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URN etd-0830111-125840 Statistics This thesis had been viewed 1431 times. Download 91 times. Author Yi-chi Chen Author's Email Address No Public. Department Bioengineering Year 2010 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 109 Title Investigation of optimal culture conditions for
the production of 1,4-exoglucanase by recombinant Escherichia coli
Keyword E. coli exoglucanase fed-batch fermentation fed-batch fermentation exoglucanase E. coli Abstract Cellulase is widely distributed in insects, molluscs, protozoa and microorganisms. Most fungi, in addition to thermophilic actinomycetes, algae, yeast, and sticky monocytogenes can secret cellulase. Different fermentation strategies were investigated in this study for the production of 1,4-exoglucanase from the recombinant E. coli. The results showed that by using LB(Luria Bertani) as the initial medium, feeding G/YE/Try as ratio of 0.5/1/0.5 w/w, resulted in the volumetric activity of 693 U/L, and protein yield of 944 mg/L. Feeding G/YE as ratio of 1/1 w/w without tryptone, could get the higher volumetric activity of 1467 U/L, and protein yield of 4239 mg/L. Therefore it confirmed that tryptone had the inhibitory on the volumetric activity.
By using TB as a alcohols-based medium, feeding G/YE as ratio of 1/1 w/w for the 1,4-exoglucanase induction resulted in the highest volumetric activity as 1469 U/L, maximum protein yield of 4793 mg/L. To study the induction temperature effect on the volumetric activity, it shown that lower temperature resulted in higher activity of 1477 U/L, but higher temperature resulted in slightly lower activity of 1231 U/L. Therefore, for the purpose of energy-saving, we could use the room temperature for the induction of enzyme production. By studying different inducing agents as 0.5mM IPTG, 0.02 mM Lactose, 0.2 mM Lactose,and 2 mM Lactose resulted in the highest volumetric activity as 1888 U/L, therefore, we could use cheaper lactose to replace IPTG. On the analysis of alcohols effects on the cell growth, the Monod model shown the μmax as 0.80 1/h, and Ks as 0.43 g/L. The kinetic model can be applied to simulate different feeding strategies for the mass production of cellulase in a way.
Advisor Committee C. Will Chen - advisor
Chi-Hsien Liu - co-chair
Ming-Tse Lin - co-chair
Files Date of Defense 2011-07-26 Date of Submission 2011-08-30