Evaluation of experimental production of milk-clotting enzymes using Rhizomucor spp strains

Experimental production of milk clotting enzymes was conducted on a laboratory culture medium for 190 h incubation, using three certified strains of Rhizomucor pusillus, miehei and two native Rhizomucor spp. BIOMI-12 and 13. The evaluation was performed by measuring the concentration of glucose and protein during incubation, estimate productivity, specific activity, rennet strength/proteolytic activity index in the crude enzyme extracts, determining the molecular weights and proteolytic activity in the partially purified enzyme extracts. All strains showed consumption rates of glucose, the same behavior observed protein content, except strain BIOMI-13. The increase in protein content after descent coincided with the recorded maximum coagulant activity each strains, being the crude extract of strain BIOMI-13 higher coagulant activity (148,15 FC), productivity (3.09 HR / h), rennet strength/proteolytic activity index (142,60 FC/U) and specific activity (1,062 FC/mg). The partially purified enzyme extracts from strains R miehei 37, Rhizomucor spp BIOMI-12 and 13, presented proteins with molecular weights in approximately 22,6 kDa and 46.52, while the extract R pusillus 39 present an additional band of 39,6 KDa. In the zymogram was observed for all strains, proteolytic activity in the bands between 40-50 KDa and 20-22 KDa, but not for the R pusillus 36, where activity was very dim. Finally it was determined that the strain BIOMI-13, has the greatest capacity to produce milk clotting enzymes