Details about the input parameters and experimental trials conducted are given in Table . The reactor was started using the direct inoculation methods as outlined in . A mix of H 2 , CO 2 , and N 2 was used as the inlet gas to the reactors. N 2 was added in the inlet gas to simulate the feed gas as biogas, where N 2 asserts an equivalent partial pressure in the feed gas as that of CH 4 in the case of a biogas feed. However, during the startup and enrichment period, only H 2 and CO 2 were fed as inlet gas to the reactors. This enables a higher partial pressure of substrate H 2 and CO 2 that assists the enrichment and development of biofilm in the BTF reactors. After the startup period, GRT reduction trials were conducted, where the objective was the incremental increase in the gas feed flowrate and in turn to maximize the PC. After that, the nutrient consumption and supply trials were conducted.