阅读说明：本技术 植酸钙的制备方法 (Preparation method of calcium phytate ) 是由 由文颖 卢金帅 王国成 于 2021-08-12 设计创作，主要内容包括：本发明属于生物化工技术领域,具体涉及一种植酸钙的制备方法。将脱脂米糠和根瘤菌加入到LB液体培养基中发酵,得到发酵液；发酵液离心后取上清液,将上清液喷洒到碱性物质上,搅拌,得到混合液；混合液过滤,得到沉淀；沉淀经洗涤、干燥得到植酸钙。本发明试剂消耗小、成本低,制得的植酸钙产品的回收率高、纯度高,回收率可达99％以上,纯度可达93％以上。(The invention belongs to the technical field of biochemical engineering, and particularly relates to a preparation method of calcium phytate. Adding defatted rice bran and rhizobium into an LB liquid culture medium for fermentation to obtain fermentation liquor; centrifuging the fermentation liquor, taking supernatant, spraying the supernatant onto alkaline substances, and stirring to obtain a mixed solution; filtering the mixed solution to obtain a precipitate; washing and drying the precipitate to obtain the calcium phytate. The method has the advantages of low reagent consumption and low cost, and the prepared calcium phytate product has high recovery rate and high purity, wherein the recovery rate can reach more than 99 percent, and the purity can reach more than 93 percent.)

1. A preparation method of calcium phytate is characterized in that defatted rice bran and rhizobia are added into an LB liquid culture medium for fermentation to obtain fermentation liquor; centrifuging the fermentation liquor, taking supernatant, spraying the supernatant onto alkaline substances, and stirring to obtain a mixed solution; filtering the mixed solution to obtain a precipitate; washing and drying the precipitate to obtain the calcium phytate.

2. The method of claim 1, wherein the defatted rice bran has a mesh size of 40 to 60 mesh.

3. The method for preparing calcium phytate according to claim 1, wherein the rhizobia is one of rhizobia phaseoloides, rhizobia meliloti or rhizobia abrotanum.

4. The method for producing calcium phytate according to claim 1, wherein the rhizobia is activated rhizobia; the preparation method of the activated rhizobia comprises the steps of inoculating the rhizobia into an LB solid culture medium for slant culture, and then inoculating the rhizobia into an LB liquid culture medium for shake culture to obtain the rhizobia.

5. The method for producing calcium phytate according to claim 1, wherein the inoculation amount of rhizobia is 2 to 4%.

6. The method for preparing calcium phytate according to claim 1, wherein the ratio of the defatted rice bran to the LB liquid medium is 1: 10-15, the weight of the defatted rice bran is g, and the weight of the LB liquid culture medium is ml.

7. The method for preparing calcium phytate according to claim 1, wherein the fermentation temperature is 28-30 deg.C and the fermentation time is 4-8 days.

8. The method for preparing calcium phytate according to claim 1, wherein the alkaline substance is nano calcium oxide or nano calcium hydroxide.

9. The method for preparing calcium phytate according to claim 1, wherein the filtration of the mixed solution is performed when the pH of the mixed solution is 6.5-7.0.

10. The method for preparing calcium phytate according to claim 1, wherein the washing is performed 1-3 times by using deionized water, and the drying temperature is 60-80 ℃.

Technical Field

The invention belongs to the technical field of biochemical engineering, and particularly relates to a preparation method of calcium phytate.

