Matrix-mediated reversal of gram-dependent removal in antimicrobial flocculation
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Microbial contamination continues to threaten safe drinking water and sanitation. Antimicrobial flocculation is being increasingly explored as an upstream strategy to reduce disinfection demand and associated risks, yet the impact of environmental matrices on its performance has been overlooked in the past. Here, we report a previously unrecognized, matrix-induced reversal of Gram-dependent bacterial removal during antimicrobial flocculation using cationic flocculants. In matrix-free suspensions, Gram-positive S. aureus is removed more efficiently than Gram-negative E. coli. However, in the presence of representative matrices, involving inorganic suspended particles (ISPs) and natural organic matter (NOM), both bacteria are removed more effectively, but the enhancement is substantially stronger for E. coli, reversing the relative removal ranking. Biomolecular signatures, microscopy and flow cytometry reveal that environmental matrices induce Gram-dependent cell envelope damage, with stronger vulnerability in Gram-negative bacteria: ISPs cause shear-enabled physical abrasion with strong hydrodynamic dependence, whereas NOM induces chemically mediated envelope injury and permeability enhancement through cell-envelope binding. These findings demonstrate that antibacterial flocculation performance is not determined by flocculant properties alone, but by complex interactions among flocculants, bacteria, and co-existing matrices, highlighting the importance of representative water-matrix conditions to microbial control strategies.
Date Issued
2027-01-01
Date Acceptance
2026-09-15
Citation
Bioresource Technology, 2027, 464 (A), pp.135871-135871
ISSN
0960-8524
Publisher
Elsevier
Start Page
135871
End Page
135871
Journal / Book Title
Bioresource Technology
Volume
464
Issue
A
Copyright Statement
Copyright © 2026 Elsevier, Bioresource Technology. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/42744024
PII: S0960-8524(26)01953-X
Subjects
Bacterial removal
Cell envelope damage
Chemical injury
Gram-type-dependent flocculation
Matrix effect
Physical abrasion
Publication Status
Published
Coverage Spatial
England
Article Number
135871
Date Publish Online
2026-09-15