E. coli is widely used as a host strain in metabolic engineering for biofuel and chemical production. Previous works have shown that the NADH/NAD⁺ ratio plays a key role in the regulation of central metabolic pathway activities in E. coli. Under aerobic conditions, E. coli regenerates NAD⁺ from NADH through respiratory chain using oxygen as an electron acceptor. Under anaerobic conditions and in the absence of an electron acceptor, NAD⁺ regeneration is achieved by excreting reduced metabolites. Therefore changing the availability of NADH in fermentation is an important tool for metabolic engineering. In the present study, pyruvate catabolic pathways in E. coli were manipulated using standard metabolic engineering methods, and the NADH availability was also increased to efficiently produce reduced metabolites such as lactate and ethanol. Several metabolic systems were constructed by combining several gene mutations to knockout carbon atom competing pathways and expressing different heterologous genes to increase NADH production. These systems were characterized under anaerobic conditions for lactate or ethanol production.