Background

Calcium phytate is calcium salt of phytic acid, widely distributed in plant, is main ingredient of plant seed, and can protect seed from oxidation and loss during storage, and is contained in cereal seed coat (such as rice bran) and beans at high content. Calcium phytate is an important chemical raw material, and has important application in daily chemical industry, pharmaceutical industry, food industry and the like. For example, when used in the food industry for the culture of alcoholic yeast, potassium phosphate is replaced to make the ethanol component of yeast proliferated more delicious; the oil industry can be used for refining high-purity vegetable edible oil to improve the refining rate; the photosensitive emulsion can be used for preparing flat plate desensitizing liquid and a positive photosensitive flat plate for pre-sensitization in the printing and photosensitive material industry; the oral medicine prepared from refined calcium phytate in pharmaceutical industry has effects of promoting metabolism, restoring phosphorus balance in vivo, nourishing brain, and treating neuritis, neurasthenia and infantile rickets. In addition, in industrial production, the liquid calcium phytate can be directly used for producing inositol without being dried, or most of calcium and magnesium ions in the calcium phytate can be removed by weak acid after washing, and then the phytic acid is prepared by ion exchange. In recent years, as calcium phytate has wide application and higher economic value, the demand of calcium phytate in food industry and medicine industry at home and abroad is rapidly increased, and the research and development strength of various countries in the world is increased.

At present, acid-base neutralization precipitation method and resin adsorption method are commonly adopted in the production of calcium phytate. The acid-base neutralization precipitation method is to soak the raw materials with strong acid such as hydrochloric acid and the like, and then to neutralize the precipitate with alkaline solution such as calcium hydroxide or sodium hydroxide and the like, so as to obtain the calcium phytate product. The acid-base neutralization precipitation method has the defects of low extraction rate, large reagent consumption, high cost, large pollution and the like. The resin adsorption method is that the raw materials are adsorbed by resin, and then eluted by strong acid such as hydrochloric acid to obtain eluent, the eluent is neutralized by alkaline reagent such as calcium hydroxide to obtain precipitate, and the precipitate is filtered and dried to obtain the calcium phytate product. The resin adsorption method has complex process and high production cost, the adsorption resin is easy to block in the production process, so that the yield of the calcium phytate is reduced, and the adsorption resin needs a large amount of labor and time to clean, so that the working efficiency is low.

Chinese patent CN 103242362A discloses a production method for preparing high-purity calcium phytate by membrane technology, which comprises the following specific operation steps: (1) crushing and acid-leaching defatted rice bran; (2) filtering with a frame plate to obtain a combined filtrate; (3) performing ultrafiltration, and collecting the obtained membrane permeate and retentate; (4) adding saturated lime water and sodium hydroxide solution for neutralization, and collecting two kinds of precipitation liquid; (5) micro-filtering, collecting the trapped fluid to obtain two kinds of liquid calcium phytate; (6) drying to obtain two kinds of solid calcium phytate. In the patent, a large amount of acid reagent is still needed for acid leaching, the reagent consumption is large, the pollution is serious, the membrane needs to be cleaned regularly, and the working efficiency is low.

Chinese patent CN 104045665 a discloses a separation and purification method of phytin, which comprises the following steps: get there is119m of corn soaking water with organic phosphorus content of 0.6 percent³Settling for 10 hours through a fast flow tank; adsorption: the supernatant fluid enters a column filled with 7 tons of treated anion exchange resin, the type D315 of the resin, the adsorption ratio of the resin to the wastewater is 1:17, and the sample loading flow rate is controlled to be 3 times of the column volume per hour; and (3) analysis and elution: blowing out corn water remained in the column by using compressed air, feeding tap water with the volume of 1 time of the column in the reverse direction, preparing, eluting the resin by 6.5 percent hydrochloric acid at the speed of 2 times of the column volume per hour for 3 hours, blowing out eluent in the column by using the compressed air, washing the resin by using the tap water with the volume of 1 time of the column, and mixing to obtain eluent; neutralizing: preparing 16% suspension with calcium hydroxide, gradually adjusting the eluate to pH 7; the plate-frame filtration is divided into two stages, the first-stage filter pressing is to primarily separate out the phytin solid in the phytin mixed solution, and the primary filtrate is recycled for preparing the eluent and the neutralizer; washing the phytin separated by the first-stage filter pressing again by using 3 times of clear water, and then sending the washed phytin into a second-stage filter pressing to separate relatively pure phytin. The resin in the patent needs to be eluted by a large amount of hydrochloric acid, the consumption of the hydrochloric acid is large, the environment is polluted, and the resin needs to be cleaned regularly, so that time and labor are wasted.

