Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Improvement in the Production of L-Lysine by Over-expression of Aspartokinase (ASK) in C. glutamicum ATCC 21799

Hilda Rastegari¹, Mohsen Chiani², Azim Akbarzadeh², Sara Cheraghi³, Zahra Saffari², Mohammad Reza Mehrabi², Ali Farhangi², Soheil Ghassemi²

¹Department of Microbiology, Azad University, Jahrom; ²Department of Pilot Biotechnology, Pasteur Institute of Iran; ³Department of Biochemistry, Payam_E_Noor University, Tehran, Iran.

For correspondence:- Soheil Ghassemi Email: ghassemiso@yahoo.com Tel:+982166968856

Received: 30 April 2012 Accepted: 5 December 2012 Published: 21 February 2013

Citation: Rastegari H, Chiani M, Akbarzadeh A, Cheraghi S, Saffari Z, Mehrabi MR, et al. Improvement in the Production of L-Lysine by Over-expression of Aspartokinase (ASK) in C. glutamicum ATCC 21799. Trop J Pharm Res 2013; 12(1):51-56 doi: 10.4314/tjpr.v12i1.9

© 2013 The authors.
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Abstract

Purpose: To clone Corynebacterium glutamicum ATCC21799 aspartokinase gene (EC 2.7.2.4) using shuttle expression vector pEKEx2 in order to increase lysine production.

Methods: C. glutamicum DNA was extracted and used for amplification of aspartokinase gene (ask) by cloning into an E. coli/C. glutamicum shuttle expression vector, pEKEx2. Initially, the recombinant vector transformed into E. coli DH5α and then into C. glutamicum.

Results: Electrophoresis of recombinant protein by SDS-PAGE showed that the molecular weight of the recombinant protein was 42 KD. The induction of recombinant vector by IPTG had an inhibitory effect on cell growth due to over-expression of the cloned gene. The results of lysine assay by Chinard method showed that lysine production increased about two-fold, compared with the parent strain, as a result of increased copy numbers of lysC gene in recombinant strain.

Conclusion: A two-fold increase in lysine production was observed by cloning of the ASK gene in C. glutamicum rather than in E. coli, due to the presence of lysine exporter channel which facilitates lysine extraction.

Keywords: LysC gene, Corynebacterium glutamicum, L- lysine, Cloning, Aspartokinase, E. coli