Chemical composition of maize stover fraction versus methane yield and energy value in fermentation process

Abstract Maize stover is a morphologically diverse biomass, consisting of cobs, leaves, husks and stalks. Technological solutions allow separation of maize stover fractions depending on harvest term, tissular and chemical composition. Different chemical compositions of lignocellulose biomasses affect energy efficiency of specific fractions in methane fermentation. The aim of this study was to correlate the chemical composition of maize stover fractions (cobs, husks, leaves and stalks) with methane yield and energy value while considering different harvest times for biogas fermentation. Pearson correlation coefficients were calculated for all results, with a very strong negative correlation (r = −0.86) between methane yield and lignin content in the maize stover fractions. The lowest methane yield (185.3 m3/Mg of TS) and the longest HRT (40 days) activity of maize stalks were obtained from those samples. Moderately negative correlation between methane yield and cellulose content (r = 0.53) or between methane yield and Na content (r = −0.52) were also observed. This helps explain why the lowest methane yields were found in peduncles with high levels of sodium, cellulose and lignin.