Authors: Olivier Chapleur Laurent Mazeas JeanJacques Godon Théodore Bouchez
Publish Date: 2015/10/22
Volume: 100, Issue: 3, Pages: 1445-1457
Abstract
In natural settings anaerobic digestion can take place in a wide temperature range but industrial digesters are usually operated under either mesophilic ~35 °C or thermophilic ~55 °C conditions The ability of anaerobic digestion microbiota to switch from one operating temperature to the other remains poorly documented We therefore studied the effect of sudden temperature changes 35 °C/55 °C in labscale bioreactors degrading 13Clabelled cellulose An asymmetric behaviour was observed In terms of methane production after an adaptation period mesophilic inoculum exhibited a functional resistance to temperature increase but no functional resilience when temperature was reset to 35 °C while thermophilic inoculum methanogenic activity strongly decreased under mesophilic conditions but partially recovered when temperature was reset to 55 °C Automated ribosomal intergenic spacer analysis community fingerprints evidenced a strong influence of temperature on microbial diversity particularly pronounced and persistent for Archaea Key phylotypes involved in 13Ccellulose degradation were identified with a coupled stable isotope probing SIP16S rDNA pyrotag sequencing approach suggesting that the hydrolytic and fermentative metabolic functions could be maintained thanks to functional redundancy between members of the class Clostridia whereas methanogenic activity primarily relied on specialized groups affiliated either to genus Methanosarcina mesophilic conditions Methanothermobacter or Methanoculleus thermophilic conditions that were irreversibly modified by temperature increaseWe are grateful to Céline Madigou for precious support in achieving this work All data are available in the supplementary material and on request from the authors The experiments were conducted on the LABE experimental platform funded by DRRT in the framework of the CPER 2007–2014 project
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