| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 98 === In 1887, cyanophycin is a non-ribosomal protein discovered by Borzi in cyanobacteria. Cyanophycin can be produced inside cyanobacteria. However, not all cyanobacteria are capable of producing cyanophycin. Cyanophycin is protein-like polymer which consists of equimolar amounts of aspartic acid and arginine arranged as a poly-aspartic acid backbone to which arginine residues are linked to the β-carboxyl group of each aspartate by its α-amino group.
This study reports the production of cyanophycin by recombinant Escherichia coli carrying the cphA gene from Synechocysis sp. PCC 6803. The pET expression system was employed to produce cyanophycin. Different concentrations of IPTG and lactose as well as different temperature were used to examine cyanophycin production.
The results showed that 0.01 mM IPTG performs inductive effects most efficiently. At 20 ℃, cyanophycin synthetase appears visibly on the electrophoresis gel. The use of TB medium is a better choice to produce cyanophycin by recombinant E. coli. Insoluble cyanophycin show a composition of aspartic acid, 50±0.53 %; arginine, 44.23±0.35 %; lysine, 5.77±0.39 %. Soluble cyanophycin showed a composition of aspartic acid, 50.24±0.36 %; arginine, 38.27±0.31 %; lysine, 11.49±0.22 %.
In conclusion, production of cyanophycin by recombinant Escherichia coli carrying the cphA gene from Synechocysis sp. PCC 6803 in TB medium at 20 ℃, and 0.01mM of IPTG , give higher production of cyanophycin.
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