Chinese patent CN 107298693A discloses a preparation method of high-purity phytin, which comprises the following steps of mixing rice bran and water according to a certain proportion, and fully stirring; adding high-purity hydrochloric acid into the mixed solution of rice bran and water to keep the pH value of the mixed solution within a certain value, and extracting the mixed solution; adding an additive for removing protein, starch, ash and saccharides into the liquid obtained by extraction, and then filtering the liquid through filtration and ion exchange to obtain a high-purity diluted phytic acid solution; adding high-purity calcium magnesium oxide or high-purity calcium magnesium hydroxide into the high-purity phytic acid diluted solution for reaction, and adding a high-purity sodium carbonate aqueous solution for pH regulation; and carrying out filter pressing, washing and drying on the solution after reaction to obtain the high-purity phytin solid. In the patent, a large amount of hydrochloric acid is needed, so that the environmental pollution is serious; in addition, in order to remove impurities such as protein, starch, ash, saccharides and the like, an additive is additionally added for treatment, so that the steps are complicated, and the cost is high.

At present, there is a need to provide a method for preparing calcium phytate with low reagent consumption, low cost and less pollution.

Disclosure of Invention

The invention aims to provide a preparation method of calcium phytate, which has the characteristics of low reagent consumption, low cost and low pollution, and the prepared calcium phytate product has high recovery rate and high purity.

The preparation method of the calcium phytate comprises the steps of adding defatted rice bran and rhizobium into an LB liquid culture medium for fermentation to obtain a fermentation liquid; centrifuging the fermentation liquor, taking supernatant, spraying the supernatant onto alkaline substances, and stirring to obtain a mixed solution; filtering the mixed solution to obtain a precipitate; washing and drying the precipitate to obtain the calcium phytate.

The mesh number of the defatted rice bran is 40-60 meshes.

The rhizobia is one of bean rhizobia, alfalfa rhizobia or acacia rhizobia.

The rhizobia is activated rhizobia; the preparation method of the activated rhizobia comprises the steps of inoculating the rhizobia into an LB solid culture medium for slant culture, and then inoculating the rhizobia into an LB liquid culture medium for shake culture to obtain the rhizobia.

The inoculation amount of the rhizobia is 2-4%.

The ratio of the defatted rice bran to the LB liquid culture medium is 1: 10-15, the weight of the defatted rice bran is g, and the weight of the LB liquid culture medium is ml.

The fermentation temperature is 28-30 ℃, and the fermentation time is 4-8 days.

The alkaline substance is nano calcium oxide or nano calcium hydroxide.

The mixed solution is filtered when the pH value of the mixed solution is 6.5-7.0.

The washing is carried out for 1 to 3 times by using deionized water.

The drying temperature is 60-80 ℃.

The preparation method of the calcium phytate comprises the following steps:

(1) pulverizing defatted rice bran, and sieving with 40-60 mesh sieve to obtain processed defatted rice bran;

(2) inoculating rhizobium into LB solid culture medium, and performing slant culture at 28-30 ℃ for 4-5 days; then inoculating into LB liquid culture medium, culturing for 3-5 days at 28-30 deg.C under the condition of 128-;

(3) adding the treated defatted rice bran obtained in the step (1) and the activated rhizobia obtained in the step (2) into an LB liquid culture medium for fermentation to obtain a fermentation liquid;

(4) centrifuging the fermentation liquor, taking supernatant, continuously spraying the supernatant on an alkaline substance, and stirring to obtain a mixed solution;

(5) stopping adding the supernatant and stirring when the pH of the mixed solution is 6.5-7.0, and filtering to obtain precipitate;

(6) washing and drying the precipitate to obtain the calcium phytate.

