Toxicological assessment of recombinant xylanase X(22) in wine

Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wine). Body weight, food and fluid intake, urinalysis, and hematology data were obtained. Postmortem examinations and histopathology by both light and electron microscopy were performed. According to the results of this study, no adverse effects were detected by oral administration of X(22).