Identification and Characterization of a Cocoon Degradable Enzyme from the Isolated Strain Bacillus subtilis Bs5C

A fibroin-degrading bacterium was isolated in a medium containing fibroin as a sole nitrogen source, and then identified and characterized. The strain was designated Bacillus subtilis strain Bs5C, and the culture medium containing the extracellular proteolytic enzymes was found to hydrolyze cocoon f...

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Bibliographic Details
Published in:Biotechnology and bioprocess engineering 2020, 25(3), , pp.442-449
Main Authors: Oh, Hyun Deok, Cho, Min Seo, Kim, Joong-Su, Kim, Min-Soo, Kim, Chul Ho, Kang, Ji Young
Format: Article
Language:English
Subjects:
Bacillus subtilis
Biodegradation
Biotechnology
Chemistry
Chemistry and Materials Science
Decomposition
Degradation
Enzymes
Fibers
Industrial and Production Engineering
Industrial applications
Ion exchange
Peptides
Protease
Proteinase
Proteolysis
Proteolytic enzymes
Research Paper
Silk
생물공학
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Summary:A fibroin-degrading bacterium was isolated in a medium containing fibroin as a sole nitrogen source, and then identified and characterized. The strain was designated Bacillus subtilis strain Bs5C, and the culture medium containing the extracellular proteolytic enzymes was found to hydrolyze cocoon fiber. A decomposition rate of 35% was achieved with the culture medium in optimized cocoon-degrading condition. In a second round of decomposition performed on the same fibers with additional culture medium, the decomposition rate reached 45.9%. To investigate the proteolytic enzymes degrading cocoon, the enzymes was purified from culture medium using ion exchange column and identified using LC-MS/MS analysis system. As a result, it was uncovered that the cocoon degradation was due to the neutral protease NprE of the strain Bs5C. Moreover, the cocoon fibers treated with semi-purified NprE enzyme solution were clearly split and degraded, as assessed by SEM, and solubilized peptides from fibroin and sericin were detected by LC-MS/MS. In conclusion, this study is the first report that peptides could be produced from cocoon by cultured medium of B. subtilis , and the newly isolated strain Bs5C and the NprE protease from the strain Bs5C could clearly be valuable for the production of silk peptides, which have various pharmacological and industrial applications.
ISSN:1226-8372
1976-3816
DOI:10.1007/s12257-019-0399-5