Size shapes the active microbiome of the methanogenic granules, corroborating a biofilm life cycle

Trego, A. C., O'Sullivan, S., Quince, C., Mills, S., Ijaz, U. Z. and Collins, G. (2020) Size shapes the active microbiome of the methanogenic granules, corroborating a biofilm life cycle. mSystems, 5(5), e00323-20. (doi: 10.1128/mSystems.00323-20) (PMID:32994285)

Abstract

Methanogenic archaea are key players in cycling organic matter in nature but also in engineered waste treatment systems, where they generate methane, which can be used as a renewable energy source. In such systems in the built environment, complex methanogenic consortia are known to aggregate into highly organized, spherical granular biofilms comprising the interdependent microbial trophic groups mediating the successive stages of the anaerobic digestion (AD) process. This study separated methanogenic granules into a range of discrete size fractions, hypothesizing different biofilm growth stages, and separately supplied each with specific substrates to stimulate the activity of key AD trophic groups, including syntrophic acid oxidizers and methanogens. Rates of specific methanogenic activity were measured, and amplicon sequencing of 16S rRNA gene transcripts was used to resolve phylotranscriptomes across the series of size fractions. Increased rates of methane production were observed in each of the size fractions when hydrogen was supplied as the substrate compared with those of volatile fatty acids (acetate, propionate, and butyrate). This was connected to a shift toward hydrogenotrophic methanogenesis dominated by Methanobacterium and Methanolinea. Interestingly, the specific active microbiomes measured in this way indicated that size was significantly more important than substrate in driving the structure of the active community in granules. Multivariate integration studywise discriminant analysis identified 56 genera shaping changes in the active community across both substrate and size. Half of those were found to be upregulated in the medium-sized granules, which were also the most active and potentially of the most important size, or life stage, for precision management of AD systems.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Quince, Dr Christopher and Collins, Dr Gavin and Ijaz, Dr Umer
• Authors: Trego, A. C., O'Sullivan, S., Quince, C., Mills, S., Ijaz, U. Z., and Collins, G.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: mSystems
• Publisher: American Society for Microbiology
• ISSN: 2379-5077
• ISSN (Online): 2379-5077
• Copyright Holders: Copyright © 2020 Trego et al.
• First Published: First published in 5(5):e00323-20
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
170256		Understanding microbial community through in situ environmental 'omic data synthesis	Umer Zeeshan Ijaz	Natural Environment Research Council (NERC)	NE/L011956/1	ENG - Infrastructure & Environment