Storage temperature and stabilizers in relation to the activity of commercial liquid feed enzymes: a case study from Egypt

The present work was carried out in order to study the storage stability at different temperatures of commercial liquid enzymes imported to Egypt. In this respect, two samples containing the same enzymes (xylanase, amylase and cellulase) with the same initial activities and from the same biological origin were divided into four bottles. The first two bottles were labeled (A, D) having water as the carrying material and the second two bottles labeled (B, C) having glycerol as the carrying material. Samples A and B were stored at 4 °C, while samples C and D were stored at 30 °C, the study was conducted for 7.5 months. The results showed that samples stored at 4 °C whether carried in water or glycerol had better enzyme recovery percentages compared to those stored at 30 °C. Also samples having glycerol as a carrying material had better enzyme stability compared to those having water as a carrying material except for cellulase stored at 30 °C. The results obtained suggest that for shipment to tropical regions, suppliers must ensure enzyme storage at refrigerated conditions below 5 °C. It is also recommended that an enzyme stabilizer is used as it will lead to a more efficient enzyme and thus will increase the economic potential of existing enzymatic processes.