xpression and Secretion of Endoglucanase in Bacillus subtilis DB430
| Autor: | Wang, Lih-Cherng, 王立成 |
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| Rok vydání: | 1998 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 86 Cellulose degradation is an important part of biological recycling of carbon. Properly use of the cellulase in the treatment of high cellul ose containing waste from fruits and vegetables processing industries will facilitate fermentation by increasing glycolysis rate. Cellulose is g enerally compose of a group of complex enzymes. From most resource s, the cost of purification of individual component to reconstitute the wh ole enzyme is very expensive. The engB and engD gene products form th e cellulase complex of Clostridium cellulovorans are potential in dustrial application enzymes due to their ability to digest many carbohydrat e such as cellulose (microgrannular, fibrous, and microcrystalline forms), carboxymethyl-cellulose,laminarin, xylan, mannan, lichenan, pNPC, pNPG, and PNPX. However, due to the absolute anaerobic culture requirement, it is very difficult to handle large-scale production. To solve the problem, we use a protease deficient Bacillus subtilis (DB430, trpC2 npr apr epr bpf ispI) mutant. Bacillus subt ilis (DB430)still retain its secretion ability but the foreign gene products will not be digested by the host protease. This mutant is an idea expression and secretion host system for foreign gene expression. Genes engB and engD were subcloned and transformed into this DB430 mutant. Results indicated that these newly constructed reco mbinant strains have high extra-cellular endoglucanase, EngB and EngD, productivity of 553 and 391 U/L culture broth with specific act ivity of 0.157 and 0.088 unit/mg protein, respectively. This accomplishm ent showed the benefit of easier preparation of cellulase than that from original anaerobic C. Cellulovorans and Escherichia coli culture system. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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