This study investigated efficient energy harvesting of a mediator-less microbial fuel cell (MFC) using Shewanella Oneidensis bacteria. Synthetic wastewater made from M9 minimal growth medium and carbon source was used to generate electricity. This experiment exhibits how concentration of bacteria in the anodic chamber, different types of carbon sources, and the substance concentration affect electricity generation. The results showed that the mediator-less MFC using Shewanella Oneidensis can produce voltage close to the maximum attainable MFC voltage. The efficient MFC can be used to treat wastewater while reducing energy needs and producing an alternative form of energy.