3D printing of synthetic microbial consortium for boosting bioelectricity generation from starch

Abstract

Starch was considered as one of the most abundant and high energy–density fuel for microbial fuel cell (MFC). However, the starch MFC usually encountered the problems of low performance and time-consuming fabrication. Here, a 3D printing approach for construction of starch MFC with rationally designed synthetic bacterial consortium was developed, which dramatically improved the MFC performance and largely simplified the bioelectrode fabrication process. The synthetic consortium containing two surface display starch depolymerization enzymes, fermentation bacterial cell and electroactive bacterial cell. With this synthetic consortium, a ready-to-use bioelectrode was simply printed by homogeneously mixing cells, sodium alginate, cellulose, and acetylene carbon black as the bioink through a 3D printer. After optimization, synthetic consortium embedded 3D-printed bioelectrode exhibited dramatically decrease on the charge transfer resistance with high capacitance, which enabled excellent extracellular electron transfer between cells and the electrode. More impressively, the MFCs with this 3D-printed bioelectrode delivered a power output of 484 mW/m² from untreated starch. This work demonstrated the potential of 3D printing for construction of high performance MFC with synthetic consortium, which would add new tool for application of synthetic biology in MFC.