Tourmaline enhanced methane yield via regulating microbial metabolic balance during anaerobic co-digestion of corn stover and cow manure.

This work performed a pilot-scale study on the effects of the substrate ratio, the concentration of tourmaline (Tur), and its high-temperature thermally modified (HTM) material on the anaerobic co-digestion of corn stover (CS) and cow manure (CM). The experimental results showed that the CH4 yield was higher at a corn stover -to- cow manure feeding ratio of 2:1. The cumulative CH4 yield increased by 22.76% and 8.31% at a concentration of tourmaline of 2.0 g/L and a tourmaline treatment temperature of 400 °C respectively. Microbial diversity analysis revealed that adding low doses of tourmaline regulated the distribution of microorganisms and that Methanobacteria became the dominant methanogenic archaea in the fermentation broth. This work clarified the effect of the concentration of tourmaline on gas production by anaerobic co-digestion from the perspective of the microbial metabolic balance and suggested the possibility of its application on a larger scale.