Production of intracellular milk-clotting enzyme in submerged cultures of Fusarium subglutinans

摘要

Fusarium subglutinans (Wollenweber and Reinking) Nelson et al. was found to produce intracellular milk-clotting enzyme (MCE) with good milk-clotting activity (MCA). The crude activity of the produced enzyme was recorded as optimum at 55 deg C and pH4.5. The highest yield i.e. 78.43 SU/mg dry biomass was obtained after 4 days of rotary shaking at 30 deg C when the fermentation medium containes wheat flour 2 percent, glucose 1 percent and (NH_4)_2SO_4 0.1 percent with an initial pH value 6.0. Under these conditions, the maximum ratio of MCA to proteolytic activity (PA) amounting to 603.31 SU/PU mg~(-1) was also achieved. Production of intracellular MCE by F. subglutinans was assumed to be active growth-associated type. This enzyme preparation was less active than the calf rennet, but was superior to those of Meito's and Pfizer's rennets.