Urethanase of Bacillus licheniformis sp. isolated from mouse gastrointestine

Trace levels of urethane, a cancer causing chemical, were detected in many kinds of wine, sherry, whisky, brandy and sake. Urethane formation from urea and ethanol in sake can be prevented by the treatment of acid urease, which is produced by Lactobacillus fermentum, but urethane, once formed, is very difficult to decompose. In order to keep the safety of alcoholic beverages, enzymatic removal of urethane has become an urgent problem. We found that Bacillus licheniformis sp., isolated from mouse gastrointestine, decomposed urethane to ethanol and ammonia. The enzyme showed higher urethanase activity at an acidic condition than at a neutral condition, and was resistant against ethyl alcohol of high concentrations. However, the enzyme had a low affinity to urethane for the industrial removal of the compound from alcoholic beverages.