Caracterización molecular de cultivos axénicos para una aplicación electrogénica en celdas de combustible microbianas

Abstract

The aim of the current research was to characterize axenic cultures in a molecular way to develop an electrogenic application related to the removal of hexavalent chromium (VI) in wastewater from "El Alce” Tannery Industry, located in Guano county, Chimborazo province to generate direct current voltage simultaneously through microbial fuel cells (MFCs). For the selection of the bacterium as inoculum, tolerance and toxicity tests for Cr, Pb and Zn were carried out. For the removal of contaminants and generation of bioelectricity, six single-chamber microbial fuel cells (MFCs) with a volume of 400 ml were designed and constructed, which worked with a 24-hour continuous flow, the MFCs were distributed as follows: three for raw industrial wastewater (RW) and three for synthetic wastewater (SW). To monitor the generated voltage (mV), a monitoring system was installed during 15 days; in addition, a mini diaphragm pump was used to maintain the 24-hour continuous flow. Molecular techniques were used to identify the following bacteria: Delfia acidovorans, Pseudomonas geniculate, Stenotrophomonas maltophilia and Citrobacter freundi. Delfia acidovorans was selected as inoculum due to its ability to resist and remove Cr (VI). The MFCs with RW produced a reduction percentage for BOD, COD and Cr (VI) of 75.20%, 74.82% and 50% respectively; regarding the SW, it was reduced by 81.30% in a 15-day period in both cases. In addition, regarding voltage, RW2 and SW2 MFCs generated a maximum voltage of 395.63 mV and 224.39 mV respectively. Thus, it is recommended to propose studies related to the synergy between conventional methods and MFCs for wastewater treatment.