“…Previous studies have reported that long-term mono-digestion of energy crops can result in biochemical or mechanical process instability (De Moor et al, 2013;Koch et al, 2009;Lebuhn et al, 2008). Anaerobic degradation is a process where microbiological and chemical aspects are closely linked (Angelidaki et al, 2009;Mittweg et al, 2012).…”