| description |
Numerous observations indicate a high flexibility of microbial communities in different biogas reactors during anaerobic digestion. Here we describe our findings regarding the functional redundancy and similarity of involved microorganisms in four continuously-stirred tank lab-scale biogas reactors (CSTRs, 39 °C, 12 L volume) supplied with different mixtures of sugar beet silage (SBS) and maize silage (MS) resulting in similar biogas yields in all reactors. CSTRs were set-up with inoculum from a full-scale biogas plant, fed with mixtures of MS and SBS in the ratios of 1:0 (CF1), 6:1 (CF2), 3:1 (CF3), 1:3 (CF4) with equal organic loading rates (OLR 1.25 kg VS m-3 d-1) and operated for 140 d. The compositions of bacterial and archaeal communities degrading the different substrate mixtures were analyzed by 454 amplicon sequencing approach based on 16S rRNA genes. Both bacterial and archaeal communities shifted with increasing amounts of SBS. As the compositional shifts within the microbial communities did not influence the respective biogas production, similar process dynamics indicate functional redundant archaeal and functional similar bacterial communities in each individual CSTR. |