Introduction of xanthan gum production processes to streamline xanthan gum toxic, colorless, odorless , viscous low concentrations has a good , and in the case of large shear force and can reduce his tack , is an ideal biological glue in the pharmaceutical industry, can be used for fillers, thickeners, emulsifiers , suspending agents . Xanthan gum is widely applied , not only for the pharmaceutical , xanthan gum was first used in oil exploration , drilling mud to reduce liquidity. Also used in food , beverages, tobacco , pesticides, such as the canned meat plus as xanthan gum, can be frozen into the broth and keep water , beer, xanthan gum , rich foam production ; adding xanthan gum in the pesticides, so pesticides not hierarchical, dependent strengthen and enhance the effective time of the drug . Xanthan gum is made Xanthomonas campestris output of an extracellular secretion , are polysaccharides. Xanthan gum fermentation medium carbon source is usually sucrose, glucose , Xanthomonas easy to use organic nitrogen sources , inorganic nitrogen and difficult to use . The organic nitrogen sources include fish meal peptone , soy peptone , fish meal, soybean meal , bran , etc., which is the best peptone meal . Furthermore , some trace salts added . Such as Fe, Mn, Zn , etc. salts.
Especially calcium and NaH2PO4 and MgSO4, they have xanthan gum synthesis significant role in promoting . According to experience, the ideal ratio of ingredients : glucose (40 g · L-1), citric acid (2.0 g · L-1), NH4NO3 (1.0 g · L-1), K2HPO4 (2.0 g · L-1 ), MgCl2 (0.5g · L-1), Na2SO4 (90mg · L-1), H3BO4 (6mg · L-1), ZnO (6mg · L-1), FeCl3 · 6H2O (20mg · L-1), CaCO3 (20mg · L-1), concentrated HCl (0.12mL · L-1), by the addition of sodium hydroxide and the pH adjusted to 7.0. Inoculum size of 5 to 8 percent . Due to the high viscosity of the medium , xanthan gum fermentation production of high oxygen demand , need a large amount of ventilation , usually 1-0.6m3 / (m3 · min). Fermentation temperature is 25-28 ℃. The initial concentration of the carbon source is generally 2 % to 5% . Fermentation temperature not only affects the yield of xanthan gum , but also to change the structure of the product components. Research indicates that higher temperatures can increase the production of xanthan gum , but reduces the product pyruvate levels , therefore , for improving the yield of xanthan gum , you should choose a temperature at 31 ℃ 33 ℃, and to increase pyruvate content should select the temperature at 27 a 31 ℃. In the fermentation of xanthan gum , the optimum temperature for cell growth is between 24-27 ℃, the optimum temperature of the xanthan gum is produced in a 33 ℃ 30 Xanthan gum is a fermentation starting pH value is generally control of 6.5-7.0 , which is conducive to cell growth and late early xanthan gum synthesis. With output of the product , increasing the acid group . pH to 5 or so. Except broth containing xanthan gum ( about 3% ) , there mycelia End unconsumed carbohydrates, inorganic salts , and large quantities of liquid . Mycelium and other solids which accounted for 20% , 10% water-soluble inorganic salt : If there mycelium solids such as xanthan gum mixed in the finished product , the color of the product will cause poor , bad taste . Thus limiting the use of xanthan gum . Thus , separation and extraction of xanthan gum , the aim of product quality specifications required by the fermentation mash in varying degrees to remove impurities by purification , separation, concentration and drying means to obtain the finished product. Finished of xanthan gum food grade, industrial grade and industrial crude three kinds . 1 . Solvent precipitation method is to add an alcohol solvent such as xanthan gum solution, and the precipitated xanthan gum .
