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Microbial community analysis of anaerobic reactors treating soft drink wastewater.

Narihiro T, Kim NK, Mei R, Nobu MK, Liu WT - PLoS ONE (2015)

Bottom Line: In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d.Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d.These results indicate that OLR strongly influences microbial community composition.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Ave, Urbana, IL 61801, United States of America; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi, Tsukuba, Ibaraki 305-8566, Japan.

ABSTRACT
The anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors containing methanogenic microbial consortia were applied to treat synthetic soft drink wastewater, which contains polyethylene glycol (PEG) and fructose as the primary constituents. The AP and HP reactors achieved high COD removal efficiency (>95%) after 80 and 33 days of the operation, respectively, and operated stably over 2 years. 16S rRNA gene pyrotag analyses on a total of 25 biofilm samples generated 98,057 reads, which were clustered into 2,882 operational taxonomic units (OTUs). Both AP and HP communities were predominated by Bacteroidetes, Chloroflexi, Firmicutes, and candidate phylum KSB3 that may degrade organic compound in wastewater treatment processes. Other OTUs related to uncharacterized Geobacter and Spirochaetes clades and candidate phylum GN04 were also detected at high abundance; however, their relationship to wastewater treatment has remained unclear. In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d. Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d. These results indicate that OLR strongly influences microbial community composition. This suggests that specific uncultivated taxa may take central roles in COD removal from soft drink wastewater depending on OLR.

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Related in: MedlinePlus

Changes in operational parameters of anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors.Closed circle, COD removal (%) in AP; open circle, COD removal (%) in HP; closed triangle, effluent COD concentration (g L−1) in AP; open triangle, effluent COD concentration (g L−1) in HP; black line, pH in AP; gray line, pH in HP; closed square, methane gas production (L d−1) in AP; open square, methane gas production (L d−1) in HP. The reactors were operated at different organic loading rates (OLR) ranging from 0.5 to 2.0 g-COD L−1 d−1. The COD concentration of influent synthetic wastewater was decreased due to absence of polyethylene glycol 200 (1,100 mg L−1) during days 398–411. The triangles in the bottom indicate the periods for biomass sampling from the reactors.
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pone.0119131.g002: Changes in operational parameters of anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors.Closed circle, COD removal (%) in AP; open circle, COD removal (%) in HP; closed triangle, effluent COD concentration (g L−1) in AP; open triangle, effluent COD concentration (g L−1) in HP; black line, pH in AP; gray line, pH in HP; closed square, methane gas production (L d−1) in AP; open square, methane gas production (L d−1) in HP. The reactors were operated at different organic loading rates (OLR) ranging from 0.5 to 2.0 g-COD L−1 d−1. The COD concentration of influent synthetic wastewater was decreased due to absence of polyethylene glycol 200 (1,100 mg L−1) during days 398–411. The triangles in the bottom indicate the periods for biomass sampling from the reactors.

Mentions: Two anaerobic up-flow bioreactors (7.6 L working volume) were operated separately at 35°C (Fig. 1). The anaerobic packed-bed reactor (AP) and hybrid packed-bed reactor (HP) were filled with the Siporax ceramic media (L×D×H; 15×15×15 mm) (Aquatic Eco Systems, Apopka, FL, USA) to fill 10.2% and 5.0% of their working volume, respectively. Seed sludge sample was taken from anaerobic digester at Urbana, IL, USA. The reactors were fed with 3,000 mg COD L−1 synthetic wastewater that mimicked the composition of wastewater discharged from soft drink-processing factory [3–5, 7, 15, 17, 20]: 1,100 mg L−1 of polyethylene glycol 200 (PEG200); 1,500 mg L−1 of Corn Sweet High Fructose 55 (ADM, IL, USA); 30 mg L−1 of acetone; 30 mg L−1 of ethanol; 10 mg L−1 of silicone grease; 16 mg L−1 of K2HPO4; 19 mg L−1 of FeSO4·7H2O; 366 mg L−1 of NaHCO3; 2 mg L−1 of NaF; 2.5 mg L−1 of NaOCl; and 28 mg L−1 of NH4HCO3. These components were dissolved in tap water, and pH was adjusted to 9.5–10.0 with 5 M KOH to maintain the pH at 7.3–7.8 in the AP and HP. The internal circulation rates were 300 mL min−1 for both reactors. The reactors were operated under different hydraulic residence time (HRT) and organic loading rates (OLR) ranging from 1.5 to 6 days and from 0.5 to 2.0 g L−1 d−1, respectively (Fig. 2). To avoid overloading of the organic compounds on initial microbial consortia, two reactors were operated for 11 days with constant recirculation of synthetic wastewater and no fresh influent. After day 11, both AP and HP reactors were fed with influent at a hydraulic residence time (HRT) of 6 days and an organic loading rate (OLR) of 0.5 g L−1 d−1. For AP reactor, the HRT was decreased to 5, 4, and 3 days and the OLR gradually increased to 0.6, 0.75, and 1.0 g L−1 d−1 at 77, 91, and 115 days of the operation, respectively. For HP reactor, the HRT was decreased to 3 days and the OLR increased to 1.0 g L−1 d−1 after 31 days. After day 655, the HRT was decreased to 2 days and the OLR increased to 1.5 g L−1 d−1 for both reactors. Furthermore, the HRT of both reactors was decreased to 1.5 days and the OLR increased to 2.0 g L−1 d−1 after 744 days of the operation.