When the pH of the mixed solution is 6.5-7.0 in the step (5), if the remaining supernatant is not treated, the remaining supernatant can be treated in the following two ways:

the first method comprises the following steps: when the pH value of the mixed solution is 6.5-7.0, adding alkaline substances into the mixed solution to increase the pH value of the mixed solution, adding the residual supernatant into the mixed solution, and continuing stirring; repeating the steps until all the supernatant is added, and filtering to obtain a precipitate.

And the second method comprises the following steps: and (5) repeating the step (4) and the step (5) on the rest supernatant until the supernatant is completely added, combining all obtained precipitates, washing and drying the combined precipitates to obtain the calcium phytate.

In the prior art, inorganic strong acid such as hydrochloric acid is generally adopted to leach raw materials, the consumption of reagents such as hydrochloric acid is large, the production cost is high, the environment is affected by using a large amount of inorganic strong acid such as hydrochloric acid, and a large amount of hydrochloric acid-containing wastewater generated in the production process is difficult to treat and has high treatment cost. And as the acid leaching process continues, inorganic strong acid such as hydrochloric acid and the like is gradually consumed, the leaching efficiency is gradually reduced, and finally the recovery rate of the prepared calcium phytate product is low. The impurities such as protein and the like contained in the raw materials can not be effectively removed in the production process, and the purity of the calcium phytate product is greatly reduced.

Because the rhizobium can release a large amount of hydrogen ions and secrete a plurality of organic acids during the fermentation, the invention leaches the defatted rice bran through the large amount of hydrogen ions and the plurality of organic acids secreted during the fermentation of the rhizobium.

The invention adopts hydrogen ions and organic acid generated by fermentation for leaching, and inorganic strong acid such as hydrochloric acid is not required to be added for leaching, so that the pollution problem of inorganic acid leaching is effectively avoided. Moreover, rhizobium can continuously secrete hydrogen ions and organic acid in the fermentation process, so that the hydrogen ions and the organic acid in the fermentation liquor are always kept at a high concentration level, the leaching efficiency is high, the leaching effect is good, and the recovery rate of the finally prepared calcium phytate product is high.

The hydrogen ions and organic acid secreted by the rhizobia not only greatly reduce the pH of the fermentation liquor, but also denaturalize and precipitate the protein contained in the defatted rice bran, and remove the protein through centrifugation, so that the purity of the final product is greatly improved.

Calcium phytate has a relatively high solubility at relatively low pH and a relatively low or even insoluble solubility at high pH, so in the prior art, alkaline substances such as calcium hydroxide are usually added into an acid leaching solution for neutralization and precipitation, but in order to increase the pH and effectively precipitate the calcium phytate, a large amount of alkaline substances such as calcium hydroxide are required to be added to neutralize inorganic strong acids such as hydrochloric acid and the like in the acid leaching solution, so that the consumption of the alkaline substances is large, and the production cost is increased. And when alkaline substances such as calcium hydroxide are added to neutralize the acid leaching solution, the pH value gradually rises from low to high, and calcium phytate can be precipitated and separated when the pH value is more than 5. In the prior art, the pH value is generally adjusted to 5-6, namely precipitation, filtration and separation are carried out, but partial phytic acid still exists in the acid leaching solution, and the phytic acid is not effectively extracted in the form of calcium phytate, so that the recovery rate of the calcium phytate product is greatly reduced; in order to sufficiently precipitate calcium phytate, a large amount of alkaline substances such as calcium hydroxide needs to be added to increase the pH value, so that the consumption of the alkaline substances is increased, and the production cost is remarkably increased.

In the invention, the supernatant is directly sprayed on the alkaline substance, so that the supernatant is always neutralized in an alkaline environment, and the precipitation is more complete. The alkaline substance adopts nano calcium oxide or nano calcium hydroxide, and the nano calcium oxide or nano calcium hydroxide has the advantages of higher specific surface area, high solubility, small particle size and high reaction activity, and can be fully neutralized and precipitated with supernatant.

