SCREENING OF THERMOSTABLE PROTEASE PRODUCING MICROORGANISMS ISOLATED FROM INDONESIAN HOTSPRING
Abstract: Although many
proteases had been studied and characterized, only a few of them are
commercially available. Protease
thermostability is one of the crucial properties for industrial application.
This research aimed to isolate and to screen the potential isolate which
produce thermostable protease. There were 6 isolates (BII-1, BII-2, BII-3,
BII-4, BII-6 and LII), isolated using solid Minimal Synthetic Medium (MSM)
supplemented with 1.5% skim milk, that have, protease activity. Based on the
16S-rRNA gene sequencing analysis, isolates BII-1, BII-2 and BII- 6 were
identified as Bacillus licheniformis, isolates BII-3 and BII-4 were identified
as Bacillus subtilis, while isolate LII was identified as Brevibacillus
thermoruber. Three isolates (BII-6, BII-4 and LII) were then further
investigated for the second screening step using liquid MSM supplemented with
1% skim milk. The isolates (BII-6, BII-4 and LII) optimally produced protease
when they were cultivated at 35, 30 and 50o C respectively after 22 h of
incubation. Protease produced by BII-6, BII-4 and LII had optimum
temperature of 65, 60 and 85o C, optimum
pH at 7-8, 8 and 9 and stable up to 100 min at 55, 60 and 75o C respectively.
Keywords: thermostable
protease, Bacillus subtillis, Bacillus licheniformis, Brevibacillus thermoruber
Author: Dewi Seswita Zilda,
Eni Harmayani, Jaka Widada, Widya Asmara, Hari Eko Irianto, Gintung Patantis,
Yusro Nuri Fawzya
Journal Code: jpperikanangg120009
