Toxicological evaluation of β-Galactosidase enzyme produced by Papiliotrema terrestris

β-Galactosidase (EC 3.2.1.23) is a glycoside hydrolase that catalyzes the release of sugar monomers from β-galactoside oligosaccharides via hydrolysis of glycosidic bonds, and has potential uses in the food industry. The safety of this enzyme and its production organism, Papiliotrema terrestris (P. terrestris), are described herein. P. terrestris was non-pathogenic upon intravenous (IV) administration of 2.4 × 10⁸ cfu and oral administration of 1.3 × 10⁹ cfu. Genotoxic results for the enzyme concentrate were negative in a bacterial reverse mutation test (Ames test) and chromosome aberration test in cultured Chinese hamster lung fibroblast (CHL/IU) cells. In a 13-week oral gavage study in Sprague-Dawley rats, no adverse effects were observed in any of the tested group and a No Observed Adverse Effects Level (NOAEL) of 2000 mg/kg bw/day [total organic solids (TOS) 1800 mg/kg bw/day)] was established, which was the highest dosage tested. Allergenicity sequence analysis revealed no evidence suggesting that β-galactosidase is an allergen. The data presented in this study support the conclusion that β-galactosidase produced from P. terrestris is safe for use in food production.