The invention has the following beneficial effects:

(1) because the rhizobium has the capacity of secreting hydrogen ions and various organic acids, the hydrogen ions and the organic acids generated by rhizobium fermentation are used for leaching the defatted rice bran, so that the method effectively avoids the use of a large amount of reagents such as hydrochloric acid and the like, and also avoids the problem of environmental pollution caused by the use of inorganic acids.

(2) The invention adopts the rhizobium fermentation mode to leach the defatted rice bran, has high leaching efficiency and good leaching effect, and is environment-friendly and pollution-free in the fermentation process.

(3) The invention directly sprays the supernatant onto the alkaline substance, so that the pH of the obtained mixed solution is always maintained in a higher range, and the neutralization and precipitation are more sufficient and complete.

(4) Compared with the conventional calcium oxide or calcium hydroxide, the nano-scale calcium oxide or nano-scale calcium hydroxide has higher specific surface area, high solubility, small particle size and high reaction activity, and can be more fully neutralized and precipitated with the supernatant liquid.

(5) The method has the advantages of low reagent consumption and low cost, and the prepared calcium phytate product has high recovery rate and high purity, wherein the recovery rate can reach more than 99 percent, and the purity can reach more than 93 percent.

Detailed Description

The present invention is further described below with reference to examples.

The rhizobia used in the examples are commercially available products, and the rhizobia phaseolus is rhizobia phaseolus BMZ070303 (nivalin boat biotechnology limited), the rhizobia meliloti is rhizobia meliloti AS 1.166M 010 (shanghai xuan biotechnology limited), and the rhizobia abri is rhizobia abri BK-J65630 (shanghai silk science limited).

Example 1

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 60-mesh sieve to obtain treated defatted rice bran, and determining the content of calcium phytate in the defatted rice bran to be 12%;

(2) inoculating rhizobium phaseolus BMZ070303 into an LB solid culture medium, and performing slant culture at 28 ℃ for 5 days; then inoculating the strain into an LB liquid culture medium, and performing shake culture for 5 days at the temperature of 28 ℃ and the speed of 130r/min to obtain activated bean rhizobia;

(3) adding 1kg of the processed defatted rice bran obtained in the step (1) and the activated bean rhizobia obtained in the step (2) into 12L of LB liquid culture medium, and fermenting at 28 ℃ for 6 days to obtain fermentation liquor, wherein the inoculation amount of the activated bean rhizobia is 3%;

(4) centrifuging the fermentation liquor, taking supernatant, continuously spraying the supernatant onto 18g of nano calcium hydroxide, and stirring to obtain a mixed solution;

(5) when the pH value of the mixed solution is 7.0, stopping adding the supernatant and stopping stirring, and filtering to obtain a precipitate;

(6) repeating the step (4) and the step (5) on the rest supernatant until the supernatant is completely added, and combining all obtained precipitates;

(7) washing the combined precipitate with deionized water for 2 times, and drying at 80 ℃ to obtain 125.68g of calcium phytate; the purity of calcium phytate is 95.1%, and the recovery rate of calcium phytate is 99.6%.

Example 2

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 40-mesh sieve to obtain treated defatted rice bran, and determining the content of calcium phytate in the defatted rice bran to be 9.6 percent;

(2) inoculating Rhizobium meliloti AS 1.166M 010 into LB solid culture medium, and performing slant culture at 30 ℃ for 4 days; then inoculating the strain into an LB liquid culture medium, and performing shake culture for 4 days at the temperature of 30 ℃ and the speed of 128r/min to obtain activated alfalfa rhizobia;

(3) adding 1kg of the treated defatted rice bran obtained in the step (1) and the activated alfalfa rhizobia obtained in the step (2) into 10L of LB liquid culture medium, and fermenting at 30 ℃ for 4 days to obtain fermentation liquor, wherein the inoculation amount of the activated alfalfa rhizobia is 2%;

