Adopt spectrophotometry to detect the content of sodium gluconate; Select spectrophotometry to detect pigment content in the solution under the absorption wavelength of 670nm; Adopt iodine B method to measure the content of reduction in solution and sodium gluconate crystallization product.
Get primary crystallization mother liquor 500g, the content of sodium gluconate is 40wt%, adopt commercially available HZ806 resin to carry out decolorization primary crystallization mother liquor, select HZ806 resin chromatography column diameter to be 1cm, the aspect ratio of HZ806 resin chromatography column is 8: 1. The flow rate of the primary crystallization mother liquor through the HZ806 resin chromatography column is 12BV/h; the operating temperature is room temperature.
Adopting commercially available HZ806 resin to decolorize the primary crystallization mother liquor comprises the following steps: (a) pretreating the macroporous adsorption resin and loading it into a chromatography column to obtain a macroporous adsorption resin chromatography column; (b) decolorizing the primary crystallization mother liquor Dilute to a sodium gluconate content of 35% by mass; (c) process the liquid after step (b) through a macroporous adsorption resin chromatography column for adsorption and decolorization to obtain an intermediate crystallization mother liquor; (d) absorb the saturated macroporous The adsorption resin is regenerated.
Commercially available HZ806 resin has an average particle size of 0.3 mm and a water content of 50 wt%. The pretreatment method is: rinse, screen, and soak in ethanol solution for 2 hours, install it in a chromatography column, pass through the resin layer with ethanol at 3 times the bed volume flow rate per hour, and 5 times the resin volume until the effluent is diluted with water and remains unchanged After being treated with ethanol, deionized water is passed through the resin layer at a flow rate of 6 times the bed volume per hour to replace the ethanol.
The regeneration treatment of macroporous adsorption resin HZ806 is washed with 0.1mol/L sodium hydroxide solution, then washed with 60% ethanol solution, and finally washed with deionized water.
Adopting commercially available HZ806 resin to decolorize the primary crystallization mother liquor, the quality of the intermediate crystallization mother liquor obtained is 490g, the content of sodium gluconate is 40wt%, and the depigmentation rate is 20%.
With 490g, sodium gluconate content is the intermediate crystallization mother liquor of 40wt% adopts ion exchange resin to carry out sugar removal. Adopt ion exchange resin to carry out sugar removal to intermediate crystallization mother liquor and comprise the following steps: (I) pack in chromatographic column after ion exchange resin pretreatment, obtain ion exchange resin chromatography column; (II) dilute intermediate crystallization mother liquor to glucose Sodium acid content is 10wt%; (III) the liquid after step (II) is processed is passed through ion-exchange resin chromatography column, and the sodium gluconate in the intermediate crystalline mother liquor is adsorbed on the ion-exchange resin, carries out adsorption treatment; (IV) Perform desorption treatment on the ion exchange resin adsorbed with sodium gluconate to obtain purified crystallization mother liquor; (V) perform regeneration treatment on the ion exchange resin.
The ion exchange resin is selected from commercially available strong base anion exchange resin D201, with an average particle diameter of 0.3 mm and a water content of 50 wt%. The pretreatment method of anion exchange resin D201 is: soak in deionized water for 2 hours, pour out the water, wash with deionized water until clarification, add 4 times the amount of 2mol/L sodium hydroxide solution after dehydration and stir for 4 hours, remove the lye, use Wash with deionized water to neutrality, then add 4 times the amount of 2mol/L hydrochloric acid solution and stir for 4 hours, remove the acid solution, wash with deionized water to neutrality, repeat three times, and finally use sodium hydroxide solution to convert the resin into alkaline (2mol/L /L sodium hydroxide solution), washed with deionized water until neutral.
The operating conditions for using ion exchange resin to remove sugar from the intermediate crystallization mother liquor are:
The operating conditions of the adsorption treatment: the adsorption temperature is 20°C; the flow rate of the intermediate crystallization mother liquor through the ion exchange resin chromatography column is 5BV/h, and after the adsorption is saturated, the ion exchange resin is desorbed;
The operating conditions of the desorption treatment: the desorption liquid is a sodium hydroxide solution of 0.5mol/l, the flow velocity of the desorption liquid through the ion exchange resin chromatography column is 2BV/h, and the desorption temperature is 30°C.
Ion-exchange resin is regenerated as washing with deionized water to neutrality, washing with sodium hydroxide solution with 2 times of column volume and a concentration of 2mol/L, and then washing with deionized water to neutrality for use.
After desugar purification treatment, the concentration of the purified crystallization mother liquor is diluted. For the convenience of material balance, when it is converted into a sodium gluconate solution with a concentration of 35wt%, the quality of the purified crystallization mother liquor is 500g, and the converted purification crystallization mother liquor The content of reducing sugar in the medium is less than 0.5wt%.
With above-mentioned purified crystallization mother liquor and 1000g, after the sodium gluconate fermentation filtrate that sodium gluconate concentration is 40wt% is mixed, get 500g, the mixed solution that sodium gluconate content is 38wt%, puts into the crystallization that has vacuum sealing stirring device Evaporated and crystallized in the device, the vacuum degree of crystallization was 0.08MPa, and the crystallization temperature was controlled to be 64°C to obtain 167.2g of sodium gluconate crystal product, wherein the content of sodium gluconate was 98.54wt%, the total yield of crystallization was 87.68%, and the appearance of the product was white. The chroma is good and the particle size is uniform.