Abstract
Recording the amount of titrant required to maintain constant pH in a bioreactor where cell metabolism causes acidity changes allows on-line determinations of growth kinetics in computer-controlled batch cultures. A system for making such measurements is described and its performance is investigated. Transient bicarbonate accumulation occurs if the culture produces CO2 at high pH values and low gas transfer rates. We have developed a mathematical model for the titrant requirement as a function of the cell growth rate, the gas transfer properties of the bioreactor and the culture pH. According to this model, bicarbonate accumulation affects the stoichiometry between titrant and biomass but does not prevent determination of growth rate constants. These predictions are confirmed using model experiments and measurements during batch growth of microbial cultures.
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Aiba S, Furuse H (1990) Some comments on respiratory quotient (RQ) determination from the analysis of exit gas from a fermentor. Biotechnol Bioeng 36:534–538
Fraleigh SP, Bungay HR, Clesceri LS (1989) Continuous culture, feedback control and auxostats. Trends Biotechnol 7:159–164
Harrison DEF, Pirt SJ (1967) The influence of dissolved oxygen concentrations on the respiration and glucose metabolism ofKlebsiella aerogenes during growth. J Gen Microbiol 46:193–211
Kempe LL, Gillies RA, West RE (1956) Acid production by homofermentative bacteria at controlled pH as a tool for studying the unit process of fermentation. Appl Microbiol 4:175–178
Mackereth FJH (1964) An improved galvanic cell for determination of oxygen concentrations in fluids. J Sci Instrum 41:38–41
Martin GA, Hempfling WP (1976) A method for the regulation of microbial population density during continuous culture at high growth rates. Arch Microbiol 107:41–47
Monod J (1942) Recherches sur la croissance des cultures bacteriènnes. Hermann Paris
Nelder JA, Mead R (1965). A simplex method for function minimalization. Computer J 7:308–313
San K-Y, Stephanopolous G (1984) Studies on on-line bioreactor identification. IV. Utilization of pH measurements for product identification. Biotechnol Bioeng 26:1209–1218
Standing CN, Frederickson AG, Tsuchiya HM (1972) Batch and continuous culture transients for two-substrate systems. Appl Microbiol 23:354–359
Thomsen JK, Cox RP (1990) Alkanesulphonates as eluents for the determination of nitrate and nitrite by ion chromatography with direct UV detection. J Chromatogr 521:53–61
Thomsen JK, Iversen JJL, Cox RP (1993) Interactions between respiration and denitrification during growth ofThiosphaera pantotropha in continuous culture. FEMS Microbiol Lett 110:319–324
Veres A, Nyeste L, Kurucz I, Kirchknopf L, Szigeti L, Halló J (1981) Automated fermentation equipment. I. Program-controlled fermentor. Biotechnol Bioeng 23:391–404
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Iversen, J.J.L., Thomsen, J.K. & Cox, R.P. On-line growth measurements in bioreactors by titrating metabolic proton exchange. Appl Microbiol Biotechnol 42, 256–262 (1994). https://doi.org/10.1007/BF00902726
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DOI: https://doi.org/10.1007/BF00902726