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Control of interspecies electron transfer flow during anaerobic digestion: Dynamic diffusion reaction models for hydrogen gas transfer in microbial flocs
Author(s) -
Ozturk Sadettin S.,
Palsson Bernhard O.,
Thiele Jurgen H.
Publication year - 1989
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.260330612
Subject(s) - methanogenesis , chemistry , anaerobic digestion , diffusion , fermentation , acetogenesis , electron transfer , substrate (aquarium) , mass transfer , chemical engineering , environmental chemistry , methane , chromatography , thermodynamics , biochemistry , ecology , biology , organic chemistry , physics , engineering
Dynamic reaction diffusion models were used to analyze the consequences of aggregation for syntrophic reactions in methanogenic ecosystems. Flocs from a whey digestor were used to measure all model parameters under the in situ conditions of a particular defined biological system. Fermentation simulations without adjustable parameters could precisely predict the kinetics of H 2 gas production of digestor flocs during syntrophic methanogenesis from ethanol. The results demonstrated a kinetic compartmentalization of H 2 metabolism inside the flocs. The interspecies electron transfer reaction was mildly diffusion controlled. The H 2 gas profiles across the flocs showed high H 2 concentrations inside the flocs at any time. Simulations of the syntrophic metabolism at low substrate concentrations such as in digestors or sediments showed that it is impossible to achieve high H 2 gas turnovers at simultaneously low steady‐state H 2 concentrations. This showed a mechanistic contradiction in the concept of postulated low H 2 microenvironments for the anaerobic digestion process. The results of the computer experiments support the conclusion that syntrophic H 2 production may only be a side reaction of H 2 independent interspecies electron transfer in methanogenic ecosystems.