Using fluorescence excitation-emission matrix spectroscopy to monitor the conversion of organic matter during anaerobic co-digestion of cattle dung and duck manure

► Spectroscopic characteristics of dissolved organic matter in anaerobic digestion. ► Co-digestion obtains remarkable organic matters removal rate. ► Tyrosine-like/fulvic-like fluorescence intensity indicates nitrogen form conversion. ► Tryptophan fluorescence intensity variations reflect microbial activity. ► Co-digestion corrects the limitation of single manure digestion.