The present study attempts to utilize the cyanobacterial species, Leptolyngbya boryana, isolated from tannery effluent contaminated site for hexavalent chromium (Cr (VI)) removal from the aqueous solution. The isolated Leptolyngbya boryana showed efficient Cr (VI) removal along with potential tolerance ability even at higher concentrations. A Box-Behnken design of experiments was employed for optimizing and evaluating the effect of various parameters onto Cr (VI) removal. During the adsorption process, effect of adsorbent dose, initial Cr (VI) concentration and temperature played the key role. Further, the experiments were up-scaled to bioreactor level with all the optimized parameters for Cr (VI) removal. Interestingly, at the batch bioreactor level a slight decline in the removal efficiency was observed. The cyanobacterial species depicted a good tolerance limit (750 mg/L) even at higher concentration of Cr (VI). The maximum removal of 96.6% was obtained via the isolated cyanobacterial species depicting its potential for the heavy metal removal from the wastewater. Display omitted •High Cr (VI) tolerant cyanobacteria, Leptolyngbya boryana (~750 mg/L) was isolated.•Batch shake flask and bioreactor studies were performed for Cr (VI) removal.•Box-Behnken design of experiments was employed for optimization of process parameters.•Effect of adsorbent dose, initial Cr (VI) concentration and temperature played key role.