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

Abstract

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.

Impact of process temperature and organic loading rate on cellulolytic / hydrolytic biofilm microbiomes during biomethanation of ryegrass silage revealed by genome-centered metagenomics and metatranscriptomics

“…Apart from fermentative bacteria, the order Thermoanaerobacteriales, including several known syntrophic acetate-oxidizing bacteria e.g., Caldanaerobacter and Alkaliphilius, was shown to increase [32]. The methanogenic archaeal community mainly consisted of members of the genera Methanosarcina [33][34][35]. The Methanobacteria, Methanomicrobiales, and/or Methanomassiliicoccaceae members were also observed in certain AD-processes featuring a high organic load, depending on other prevailing conditions [36].…”

High salinity in molasses wastewaters shifts anaerobic digestion to carboxylate production

“…Methanomicrobiales are, similar to Methanobacteriales, often observed at deteriorating conditions, i.e. the accumulation of VFA, in AD (Hao et al 2013, Leite et al 2015, Munk et al 2010. However, while Methanobacteriales could be correlated to biogas production in AD, this was not the case for Methanomicrobiales (De Vrieze et al 2015c).…”

Characterization of Core Microbiomes and Functional Profiles of Mesophilic Anaerobic Digesters Fed With Chlorella vulgaris Green Microalgae and Maize Silage

“…The VOAs/TIC (Volatile Organic Acids/Total Inorganic Carbon) ratio is a reliable indicator of a stable digestion process (Lienen et al, 2013). The optimal ratio ranges between 0.1 and 0.5 (Leite et al, 2015). Most of our values fell within this range, due to the low organic loading rate (OLR), indicating a stable and balanced operation in all three reactors, although toward the end of the experimental period the VOAs/TIC in the reactor digesting C. vulgaris alone started to increase (Figure 1B).…”

“…Methanosaeta outcompeted Methanosarcina at low acetate concentration, while Methanosarcina predominated Methanosaeta at high acetate levels (Smith and Ingram-Smith, 2007;De Vrieze et al, 2012). Other operational parameters, e.g., NH 3 concentration, may also change the equilibrium between these two genera (Chen and He, 2015;Leite et al, 2015;Narihiro et al, 2015;Chen et al, 2017). The genus Methanosarcina is more tolerant to ammonia, than Methanosaeta (Fotidis et al, 2013;Gao et al, 2015;Niu et al, 2015).…”