Two-step carbon fixation provides a wider range of products that can be formed with this model, in both \(H_2\) mediation and EET-mediation, as it has the potential to create a product that requires a greater potential than the NADH reduction potential, allowing for lower energy NADH electrons to form products a single-step \(H_2\)-mediated molecule such as ethanol and ethane by initially forming formate. Examples are given in Table 1. However these two compounds (ethanol and ethane) are often not worth making as a primary substrate, as it requires more electrons per carbon compared to other substrates (8 and 7 electrons per carbons respectively) (Ref!!??).