Selenium reduction by a defined co-culture of Shigella fergusonii strain TB42616 and Pantoea vagans strain

Document Type


Publication Title

Bioprocess Biosystems Engineering


Selenium reduction was evaluated with pure batch cultures of Shigella fergusonii strain TB42616 (TB) and Pantoea vagans strain EWB32213-2 (EWB), respectively. A two-stage process, from Se(VI) to Se(IV) and then from Se(IV) to Se(0), was observed. The second stage of reduction, from Se(IV) to Se(0), was observed as the rate-limiting step resulting in accumulation of the more toxic Se(IV). In order to facilitate Se(VI) reduction and reduce Se(IV) accumulation, the Se(VI)-reducing strain TB was co-cultured with a Se(IV)-reducing strain EWB. Although Se(VI) reduction rate was not affected, Se(IV) reduction was significantly enhanced with low Se(IV) accumulation in the defined co-culture. Effects of culture composition as well as nitrate and arsenate on Se(VI) reduction were also investigated. A co-culture composition of 10:1 (EWB:TB) ratio was observed to achieve the best total selenium reduction. In addition, nitrate at 50 mg/L was observed to inhibit Se(IV) reduction but not Se(VI) reduction, while arsenate at 200 mg/L exhibited slight inhibition on both Se(VI) and Se(IV) reduction.

First Page


Last Page



Publication Date


Funding Information

This research was supported by the Kentucky Water Resources Research Institute and a teaching assistantship from the Department of Civil Engineering at the University of Kentucky. We are also grateful to Dr. David Price for providing wastewater samples from the Town Branch Wastewater Treatment Plant.