Biochemical response of cyanobacterial species to trivalent chromium stress

Toxic metal reclamation from wastewaters using biotechnology has focused attention on a variety of microbes and one such potential group is Cyanobacteria. Effluent water discharged from tanneries support the growth of many microbial species including Cyanobacteria. In the present study an attempt has been made to study the growth response of six cyanobacterial species to trivalent chromium (Cr3 +), before being used for phycoremediation. The studies relate to biochemical response of these species to different concentrations of Cr3 + under stress and their metal binding capacity in the media vis-à-vis its uptake in lab conditions. The results indicated that Aulosira sp. A287 exhibited high tolerance to Cr3 + (750 mg L− 1) in the media although the maximum uptake was observed in Spirulina platensis (214 mg g− 1). The biochemical analysis showed quantitative reduction in chlorophyll-a in S. platensis, Oscillatoria sp. A280 and Lyngbya sp. with increasing Cr3 + dosage, whereas the rest of the species showed decreasing trend. This change in protein profile was validated using SDS-PAGE. However, total carbohydrate increased in all the species tested when compared to controls. Among the species studied the response of S. platensis to Cr3 + stress was higher. The present study demonstrates the capability of cyanobacteria to withstand Cr3 + stress and their possible utilization in wastewater treatment.