Engineering Shewanella oneidensis to efficiently harvest electricity power by co-utilizing glucose and lactate in thin stillage of liquor industry

Abstract

Thin stillage, rich in glucose and lactate, can seriously pollute water resources when directly discharged into the natural environment. Microbial fuel cells (MFC), as a green and sustainable technology, could utilize exoelectrogens to break down organics in wastewater and harvest electricity. Nevertheless, Shewanella oneidensis MR-1, cannot utilize thin stillage for efficient power generation. Here, to enable S. oneidensis to co-utilize glucose and lactate from thin stillage, an engineered S. oneidensis G7∆RSL1 was first created by constructing glucose metabolism pathway, promoting glucose and lactate co-utilization, and enhancing biofilm formation. Then, to enhance biofilm conductivity, we constructed a 3D self-assembled G7∆RSL1-rGO/CNT biohybrid with maximum power density of 560.4 mW m−2 and 373.7 mW m−2 in artificial and actual thin stillage, respectively, the highest among the reported genetically engineered S. oneidensis with thin stillage as carbon source. This study provides a new strategy to facilitate practical applications of MFC in wastewater remediation and efficient power recovery.