Sodium gluconate is a common and versatile sodium salt of organic acid. Industrial sodium gluconate is commonly used in construction, chemical and other industries. In the construction industry, it can be used as a water reducer and retarder, because adding a certain amount of sodium gluconate to the cement can increase the plasticity and strength of the concrete, has a retarding effect, and can delay the initial and final setting time of the concrete.
At present, the production methods of sodium gluconate in my country mainly include biological fermentation, double enzyme and heterogeneous catalytic oxidation. At present, biological fermentation and double enzymes are mainly used in domestic large-scale industrial production. Due to the use of heavy metal catalysts, the heterogeneous catalytic oxidation method has high toxicity, low yield and purity, and its products generally cannot be used as food additives for food production, so the production process is basically stopped. Let’s take a closer look at these methods .
Biological fermentation method
The biological fermentation method is a relatively traditional production method of sodium gluconate. Among them, Aspergillus niger fermented sodium gluconate technology, the initial sugar concentration is high, and the control temperature is high (the concentration is more than 30%, and the temperature is 40 ℃, which is rare in all fermented organic acids. ), the fermentation process is easy to control, the production is stable and mild, and the large-scale industrial production is easy. This method has the advantages of low cost and convenient quality control, and is currently the main method for domestic industrial production of sodium gluconate. The disadvantage is that the production cycle is long (48-56 h), the mycelium is difficult to filter during the production process, difficult to handle, the number of fermentation equipment is large, the investment is large, and the amount of activated carbon is large.
Heterogeneous catalytic oxidation
The method has simple process and stable reaction . The disadvantage is that after the catalyst used is recycled for a certain number of times, the catalytic efficiency is reduced, the reaction time is prolonged, and even there is basically no catalytic activity, and the catalyst must be scrapped and renewed, thereby increasing the catalyst consumption per unit product and increasing the production cost of sodium gluconate products. . In addition, due to the certain toxicity of metal catalysts, their products are usually not used as food additives in food production, so the application of the products is limited.
Double enzymatic method
The double-enzyme production of sodium gluconate is a newly developed method in recent years, which is mainly suitable for large and medium-sized production, and is suitable for the production of liquid sodium gluconate. Enzymatic production of sodium gluconate is the use of glucose oxidase and catalase and glucose solution for enzymatic reaction, and sodium hydroxide is added during the reaction to finally obtain sodium gluconate. The enzymatic production technology has the advantages of simple technology, mild reaction conditions, high product purity, short production cycle (20-24 h), and less equipment than fermentation methods.
Compared with several other processes, the double-enzymatic production of sodium gluconate has a short process flow, a high degree of automation, and a relatively reduced total investment in equipment. Bacteria contamination, so there is no need for steam sterilization, and steam is basically not consumed; in the production process, oxygen reacts completely, absorbs completely, basically does not emit exhaust gas, and the reaction conversion rate and purity are relatively high. The best process choice for efficiency and cost saving!