Sulfate and heavy metals are two main types of pollution in most of the mining areas. It is noted that sulfide produced from microbial sulfate reduction can combine heavy metals to form precipitates, which has become an important method for treatment of heavy metal waste water. However, the lack of organic carbon source in most mining areas restricts microbial sulfate reduction.

Hence, exploring an approach for sulfate reduction without organic carbon becomes urgent and significant. Prof. LI Daping’ team from Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, has long been engaged in biotransformation of nitrogen and sulfur in bio-electrochemical systems (BESs). Recently, they developed a novel method for sulfate reduction with electrons directly derived from electrodes in a BES.

According to the findings of researches, microbial sulfate reduction was achieved with polarizable electrode (- 400 mV vs. Ag/AgCl) as sole electron donor. More importantly, it revealed that the sulfate-reducing bacteria (eg. Geobacter sp. and Desulfobulbus propionicus) could directly accept electrons from electrodes without electron shuttles or hydrogen production. The results provide a new approach for sulfate reduction and heavy metal wastewater treatment with the lack of organic carbon source.

This research entitled “Sulfate reduction with electrons directly derived from electrodes in bioelectrochemical systems” has just been published in Electrochemistry Communication (DOI: 10.1016/j.elecom.2012.04.030)