Biohydrogen production potential with sulfate and nitrate removal by heat-pretreated enriched sulfate-reducing microorganisms-based bioelectrochemical system

In this study, heat-pretreated sulfate-reducing bacteria (SRBs) were evaluated for simultaneous sulfate and nitrate removal in a bioelectrochemical system (BES). The effect of the applied potential of 20 mV to SRBs was evaluated at a sulfate concentration of 3 g/L and/or nitrate concentration of 0.5 g/L supplemented before heat pretreatment for sulfate and nitrate removal. The highest H-2 production of 2.24 +/- 0.04 mM/L in heat-pretreated culture was observed in the presence of sulfate at an applied potential of 20 mV (BHE-S). Simultaneous reduction of sulfate and nitrate was significant in BESs supplemented with either sulfate or nitrate during heat-shock pretreatment of the culture. The highest SO42- removal of 88.91 +/- 0.8% was found in culture heat pretreated with NO3- and applied with 20 mV potential (BHE-N). The kinetics of heat-pretreated culture showed higher R-2 and ultimate potential for H-2 on the continuous application of 20 mV potential.

Automated summary

In this study, the ability of heat-pretreated sulfate-reducing bacteria (SRBs) to simultaneously remove sulfate and nitrate in a bioelectrochemical system (BES) was evaluated. The effect of an applied potential of 20 mV on SRBs was assessed at sulfate and/or nitrate concentrations before heat pretreatment. The highest H-2 production was observed in the presence of sulfate at an applied potential of 20 mV, and simultaneous reduction of sulfate and nitrate was significant during heat-shock pretreatment. The kinetics of heat-pretreated culture showed higher H-2 production with continuous application of 20 mV potential.