Cadmium biosorption by Streptomyces sp. F4 isolated from former uranium mine

MANUEL SIñERIZ LOUIS; ERIKA KOTHE; CARLOS MAURICIO ABATE

JOURNAL OF BASIC MICROBIOLOGY

Wiley - VCH

Lugar: Jena; Año: 2008

0233-111X

Abstract 46 actinomycetes were isolated from two polluted sites and one pristine site. By primary qualitative screening assays one strain, F4, was selected because of cadmium resistance and characterized physiologically and taxonomically; it grew up to 7.5% NaCl, until 100 ìg/ml lysozyme and at a pH range from 6 to 10. 16S rDNA sequence analysis showed that the strain F4 was very closely related with Streptomyces tendae. On culture medium with 8 mg L-1 Cd, 80% inhibition was observed for Streptomyces sp. F4 after 8 days of growth. The maximum specific biosorption was 37.3 mg Cd/g dry weight after 7 days of growth. The highest Cd2+ concentration was found on the cell wall (41.2%). The exopolysaccharide layer contained only 7.4%, while in the cytosolic fraction remained 39.4% of Cd. On the ribosomes and membrane fraction, 12% were found. This localization was verified by TEM, where cells of Streptomyces sp. F4 showed a cytoplasm with dark granulate appearance. This study could present the potential capacity of Streptomyces sp. F4 for Cd bioremediation.