Chromium accumulation by two Streptomyces spp. isolated from riverine sediments

Strains designated R22 and R25, isolated from Sail River sediments, Argenti na, were highly resistant to chromium. These strains were shown by 16S rRNA sequencing studies to be Strepyomyces spp.; this affiliation was consisten t with morphological and chemical characteristics. Growth of strains R22 an d R25 in medium containing 100 mg l(-1) chromate was reduced by only 23% an d 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(-1) of dry weight, respectively, and a chromate co ncentration of 50 mg ml(-1). Cell fractionation studies with strain R22 sho wed that the great majority of the chromium were associated with the cell w all fraction. Streptomyces strains R22 and R25 may have applications in bio remediation of chromium contamination.