Quantitative Real‐Time Polymerase Chain Reaction (qPCR) Analysis as a Decision Support Tool for High‐Rate Biohydrogen Production Under Process Disturbance

This study investigated the feasibility of quantitative real‐time polymerase chain reaction (qPCR) as a monitoring and decision‐making support tool for high‐rate continuous biohydrogen production. Three identical lab‐scale dynamic membrane (DM) bioreactors were operated under operational disturbances, and the microbial dynamics were monitored using qPCR analysis of major bacterial strains, including Clostridium pasteurianum and Streptococcus equinus , alongside the universal bacterial primer. Despite a similar performance and metabolic flux of hydrogen production after the disturbance, the qPCR copy numbers of target strains showed significant differences. When the normalized abundance of C. pasteurianum to the universal primer was no less than 2.6 copies/copies, the process performance eventually recovered, whereas the performance deteriorated when the normalized abundance of C. pasteurianum was lower than 2.6 copies/copies. The increased abundance of S. equinus was also associated with the deterioration of process performance. These results suggest that qPCR monitoring of key strains is a useful decision‐making tool for continuous biohydrogen production.