Cloning and enhancing production of a detergent- and organic-solvent-resistant nattokinase from Bacillus subtilis VTCC-DVN-12-01 by using an eight-protease-gene-deficient Bacillus subtilis WB800

Table 4 Effect of organic solvents on Nk activity

Solvent	Remaining activity (%) at concentration (%) of
Solvent	10	30
Methanol	100 ± 10.86	99 ± 3.44
Ethanol	118 ± 1.85	97 ± 2.65
Isopropanol	110 ± 6.36	92 ± 1.32
1-Butanol	120 ± 6.89	124 ± 16.68
Acetonitrile	113 ± 7.15	60 ± 1.59
Acetone	124 ± 4.24	120 ± 5.83

0.6 μg of the Nk was incubated in 50 mM Na-phosphate buffer pH 8 at 30°C for 1 h in the presence of 10 or 30% (v/v) of different organic solvents. The Nk activity was measured with 1 mM Suc-AAPF-p NA as a substrate at pH 9 and 65°C.

ISSN: 1475-2859