The effect of effective microorganisms-4 (em-4) on biogas yield in solid-state anaerobic digestion of corn stover

Biogas production from various organic wastes such as corn stover can be used as an alternative fuel. Corn stover is one of the agricultural wastes that are widely generated in Indonesia. It contains cellulose which has the potential to be used as raw material for producing biogas. The biogas production process was carried out in solid-state anaerobic digestion (SS-AD), i.e., a biological process that occurs naturally by a microorganism that breaks down molecules of organic material with a total solid content greater than 15%. This research was aimed to investigate the effect of EM-4 concentration on biogas yield. The volatile solids (VS) reduction was also measured in this study. The results of the study showed that EM-4 concentration had a significant effect on biogas yield (p < 0.05). The positive linear relationship was found between EM-4 concentration and biogas yield. The highest biogas yield of 597.98 L/kg VS was obtained at EM-4 15%. The main source of biogas production during SS-AD of corn stover was the reduction of VS.