Manufacture of acid urease by lactobacillus fermentumfermentation

Abstract

Ethyl carbamate can be found in fermented foods and alcoholic beverages, such as sake, beer and wine. It is considered as a carcinogenic compound for some animals, and probably carcinogenic to humans, as well. Ethyl carbamate is formed by a chemical reaction of ethanol and urea. The urea content should be reduced to less than 1 mg/l to prevent the formation of ethyl carbamate. Urease is an enzyme, which hydrolyzes urea into ammonia and carbon dioxide. The acidic condition of fermented beverages is optimal for these types of ureases, which show high activity at low pH. Acid urease is an intracellular enzymeproduced by Gram positive bacteria like Lactobacillus fermentum. It is commercially not easily available, hence it has to be produced by fermentation, extracted from the bacteria and purified properly.