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Escherichia coli expression system is a robust and cost-effective recombinant protein expression system. In order to maximize the productivity of this system, increasing the cultivation scale and cell density is necessary. However, several engineered E. coli strains, such as E. coli DH5a, are auxotrophic mutants therefore are unable to grow in the synthetic medium that is generally designed for high cell density cultivation. Thus, to achieve high cell density of the auxotrophic mutant strains of E. coli, the cultivation medium was newly developed by supplementing yeast extract and peptone to the Bylund’s synthetic medium, designated Bylund:LB medium. The results showed that E. coli DH5a was able to grow and reached OD600 of 17.70 in Bylund:LB medium with 1 g/L yeast extract and 2 g/L peptone using fed-batch process in a bioreactor. However, an increase in yeast extract to 2 g/L and peptone to 4 g/L did improve the OD600 to 53.10. It was obvious that the obtained cell density was directly correlated to an increase in yeast extract concentrations and peptone supplemented in Bylund:LB medium.
Beckmann, B., Hohmann, D., Eickmeyer, M., Bolz, S., Brodhagen, C., Derr, P. and Sanders, E.A., 2017, An improved high cell density cultivation–iHCDC–strategy for leucine auxotrophic Escherichia coli K12 ER2507, Eng. Life Sci. 17: 857-864.
Bylund, F., Collet, E., Enfors, S.O. and Larsson, G., 1998, Substrate gradient formation in the large-scale bioreactor lowers cell yield and increases by-product formation, Bioproc. Eng. 18: 171-180.
Charoenrat, T., Khumruaengsri, N., Promdonkoy, P., Rattanaphan, N., Eurwilaichitr, L., Tanapongpipat, S. and Roongsawang, N., 2013, Improvement of recombinant endoglucanase produced in Pichia pastoris KM71 through the use of synthetic medium for inoculum and pH control of proteolysis, J. Biosci. Bioeng. 116: 193-198.
Jung, S.C., Smith, C.L., Lee, K.S., Hong, M.E. and Kweon, D.H., Stephanopoulos, G. and Jin, Y.S., 2010, Restoration of growth phenotypes of Escherichia coli DH5α in minimal media through reversal of a point mutation in purB, Appl. Environ. Microbiol. 76: 6307-6309.
Miller, G.L., 1959, Use of dinitrosalicylic acid reagent for determination of reducing sugar, Anal. Chem. 31: 426-428.
Pinhal, S., Ropers, D., Geiselmann, J. and Jong, H., 2019, Acetate metabolism and the inhibition of bacterial growth by acetate, J. Bacteriol. 201: e00147-19.
Riesenberg, D., Schulz, V., Knorre, W.A., Pohl, H.D., Korz, D., Sanders, E.A., Roß, A. and Deckwer, W.D., 1991, High cell density cultivation of Escherichia coli at controlled specific growth rate, J. Biotechnol. 20: 17-27.