Application of a two-dimensional disposable rocking bioreactor to bacterial cultivation for recombinant protein production

Disposable rocking bioreactors (RBs) are widely employed for cultivation of recombinant mammalian and insect cell lines, although the perception of inadequate mass transfer has prevented their application to bioprocesses based on microbial platforms. In this study, one-dimensional (1D) and two-dimensional (2D) RBs were assessed and compared with the conventional stirred tank reactor (STR) for recombinant therapeutic protein production in Escherichia coli. The comparison involved: (1) physical characterization of oxygen mass transfer efficiency and mixing intensity, (2) growth characteristics in batch cultivation, and (3) culture performance for the production of recombinant protein. Our results show that oxygen mass transfer was comparable between the 1D RB and STR at low working volume (WV), declining linearly with increasing WV, and was highest in the 2D RB for all tested WVs with the maximum mass transfer coefficient (k_La) at 3 L WV. Well mixing behavior was observed in all three systems for water and aqueous carboxymethylcellulose (CMC) solutions. Batch growth characteristics were similar in all bioreactor systems, although metabolite accumulation was significant in the 1D RB. Culture performance for the production of recombinant GST-hCD83ext (glutathione S-transferase-hCD83ext fusion protein) was similar in terms of soluble protein yield and inclusion body formation for all bioreactor systems.