A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation
The viscosity of sodium gluconate mother liquor is reduced by fermentation, and impurities are removed by using ceramic membranes and nanofiltration membrane systems to achieve efficient crystallization of sodium gluconate, solving the problem of crystallization caused by excessive sugars in the mother liquor, and improving the construction industry resource utilization efficiency.
Patent Information
- Application Number
- CN202411311678.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2044-09-20
AI Technical Summary
The large amount of sugars in sodium gluconate mother liquor leads to difficulty in crystallization and is unsalable in the construction industry, so it needs to improve its utilization value.
The fermentation method is used to reduce the viscosity through Saccharomyces cerevisiae fermentation, remove impurities in combination with ceramic membrane and nanofiltration membrane system, and evaporation concentration and gradient cooling and crystallization are carried out to improve the crystallization rate of sodium gluconate.
It has achieved efficient crystallization of sodium gluconate mother liquor, with a crystal extraction rate of more than 58%, and a product purity of more than 98.5%, which has improved the resource utilization value.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of sodium gluconate mother liquor crystallization, and more particularly to a method for improving the crystallization rate of sodium gluconate mother liquor by a fermentation method. Background Art
[0002] Sodium gluconate is white crystalline granules or powder, easily soluble in water, slightly soluble in alcohol, insoluble in ether, and widely used in food additives, electroplating complexing agents, water stabilizers, color leveling agents in the printing and dyeing industry, steel surface treatment agents, and concrete retarders.
[0003] Sodium gluconate mother liquor is the residual liquid that cannot be extracted after sodium gluconate is extracted during the production of sodium gluconate. The solid content of sodium gluconate mother liquor is 36-60%, including 30-40% sodium gluconate, 5-15% oligosaccharides, and 1-5% glucose. Due to the high content of sugars, the mother liquor is viscous, which makes it difficult for the sodium gluconate mother liquor to crystallize.
[0004] Sodium gluconate mother liquor is mainly used as a concrete admixture in construction. In the past two years, due to the sluggish local construction industry and strict requirements for the addition of admixtures, sodium gluconate mother liquor has been unsalable and cheap, while direct discharge will waste resources and pollute the environment. Therefore, a method for treating sodium gluconate mother liquor is needed to improve the utilization value of sodium gluconate mother liquor.
[0005] Therefore, providing a method for increasing the crystallization rate of sodium gluconate mother liquor by fermentation is a problem that those skilled in the art need to solve urgently. Summary of the invention
[0006] In view of this, the present invention provides a method for improving the crystallization rate of sodium gluconate mother liquor by a fermentation method.
[0007] In order to achieve the above object, the present invention adopts the following technical solution:
[0008] A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation, comprising the following specific steps:
[0009] (1) Preparation of culture medium: Add sodium gluconate mother liquor and protein powder into a fermentation tank at a ratio of (50-60):1, and dilute with water until the soluble solid content (measured by a digital refractometer) is 30-35%; adjust the pH to 5.0-5.5 with sodium hydroxide solution, add brewer's yeast, and ferment for 30-36 hours.
[0010] (2) The fermentation reaction liquid is 10-12m 3 / h is filtered through a ceramic membrane with a pore size of 0.1µm to remove solid matter and brewer's yeast, and a ceramic membrane filtrate is obtained; a flocculant is added at a ratio of 0.1% of the soluble solid content in the ceramic membrane filtrate, the mixture is stirred evenly, reacted for 1-2h, and the flocculants are filtered through a plug-in filter with a pore size of 28μm to obtain a plug-in filter filtrate.
[0011] (3) Press the filter plate filter to filter the liquid at 10-12m 3 / h is filtered through a nanofiltration membrane system to separate the sodium gluconate to obtain a sodium gluconate clear solution.
[0012] (4) The sodium gluconate clear liquid is evaporated and concentrated to a soluble solid content of 65-68%, and then crystallized by gradient cooling. The crystals are separated by a centrifuge and dried in a fluidized bed to obtain a sodium gluconate product.
[0013] Furthermore, the pH of the sodium gluconate mother liquor in step (1) is 4.4-5.5, the soluble solid content is 45-55%, and the reducing sugar content is 12-16%.
