Improved biogas production from whole stillage by co-digestion with cattle manure

► Biogas production from whole stillage in mesophilic lab-scale reactors. ► Clear instability of the processes using whole stillage as sole substrate. ► Co-digestion with manure improved biogas productivity and process stability. ► Methanogenic and acetogenic populations were studied with quantitative analysis. ► Stable abundances of the populations throughout the whole operation.