Metabolic Engineering Modification and Electricity Production Condition Optimization of Salt-Tolerant Electricigen Shewanella Algae

Abstract

Electricigens are a type of microorganism with extracellular electron transfer ability, which can convert stored chemical energy in organic matter into electrical energy through their own metabolism. Previous studies have shown that electricigens can be used as catalysts to construct microbial fuel cells (MFCs). However, low electricity production remains the most urgent issue for electricigens. This study is based on a salt-tolerant electricigen, Shewanella algae, and uses CRISPRa technology to regulate the expression of pflb and mdh genes in the extracellular electron metabolism pathway, thereby enhancing the ability to produce electricity. Simultaneously, we aim to optimize power generation conditions of Shewanella algae by adding surfactants or electron mediators in the bipolar chamber of fuel cells to enhance electron transfer. The results show that overexpression of pflb and mdh genes increases the current density by 3.51% and 14.17%, respectively. The use of surfactants such as Tween-80 increases the current density by approximately 20%-40%. These results indicate that an increase in extracellular electron transfer or electron metabolism can increase power generation, providing a basis for further optimization and transformation of salt-tolerant electricigen Shewanella algae.

Keywords

Shewanella algae / metabolic engineering / microbial fuel cell (MFC) / surfactant / electron mediator

Funding

Innovation and Entrepreneurship Training Program for College Students, China(202210255065)

Innovation and Entrepreneurship Training Program for College Students, China(117-03-0178012/017)