Chromium accumulation by two Streptomyces spp. isolated from riverine sediments

Abstract

Strain desinganted R22 and R25, isolated from Sali River sediments, Argentina, were highly resistant to chromium. these strains were shown by 16S rRNA sequencing studies to be Streptomyces spp.; this affiliation was consistent with morphological and chemical characteristics. Growth of R22 and R25 in medium containing 100 mg/l chromate was reduced by only 23% and 34%, respectively, compared with growth in medium without added chromium. Streptomyces sp. strains R22 and R25 both accumulated chromium with yields of 10.0 and 5.6 mg Cr/g of dry weight, respectively, and chromate concentration of 50 mg/ml. Cell fractionation studies with strain R22 showed that the great majority of the chromium were associated with the cell wall fraction. Streptomyces R22 and R25 may have applications in bioremediation of chromium contamination.