FIGURE 1.
Cell yield of strain 019 cultures as dependent on availability of Fe(III), organic carbon and a reductant in the medium. Indicated above the bars are cell yields and corresponding error limits (×108 cells ml-1). Note that two types of anaerobic culture media (high Eh and low Eh) were used to test each couple of electron donor and acceptor with both C. thermautotrophica strains. The initial Eh values were identical in the culture media of a particular type and are indicated on the diagram. Low Eh medium was pre-reduced with sodium sulfide (refer to “Materials and Methods” section for details). Electron donor/acceptor couples which have been tested but did not support the growth of a C. thermautotrophica strain are shown as flat filled squares. Empty squares indicate donor/acceptor couples which are biochemically senseless (lactate and H+) or physico-chemically restricted [rapid chemical reduction of Fe(III) minerals by sulfides]. Asterisk indicates autotrophic growth conditions when CO was the only carbon source and electron donor available in the culture medium. Thick arrow indicates the conditions supporting the growth of the type strain 41T; data on its cell yields are not presented.