Technology of obtaining milk-clotting enzyme from fungal culture Funalia Sp. for application in cheese production

Abstract

Cheese-making is a process known since ancient times. Traditionally, cheese preparation was based on coagulation of milk using rennet. Due to the high cost of rennet, an important task of the cheese industry is finding its alternatives. An important requirement for milk-clotting enzymes is low non-specific total proteolytic activity. One of the promising sources of milk-clotting enzymes are basidial fungi. Earlier, we found a high milk-clotting activity (MCA) of the fungus Funalia sp. The aim of our research was to find the optimal cultivation conditions for the fungus Funalia sp., which ensure the maximum yield of the milk-clotting enzyme. The fungus was submerge-cultured on a glucose-peptone nutrient medium for 7 days. The MCA determination of the native solution was carried out using the Kawai-Mukai method. To optimize the composition of the nutrient medium the method of full factorial experiment was used. According to the results of the study, a nutrient medium with a concentration of glucose and peptone of 15.5 and 3.6 g L-1 was selected. For further concentration and purification of the enzyme the method of ultrafiltration was used. As a result, an enzyme preparation with a high level of MCA (333.5 U mg-1) and a low level of proteolytic activity (0.096 U mg-1) was obtained. According to its characteristics, the enzyme is not inferior to commercial rennet and is promising for use in the food industry.