Improving the ecological relevance of aquatic bacterial communities in biodegradability screening assessments

TY - JOUR

T1 - Improving the ecological relevance of aquatic bacterial communities in biodegradability screening assessments

AU - Martin, Timothy J.

AU - Goodhead, Andrew K.

AU - Snape, Jason R.

AU - Davenport, Russell J.

N1 - Funding Information: Funding for this work was received from EPSRC (including a Challenging Engineering award, EP/I025782/1 ), RCUK ( EP500501/1 ), BBSRC ( BB/H530897/1 ) and AstraZeneca (AZSHE 28051 ) Global SHE Research Programme. Funding Information: This work represents an AstraZeneca Global Environment contribution to the Innovative Medicines Initiative (IMI) under grant agreement no. 115735 – iPiE: Intelligent led assessment of Pharmaceuticals in the Environment. Publisher Copyright: © 2018 The Authors

PY - 2018/6/15

Y1 - 2018/6/15

N2 - Concentrating cells from aqueous samples is a common requirement for the enumeration of biomass, investigations of microbial diversity and detection of relatively rare organisms in the environment. Accurately representing the initial sampled environments in the concentrated cells is of particular importance when the subsequent analyses have tangible environmental, economic and societal consequences, as is the case with environmental exposure and risk assessment of chemicals. This study investigated the potential use of four different cell concentration methods: centrifugation, membrane filtration, tangential flow filtration and column colonisation. These methods were assessed against a series of scientific and practical criteria, including: similarity of concentrated community to initial environmental sample; cell concentration achieved; biodegradation test outcome; sample throughput; and capital and maintenance costs. All methods increased cell concentration by as little as 10-fold to as much as 1000-fold. DGGE and 454 pyrosequencing analysis showed concentrated communities to have >60% similarity to each other, and the initial sample. There was a general trend for a more reliable assessment of 4-nitrophenol biodegradation in 96-well plate biodegradation assays, with increasing cell concentration. Based on the selection criteria, it is recommended that there is not one concentration method fit for all purposes, rather, the appropriate method should be selected on a case-by-case basis. Membrane filtration would be the most suitable method for low sample volumes; the increased throughput capacity of tangential flow filtration renders it most suitable for large volumes; and centrifugation is most suitable for samples with high initial biomass concentrations. The poor similarity in microbial community composition of the column colonised samples compared to the initial samples, suggested a concentration basis; this combined with its low sample throughput precluded this approach for future concentration studies of planktonic bacterial samples.

AB - Concentrating cells from aqueous samples is a common requirement for the enumeration of biomass, investigations of microbial diversity and detection of relatively rare organisms in the environment. Accurately representing the initial sampled environments in the concentrated cells is of particular importance when the subsequent analyses have tangible environmental, economic and societal consequences, as is the case with environmental exposure and risk assessment of chemicals. This study investigated the potential use of four different cell concentration methods: centrifugation, membrane filtration, tangential flow filtration and column colonisation. These methods were assessed against a series of scientific and practical criteria, including: similarity of concentrated community to initial environmental sample; cell concentration achieved; biodegradation test outcome; sample throughput; and capital and maintenance costs. All methods increased cell concentration by as little as 10-fold to as much as 1000-fold. DGGE and 454 pyrosequencing analysis showed concentrated communities to have >60% similarity to each other, and the initial sample. There was a general trend for a more reliable assessment of 4-nitrophenol biodegradation in 96-well plate biodegradation assays, with increasing cell concentration. Based on the selection criteria, it is recommended that there is not one concentration method fit for all purposes, rather, the appropriate method should be selected on a case-by-case basis. Membrane filtration would be the most suitable method for low sample volumes; the increased throughput capacity of tangential flow filtration renders it most suitable for large volumes; and centrifugation is most suitable for samples with high initial biomass concentrations. The poor similarity in microbial community composition of the column colonised samples compared to the initial samples, suggested a concentration basis; this combined with its low sample throughput precluded this approach for future concentration studies of planktonic bacterial samples.

KW - Biodegradation

KW - Environmental risk assessment

KW - Exposure assessment

KW - PBT

KW - Persistence

UR - http://www.scopus.com/inward/record.url?scp=85041534742&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2018.01.264

DO - 10.1016/j.scitotenv.2018.01.264

M3 - Article

C2 - 30857116

AN - SCOPUS:85041534742

SN - 0048-9697

VL - 627

SP - 1552

EP - 1559

JO - Science of the Total Environment

JF - Science of the Total Environment

ER -