[0014] Furthermore, the protein powder in step (1) is corn protein powder, and the indexes thereof are controlled as follows: protein content is 58-62%, and moisture content is 8-10%.
[0015] Furthermore, in step (1), the OD value of the bacterial liquid during inoculation of the brewer's yeast is 20-25, the inoculation amount is 10%, the fermentation temperature is 30-35°C, and the dissolved oxygen DO is 3-10%.
[0016] Furthermore, the flocculant in step (2) is one or two of polyacrylamide, chitosan, sodium carboxymethyl cellulose, and polyaluminium chloride.
[0017] Furthermore, the molecular weight of the membrane used in the nanofiltration membrane system in step (3) is 250Da.
[0018] Furthermore, the evaporation concentration method in step (4) is four-effect evaporator concentration, and the soluble solid content is concentrated to 65-68%, and the discharge temperature is 70°C; the cooling crystallization is 70-50°C with a cooling rate of 10°C / h, and 50-35°C with a cooling rate of 15°C / h; when the temperature is cooled to 35°C, the crystals are separated by an overhead centrifuge.
[0019] Furthermore, in step (4), the fluidized bed drying has an air inlet temperature of 90°C and an air outlet temperature of 50°C.
[0020] Saccharomyces cerevisiae can use some oligosaccharides such as glucose and galactose to grow and produce ethanol, while sodium gluconate is insoluble in ethanol, and ethanol has the effect of reducing viscosity. Protein powder is rich in a variety of amino acids, minerals and vitamins, which can meet the growth and metabolic needs of bacteria.
[0021] By adding protein powder and yeast to the sodium gluconate mother liquor for fermentation, the sugar in the sodium gluconate mother liquor is consumed and the viscosity is reduced. After adding the flocculant, some soluble proteins and other substances are flocculated, so that the purity of the sodium gluconate mother liquor is improved and it is easier to crystallize.
[0022] Solids and yeast cells can be removed by a ceramic membrane system, flocculants can be removed by a plug filter, and sodium gluconate and polysaccharides can be effectively separated by a nanofiltration membrane system. The separated sodium gluconate solution can effectively improve the crystallization rate and extraction rate through evaporation concentration, cooling crystallization and other measures, thereby achieving effective utilization of sodium gluconate mother liquor.
[0023] It can be seen from the above technical scheme that compared with the prior art, the present invention discloses a method for improving the crystallization rate of sodium gluconate mother liquor by fermentation, using saccharomyces cerevisiae to ferment, remove oligosaccharides such as glucose and galactose in the sodium gluconate mother liquor, and the product can reduce the viscosity of the mother liquor, and then remove impurities through a ceramic membrane and a nanofiltration membrane system, which is conducive to the crystallization of sodium gluconate, and the crystallization extraction rate is greater than 58%. The product purity is above 98.5%. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0025] Saccharomyces cerevisiae was purchased from Angel Yeast Co., Ltd.
[0026] Example 1
[0027] A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation, comprising the following specific steps:
[0028] (1) Preparation of reaction system: Sodium gluconate mother liquor (pH = 4.4, soluble solid content of 45%, reducing sugar of 12%) was taken; sodium gluconate mother liquor and corn protein powder (protein content: 58.2%, water content: 8.12%) were added into a fermentation tank in a ratio of 50:1, water was added to dilute to a soluble solid content of 30%, and sodium hydroxide solution was added to adjust the pH to 5.0.
[0029] (2) Fermentation: Add brewer's yeast that has been expanded to a bacterial concentration OD value of 20 for fermentation reaction, the inoculation amount is 10%, the fermentation temperature is controlled at 30-32°C during the fermentation process, the dissolved oxygen DO is 3-5%, and the reaction is carried out for 30 hours.
[0030] (3) Nanofiltration membrane filtration to remove impurities: The above fermentation reaction liquid was filtered at 10m 3 / h is filtered through a ceramic membrane with a pore size of 0.1µm to remove solid matter and brewer's yeast, thereby obtaining a ceramic membrane filtrate; polyacrylamide with a soluble solid content of 0.1% is then added to the ceramic membrane filtrate, stirred evenly, and after reacting for 1h, the flocculants are filtered through a plug-in filter with a pore size of 28μm to obtain a plug-in filter filtrate.
