Journal of Pure and Applied MicrobiologyVol. 8 No. May 2014 Special Edition

Screening of Important Autoinduction Medium Composition for High Biomass Production of E. coli Expressing Recombinant Bromelain

Mohd Jamil Aizat Jamaluddin1, Azura Amid1,2*, Azlin Suhaida Azmi1,2 and Muhd. EzzaFaiez Othman1

1Department of Biotechnology Engineering, Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak 53100 Kuala Lumpur, Malaysia. 2Bioprocess and Biomolecular Engineering Research Unit (BPMERU), Department of Biotechnology Engineering, Faculty of Engineering, International Islamic University Malaysia, Jalan Gombak 53100 Kuala Lumpur, Malaysia.

Received on 08 January 2014 and accepted on 24 March 2014

 

ABSTRACT

Bromelain, a naturally available therapeutic protease enzyme from pineapple stem, was expressed in Escherichia coli using autoinduction-based fermentation medium. There are numerous recombinant proteins functionally expressed in E. coli using this autoinduction approach. Preliminary media trials have shown that this medium is capable of producing a high cell density batch culture as claimed. Since the level of soluble expression is both protein and host/strain specific, further screening to identify significant media components affecting biomass production is therefore required. Currently, screening of full autoinduction medium components has yet to be examined elsewhere in the literature due to its tedious nature. Hence, the application of a fractional factorial design for identifying significant components in the autoinduction formulation was reported. Statistical analysis showed that glucose, glycerol and L-arabinose were most significant components influencing the biomass production. However, their effects were demoting rather than promoting the biomass production at elevated concentrations in shake flask culture. The highest biomass production (7.3 g/l) was achieved at low levels (-1). This represents 0.05 % (w/v) glucose, 0.5 % (w/v) glycerol, without the need of additional L-arabinose inducer. For a low number of experimental runs, this statistical approach has been proven efficient for screening vital medium components in comparison to conventional method.

Keywords : Cysteine protease, fractional factorial design, Studier formulation, T7 expression system.