Comparative Study of Sulfate-Reducing Bacteria from the Desulfovibrio genus

摘要

A study was made to evaluate the effect of soluble iron and media composition on the growth and metabolism of sulfate-reducing bacteria (SRB) from the Desulfovibrio genus: D. gigas, D. vulgaris, D. desulfuricans, D. alaskensis and D. indonensis. Cultures of D. gigas were grown in Postgate C, lactate / sulfate and in VMN (semidefined medium) media. The other strains were grown in VMN. All the strains were studied in the presence or absence of iron. Bacterial growth kinetics were affected by iron concentrations and culture media composition. Aditionally, D. gigas was studied with respect to the production and composition of Extracelullar Polymeric Substances (EPS) secreted in the culture media. For this purpose, the strain was grown in iron-containing and iron-free semidefined culture media, in the presence and absence of mild steel coupons. The EPS collected at the late exponential phase were quantitatively characterised for their protein, neutral hexoses, nucleic acid and uronic acid contents. The ability of EPS molecules to bind iron was investigated by Atomic Absoption and Electron Paramagnetic Resonance.