Four stralns of Bacillus subtifis (MZ. M14, M35 and M54) were selected. for
production ot protease enzyme and degumming of silk fibers. The data revealed that.
maximum protease activity and specific activity were obtained by B. subtifis(M14)
followed by' B. subtilis(M54) when grown in Chopra and Malhur medium al 30°C for 5
days under shake culture conditions. When the strains individually incubated In Ihe
medium supported with silk fiber. the loss of the gum might amnl!nt to 30.56%' i!h
high lotal activity of protease In Ihe culture supematants. Culture supernatants of four
strains with high protease activity were most effective in reducing the gum content of
silk fibe~ within 4 Iv and slightly Increase within 8 and 16 hr. Four grams silk fiber 'Per
100 ml culture filtrate was the best ratio for the highest degumming by B. subtilis M14,
M35 and M54 strains while 3:100 (wN) was the best ratio tor degumming by B. subtills
(M2). Degumming or silk fibers increased with the using of erude e!l2.yme of B. subtilis
(M14) followed by (M54) and (M2) strains at 30 ·C, while B, subtilis (M35) gave ~the
highest silk degumming at saoc. Results showed that, maximum degumming and total
aQMty of protease have been observed at pH 7.0 to all filtrates of the four strains.
These results indicated that, protease of B. suM/is plays an active role in he
degumming or silk libe~.