How does copper stress influence the relationships among the anaerobic co-fermentation parameters?

The presence of heavy metals influences the efficiency of anaerobic fermentation and results in the variations of the relationships among the fermentation parameters. In this study, the impacts of elevated Cu2+ concentrations on relationships among biogas properties, process stability, substrate biodegradation, and enzyme activity were analysed by Pearson correlation analysis based on the experimental data of a mesophilic anaerobic co-fermentation with mixed acid pretreated Phragmites australis straw and raw cow dung as feedstocks. The results showed that in the absence of Cu2+, the cumulative biogas yields were positively related to pH values (0.780, p