A novel iron-reducing yeast, Candida sp. IR11, was isolated from an anodic biofilm in a MFC reactor fed glucose as a feedstock. 200-250 mV of voltage was produced in the air-cathode MFC inoculated with a pure culture of the strain IR11 where glucose was supplied as a feedstock. When the strain IR11 was inoculated into a conventional MFC treating rejected wastewater from an upflow anaerobic sludge blanket, maximum power density and coulombic efficiency were enhanced from 15.2 +/- 0.36 to 20.6 +/- 1.52 mW m(-2) and from 14.4 +/- 0.45% to 21.9 +/- 0.71%, respectively. In addition, the inoculation with IR11 improved COD removal from 79.1 +/- 1.53% to 91.3 +/- 5.29%. The quantitative PCR results showed that the strain IR11 successfully attached the anodic biofilm of the MFC reactors. These results indicate that Candida sp. IR11 is a promising biocatalyst for the enhancement of MFC performance. (C) 2015 Elsevier Ltd. All rights reserved.