Effect of structural carbohydrates and lignin content on the anaerobic digestion of paper and paper board materials by anaerobic granular sludge (Biotechnology and Bioengineering)

Anaerobic digestion (AD) of lignocellulosic materials is commonly limited by the hydrolysis step. Unlike unprocessed lignocellulosic materials, paper and paper board (PPB) are processed for their fabrication. Such modifications may affect their methane yields and methane production rates. Previous studies have investigated the correlation between lignin and biomethane yields of unprocessed lignocellulosic materials; nevertheless, there is limited knowledge regarding the relationship between the AD kinetic parameters and composition of PPB. This study evaluated correlations of methane yields and Monod and Gompertz kinetic parameters with structural carbohydrates, lignin, and ash concentration of five types of PPBs. All components were used as single and combined independent variables in linear regressions to predict methane yield, maximum specific methanogenic activity (SMAmax), saturation constant (Ks), and lag phase (?). Additionally, microbial community profiles were obtained for each PPB assay. Results showed methane yields ranging from 69.2 ± 8.61 to 97.2 ± 2.29% of PPB substrates provided. The highest correlation coefficients were obtained for SMAmax as function of hemicellulose / (lignin + ash) (R2 = 0.86) and for ? as a function of lignin + cellulose (R2 = 0.85). All other parameters exhibited weaker correlations (R2