The relationship between inorganic nitrogen oxidation and organic carbon production in batch and chemostat cultures of marine nitrifying bacteria
✍ Scribed by Hilary E. Glover
- Publisher
- Springer
- Year
- 1985
- Tongue
- English
- Weight
- 543 KB
- Volume
- 142
- Category
- Article
- ISSN
- 0302-8933
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✦ Synopsis
Rates of nitrification and organic C production were determined in batch and chemostat cultures of marine nitrifying bacteria; two NH+-oxidizing species and one NO2-0xidizing spezies. With increasing age in batch cultures and with decreasing flow rates in chemostats, cellular organic C and N concentrations declined while the intracellular ratio of C:N remained constant. With decreasing flow rates in chemostats, there was a reduction in (a) carboxylating enzyme activity per unit of cellular organic C (the potential for chemoautotrophic C02 fixation), and (b) the yield of organic C. For both NH + and NOy oxidizers, rates of nitrification and C yield were lowest at very slow chemostat growth rates, when compared with optimal growth rates in batch cultures. For both NH~ and NO2oxidizing species, the stoichiometric relationship between nitrification and organic C production did not remain constant and appeared to be dependent on the availability of the inorganic N substrate. The organic C yield from NH~ oxidation and hence the free energy efficiency declined with increasing age in batch cultures and with decreasing flow rates in chemostats. The C yield from NO2 oxidation and the free energy efficiency at slow chemostat growth rates was also lower than that at the optimal growth rate in batch culture.