The effect of adding mixed cultures methanogenic archaebacteria on anaerobic degradation of food waste

<h2>Abstract</h2> Food waste is the largest percentage of solid waste (by mass) in Indonesia. It can be processed into new products using anaerobic digestion (AD). This study was conducted to examine the effect of mixed cultures of methanogenic archaebacteria (MCM) as inoculum on the anaerobic waste degradation process. The inoculum originated from wastewater treatment plants of dairy factory industries. The quantity of MCM added based on the weight percentage of MCM to solid waste (10 %, 30 %, 50 %) and the frequency (every 10 days and 15 days). After 30 days of AD, microbial communities showed that the addition of inoculum could accelerate AD phases, where methanogenesis could be achieved faster. This is also in line with the biogas production, which became higher with the increasing percentage and frequency of MCM added. This study showed that adding MCM can increase the production of biogas up to 7 times, with highest specific daily production of 248.53 mL/g VS added/day. Food waste composition that predominantly consisted of vegetables (75 %) contributed to the shift in microbial communities present in AD from acetoclastic to hydrogenotrophic methanogens.