[0031] (4) Press the filter plate filter to filter the liquid at 10m 3 / h through a 250Da nanofiltration membrane system to separate the sodium gluconate and obtain a sodium gluconate clear solution.
[0032] (5) The sodium gluconate clear liquid is concentrated by four-effect evaporation to a soluble solid content of 65%, and the discharge temperature is controlled at 70°C. Then, the liquid is crystallized by gradient cooling. The cooling crystallization control conditions are 70-50°C cooling rate of 10°C / h, and 50-35°C cooling rate of 15°C / h. When the temperature drops to 35°C, the crystals are separated by an overhead centrifuge. The liquid is passed into a fluidized bed for drying, with the inlet air temperature of 90°C and the outlet air temperature of 50°C to obtain the sodium gluconate product. Calculation: Crystallization extraction rate = 60%, and the purity of the finished product is 99.1%.
[0033] Calculation of crystal extraction rate: the mass of crystals after centrifugation divided by the mass of crystals in the solution before centrifugation; the purity of the finished product is determined by the conventional titration method in GB1886.320-2021.
[0034] Example 2
[0035] A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation, comprising the following specific steps:
[0036] (1) Preparation of reaction system: Sodium gluconate mother liquor (pH = 4.32, soluble solid content of 50%, reducing sugar of 14%) was taken; sodium gluconate mother liquor and corn protein powder (protein content: 60.2%, water content: 9.12%) were added into a fermentation tank in a ratio of 55:1, water was added to dilute to a soluble solid content of 33%, and sodium hydroxide solution was added to adjust the pH to 5.2.
[0037] (2) Fermentation: Add brewer's yeast that has been expanded to a bacterial concentration OD value of 23 for fermentation reaction, the inoculation amount is 10%, the fermentation temperature is controlled at 32-34°C during the fermentation process, the dissolved oxygen DO is 5-8%, and the reaction is carried out for 33 hours.
[0038] (3) Nanofiltration membrane filtration to remove impurities: The above fermentation reaction liquid was filtered at 11m 3 / h is filtered through a ceramic membrane with a pore size of 0.1µm to remove solid matter and brewer's yeast, thereby obtaining a ceramic membrane filtrate; polyacrylamide with a soluble solid content of 0.05% and polyaluminium chloride of 0.05% are added to the ceramic membrane filtrate, and the mixture is stirred evenly. After reacting for 1.5h, the flocculants are filtered through a plug filter with a pore size of 28μm to obtain a plug filter filtrate.
[0039] (4) Press the filter plate filter to filter the liquid at 11m 3 / h through a 250Da nanofiltration membrane system to separate the sodium gluconate and obtain a sodium gluconate clear solution.
[0040] (5) The sodium gluconate clear liquid is concentrated by four-effect evaporation to a soluble solid content of 66%, and the discharge temperature is controlled at 70°C. Then, the liquid is crystallized by gradient cooling. The cooling crystallization control conditions are 70-50°C at a cooling rate of 10°C / h and 50-35°C at a cooling rate of 15°C / h. When the temperature drops to 35°C, the crystals are separated by an overhead centrifuge. The liquid is passed through a fluidized bed for drying, with an inlet air temperature of 90°C and an outlet air temperature of 50°C to obtain a sodium gluconate product. Calculation: Crystallization extraction rate = 65%, and the purity of the finished product is 99.5%.
[0041] Example 3
[0042] A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation, comprising the following specific steps:
[0043] (1) Preparation of reaction system: Sodium gluconate mother liquor (pH=5.50, soluble solid content of 55%, reducing sugar of 16%) was taken; sodium gluconate mother liquor and corn protein powder (protein content of 62%, water content of 10%) were added into a fermentation tank in a ratio of 60:1, water was added to dilute the mixture to a soluble solid content of 35%, and sodium hydroxide solution was added to adjust the pH to 5.5.
[0044] (2) Fermentation: Add brewer's yeast that has been expanded to a bacterial concentration OD value of 25 for fermentation reaction, the inoculation amount is 10%, the fermentation temperature is controlled at 33-35℃, the dissolved oxygen DO is 8-10%, and the reaction is carried out for 36 hours.
