ISSN:
1432-072X
Keywords:
Continuous Culture
;
Rhodopseudomonas capsulata
;
Bacteriochlorophyll
;
Protein
;
Poly-β-Hydroxybutyrate
;
Nitrogen Limitation
;
Oxygen Control
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A continuous culture apparatus is described, which allows cultivation of photosynthetic bacteria anaerobically in the light and semiaerobically in the dark at constant oxygen tensions. The growth-parameters 1. substrate concentration at half maximum growth rate (K s) and 2. yield (Y) forRhodopseudomonas capsulata are calculated. An automatic control system of the oxygen partial pressure in the culture medium is elaborated. It is shown, that the discontinuous regulation with a control unit in connection with two magnetic valves, which give short pulses of either oxygen-free gas or gas mixed with oxygen, is an economic, practicable and reliable method. The yield coefficientY during growth limited by ammonium sulfate is variable due to the synthesis of nitrogen independent metabolites, such as poly-β-hydroxybutyrate. The storage of poly-β-hydroxybutyrate in continuous culture is a function of both the actual concentration of ammonia and of theC/N ratio. At very low growth rates (1/6 µ m ) the poly-β-hydroxybutyrate content increases amounting to 33% of the dry weight. In semiaerobically dark grown cells (pO2: 5 mm Hg) the protein and bacteriochlorophyll content increased definitely on dry weight basis with increasing growth rates. In contrast, in anaerobic light cultures only a small increase of the bacteriochlorophyll level but no change of the protein content per dry weight of cells was observed at increasing growth rates.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00696228
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