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Influence of mass transfer limitations on determination of the half saturation constant for hydrogen uptake in a mixed‐culture CH 4 ‐producing enrichment
Author(s) -
GiraldoGomez Eugenio,
Goodwin Steve,
Switzenbaum Michael S.
Publication year - 1992
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260400704
Subject(s) - mass transfer , formate , saturation (graph theory) , chemistry , kinetics , electron transfer , reaction rate constant , diffusion , mass transport , thermodynamics , kinetic energy , constant (computer programming) , electron transport chain , analytical chemistry (journal) , chromatography , biochemistry , catalysis , physics , mathematics , combinatorics , quantum mechanics , engineering physics , computer science , programming language
There is strong evidence in the literature supporting the existence of significant mass transfer limitations on the kinetics of exogenous H 2 consumption by methanogens. The half saturation constant for H 2 uptake by a mixed‐culture, CH 4 producing enrichment was measured using an experimental protocol that avoided internal mass transfer limitations. The value obtained was two orders of magnitude smaller than any other previously reported. A mathematical model for acetogenic syntrophic associations was developed to check the capacity of H 2 as electron transporter between syntrophic partners. It was found that H 2 diffusion could account for the rate of transport of electrons between the syntrophic microorganisms and that formate is not a necessary intermediate. The possibility that formate may be an intermediate in this system was not ruled out. A Monod‐type kinetic equation was modified to include the observed H 2 threshold effect. This modified equation was used to predict the CH 4 ‐production rate in a batch‐fed digester. The results show that the external and internal H 2 pools are kinetically coupled. © 1992 John Wiley & Sons, Inc.