Effect of inoculum to substrate ratio on the hydrolysis and acidification of food waste in leach bed reactor

► High inoculum:substrate ratio (ISR) significantly increased the hydrolysis rate of protein. ► High ISR exhibit only a modest increase in the decomposition of carbohydrate. ► Chemical oxygen demand of leachates increase with the increasing ISR from 20% to 80% (w/w), however not significant. ► High ISR reduce the waste throughput; thus lower ISR of 20% (w/w) during acidogenesis is recommended.