[0045] (3) Nanofiltration membrane filtration to remove impurities: The fermentation reaction liquid was filtered at 12m 3 / h is filtered through a ceramic membrane with a pore size of 0.1µm to remove solid matter and brewer's yeast, thereby obtaining a ceramic membrane filtrate; polyaluminium chloride with a soluble solid content of 0.1% is then added to the ceramic membrane filtrate, stirred evenly, and after reacting for 2h, the flocculants are filtered through a plug filter with a pore size of 28μm to obtain a plug filter filtrate.
[0046] (4) Press the filter plate filter to filter the liquid at 12m 3 / h through a 250Da nanofiltration membrane system to separate the sodium gluconate and obtain a sodium gluconate clear solution.
[0047] (5) The sodium gluconate clear liquid is concentrated by four-effect evaporation to a soluble solid content of 68%, and the discharge temperature is controlled at 70°C. Then, the liquid is crystallized by gradient cooling. The cooling crystallization control conditions are 70-50°C cooling rate of 10°C / h, and 50-35°C cooling rate of 15°C / h. When the temperature drops to 35°C, the crystals are separated by an overhead centrifuge. The liquid is passed into a fluidized bed for drying, with the inlet air temperature of 90°C and the outlet air temperature of 50°C, to obtain the sodium gluconate product. Calculation: Crystallization extraction rate = 58%, and the purity of the finished product is 98.5%.
[0048] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for increasing the crystallization rate of sodium gluconate mother liquor by fermentation, characterized in that: The specific steps include: (1) Preparation of culture medium: add sodium gluconate mother liquor and protein powder into a fermentation tank at a ratio of (50-60):1, dilute with water to a soluble solid content of 30-35%; adjust the pH to 5.0-5.5 with sodium hydroxide solution, add brewer's yeast, and ferment for 30-36 hours; (2) The fermentation reaction liquid is 10-12m 3 / h through a ceramic membrane with a pore size of 0.1µm to obtain a ceramic membrane filtrate; add a flocculant at a ratio of 0.1% of the soluble solid content in the ceramic membrane filtrate, stir evenly, react for 1-2h, and filter through a plug-in filter with a pore size of 28μm to obtain a plug-in filter filtrate; (3) Press the filter plate filter to filter the liquid at 10-12m 3 / h through the nanofiltration membrane system to obtain a sodium gluconate clear solution; (4) The sodium gluconate clear liquid is evaporated and concentrated to a soluble solid content of 65-68%, and then crystallized by gradient cooling. The crystals are separated by a centrifuge and dried in a fluidized bed to obtain a sodium gluconate product.
2. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: The sodium gluconate mother liquor in step (1) has a pH value of 4.4-5.5, a soluble solid content of 45-55%, and a reducing sugar content of 12-16%.
3. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: The protein powder in step (1) is corn protein powder, and the indexes thereof are controlled as follows: protein content is 58-62%, and moisture content is 8-10%.
4. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: In step (1), when the brewer's yeast is inoculated, the OD value of the bacterial liquid is 20-25, and the inoculation amount is 10%; the fermentation temperature is 30-35° C., and the dissolved oxygen DO is 3-10%.
5. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: The flocculant in step (2) is one or two of polyacrylamide, chitosan, sodium carboxymethyl cellulose and polyaluminium chloride.
6. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: The molecular weight of the membrane used in the nanofiltration membrane system in step (3) is 250Da.
7. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: The evaporation concentration method in step (4) is four-effect evaporator concentration, which is concentrated to a soluble solid content of 65-68% and a discharge temperature of 70°C; the cooling crystallization is 70-50°C at a cooling rate of 10°C / h, and 50-35°C at a cooling rate of 15°C / h; when the temperature is cooled to 35°C, the crystals are separated by an overhead centrifuge.
8. A method for improving the crystallization rate of sodium gluconate mother liquor by fermentation according to claim 1, characterized in that: In step (4), the fluidized bed drying has an air inlet temperature of 90°C and an air outlet temperature of 50°C.