformed 480h, the cell catalysis vigor was still stable, and promptly be 480h the work-ing life of immobilized cell.
(5) separation and purification of L-citrulline comprises following three steps:
D, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.
Embodiment 5
(1) preparation of somatic cells:
Enterococcus faecalis (Enterococcus faecalis) the CGMCC NO.1866 bacterial strain that picking 1 ring inclined-plane is preserved, joining volume is in the 50ml substratum, at 40 ℃, the 170r/min shaking table gets primary seed solution after cultivating 24h; Primary seed solution is inoculated in the 500ml Erlenmeyer flask that contains the above-mentioned substratum of 100ml, at 40 ℃, the 170r/min shaking table is cultivated 24h and is got secondary seed solution again; With 10% secondary seed solution inoculation fermentation jar, fermented liquid is at 6000r/min, and 4 ℃ of centrifugal 15min get enterococcus faecalis (Enterococcus faecalis) CGMCC NO.1866 cell.
Seed liquor and fermentation tank culture medium are made up of following parts by weight of component:
60 parts of glucose, 50 parts of peptones, 100 parts of extractum carniss, (NH
4)
2SO
48 parts, 2 parts in sal epsom, 1.5 parts in sodium-chlor, 5 parts of L-arginine, CaCl
22H
20.05 part of O, FeCl
24H
20.1 part of O, 0.002 part of VITMAIN B1,0.005 part of vitamin B12,0.004 part of calcium pantothenate, 0.001 part in nicotinic acid, para-amino benzoic acid are received 0.002 part, 1000 parts in pH7.0 and water:
The processing condition of fermentation are 10% for the fermented liquid inoculum size, and the pH value is 8.0, and culture temperature is 40 ℃, and ventilation is 0.8vvm, and mixing speed is 140r/min, and fermentation time is 56h.
(2) immobilization of somatic cells:
With mass percent concentration is that 3% sodium alginate adding distil water boils dissolving, and the cooling back is the bacteria suspension mixing of 50g/L with the equal-volume cell concn, gets the emulsion tube of the suitable 4mm * 6mm of length, at one end adopts the water dropper of the about 1.0mm of internal diameter.With the emulsion tube peristaltic pump of packing into, regulate peristaltic pump speed to 50drop/min.Under agitation condition, mixed solution is dropwise splashed into 0.5mol/L boric acid and 1.0mol/L CaCl
2In the mixing solutions, form immobilization gel beads of uniform size, diameter maximum difference≤0.5mm takes out after solidifying 5h, and making diameter is the 3.5mm gel beads, and the cellular enzymes after the immobilization is lived and is 99% of immobilized thallus not.
(3) immobilized cell is filled in the packed column:
Get an aspect ratio and be 35 synthetic glass post as packed column, immobilized cell is packed in the packed column.
(4) the synthetic L-citrulline of immobilized cell packed column catalysis:
(0.2mol/l pH6.0), is under 30 ℃ of conditions in temperature, is the 0.3BV/h packed column of flowing through with the flow velocity with the arginic amount concentration phosphate buffer solution that is 0.70mol/l.Under this reaction conditions, the arginic transformation efficiency of L-is 98.5%, contains L-citrulline 120.1g in every liter of fermented liquid, and after immobilized cell transformed 840h, the cell catalysis vigor was still stable, and promptly be 840h the work-ing life of immobilized cell.
(5) separation and purification of L-citrulline comprises following three steps:
E, the effusive reaction solution of collection packed column add gac and decolour, and bleaching temperature is 60 degree;
B, concentrate through the reaction solution vacuum decompression after a step, crystallization, can obtain purity and be the L-citrulline 99% or more, vacuum concentration vacuum tightness is 0.1Mpa, temperature is 60 degree, Tc is 4 to spend;
C, through the vacuum-drying of b step crystal, dry vacuum tightness is 0.1Mpa, temperature is 60 degree, dried finished products is a white powder.