A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

Abstract

Abstract:The structure of biofilms in drinking water systems is influenced by the interplay between biological and physical processes. Bacterial aggregates in bulk fluid are important in seeding biofilm formation on surfaces. In simple pure and co-cultures, certain bacteria, including Methylobacterium, are implicated in the formation of aggregates. However, it is unclear whether they help to form aggregates in complex mixed bacterial communities. Furthermore, different flow regimes could affect the formation and destination of aggregates. In this study, real drinking water mixed microbial communities were inoculated with the Methylobacterium strain DSM 18358. The propensity of Methylobacterium to promote aggregation was monitored under both stagnant and flow conditions. Under stagnant conditions, Methylobacterium enhanced bacterial aggregation even when it was inoculated in drinking water at 1% relative abundance. Laminar and turbulent flows were developed in a rotating annular reactor. Methylobacterium was found to promote a higher degree of aggregation in turbulent than laminar flow. Finally, fluorescence in situ hybridisation images revealed that Methylobacterium aggregates had distinct spatial structures under the different flow conditions. Overall, Methylobacterium was found to be a key strain in the formation of aggregates in bulk water and subsequently in the formation of biofilms on surfaces.

The microbial ecology of a Mediterranean chlorinated drinking water distribution systems in the city of Valencia (Spain)

“…This supports previous observations from UK DWDS, where a core bacterial community in biofilms was observed independently of the characteristics of the incoming water or localised conditions between sites (Douterelo et al, 2017(Douterelo et al, , 2018(Douterelo et al, , 2020. Similar observations were proposed by other researchers from different countries like Germany, USA Portugal or China studying mixed species biofilms (Henne et al, 2012;Kelly et al, 2014;Ling et al, 2016;Rickard et al, 2004;Simões et al, 2007Simões et al, , 2008Tsagkari et al, 2017). In these studies, bacteria belonging to genera like Acinetobacter, Burkholderia, Methylobacterium, Mycobacterium, Pseudomonas, Sphingomonas and Staphylococcus played an important role in the formation of biofilms and aggregates.…”

Influence of phosphate dosing on biofilms development on lead in chlorinated drinking water bioreactors

“…It can be suggested that these microorganisms form a core community and play a key role in biofilm formation, as proposed by other researchers studying mixed-species biofilms [72][73][74][75][76][77] . In these studies, bacteria belonging to the genera Acinetobacter, Burkholderia, Methylobacterium, Mycobacterium, Sphingomonas and Staphylococcus played an important role in the formation of biofilms an aggregates [78][79][80][81] .…”

The Role of the Motility of Methylobacterium in Bacterial Interactions in Drinking Water

“…The Methylobacterium strain DSM 18358 (DSMZ: Deutsche Sammlung von Mikroorganismen und Zellkulturen, Leibniz-Institute, Braunschweig, Germany) was chosen for experimental analysis in this study. The strain was cultured as described in an earlier study [49]. Two sets of experiments were conducted.…”

“…A number of species, such as Methylobacterium species [12], Acinetobacter calcoaceticus [4], and Mycobacterium species [12,14], have been implicated in promoting bacterial aggregation in pure or simple mixed cultures. Specifically, the Methylobacterium DSM 18358 was previously proved to be a key strain in the formation of aggregates in drinking water and, subsequently, in the formation of biofilms on available surfaces exposed to drinking water [49]. Thus, in this study the role of the motility of the Methylobacterium strain DSM 18358 in the interactions between drinking water bacteria was explored in agar plate experiments to understand if this is a significant factor for the communication between bacteria in drinking water.…”