Bioprocess Engineering

, Volume 3, Issue 3, pp 113–122

Transient responses of hybridoma cells to lactate and ammonia pulse and step changes in continuous culture

Authors

  • W. M. Miller
    • Department of Chemical EngineeringUniversity of California
  • C. R. Wilke
    • Department of Chemical EngineeringUniversity of California
  • H. W. Blanch
    • Department of Chemical EngineeringUniversity of California
Originals

DOI: 10.1007/BF00373474

Cite this article as:
Miller, W.M., Wilke, C.R. & Blanch, H.W. Bioprocess Engineering (1988) 3: 113. doi:10.1007/BF00373474

Abstract

Ammonia and lactate are the major byproducts from mammalian cells grown in medium containing glutamine and glucose. Both can be toxic to cells, and may limit the productivity of commercial bioreactors. The transient and steady-state responses of hybridoma growth and metabolism to lactate and ammonia pulse and step changes in continuous suspension culture have been examined. No inhibition was observed at 40 mM lactate. Cell growth was inhibited by 5 mM ammonia, but the cells were able to adapt to ammonia concentrations as high as 8.2 mM. Ammonia production decreased and alanine production increased in response to higher ammonia concentrations. Increased ammonia concentrations also inhibited glutamine and oxygen consumption. The specific oxygen consumption rate decreased by an order of magnitude after an ammonia pulse to 18 mM. Under these conditions, over 90% of the estimated ATP production was due to glycolysis and a large fraction of glutamine was converted to lactate.

List of Symbols

D d−1

Dilution rate = (volumetric feed rate) (reactor volume)

P/0

Molecules of ATP generated per molecule of NADH oxidized

qATP mmol cell−1 d−1

Specific ATP production rate

\(q_{{\text{O}}_2 } \) mmol cell−1 h−1

Specific oxygen uptake rate

qpmmol cell−1 d−1

Specific product formation rate

qsmmol cell−1 d−1

Specific substrate consumption rate

Y′p,smol/mol

True yield of product from substrate

Yp,s. mol/mol

Apparent yield of product from substrate = qp/qs

Subscripts

ala

alanine

NH3

ammonia

gluc

glucose

glu

glutamate

gln

glutamine

lac

lactate

Copyright information

© Springer-Verlag 1988