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Method A: The first fermentation broth with 6mol / L HCl acidification , then add xanthan gum to make industrial alcohol precipitation . The precipitate was filtered and successively washed with industrial alcohol with 10% KOH , filtered and the precipitate was dried pulverized , sieved to obtain the finished product . Because of this law and industrial alcohol with HCL direct acidification of precipitation , did not get rid of bacteria , and therefore can only be obtained by industrial-grade xanthan gum. Method B: In order to obtain food grade xanthan gum , based on the increase in the method A centrifugal body and the repeated sterilization with alcohol precipitation , washing operation , thereby increasing the purity of the finished product . Plus a small amount of alcohol fermentation was diluted pretreated bactofugation body , ethanol precipitated and then add xanthan gum. The precipitate was dissolved in water , together with the alcohol to make xanthan gum precipitate , the precipitate was dried, pulverized and sieved to obtain a food-grade product. Solvent precipitation process is simple, high- quality , large-scale production technology is mature , is mainly used in domestic production methods , but the method is the large amount of solvent , solvent recovery equipment to be set , the larger the investment , high production costs . Law extraction yield of 97.7%. 2 . Calcium - industrial alcohol precipitation method under acidic conditions , xanthan gum and xanthan gum, calcium chloride to form a gelatinous precipitate. Acidic removal of the alcohol added calcium ions, so that a short floc . Filtered, and the precipitate was added ethanol with potassium hydroxide solution to adjust the PH . Filtered to obtain industrial products . Compared with solvent Act less solvent consumption , reduce by half the amount of alcohol , but in the finished product into a calcium ion, a slightly gray color of the finished product . Law extraction yield of about 93.2% . 3 . Flocculant and flocculation effect of xanthan gum produced flocculent precipitate , the precipitate is then dehydrated to give a solid- matter content of about 25% wet cake . Polysaccharide with a non-solvent wash under appropriate conditions mentioned above wet cake , so that it becomes water-soluble polysaccharides. Then filtered, and the filter cake was dried soluble . Crushed , sieved to obtain qualified xanthan gum products. The key lies in flocculation flocculation and elution these two steps , select the appropriate flocculants and eluent to control optimum flocculation and elution conditions is a necessary condition for the success achieved by the Act . The flocculant used for the metal salts having a polyvalent cation , typically eluent alcohols such as ethanol . 4 . Law using direct drying drum drying or spray drying method, the direct fermentation broth was dried thereby forming a crude product of industrial grade xanthan gum. This method because there is no separation and purification processes, so poor product quality , limited to occasions xanthan gum mass less demanding use , help to reduce product costs. 5. Modern desalination method using ultrafiltration membrane separation technology of this Act , the polymer xanthan gum and small molecule salts and water ultrafiltration . Xanthan gum can be concentrated broth to 2.5 % to 5 %, while the inorganic salt content reduced from 10% to 0.5% - 1 % and then spray dried. Law Compared with direct drying method , product quality has improved , refined products reached industrial level . 6. Sterilization clarification - ultrafiltration - precipitation mixture was diluted with water broth , and then centrifuged to remove cells , followed by addition broth was concentrated by ultrafiltration , and finally under conditions of pH 11 ~ 13 , and a divalent metal salt with water- miscible organic solvent mixture dubbed as the precipitating agent , xanthan gum precipitation analysis
Out . This method has substantially reduced the amount of the solvent , and the xanthan gum to improve product purity . 7 enzyme treatment - ultrafiltration , this method is treatment with an enzyme fermentation broth , the protein is hydrolyzed so that the broth becomes clear that simplifies this step centrifugation step . Use of this Act , including the enzyme protease, acidic or neutral protease , or a joint action with the enzyme . After enzyme treatment , not only to improve the clarity of the fermentation broth , and the nitrogen content is reduced , improved filter performance , a microporous filtration filtration rate can be increased 3-20 times , product quality has increased. Summing Also , separation and extraction methods xanthan gum a lot, but in the application are restricted by their own conditions , characteristics . In comparison, concentrated and purified fermentation broth using ultrafiltration method is an ideal choice. If the production of industrial grade xanthan gum , can be used enzyme treatment - concentrated by ultrafiltration method. Sterilization using microfiltration - ultrafiltration desalting and dehydration - fluidized bed drying process can be obtained food grade xanthan gum. The advantages of this process as follows: ① no solvent extraction and separation of flocculating agent , solvent recovery is not required , which reduces production costs. Moreover, the operating environment has also been improved , and improved operational safety. Most ② mycelium fermentation broth , solids and inorganic salts are removed , thus greatly improving the quality of the product can reach food-grade requirements. ③ easy to implement continuous operations , reduce labor intensity . Technical difficulties of this Act are: high density , high viscosity glue membrane materials for membrane technology and a higher requirement. The present invention discloses a method for extracting dust xanthan gum , which is added to the volume concentration of alcohol is 50 to 70% of xanthan gum in alcohol fermentation broth was stirred for 30 ~ 90 minutes ; solid-liquid separation to give xanthate gum precipitate ; xanthan gum and then the precipitate was dissolved in water is diluted , and controls the weight of xanthan gum was dissolved at a concentration of from 1 to 4% ; then spray dried , the drying temperature is controlled at 220 ~ 280 ℃, head speed control in 5000 ~ 8000r / min; Finally, the product was sieved to remove 120 mesh product , that was clean xanthan gum. Extraction method of the present invention is xanthan gum , xanthan gum increased dispersion , reducing workplace dust , improved working environment , with good environmental and economic benefits , resulting xanthan gum product of large particles , density, no dust , dissolved quickly , the market demand . A dust extraction technology in the field of xanthan gum : The invention belongs to the technical field of production of xanthan gum , dust extraction method involves xanthan gum . BACKGROUND : xanthan gum , also known as yellow gum , xanthan gum , a natural polysaccharide and important biological polymers , black rot of cabbage Xanthomonas campestris carbohydrates as the main raw material, aerobic produced by fermentation biotechnology . 