A new article “Bioremediation of a polymetallic, arsenic-dominated reverse osmosis reject stream” was published in Letters in Applied Microbiology by our team (Dr. Lucian Staicu and Paulina Wojtowicz) in collaboration with Prof. Mihaly Posfai and Zsombor Molnar (University of Pannonia, Veszprem, Hungary), Prof. Encarnacion Ruiz-Agudo (University of Granada, Spain) and Dr. Diego Baragano and Prof. Jose Luis Gallego (University of Oviedo, Spain).
The article explores the bioremediation potential of a real industrial effluent (retentate stream from a full-scale reverse osmosis plant treating mine water) using a metal-resistant bacterial culture, Shewanella sp. O23S. The results show cysteine metabolism significantly increases the removal yield of several pollutants such as As (27%), Co (80%), Cu (96%), Mo (78%), Se (88%), Sb (83%), and Zn (90%). The contribution of cysteine as a source of H2S to enhancing the removal yield was confirmed by its addition after seven days of incubations initially lacking it. Additionally, the cysteine-sourced H2S was confirmed by its capture onto headspace-mounted Pb-acetate test strips that were analyzed by X-ray diffraction. We show that real metal-laden industrial effluents can be treated to medium-to-high efficiency using a biological system (naturally-sourced inocula) and inexpensive reagents (yeast extract, lactate and cysteine).
This study provides evidence of the medium-to-high removal of metals and metalloids present in real industrial effluents by using naturally-sourced metal-resistant bacterial inocula. Apart from the applied research significance, the coupling of cysteine degradation to metal removal sheds light into the microbially-driven natural attention of industrial pollution in specific geochemical settings. The results warrant the scaling up of the process to treat larger effluent volumes and potentially recover valuable metals in the form of metal sulfides.