Search bioRxiv⌕ Search

Biology subjects

Wuertz, S.

Publications and source records attributed to Wuertz, S..

At least 19 recordsLinked to original sources
bioRxiv2026

Dual-loop involving microbial single-cell protein production from soybean-processing wastewater and effluent-based refinement for circular bioeconomy applications

Nutrient-rich food-processing wastewaters represent valuable yet under-utilised side streams for sustainable protein production in the form of microbial biomass. Here we present an integrated dual-loop bioprocess that converts soybean-processing wastewater into microbial single-cell protein (SCP) while achieving substantial nutrient removal and product refinement. In the first loop, previously enriched microbial consortia were inoculated and cultivated in four parallel sequencing batch reactors (SBRs) for 44Ldays at a hydraulic retention time (HRT) of 3Ldays. This bioprocess configuration demonstrated features that support future scale-up while maintaining process stability, achieving a protein content of 33.3L{+/-}L3.2%, doubling the protein yield (15.32L{+/-}L3.49Lg dry weight per g soluble TKN) and quadrupling the production rate (0.29L{+/-}L0.06Lg dry weight LL{superscript 1} dL{superscript 1}) compared to operating reactors without inoculation (HRT: 7.2Ldays). Effluent treatment was stable, with 84% carbon and 78% nitrogen removal efficiencies, demonstrating efficient nutrient recovery. The SCP biomass was enriched in functional taxa, including Acidipropionibacterium, Lactococcus, Megasphaera, and Azospirillum, suggesting that reactor conditions and inoculum selection promoted a stable, protein-productive microbial community with potential probiotic benefits. In the second loop, bioreactor effluent was reused as aqueous matrix for heat treatment (60{degrees}C) of the SCP biomass, reducing the RNA content from 8.6% to 2.6%, with a 39% biomass loss accompanied by a 30% increase in total amino acid concentration. Hence, our valorisation approach integrates microbial biomass production, effluent reuse, and product refinement within a circular framework. The system provides a resource-efficient pathway for converting food-sector side streams into high-quality microbial community-based SCP, highlighting its potential scalability for sustainable nutrient and water management.

microbiology↗
bioRxiv2026

Microbial community-based single-cell protein supports partial fishmeal replacement in juvenile Asian seabass diets across feeding trials and production scales

The growing demand for sustainable aquafeeds has intensified interest in alternative protein ingredients capable of reducing reliance on fishmeal without compromising fish performance. Here, we evaluated microbial community-based single-cell protein (SCP) as a fishmeal substitute in juvenile Asian seabass (Lates calcarifer) diets in two independent feeding trials of juvenile fish conducted over 49 and 56 days, respectively and compared them to a previous study that lasted 24 days. SCP was produced from nutrient-rich soybean-processing side streams by microbial communities in fermenters and incorporated into experimental diets at inclusion levels ranging from 10% to 100% fishmeal replacement. In the 24-day trial, a diet containing 50% fishmeal replacement with lab-scale produced SCP achieved 100% survival and a feed conversion ratio (FCR), specific growth rate (SGR), and weight gain comparable to the fishmeal control diet. In the 49-day trial using pilot-scale produced SCP, a 50% fishmeal replacement also maintained an FCR and feed intake comparable to the control, whereas complete replacement reduced feed intake and growth performance. In a 56-day pilot-scale trial that used 500-L fish tanks, diets containing up to 50% fishmeal replacement maintained comparable survival, weight gain, and SGR, although moderately higher FCR values were observed at higher SCP inclusion levels. Proximate composition and essential amino acid profiles of fish fed control or SCP-containing diets were comparable. Genome-resolved metagenomic analyses revealed diverse microbial taxa associated with the SCP. Collectively, these findings support microbial community-based SCP as a scalable and reproducible alternative protein platform for aquaculture feeds across independent trials and production scales.

