Bioreactor scalability: laboratory-scale bioreactor design influences performance, ecology, and community physiology in expanded granular sludge bed bioreactors

Connelly, S. , Shin, S. G., Dillon, R. J., Ijaz, U. Z. , Quince, C., Sloan, W. T. and Collins, G. (2017) Bioreactor scalability: laboratory-scale bioreactor design influences performance, ecology, and community physiology in expanded granular sludge bed bioreactors. Frontiers in Microbiology, 8, 664. (doi: 10.3389/fmicb.2017.00664) (PMID:28507535) (PMCID:PMC5410579)

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Studies investigating the feasibility of new, or improved, biotechnologies, such as wastewater treatment digesters, inevitably start with laboratory-scale trials. However, it is rarely determined whether laboratory-scale results reflect full-scale performance or microbial ecology. The Expanded Granular Sludge Bed (EGSB) bioreactor, which is a high-rate anaerobic digester configuration, was used as a model to address that knowledge gap in this study. Two laboratory-scale idealizations of the EGSB—a one-dimensional and a three- dimensional scale-down of a full-scale design—were built and operated in triplicate under near-identical conditions to a full-scale EGSB. The laboratory-scale bioreactors were seeded using biomass obtained from the full-scale bioreactor, and, spent water from the distillation of whisky from maize was applied as substrate at both scales. Over 70 days, bioreactor performance, microbial ecology, and microbial community physiology were monitored at various depths in the sludge-beds using 16S rRNA gene sequencing (V4 region), specific methanogenic activity (SMA) assays, and a range of physical and chemical monitoring methods. SMA assays indicated dominance of the hydrogenotrophic pathway at full-scale whilst a more balanced activity profile developed during the laboratory-scale trials. At each scale, Methanobacterium was the dominant methanogenic genus present. Bioreactor performance overall was better at laboratory-scale than full-scale. We observed that bioreactor design at laboratory-scale significantly influenced spatial distribution of microbial community physiology and taxonomy in the bioreactor sludge-bed, with 1-D bioreactor types promoting stratification of each. In the 1-D laboratory bioreactors, increased abundance of Firmicutes was associated with both granule position in the sludge bed and increased activity against acetate and ethanol as substrates. We further observed that stratification in the sludge-bed in 1-D laboratory-scale bioreactors was associated with increased richness in the underlying microbial community at species (OTU) level and improved overall performance.

Item Type:Articles
Keywords:16S rRNA gene, anaerobic digestion, EGSB, Illumina MiSeq, laboratory-scale, full-scale, industrial wastewater, specific methanogenic activity.
Glasgow Author(s) Enlighten ID:Collins, Dr Gavin and Sloan, Professor William and Shin, Dr Seung Gu and Quince, Dr Christopher and Ijaz, Dr Umer and Connelly, Dr Stephanie
Authors: Connelly, S., Shin, S. G., Dillon, R. J., Ijaz, U. Z., Quince, C., Sloan, W. T., and Collins, G.
Subjects:Q Science > QR Microbiology
T Technology > TD Environmental technology. Sanitary engineering
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Research Group:Water and Environment
Journal Name:Frontiers in Microbiology
Publisher:Frontiers Media
ISSN (Online):1664-302X
Copyright Holders:Copyright © 2017 Connelly, Shin, Dillon, Ijaz, Quince, Sloan and Collins
First Published:First published in Frontiers in Microbiology 8: 664
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
574521A Global Solution To Protect Water By Transforming WasteGavin CollinsEngineering and Physical Sciences Research Council (EPSRC)EP/J00538X/1ENG - ENGINEERING INFRASTRUCTURE & ENVIR
621351Synthetic Biology applications to Water Supply and RemediationSteven BeaumontEngineering and Physical Sciences Research Council (EPSRC)EP/K038885/1VPO VICE PRINCIPAL RESEARCH & ENTERPRISE
652771Understanding microbial community through in situ environmental 'omic data synthesisUmer Zeeshan IjazNatural Environment Research Council (NERC)NE/L011956/1ENG - ENGINEERING INFRASTRUCTURE & ENVIR