INTERACTION OF FLUORESCENT PSEUDOMONAS WITH FE(III)-COMPOUNDS

We used Mossbauer spectroscopy and magnetic measurements to examine th e interaction of Fe(III)-compounds with Pseudomonas putida 90 and with Pseudomonas fluorescens VKM 1472, as a function of the nature of the iron source (Fe(III)-citrate and FeCl3), of the organic substrate (glu cose, acetate, malate, sodium lactate) and of the length of the growth period. With both pseudomonads grown in the presence of glucose and F e(III)-citrate, the yield, as well as the amount of accumulated parama gnetic complexes, were higher than with FeCl3 whilst the proportion of magnetically-aligned complexes was higher with ferric chloride. Pseud omonads grown with glucose and FeCl3 accumulated Fe(III) oxides and hy droxides, whilst those grown with Fe(III)-citrate accumulated low-dens ity Fe(III)-hydroxide and ferric hydrate, regardless of the nature of the carbon source. The bacteria also accumulated Fe(II)-compounds when grown on malate and lactate. Long-term growth of the pseudomonads on lactate led to an increase of the bacterial paramagnetism and a fall i n the proportion of magnetically-aligned compounds.