Safety assessment of glutaminase from Aspergillus niger

Glutaminase (glutamine aminohydrolase EC 3.5.1.2) is used in the production of food ingredients rich in l-glutamic acid that are added to finished foods for the purpose of enhancing or improving the savory flavor profile of food. The glutaminase enzyme preparation evaluated in these studies, designated as Sumizyme GT hereafter, is obtained by fermentation of Aspergillus niger strain GT147. The safety of Sumizyme GT was evaluated in a series of standard toxicological studies, including a 90-day oral toxicity study in rats, an in vitro bacterial reverse mutation assay, an in vitro mammalian chromosome aberration test, and an in vivo alkaline Comet assay. Sumizyme GT was not mutagenic or genotoxic, and administration of the enzyme by gavage at doses up to 2,570 mg total organic solids (TOS)/kg body weight (bw) per day for 90 days was without any systemic toxicity. The no-observed-adverse-effect level was concluded to be 2,570 mg TOS/kg bw per day, the highest dose tested. Considering that A. niger has an established history of safe use in the food industry and its safety in the production of food ingredients and food enzymes is well documented, the results of these studies provide further support of the safety of glutaminase from A. niger when used in food production.