Abstract: According to the protein expression system in which a variety of desired useful proteins are highly produced by fusing a coding region of useful protein gene to the downstream of a promoter region of a tyrosinase-encoding gene (melO) of Aspergillus oryzae by a usual method of DNA manipulation, transferring a plasmid containing the resulting novel fusion gene into Aspergillus oryzae and incubating the thus-obtained transformant, various proteins can efficiently be produced at a high purity and in a high yield.

Abstract: Alcoholic liquors containing carbamide are treated with the urease which has the optimal pH for the activity in an acid region, especially in the region of pH2 to 5. By such treatment, the carbamide can be completely decomposed and removed from the alcoholic liquors in a much smaller amount of urease and in a short time as compared with a conventional treatment according to a urease having the optimal pH in the neutral to alkaline region. This method is more advantageous from the viewpoint of practical use and the quality of the thus obtained alcoholic liquors are superior to that obtained by the conventional treatment.