(4) centrifuging the fermentation liquor, taking supernatant, continuously spraying the supernatant onto 15g of nano calcium hydroxide, and stirring to obtain a mixed solution;

(5) when the pH value of the mixed solution is 6.5, stopping adding the supernatant and stopping stirring, and filtering to obtain a precipitate;

(6) repeating the step (4) and the step (5) on the rest supernatant until the supernatant is completely added, and combining all obtained precipitates;

(7) washing the combined precipitate with deionized water for 3 times, and drying at 60 ℃ to obtain 100.77g of calcium phytate; the purity of calcium phytate is 94.6%, and the recovery rate of calcium phytate is 99.3%.

Example 3

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 50-mesh sieve to obtain treated defatted rice bran, and measuring the content of calcium phytate in the defatted rice bran to be 10.2%;

(2) inoculating rhizobium abri BK-J65630 to LB solid culture medium, and slant culturing at 29 deg.C for 4 days; then inoculating into LB liquid culture medium, culturing for 3 days at 29 deg.C and 129r/min to obtain activated Rhizobium abri;

(3) adding 1kg of the processed defatted rice bran obtained in the step (1) and the activated acacia rhizobia obtained in the step (2) into 15L of LB liquid culture medium, and fermenting at 29 ℃ for 8 days to obtain fermentation liquor, wherein the inoculation amount of the activated acacia rhizobia is 4%;

(4) centrifuging the fermentation liquor, taking supernatant, continuously spraying the supernatant onto 12g of nano calcium oxide, and stirring to obtain a mixed solution;

(5) when the pH value of the mixed solution is 6.8, stopping adding the supernatant and stirring, supplementing 12g of nano calcium oxide into the mixed solution, adding the remaining supernatant into the mixed solution, and continuing stirring; repeating the steps until all the supernatant is added, and filtering to obtain a precipitate;

(6) washing the precipitate with deionized water for 1 time, and drying at 70 ℃ to obtain 108.09g of calcium phytate; the purity of calcium phytate is 93.8%, and the recovery rate of calcium phytate is 99.4%.

Comparative example 1

(1) Acid leaching: after being crushed, the defatted rice bran passes through a 40-mesh sieve, and 2kg of defatted rice bran is weighed according to the weight ratio of 1: 10 adding water, adjusting the pH value to 3.0 by using 0.2mol/L hydrochloric acid, heating to 40 ℃, keeping the temperature constant, continuously stirring, and maintaining for 2.5 hours;

(2) frame plate filtration: cooling the pickle liquor, squeezing and filtering with frame plate filter cloth, filtering twice with 100-mesh filter cloth, filtering twice with 200-mesh filter cloth, collecting filtrate, washing filter residue for 3 times, and mixing filtrates;

(3) and (3) ultrafiltration: carrying out ultrafiltration separation on the combined filtrate by using JY-SUF60 membrane equipment, selecting an ultrafiltration membrane with the aperture of 500A degrees, and separating the combined filtrate by using the ultrafiltration membrane under the pressure condition of 0.2 MPa; adding appropriate amount of water at proper time during membrane separation for dialysis to increase the amount of permeate, adding water accounting for 30% of the total amount of the combined filtrate at proper time in 3 batches, and collecting the obtained membrane permeate and trapped fluid;

(4) neutralizing: respectively adding fresh saturated limewater into the membrane permeation solution and the trapped fluid while stirring, adjusting pH, when the pH is 6.0, adjusting pH to 7 with 15% sodium hydroxide solution, layering the solution, detecting whether free phytate ions exist in the supernatant with saturated calcium chloride solution, standing for 2h, discharging the supernatant, and collecting two precipitation solutions;

(5) and (3) microfiltration: carrying out microfiltration separation on the two kinds of precipitation solution by using JY-SMF300 microfiltration membrane equipment respectively, wherein the aperture of a microfiltration membrane is 5 mu m, the pressure is 0.2MPa, and collecting trapped solution to obtain two kinds of liquid calcium phytate;

(6) and (3) drying: drying the two separated liquid calcium phytates in an infrared drying oven at 70 deg.C to obtain two calcium phytates, and weighing. The membrane permeation liquid obtains 100.4g of solid calcium phytate with the purity of 82.87 percent, the trapped liquid obtains 12.8g of solid calcium phytate with the purity of 69.36 percent, and the yield of the dry product of the calcium phytate is 12.5 percent calculated according to the raw material of the degreased rice bran.

