ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Proteus vulgaris and P. mirabilis were grown anaerobically on glucose in the absence or presence of dimethylsulphoxide (DMSO) as electron acceptor or on (S)- or (RS)-lactate in the presence of nitrogen (N)-oxides, sulphur (S)-oxides or pyruvate. During growth on glucose the main fermentation product was ethanol and in the presence of DMSO it was (R)-lactate. Growth on (RS)-lactate led to acetate and (R)-lactate and growth on (S)-lactate produced almost only acetate. Depending on the growth medium, in crude extracts of P. vulgaris the activities of (R)-2-hydroxycarboxylate viologen oxidoreductase (HVOR), measured as (R)-lactate dehydrogenase, and DMSO reductase were 0.5–8.0 and 0.3–1.1 units (U)/mg protein, respectively. Addition of nitrate to the growth medium diminished both enzyme activities to 〈0.1 U/mg protein. P. mirabilis showed also high HVOR activity when grown on (RS)-lactate in the presence of DMSO. Also, Clostridium homopropionicum contained 1.8 U/mg of a pyridine-nucleotide-independent reversible (R)-lactate dehydrogenase when tested with the electron acceptor 1,1′-carbomoylmethylviologen (NH2CO-MV). None of the organisms studied were significantly active with (S)-lactate and NH2CO-MV. The possible physiological role of the HVOR may be as a dissimilatory (R)-lactate dehydrogenase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00242950
