Toxicological studies on laccase from Myceliophthora thermophila expressed in Aspergillus oryzae

The bioindustrially produced enzyme laccase can be used in different technical and food applications to facilitate processes. It can be added to different oral care products such as mouthwash, toothpaste, mints, and gums to prevent halitosis. Laccase, produced by submerged fermentation of Aspergillus oryzae, containing a gene originating from Myceliophthora thermophila, was subject to a series of toxicological tests to document its safety in use. It was not found to be mutagenic in the Salmonella typhimurium reverse mutation assay, nor did it cause chromosomal aberrations in cultured human lymphocytes. No evidence of inhalation toxicity or skin and eye irritation was found. There was no evidence of possible skin sensitization in a human skin sensitization test when Laccase was tested at 10% (w/v): thus Laccase would appear to have a low skin sensitization potential. Oral administration to rats of up to 10.0 mL/kg body wt/day (equivalent to a total organic solids dosage of 1.72 g/kg body wt/day) for 13 weeks did not cause any adverse effect. (C) 2002 Elsevier Science (USA).