Relationship between chromium(VI) resistance and extracellular polymeric substances (EPS) concentration by some cyanobacterial isolates.
OBJECTIVE
Chromium(VI) resistance and its association with extracellular polymeric substance (EPS) concentration in cyanobacteria was investigated. Increased EPS concentration was associated with Cr(VI) resistance. The most resistant isolate, Chroococcus sp. H(4), secreted the most EPS (427 mg/L).


METHODS
EPS concentration of the two most resistant isolates (Chroococcus sp. H(4) and Synechocystis sp. S(63)) was investigated following exposure to 15 and 35 ppm Cr(VI). The composition of EPS produced by Chroococcus sp. H(4) following exposure to 10 ppm Cr(VI) was analyzed using high-performance liquid chromatography. Control EPS was composed of glucose (99%) and galactronic acid (1%); in the presence of 10 ppm Cr(VI), EPS composition changed to glucose (9%), xylose (75%), rhamnose (14%), and galacturonic acid (2%).


CONCLUSIONS
Results indicated that (1) exposure to elevated concentrations of Cr(VI) affected the composition of EPS produced by Chroococcus sp. H(4), and (2) there was a correlation between Cr(VI) resistance and EPS concentration in some cyanobacteria.
Ozturk
Sahlan
S
Faculty of Science and Arts, Department of Biology, Gazi University, Teknikokullar, Ankara, Turkey. sahlan@gazi.edu.tr
Aslim
Belma
B
D001673:Biodegradation, Environmental; D002857:Chromium / Q000494:pharmacology*; D000458:Cyanobacteria / Q000187:drug effects* / Q000378:metabolism; D024881:Drug Resistance, Bacterial
D002857:Chromium