Bioremediation strategies for chromium removal: Current research, scale-up approach and future perspectives

Industrial applications and commercial processes release a lot of chromium into the environment (soil, surface water or atmosphere) and resulting in serious human diseases because of their toxicity. Biological Cr-removal offers an alternative to traditional physic-chemical methods. This is considered as a sustainable technology of lower impact on the environment. Resistant microorganisms (e.g. bacteria, fungi, and algae) have been most extensively studied from this characteristic. Several mechanisms were developed by microorganisms to deal with chromium toxicity. These tools include biotransformation (reduction or oxidation), bioaccumulation and/or biosorption, and are considered as an alternative to remove the heavy metal. The aim of this review is summarizes Cr(VI)-bioremediation technologies oriented on practical applications at larger scale technologies. In the same way, the most relevant results of several investigations focused on process feasibility and the robustness of different systems (reactors and pilot scale) designed for chromium-removal capacity are highlighted.