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Katabole Repression bei aerobem und O 2 ‐limitiertem Wachstum — energetische und stoffliche Bilanz des Kohlenhydratmetabolismus bei Hefen
Author(s) -
Röber B.
Publication year - 1985
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620250907
Subject(s) - fructose , chemistry , hexose , citric acid cycle , biochemistry , oxidative decarboxylation , mannose , substrate (aquarium) , energy source , biology , metabolism , organic chemistry , enzyme , coal , ecology
Radiorespirometry during aerobic and O 2 ‐limited growth with Candida maltosa H and mutants oxidizing glucose specifically labelled with 14 C in carbon atoms 1–4, 6 or universally labelled demonstrated the simultaneous operation of the pentosephosphate pathway, tricarboxylic cycle and pyruvate decarboxylation (Röber and Reuter 1984a). Therefore, material and energy balances are developed for product formation and biomass production by Candida maltosa H and mutant strains using 14 C‐glucose, 14 C‐fructose, 14 C‐mannose as sole source of carbon and energy or glucose/mannose as a mixed substrate. Measured values of 14 C‐incorporation into 14 CO 2 , 14 C‐biomass and 14 C‐product are used to obtain estimates of biomass energetic yield, of the fraction of substrate energy evolved as heat, of Y 0 , of the P/O‐quotient and of the ATP synthesis. Aerobic growth on glucose resulted in repression of the tricarboxylic cycle (strain H, mutant H3). An increased efficiency of the utilization of the substrate energy was found during O 2 ‐limited growth of the mutant strains based on the increased hexose catabolism via tricarboxylic cycle and increased P/O quotients. Mutant strains showed no or less product formation with fructose or mannose as the sole source of carbon and energy under aerobic growth conditions.