TS and VS were measured according to the APHA standard methods (1998). Total carbon (TC), total nitrogen (TN) and total hydrogen (TH) were determined by an elemental analyzer (varioEL cube, Elementar Analysensysteme GmbH). The samples were prepared by suspending 5g wet digestate into 50ml distilled water prior to pH determination by pH meter (PB-21, Sartorius, Germany) (Zhu et al., 2010). The contents of cellulose, hemicellu- lose and lignin were determined according to the procedure of Van Soest et al. (1991).