Microbial community structure and dynamics in anaerobic fluidized‐bed and granular sludge‐bed reactors: influence of operational temperature and reactor configuration

Abstract

SummaryMethanogenic community structure and dynamics were investigated in two different, replicated anaerobic wastewater treatment reactor configurations [inverted fluidized bed (IFB) and expanded granular sludge bed (EGSB)] treating synthetic dairy wastewater, during operating temperature transitions from 37°C to 25°C, and from 25°C to 15°C, over a 430‐day trial. Non‐metric multidimensional scaling (NMS) and moving‐window analyses, based on quantitative real‐time PCR data, along with denaturing gradient gel electrophoresis (DGGE) profiling, demonstrated that the methanogenic communities developed in a different manner in these reactor configurations. A comparable level of performance was recorded for both systems at 37°C and 25°C, but a more dynamic and diverse microbial community in the IFB reactors supported better stability and adaptative capacity towards low temperature operation. The emergence and maintenance of particular bacterial genotypes (phylum Firmicutes and Bacteroidetes) was associated with efficient protein hydrolysis in the IFB, while protein hydrolysis was inefficient in the EGSB. A significant community shift from a Methanobacteriales and Methanosaetaceae towards a Methanomicrobiales‐predominated community was demonstrated during operation at 15°C in both reactor configurations.

Effect of Seasonal Temperature on the Performance and on the Microbial Community of a Novel AWFR for Decentralized Domestic Wastewater Pretreatment

“…Hydrogenotrophic genera (>63.7%) made up a large portion of the archaeal community in winter. These findings were in line with the previous observations of methanogen population shifts to favor hydrogen utilization under low temperatures [25,[41][42][43]. It might be explained that lower temperature in winter affected the microbial membrane fluidity and inhibited the utilization of acetate than H 2 [44].…”

Microbial Community Response to Seasonal Temperature Variation in a Small-Scale Anaerobic Digester

“…By 7 February 2011, the percentage of Methanosaeta concilii had decreased to 61% of the clones, while Methanobrevibacter smithii had increased to 39% of the clones. The increase in the abundance of hydrogenotrophic methanogens due to decreasing temperature was also observed by Bialek et al [15].…”

Outlining microbial community dynamics during temperature drop and subsequent recovery period in anaerobic co-digestion systems

“…Leven et al (2007) showed that Chloroflexi and Bacteroidetes represented the major phyla at mesophilic temperatures, whilst the phylum Thermotogae was the dominant group in the thermophilic range. In relation to the archaeal community, Methanomicrobiales dominated at 15 • C, and Methanosaeta and Methanomicrobiales were the most abundant at 37 • C (Bialek et al, 2012). Summarizing, these studies confirm the temperature as a parameter affecting the structure of the microbial communities, even more than the increase in the organic loading rate (OLR) (Guo et al, 2014), but they lack transient membership of the microbial community during the days of the temperature perturbation.…”