TY - JOUR
T1 - Focused-Pulsed sludge pre-treatment increases the bacterial diversity and relative abundance of acetoclastic methanogens in a full-scale anaerobic digester
AU - Zhang, Husen
AU - Banaszak, James E.
AU - Parameswaran, Prathap
AU - Alder, Jared
AU - Krajmalnik-Brown, Rosa
AU - Rittmann, Bruce
PY - 2009/10
Y1 - 2009/10
N2 - The low yield of methane in anaerobic digestion systems represents a loss of energy that can be captured as renewable energy when the input sludge is pre-treated to make it more bioavailable. We investigated Focused-Pulsed (FP) pre-treatment, which make complex biological solids more bioavailable by exposing them to rapid pulses of a very strong electric field. We investigated how the microbial ecology in full-scale anaerobic digesters was altered when the digesters' methane production rate was significantly increased by FP pre-treatment. Using clone libraries and quantitative PCR, we demonstrated a shift in methanogenic genera to the acetate-cleaving Methanosaeta and away from the H2-oxidizing Methanoculleus. In addition, the acetate concentration in the effluent was very low, probably due to the dominance of Methanosaeta, which are capable of scavenging low acetate concentrations. By analyzing 36,797 pyrosequencing tags from the V6 region of the bacterial 16S rRNA gene, along with archaeal and bacterial clone libraries and quantitative PCR, we compared the microbial community composition before and after FP treatment. The bacterial community became more diverse after FP pre-treatment and was populated more by phylotypes associated with cellulose fermentation (Ruminococcus), scavenging of biomass-derived organic carbon (Chloroflexi), and homo-acetogenesis (Treponema). We interpret that, as the overall activity of the community was stimulated by addition of more bioavailable organic matter, the bacterial community became more phylogenetically diverse to take advantage of the added input of biodegradable material and in response to the more efficient utilization of acetate by Methanosaeta.
AB - The low yield of methane in anaerobic digestion systems represents a loss of energy that can be captured as renewable energy when the input sludge is pre-treated to make it more bioavailable. We investigated Focused-Pulsed (FP) pre-treatment, which make complex biological solids more bioavailable by exposing them to rapid pulses of a very strong electric field. We investigated how the microbial ecology in full-scale anaerobic digesters was altered when the digesters' methane production rate was significantly increased by FP pre-treatment. Using clone libraries and quantitative PCR, we demonstrated a shift in methanogenic genera to the acetate-cleaving Methanosaeta and away from the H2-oxidizing Methanoculleus. In addition, the acetate concentration in the effluent was very low, probably due to the dominance of Methanosaeta, which are capable of scavenging low acetate concentrations. By analyzing 36,797 pyrosequencing tags from the V6 region of the bacterial 16S rRNA gene, along with archaeal and bacterial clone libraries and quantitative PCR, we compared the microbial community composition before and after FP treatment. The bacterial community became more diverse after FP pre-treatment and was populated more by phylotypes associated with cellulose fermentation (Ruminococcus), scavenging of biomass-derived organic carbon (Chloroflexi), and homo-acetogenesis (Treponema). We interpret that, as the overall activity of the community was stimulated by addition of more bioavailable organic matter, the bacterial community became more phylogenetically diverse to take advantage of the added input of biodegradable material and in response to the more efficient utilization of acetate by Methanosaeta.
KW - Anaerobic digestion
KW - Fermentation
KW - Methanogen
KW - Methanosaeta
KW - Pyrosequencing
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U2 - 10.1016/j.watres.2009.07.034
DO - 10.1016/j.watres.2009.07.034
M3 - Article
C2 - 19732933
AN - SCOPUS:71749116268
SN - 0043-1354
VL - 43
SP - 4517
EP - 4526
JO - Water Research
JF - Water Research
IS - 18
ER -