Effects of Oxygen Supply Modes on the Production of Human Growth Hormone in Different Scale Bioreactors

Abstract

Recombinant Escherichia coli has been studied as a main host for recombinant protein productions, but it is still difficult to cultivate E. coli in a large industrialscale process due to the oxygen supply limitation. In this study, E. coli BL(21) harboring a new constructed plasmid (pEHUb-hGH) was used for producing recombinant human growth hormone (r-hGH) in 5-L and 30-L scale fermentors by supplying air and high purity oxygen, respectively, where the high purity oxygen was produced from a vacuum pressure swing adsorption (PSA). The impact of oxygen supply modes, i.e., air and high purity oxygen, on cell growth and r-hGH production was investigated in different scale fermentors. In the case of high purity oxygen supply, the final cell density and r-hGH concentrations were 63.0 and 4.8 g/L in the 5-L fermentor, 51.6 and 4.0 g/L in the 30-L fermentor, respectively. In addition, the productivity of r-hGH was doubled in the 5-L fermentor, and increased 4-fold in the 30-L fermentor, compared to the results obtained in the case of the air supply. The supply of high purity oxygen eliminated the oxygen limitation and acetate formation effectively, and apparently, did not affect the degradation of r-hGH. This shows that the recombinant E. coli cultivation with high purity oxygen produced from PSA may provide an effective method for large-scale industrial production of recombinant proteins.

Production of recombinant protein by a novel oxygen-induced system in Escherichia coli

“…It is possible that the expression levels of soxS could be increased by using stronger RBS sequences or increasing the strength of the promoter by changing the consensus promoter sequence [ 17 ]. Supplying higher concentrations of dissolved oxygen may be difficult and likely expensive when dealing with large bioreactors, but with recent development of oxygen generation technologies [ 18 , 19 ] this method could also be suitable for large scale, however, at present, this technology is limited to applications for laboratory and pilot-scale bioreactors.…”

Feeding strategy design for recombinant human growth hormone production by Bacillus subtilis

“…Kajino et al [7] produced 240 mg L -1 rhGH by Bacillus brevis, which is 2.1-fold lower than that attained in this work. By E. coli [28], 63.2 g L -1 cell and 4.9 g L -1 rhGH concentrations were obtained in a fed-batch cultivation. Recently, a methanol-stat feeding strategy was designed in our research group by r-P. pastoris [29], and the highest rhGH production was reported as C rhGH = 1.3 g L -1 when the cell concentration reached to C X = 82 g L -1 .…”

Effect of elevated oxygen concentration on bacteria, yeasts, and cells propagated for production of biological compounds

“…However, the usage of oxygen enriched air (0.40 atm of O 2 ) to control dO 2 concentration above 20% air-saturation in a glucose defined medium contributed to higher biomass and higher acetate concentrations but decreased the specific production of rhGH produced by E. coli K-12 strain compared with air supply control experiment [ 25 ]. In contrast, the productivity of rhGH in E. coli BL21 growing in a complex medium and using 0.93 atm of O 2 in inlet gas to control dO 2 at the same levels (20% air saturation), was 2-fold higher than in air-control culture [ 26 ]. In addition to the difference in the E. coli strain and induction time, the availability of amino acids in the complex medium might explain the contrasting results.…”