Improved Monitoring of Semi-Continuous Anaerobic Digestion of Sugarcane Waste: Effects of Increasing Organic Loading Rate on Methanogenic Community Dynamics

• Main Authors: Athaydes Francisco Leite, Leandro Janke, Zuopeng Lv, Hauke Harms, Hans-Hermann Richnow, Marcell Nikolausz
• Format: Article
• Language: English
• Published: MDPI AG 2015-09-01
• Series: International Journal of Molecular Sciences
• Subjects: sugarcane waste; biogas reactor overloading; methanogenic pathways; stable isotope fingerprinting; monitoring tool
• Online Access: http://www.mdpi.com/1422-0067/16/10/23210
• ISSN: 1422-0067

The anaerobic digestion of filter cake and its co-digestion with bagasse, and the effect of gradual increase of the organic loading rate (OLR) from start-up to overload were investigated. Understanding the influence of environmental and technical parameters on the development of particular methanogenic pathway in the biogas process was an important aim for the prediction and prevention of process failure. The rapid accumulation of volatile organic acids at high OLR of 3.0 to 4.0 gvs·L−1·day−1 indicated strong process inhibition. Methanogenic community dynamics of the reactors was monitored by stable isotope composition of biogas and molecular biological analysis. A potential shift toward the aceticlastic methanogenesis was observed along with the OLR increase under stable reactor operating conditions. Reactor overloading and process failure were indicated by the tendency to return to a predominance of hydrogenotrophic methanogenesis with rising abundances of the orders Methanobacteriales and Methanomicrobiales and drop of the genus Methanosarcina abundance.