Copper removal ability by Streptomyces strains with dissimilar growth patterns and endowed with cupric reductase activity

ALBARRACÍN V. H.; AVILA, A. L.; AMOROSO M. J.; ABATE C.M.

FEMS MICROBIOLOGY LETTERS

Blackwell Publishing

Año: 2008 vol. 288 p. 141 - 148

0378-1097

Morphological, physiological and molecular characterization of three copper resistant actinobacterial strains (AB2A, AB3 and AB5A) isolated from copper polluted sediments of a drainage channel revealed that they belonged to the genus Streptomyces. These characteristics plus their distinctive copper resistance phenotypes revealed a great divergence among the isolates. Highly dissimilar growth patterns and copper removal efficiency were observed for the selected Streptomyces strains grown in Minimal Medium added with 0.5 mM of copper sulphate (MMCu). Strain AB2A showed an early mechanism of copper uptake/retention (80% until day 3) followed by a drastic metal efflux process (5 to 7 day). In contrast, Streptomyces sp. AB3 and AB5A showed only copper retention phenotypes in the same culture conditions. Particularly, Streptomyces sp. AB5A, showed a better efficiency in copper removal (94%), although a longer lag-phase was observed for this microorganism grown for seven days in MMCu. Cupric reductase activity was detected in both, copper adapted cells and non adapted cells of all three strains but this activity was up to 100-fold higher in pre-adapted cells of Streptomyces sp. AB2A. To our knowledge this is the first time that cupric-reductase activity was demonstrated in Streptomyces strains.