Electrodes boost microbial metabolism to mineralize antibiotics in manure

Abstract

Livestock manures are potential sources of antibiotics in the environment. Sulfamethazine (SMZ), frequently used in veterinary medicine, can enter the environment by using manure as soil fertilizer due to its incomplete absorption in the animal gut and its unmetabolized excretion. The objective of this study was to evaluate the mineralization of 14 C-labelled SMZ in manure under a new redox scenario provided by microbial electrochemical reactors, termed microbial electroremediating cells (MERC). These devices aim to overcome the electron acceptor limitation in bacterial oxidative metabolism by means of using electrodes to enhance the biodegradation of pollutants in the environment. Our results revealed that the total degradation of 14 C-SMZ reached 43.5% in short term batch laboratory scale experiments under reducing conditions (−400 mV vs. Ag/AgCl). Actually, SMZ mineralization was enhanced up to 10-fold in the early stages (after 2 weeks) in comparison with an electrode-free natural attenuation assay. Moreover, mineralization showed a dependence on electrode potential, with negligible results for conditions set to +400 mV vs Ag/AgCl. The impact of merging electrodes and microorganisms for manure bioremediation suggests a promising future for this emerging technology to treat polluted livestock wastes and prevent soil and groundwater pollution.

Unraveling Anaerobic Metabolisms in a Hypersaline Sediment

“…Microorganisms interacting with electrodes are presently boosting a myriad of biotechnological processes ( Clauwaert et al, 2008 ; Rosenbaum and Franks, 2014 ; Rodrigo Quejigo et al, 2019 ; Prévoteau et al, 2020 ), but little is known yet about halophiles with this capacity ( Carmona-Martínez et al, 2013 ; Shrestha et al, 2018 ). Although not directly comparable in terms of growth yield, data from cultures grown here by using a polarized electrode as the electron acceptor show that they developed in the same time frame of those growing on fumarate, exhibiting a doubling time of approximately 6 days and reaching the maximal current beyond day 12 ( Figure 1 and Table 1 ).…”

Microbial Electrochemical Fluidized Bed Reactor: A Promising Solution for Removing Pollutants From Pharmaceutical Industrial Wastewater

“…At higher anode polarization, + 600 mV (vs. Ag/AgCl), the TOC removal decreased to 63%, while CBZ and SMX showed a slight decrease compared to the operation at lower anode potentials. The reduced electrobioremediation efficiency at potentials as high as + 600 mV has been previously reported and is most likely due to an alteration in the permeability of the bacterial membrane (Rodrigo Quejigo et al, 2019), resulting in lower microbial viability.…”

“…Furthermore, MET have been historically evaluated regarding wastewater treatment capacity through three different approaches: microbial fuel cells (MFC) (Logan, 2008;Domínguez-Garay et al, 2016;Cecconet et al, 2018;Gajda et al, 2018;Gao et al, 2020;Lin et al, 2020), microbial electrolysis cells (MEC) (Srikanth et al, 2008;Zhang and Angelidaki, 2014;Scott and Yu, 2015;Bajracharya et al, 2016;Leon-Fernandez et al, 2019), and microbial electrochemical snorkel (MES) (Yang et al, 2013(Yang et al, , 2015Viggi et al, 2017;Hoareau et al, 2019;Pun et al, 2019;Ramírez-Vargas et al, 2019). Among them, dual-chamber MEC has been the most evaluated system for removing pharmaceutical pollutants like CBZ and SMX due to successful performance at lab scale (Harnisch et al, 2013;Rodrigo Quejigo et al, 2019;Tahir et al, 2019). Nevertheless, some bottlenecks, such as the ionic exchange membrane (IEM) cost or a large limitation in mass transfer, have delayed the further scaling of such a system.…”