Lactic acid is used as a plant growth regulator to promote crop growth and increase yield. It can be used in: almonds, apples, citrus, pineapples, plums, walnuts, cherries, grapes, strawberries, sugar cane, tomatoes, green peppers, lettuce, beans, cabbage, cabbage, Cauliflower, cotton, corn, etc. Lactic acid exists widely in nature and can be rapidly generated and degraded in soil.
What is lactic acid and the history of lactic acid？
As early as 1780, the Swedish chemist Sheele discovered lactic acid from waste milk; the production of lactic acid by fermentation originated from the natural fermentation of Boutron and Fremy in 1941; the industrial production of lactic acid by pure fermentation was started by Charles E. Avery in 1881. began; and large-scale industrial production of L-lactic acid was formed in the early 1990s. In 1982, the world’s lactic acid production was 24,000 to 28,000 tons, which increased to 30,000 tons in 1989, of which 50% to 60% was produced by fermentation, mainly DL-type lactic acid and calcium lactate. In recent years, in studies to eliminate the “white pollution” of plastic products, countries around the world have discovered that plastic films made of L-lactic acid polymer are 100% biodegradable. In view of the harmful effects of D-lactic acid on the human body, the World Health Organization advocates the use of L-lactic acid and not the use of DL-lactic acid in the fields of food and medicine. Therefore, there has been a breakthrough development in the production of L-lactic acid. The Netherlands, Brazil, Spain, the United States, and Japan have successively expanded and built L-lactic acid plants of considerable scale, especially the United States. It is estimated that the current world lactic acid production reaches 100,000 tons/year, while the production capacity of the United States is about 45,000 tons/year.
A.E.stally Company was originally the only lactic acid production plant in the United States, with an annual output of approximately 7,300 tons. In 1995, the company announced that it would build another lactic acid plant, which would be put into operation in April 1997. ADM claims to have doubled its production of lactic acid based on the existing annual output of 9,000 to 18,200 tons of lactic acid. According to estimates by relevant Japanese experts, the world’s L-lactic acid consumption will reach 3 million tons. Our country has long carried out a large amount of research work on lactic acid production strains and processes. In 1944, Chongqing Zhenyuan Chemical Factory fermented Lactobacillus delbrueckii to produce calcium lactate. At present, there are more than a dozen lactic acid production plants in my country, which use fungal enzyme preparations to replace the traditional saccharification of furfural yeast for industrial production of DL-lactic acid and calcium lactate. However, the scale is small and the production process and equipment are old, so the yield is low and the cost is high. The current production capacity is about 10,000 tons/year.
Lactic acid and its derivatives
Lactic acid and its derivatives are widely used in food (such as beverages, wine, cans, jams, preserves, etc.), medicine, chemical industry, etc. as sour agents, preservatives, and fortifiers. In the food industry, lactic acid is very popular among users because it has stronger sensory acidity and pure sour taste than citric acid, and does not require filtration when used. If used in conjunction with citric acid, malic acid, etc., it will give the food a richer and softer sour taste. Used in baked goods, it can extend the shelf life and improve the quality. Derivatives of lactic acid (such as calcium lactate, zinc lactate and ferrous lactate) are not only fortifiers of food, beverages and health products, but also drugs for the treatment of certain metal element deficiencies. In addition, sodium lactate is an important raw material for large-scale infusion to treat acidosis. Esters of lactic acid, such as ethyl lactate, are extremely important flavoring agents and are the main aroma components of many famous liquors. Ethyl lactate is indispensable for the flavoring of liquors. Butyl lactate is an excellent solvent used in paint production.
Lactic acid, especially L-lactic acid, due to its right-handedness, is used in the above fields, which greatly improves safety, is harmless to humans and animals, and has a strong bactericidal effect. Its bactericidal ability is that of citric acid and tartaric acid. , several times that of succinic acid. According to literature, adding 3% citric acid, tartaric acid, and succinic acid to 10% sugar solution will cause it to go rancid after 2 to 3 days. However, when the same amount of 3% lactic acid was added, no abnormality appeared after one month. Escherichia coli, cholera bacteria, and typhoid bacteria were added to a solution containing 10% sugar. 0.1% lactic acid was added to the sugar solution. After 3 hours, all these bacteria died. This is something that other organic acids cannot compete with. Therefore, lactic acid can be directly used as a disinfectant in operating rooms, wards, laboratories, workshops and other places. In addition, it is the main raw material for the production of biodegradable plastics that eliminate white pollution. This kind of plastic can be completely degraded into carbon dioxide and water in nature, and will not harm the environment like the polyethylene, polypropylene, polystyrene and other plastics currently used. It has become a commodity in Europe, America and Japan and is developing rapidly. L-lactic acid is also the main raw material for the production of highly efficient, low-toxic, and safe phenoxypropionic acid herbicides, which has been put into production in my country. In addition, special treatises can be found on the application of L-lactic acid in medical materials and special feeds.