Comparative example 2

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 60-mesh sieve to obtain treated defatted rice bran, and determining the content of calcium phytate in the defatted rice bran to be 12%;

(2)1kg of defatted rice bran is stirred and soaked for 8 hours at room temperature by using a hydrochloric acid solution with the concentration of 20%, 10g of urea is added while soaking is carried out, and after soaking is finished, filtering is carried out to obtain a filtrate, wherein the ratio of the defatted rice bran to the hydrochloric acid solution is 1: 9, the degreased rice bran is counted by g, and the hydrochloric acid solution is counted by ml;

(3) adding lime milk into the filtrate for neutralization, stirring, adjusting the pH value to 7.0, filtering to obtain precipitate, drying the precipitate at 80 ℃ to obtain 125.33g of calcium phytate, wherein the purity of the calcium phytate is 78.8 percent, and the recovery rate of the calcium phytate is 82.3 percent.

Comparative example 3

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 60-mesh sieve to obtain treated defatted rice bran, and determining the content of calcium phytate in the defatted rice bran to be 12%;

(2)1kg of defatted rice bran is stirred and soaked for 8 hours at room temperature by using a hydrochloric acid solution with the concentration of 20%, 10g of urea is added while soaking is carried out, and after soaking is finished, filtering is carried out to obtain a filtrate, wherein the ratio of the defatted rice bran to the hydrochloric acid solution is 1: 9, the degreased rice bran is counted by g, and the hydrochloric acid solution is counted by ml;

(3) continuously spraying the filtrate on 18g of nano calcium hydroxide, and stirring to obtain a mixed solution;

(4) when the pH value of the mixed solution is 7.0, stopping adding the filtrate and stirring, and filtering to obtain a precipitate;

(5) repeating the step (3) and the step (4) on the rest filtrate until the filtrate is completely added, and combining all obtained precipitates;

(6) washing the combined precipitate with deionized water for 2 times, and drying at 80 ℃ to obtain 129.73g of calcium phytate; the purity of calcium phytate is 80.2%, and the recovery rate of calcium phytate is 86.7%.

Comparative example 4

(1) Crushing the defatted rice bran, sieving the crushed defatted rice bran with a 60-mesh sieve to obtain treated defatted rice bran, and determining the content of calcium phytate in the defatted rice bran to be 12%;

(2) inoculating rhizobium phaseolus BMZ070303 into an LB solid culture medium, and performing slant culture at 28 ℃ for 5 days; then inoculating the strain into an LB liquid culture medium, and performing shake culture for 5 days at the temperature of 28 ℃ and the speed of 130r/min to obtain activated bean rhizobia;

(3) adding 1kg of the processed defatted rice bran obtained in the step (1) and the activated bean rhizobia obtained in the step (2) into 12L of LB liquid culture medium, and fermenting at 28 ℃ for 6 days to obtain fermentation liquor, wherein the inoculation amount of the activated bean rhizobia is 3%;

(4) centrifuging the fermentation liquor, taking supernatant, adding lime milk into the supernatant for neutralization, stirring, adjusting the pH to 7.0, and filtering to obtain a precipitate;

(5) washing the precipitate with deionized water for 2 times, and drying at 80 ℃ to obtain 122.73g of calcium phytate; the purity of calcium phytate is 92.4%, and the recovery rate of calcium phytate is 94.5%.