Microbiome-based monitoring as strategy for an anhenced operation of anaerobic (co-)digestion system

Abstract

To improve understanding into the microbiome-functionality relationship in anaerobic digestion (AD) process, several reactors were studied at lab and industrial scale, particularly paying attention to substrate composition, temperature drop, hydraulic and organic overloads, and high ammonia and long chain fatty acids (LCFA) environments. Molecular fingerprint DGGE technique, FISH analysis and Illumina MiSeq of 16S rRNA genes were applied to characterize the AD microbiome. Feedstock clearly determines the microbial community structure, although in co-digestion the basis substrate gains importance driving the microbiome evolution over time. The adaptation to inhibitory environments allows a fast recovery period without noticeable changes in the community structure. The use of real substrates, in this case manure, made difficult the identification of microbial communities related with one substrate type of with one macroscopic parameter, since the entry of several adapted communities with the manure fed overshadowed possible changes due to other operational and /or environmental shifts. To sum up, these findings provide new insights into the nexus of microbial community structure/dynamics and reactor performance, mainly in non-steady state systems and related to several co-substrates. It also show evidence that microbial-based knowledge can be used as a tool of control in AD plants, helping reactor optimization and stabilization.