Premium
Metabolic Pathway of Propionibacterium Growing with Oxygen: Enzymes, 13 C NMR Analysis, and Its Application for Vitamin B 12 Production with Periodic Fermentation
Author(s) -
Ye Kaiming,
Shijo Miyako,
Miyano Kenichiro,
Shimizu Kazuyuki
Publication year - 1999
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp990012s
Subject(s) - propionate , propionibacterium , citric acid cycle , fermentation , chemistry , oxygen , electron acceptor , biochemistry , anaerobic exercise , enzyme , metabolic pathway , food science , organic chemistry , bacteria , biology , physiology , genetics
The metabolic pathway of Propionibacterium grown under an aerobic condition is still not clear so far. In this work, cell growth, organic acid formation, vitamin B 12 synthesis, and enzyme activities were determined in different aerobic cultivation systems. It was found that the propionate, which is accumulated during anaerobic cultivation, was completely decomposed when the cultivation was shifted to an aerobic condition. Moreover, pyruvate was formed in accordance with the decomposition of the propionate. Besides, more acetate was produced and a large amount of malate was formed during the aerobic cultivation. Such phenomena could be repeatedly observed in a periodic cultivation in which the dissolved oxygen concentration was alternatively controlled at 0 or 1 ppm. Enzyme analysis indicates that the regulation of organic acid formation depends on which molecule, i.e., oxygen or fumarate, serves as an electron acceptor in the respiratory chain reactions. No tricarboxylic acid cycle was found to exist in this species grown under an aerobic condition. It is evident that the randomizing pathway worked in a reversed direction in the presence of oxygen, through which the propionate is oxidized to pyruvate. The 13 C NMR spectral analysis confirmed this observation.