Vitamins are called "ten thousand years" products. They are a kind of organic substances that are necessary to maintain animal life. They are also important active substances to maintain the body's health.

Vitamin C production has two fermentation processes: Reichstein method and two-step fermentation. Impurities in fermentation broth are removed by the use of heat precipitation method for the above two traditional vitamin C extraction process .After the fermentation broth was allowed to settle, it was separated by a cation exchange resin. However, the fermentation broth is passed directly through the ion exchange resin, which can cause serious contamination of the resin surface and reduce the exchange capacity.

Modern extraction process generally applies ultrafiltration membrane gulonic acid fermentation broth production, because the broth protein molecular weight range is generally 1-10kDa, so to choose a certain molecular weight cut-off can remove most of the protein and some macromolecular impurities in place of the traditional heating method to remove protein.

Compared with the traditional process, Gulonic acid fermentation broth has obvious advantages: simple process, fully automatic operation and good stability; the yield is improved, generally reach more than 99% during membrane filtration for removing impurities . At present, integrated membrane technology including ceramic membrane ,ultrafiltration &nanofiltration membrane are applied to vitamin C production enterprises because membrane process has more important feature is the separation of relatively high accuracy, which can be verified from the fermentation broth protein removal rate.

Vitamins: Vitamin C, vitamin B2, vitamin B12 and so on