Estimating evolution of during methanization of cellulosic waste based on stoichiometric chemical reactions, microbial dynamics and stable carbon isotope fractionation

A change in δ 13 CH 4 during mesophilic methanization of cellulosic waste (paper and cardboard) was described using a mathematical model based on stoichiometric chemical reactions, microbial dynamics and the equation for the 13 C isotope accumulation in products including isotope fractionation. In this study, experimental data, previously obtained by Qu et al. (2009), was used to model metabolic pathways of cellulose transformation. A significant change in δ 13 CH 4 occurred in time during cellulosic waste methanization which was in accordance with the model. It was explained by the change in input of acetoclastic and hydrogenotrophic methanogenesis as well as by fractionation of stable carbon isotopes 13 C and 12 C which was much higher for hydrogenotrophic methanogenesis when compared to acetoclastic methanogenesis.