Evolution ofShewanella oneidensisMR-1 in competition withCitrobacter freundii

Abstract

AbstractInterspecific competition is one of the most important metabolic interactions within microbial communities, and exoelectrogenic bacteria that can conduct extracellular electron transfer act essential roles in nature and engineering systems for pollutants removal. In the present study we investigated the long-term impact of substrate competition from non-exoelectrogenicCitrobacter freundiiAn1 on exoelectrogenicShewanella oneidensisMR-1. Without additional electron acceptor or with electron acceptor of oxygen,C. freundiiAn1 typically suppressed the growth ofS. oneidensisMR-1. In contrast,S. oneidensisMR-1 grown better with electron acceptor of ferrihydrite by taking advantage of extracellular electron transfer. However, the presence of ferrihydrite did not enhance the ferrihydrite reduction ofS. oneidensisMR-1 after the 160 d-acclimation. The whole genome resequencing showed a complex evolution ofS. oneidensisMR-1 when the strain faced the competition fromC. freundiiAn1 for substrate.