title: Enhanced cyanophycin production by Escherichia coli overexpressing the heterologous cphA gene from a deep sea metagenomic library.
abstract: Cyanophycin is a non-ribosomally synthesized polymer and its microbial production has attracted increased attention due to its pharmaceutical and chemical values. For the characterization and production of cyanophycin, the cphA49gene was cloned and expressed in Escherichia coli. Soluble cyanophycin was isolated from the cultures and characterized. The results showed that it was composed of 50% of aspartic acid, 45% of arginine, and 3.5% of lysine, and exhibited a homogenous molecular mass of 35 kDa. To improve soluble cyanophycin production, the induction conditions for cphA49gene expression were optimized. Meanwhile, the effects of medium content and induction duration on soluble cyanophycin production were also investigated, and the soluble cyanophycin yield reached a maximum at 72 h. Finally, to further increase the soluble cyanophycin production, the cultivation was carried out by supplement of arginine, aspartic acid, lysine and glucose into the minimal resource medium after cphA49gene expression level was improved under optimized conditions, and the maximum concentration of soluble cyanophycin reached 1.72 g/L.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 291 Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea.
authors.forename: Jikun
authors.initials: J
authors.lastname: Du
authors.affiliation: Dongguan Scientific Research Center, Guangdong Medical University, 1 Xincheng, Dongguan 523808, PR China. Electronic address: china_lovelylily@hotmail.com.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China.
authors.forename: Shining
authors.initials: S
authors.lastname: Zhou
mesh_terms: D059001:Aquatic Organisms / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015723:Gene Library; D056186:Metagenomics / Q000379:methods; D009792:Oceans and Seas; D030781:Organisms, Genetically Modified; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; C024250:cyanophycin; D010453:Peptide Synthases; C113257:cyanophycin synthase, bacteria
keywords: CphA; Cyanophycin; Escherichia coli; Optimization; Overexpression