Our recent study investigated the potential for CO conversion using an anaerobic mixed culture from a biogas plant in a TBR system over an extended period of 212 days . The results demonstrated complete conversion of CO to CH4 and CO2 at a CO loading rate (COLR) of 3.10 Nm³ m⁻³ d⁻¹ and a gas retention time (GRT) of 60 minutes. A notable observation was the codominance of methanogenic archaea Methanothermobacter and syntrophic acetate-oxidizing bacteria Syntrophaceticus, both of which played a crucial role in the efficiency of the CO conversion process. Despite these promising results, the study also highlighted that complete conversion was not achieved at higher COLRs and shorter GRTs, indicating potential limitations in the inoculum performance under more challenging operational conditions. These findings prompted important questions regarding the influence of inoculum composition on reactor performance. Specifically, was the chosen inoculum from the biogas plant the most suitable for this process? Could the efficiency of the CO conversion be further enhanced by using a different or less studied inoculum, such as cow manure? How do variations in inoculum sources affect CO conversion efficiency and the enrichment of microbial community? What impact does the type of inoculum have on biofilm formation? And to what extent can these factors be optimized to enhance the overall performance of the reactor?