The Anaerobic Digestion of Rice Straw: A Review

The anaerobic digestion of rice straw has been studied for the past century, but the renewable energy potential is barely utilized. Greenhouse gas emissions from rice fields can be substantially reduced if straw is removed. Methane yields ranging from 92 to 280 l/kg of volatile solids have been achieved. Optimal digestion conditions such as pH (6.5–8.0), temperature (35–40°C), and nutrients (C:N ratio of 25–35) are defined. Pretreatment (i.e., fungi, acid, and alkali solutions) and microbial engineering can increase biogas production, but research is lacking on the overall logistics for a full-scale system.