1952 by the United States Department of Agriculture , Illinois Institute of separation resulting in Lille in northern Peoria cabbage black rot Xanthomonas , make cabbage extract into a water-soluble acidic extracellular heteropolysaccharide obtained . Xanthan gum can be dissolved in cold water and hot water , high viscosity, high acid, alkali, salt properties, high heat stability, suspension, thixotropic , etc., often used as a thickener, emulsifier , suspending agent , stabilizers, and has broad market prospects, are widely used in daily chemical , food , pharmaceutical , oil , textiles , ceramics, printing and other fields. Since xanthan gum has multiple functions, which can occur when using two or more products in the same function , therefore , is a great market potential, production and development prospects of good microbial polysaccharides . From the point of view of domestic sales , the annual production of xanthan gum, most for the food industry , other industrial applications such as oil field is limited to a few sectors , the total market share
The amount is small. In the international market , xanthan gum is widely used not only in the food industry , in oil drilling, EOR , textile, printing and dyeing , ceramics processing, paints , explosives , hydrometallurgy , pharmaceuticals, pesticides , cosmetics and other industries are has a wide range of applications . With foreign dozens of xanthan gum used in dozens of industries compared to the product , we disparities in the application of large, so we need to strengthen the nature of xanthan gum and its research applications in various industries , in order to expand its use in other industries to provide a theoretical basis , and thus it applied to more sectors, generating greater social and economic benefits. Different effects of xanthan gum produced by different manufacturing processes , the traditional extraction process there is a large density of the product pulverized , dust easily dissolved slowly defects. Summary of the Invention : The present invention is to provide a dust extraction xanthan gum , extracts of the prior art to overcome the xanthan gum there is a large density of the product , the dust is easy to dissolve slowly defects. Dust extraction method of the present invention xanthan gum , the point is the following process steps: a ) addition of alcohol in the fermentation broth of xanthan gum , the control volume of the alcohol concentration in the solution is 50 to 70% , 30 to 90 minutes with stirring , the purpose of this step is to remove most of the fermentation broth and organic and inorganic impurities ; 2 ) step 1 ) was subjected to solid-liquid separation to obtain a precipitate xanthan gum ; 3 ) step 2 ) is separated out xanthan gum was dissolved precipitate was diluted with water , and controlling the weight of xanthan gum dissolved concentration of 1 to 4% ; 4 ) in step 3 ) was obtained by spray drying, drying in a controlled temperature 220 ~ 280 ℃, the head speed control 5000 ~ 8000r/min, which is aimed at the control of the particle shape of water while ensuring qualified product is not damaged and its properties , the viscosity of the xanthan gum of this great product, we can make use of this spray drying pumpability liquid paste to form a uniform particulate solid products, and the product obtained has a good uniformity, flowability or solubility , high purity and good quality ; 5 ) the product was sieved to remove 120 mesh product, i.e., a clean xanthan gum. Extraction method of the present invention is xanthan gum , xanthan gum increased dispersion of dust can reduce workplace , improve working environment , with good environmental and economic benefits , resulting xanthan gum product of large particles , the density small , no dust , dissolved quickly , the market demand . Specific Embodiment: a dust extraction embodiment xanthan gum embodiment , the following process steps: a ) addition of alcohol in the fermentation broth of xanthan gum , the volume concentration of the control solution of 50% alcohol and stirred for 30 minutes ; 2 ) step 1 ) was subjected to solid-liquid separation to obtain a precipitate xanthan gum ; 3 ) step 2 ) in the separated precipitate was dissolved xanthan gum was diluted with water , and to control the weight of xanthan gum was dissolved at a concentration of 1% ; 4 ) in the step 3 ) was obtained by spray drying , the drying temperature is controlled at 220 ℃, head speed control in 5000r/min; 5) the product was sieved to remove 120 mesh product, i.e., a xanthan gum dust . Example 2 According to a method of extracting dust embodiment of xanthan gum , the following process steps:
A ) addition of alcohol in the fermentation broth of xanthan gum , the control volume of the solution concentration of 70% ethanol , stirred 90 minutes ; 2 ) step 1 ) was subjected to solid-liquid separation to obtain a precipitate xanthan gum ; 3) step 2 ) separating the precipitate xanthan gum is diluted with water to dissolve , and to control the weight of xanthan gum was dissolved at a concentration of 4% ; 4 ) in the step 3 ) was obtained by spray drying, drying temperature was controlled at 280 ℃, nozzle speed control at 8000r/min. Example 3 according to Example 1, the dust extraction xanthan gum , the following process steps: a ) addition of alcohol in the fermentation broth of xanthan gum , the concentration of the control solution of 65% by volume of alcohol , and stirred 70 minutes ; 2 ) step 1 ) was subjected to solid-liquid separation to obtain a precipitate xanthan gum ; 3 ) step 2 ) is separated precipitate xanthan gum is diluted with water to dissolve and control the dissolved concentration by weight of xanthan gum 3 % ; 4 ) in the step 3 ) was obtained by spray drying, drying temperature was controlled at 250 ℃, head speed control in 7000r/min.
