Construction of Shewanella oneidensis chassis for unbalanced fermentation with glycerol by adaptive laboratory evolution

Shewanella oneidensis MR-1 is an electrochemically active bacterium with high potential for use in unbalanced fermentation. However, its efficiency in bioelectricity production using cheap substrates such as glycerol is limited. In this study, the ES3-16 evolved strain of Shewanella oneidensis was developed by adaptive laboratory evolution and exhibited an excellent ability to generate bioelectricity from glycerol with an electricity production efficiency of 502.1±13.9 mW/m 2 . The evolved strain with an acetoin-producing vector co-produced 473.3±21.2 mg/L acetoin and generated a power density of 1269.6±19.7 mW/m 2 by unbalanced fermentation. Mutational analysis showed that increased glycerol utilization and altered cell morphology are vital for improving the bioelectricity synthesis capacity of S. oneidensis . Analysis of the genetic basis of the evolved strains provides important guidance for the efficient utilization of glycerol and unbalanced fermentation.