Microbial community analysis of anaerobic reactors treating soft drink wastewater.

Narihiro T, Kim NK, Mei R, Nobu MK, Liu WT - PLoS ONE (2015)

Changes in operational parameters of anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors.Closed circle, COD removal (%) in AP; open circle, COD removal (%) in HP; closed triangle, effluent COD concentration (g L−1) in AP; open triangle, effluent COD concentration (g L−1) in HP; black line, pH in AP; gray line, pH in HP; closed square, methane gas production (L d−1) in AP; open square, methane gas production (L d−1) in HP. The reactors were operated at different organic loading rates (OLR) ranging from 0.5 to 2.0 g-COD L−1 d−1. The COD concentration of influent synthetic wastewater was decreased due to absence of polyethylene glycol 200 (1,100 mg L−1) during days 398–411. The triangles in the bottom indicate the periods for biomass sampling from the reactors.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352018&req=5

pone.0119131.g002: Changes in operational parameters of anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors.Closed circle, COD removal (%) in AP; open circle, COD removal (%) in HP; closed triangle, effluent COD concentration (g L−1) in AP; open triangle, effluent COD concentration (g L−1) in HP; black line, pH in AP; gray line, pH in HP; closed square, methane gas production (L d−1) in AP; open square, methane gas production (L d−1) in HP. The reactors were operated at different organic loading rates (OLR) ranging from 0.5 to 2.0 g-COD L−1 d−1. The COD concentration of influent synthetic wastewater was decreased due to absence of polyethylene glycol 200 (1,100 mg L−1) during days 398–411. The triangles in the bottom indicate the periods for biomass sampling from the reactors.
Mentions: Two anaerobic up-flow bioreactors (7.6 L working volume) were operated separately at 35°C (Fig. 1). The anaerobic packed-bed reactor (AP) and hybrid packed-bed reactor (HP) were filled with the Siporax ceramic media (L×D×H; 15×15×15 mm) (Aquatic Eco Systems, Apopka, FL, USA) to fill 10.2% and 5.0% of their working volume, respectively. Seed sludge sample was taken from anaerobic digester at Urbana, IL, USA. The reactors were fed with 3,000 mg COD L−1 synthetic wastewater that mimicked the composition of wastewater discharged from soft drink-processing factory [3–5, 7, 15, 17, 20]: 1,100 mg L−1 of polyethylene glycol 200 (PEG200); 1,500 mg L−1 of Corn Sweet High Fructose 55 (ADM, IL, USA); 30 mg L−1 of acetone; 30 mg L−1 of ethanol; 10 mg L−1 of silicone grease; 16 mg L−1 of K2HPO4; 19 mg L−1 of FeSO4·7H2O; 366 mg L−1 of NaHCO3; 2 mg L−1 of NaF; 2.5 mg L−1 of NaOCl; and 28 mg L−1 of NH4HCO3. These components were dissolved in tap water, and pH was adjusted to 9.5–10.0 with 5 M KOH to maintain the pH at 7.3–7.8 in the AP and HP. The internal circulation rates were 300 mL min−1 for both reactors. The reactors were operated under different hydraulic residence time (HRT) and organic loading rates (OLR) ranging from 1.5 to 6 days and from 0.5 to 2.0 g L−1 d−1, respectively (Fig. 2). To avoid overloading of the organic compounds on initial microbial consortia, two reactors were operated for 11 days with constant recirculation of synthetic wastewater and no fresh influent. After day 11, both AP and HP reactors were fed with influent at a hydraulic residence time (HRT) of 6 days and an organic loading rate (OLR) of 0.5 g L−1 d−1. For AP reactor, the HRT was decreased to 5, 4, and 3 days and the OLR gradually increased to 0.6, 0.75, and 1.0 g L−1 d−1 at 77, 91, and 115 days of the operation, respectively. For HP reactor, the HRT was decreased to 3 days and the OLR increased to 1.0 g L−1 d−1 after 31 days. After day 655, the HRT was decreased to 2 days and the OLR increased to 1.5 g L−1 d−1 for both reactors. Furthermore, the HRT of both reactors was decreased to 1.5 days and the OLR increased to 2.0 g L−1 d−1 after 744 days of the operation.

Bottom Line: In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d.Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d.These results indicate that OLR strongly influences microbial community composition.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Ave, Urbana, IL 61801, United States of America; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi, Tsukuba, Ibaraki 305-8566, Japan.

ABSTRACT
The anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors containing methanogenic microbial consortia were applied to treat synthetic soft drink wastewater, which contains polyethylene glycol (PEG) and fructose as the primary constituents. The AP and HP reactors achieved high COD removal efficiency (>95%) after 80 and 33 days of the operation, respectively, and operated stably over 2 years. 16S rRNA gene pyrotag analyses on a total of 25 biofilm samples generated 98,057 reads, which were clustered into 2,882 operational taxonomic units (OTUs). Both AP and HP communities were predominated by Bacteroidetes, Chloroflexi, Firmicutes, and candidate phylum KSB3 that may degrade organic compound in wastewater treatment processes. Other OTUs related to uncharacterized Geobacter and Spirochaetes clades and candidate phylum GN04 were also detected at high abundance; however, their relationship to wastewater treatment has remained unclear. In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d. Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d. These results indicate that OLR strongly influences microbial community composition. This suggests that specific uncultivated taxa may take central roles in COD removal from soft drink wastewater depending on OLR.

Show MeSH
Related in: MedlinePlus