Microbial electrochemical systems represent a sustainable and green approach for the production of pharmaceuticals, chemicals, and bioenergy by facilitating electron transfer between microbes and the extracellular environment. These systems include microbial electrolytic cells for biohydrogen production, microbial desalination cells for seawater desalination, microbial fuel cells for bioelectricity generation, microbial electrosynthesis systems for chemical synthesis, and microbial photosynthetic systems for light energy capture. Despite advancements, the efficiency of electron transfer remains a critical limitation. Electrode material, structure, and operational conditions significantly impact electron transfer efficiency. Recent reviews have focused on enhancing electron transfer in microbial electrochemical systems. Gene engineering strategies are being explored to improve extracellular and intracellular electron transfer efficiency, as well as interactions within microbial consortia. Applications of these systems include bioelectricity generation and chemical production. Efforts to scale up microbial electrochemical systems for industrial use involve strategies such as increasing unit size and stacking multiple units together. The overall sentiment of the article is positive, highlighting the potential of gene engineering to enhance the efficiency of microbial electrochemical systems.