Isolats Bakteri Indigenous Penghasil Milk-Clotting Protease untuk Fermentasi Keju

Abstract

The aims of this research is to isolation of bacteria that potential to produce of milk clotting protease enzymes from
fermented food that will be used as a substitute for rennet in cheese making. There are five food fermentations such
as tauco, tempeh, red oncom, sticky tape, and pickled mustard greens that are used as a source for isolation of bacteria
that could produce milk clotting protease. The results obtained four isolates proteolytic bacteria from two fermented
food samples, three isolates bacteria from tauco (TCN 1, TCN 2, TCN 3) and one isolate from pickled
mustard greens (DSN 1). Based on 16S rDNA, these isolates were identified as Bacillus sp. Bacterial isolate TCN 1
has a milk clotting activity of 29.17 U/mL, whereas bacteria isolates of TCN 2, TCN 3 and DSN 1 have activities of
70 U/mL achieved at the 24 hours incubation, respectively. The proteolytic activities of bacteria isolates TCN 1,
TCN 2, TCN 3 and DSN 1 at the 24 hours fermentation process were 0.0117 U/mL, 0.0021 U/mL, 0.0150 U/mL,
and 0.200 U/mL, respectively. The ratio of milk clotting protease activity and the proteolytic activity for bacteria
isolates TCN 1, TCN 2, TCN 3 and DSN respectively were 5402, 175000, 7292, and 3333. This showed that the
enzyme from bacterial isolates TCN 2 can be used as an alternative to rennin in cheese making.
Keywords: milk clotting protease, cheese, calf rennet, fermentation food