microbiology↗
bioRxiv2025

Microbial community-based protein enables sustainable fishmeal replacement and improved resilience in Pacific white shrimp (Litopenaeus vannamei)

The growing demand for aquaculture feeds requires sustainable alternatives to fishmeal. Microbial community-based single-cell protein (SCP) produced from soybean-processing wastewater offers a circular approach that combines nutrient recovery with aquafeed production. We evaluated SCP as a fishmeal replacement for Pacific white shrimp (Litopenaeus vannamei) across four feeding trials lasting 42-84 days, involving shrimp from different hatcheries and SCP produced at laboratory and pilot scales. Diets containing 0-100% fishmeal replacement, corresponding to up to 220 g SCP kg-1 feed, were tested. Replacement of 50% was consistently supported across trials, while levels up to 90% maintained several key performance outcomes, including specific growth rate, feed conversion ratio, and survival, without significant differences from the fishmeal control. Complete replacement reduced growth in one trial, potentially reflecting the lower protein content and less favourable amino acid balance of SCP relative to fishmeal, particularly its lower lysine and methionine proportions. Shrimp tissue proximate and amino acid compositions showed no clear adverse responses to SCP inclusion in the trial in which they were assessed. Cross-trial analysis revealed a positive association between SCP replacement and survival after accounting for trial-specific baseline differences, with survival increasing by an estimated 1.53 percentage points for every 10-percentage-point increase in replacement (HC3 95% CI: 0.90-2.17; P < 0.001). Although the mechanisms underlying this association remain to be established, the findings support investigation of potential functional effects through targeted challenge and mechanistic studies. Overall, performance across four heterogeneous trials supports substantial fishmeal replacement by microbial community-based SCP and demonstrates its potential for practical application as a circular aquafeed ingredient.

microbiology↗
bioRxiv2025

Uncovering microbial life-history strategies under disturbance: a trait-based computational analysis of anaerobic systems

Trait-based approaches are helpful in simplifying ecosystem complexity to explore disturbance-diversity-function relationships. These frameworks classify organisms based on their functional characteristics--traits that influence growth, survival and reproduction--providing a mechanistic basis to understand how communities respond to changes in their environment. The application of these approaches has been successful in ecology, but to date has only been tested in a few microbial ecosystems, namely, soil microbial communities and aerobic bioreactors treating wastewater. Here, we employed Grimes competitor-stress-tolerant-ruderal framework in replicated mesophilic anaerobic bioreactors exposed to a disturbance (biomass removal) with varied frequencies at a constant number of disturbance events for 90 days. Bioreactors were inoculated with sludge from full-scale anaerobic digesters and fed with a mixture of primary and waste activated sludge. A genome-resolved metagenomics approach was utilised to assess the microbial communities. We found that communities across the disturbance range were clustered into three groups, suggesting the adoption of a three-way life-history strategy. This study demonstrates, for the first time, the applicability of trait-based life-history strategies in anaerobic microbial systems under disturbance, providing a new perspective for understanding and managing microbial ecosystems under disturbance conditions.

ecology↗
bioRxiv2025

Predicting microbial community responses to disturbance using genome-resolved trait-based life-history strategies

Understanding how microbial communities respond to disturbance remains a fundamental question in ecology, with broad implications for biodiversity, ecosystem function, and biotechnology. Trait-based approaches offer general rules to predict community responses by linking ecological strategies to measurable traits. While life-history strategy frameworks such as the competitor-ruderal-stress-tolerant (CSR) model are well established in plant and animal ecology, their application to microbial communities has been limited. Here, we experimentally tested how microbial communities shift across a gradient of disturbance frequency in replicated bioreactors treating synthetic wastewater. We applied six conditions by doubling the organic loading rate at different frequencies, from undisturbed to press disturbance, and monitored changes over 42 days using genome-resolved metagenomics, 16S rRNA gene sequencing, biomass quantification, and effluent chemistry. By integrating ordination, network analysis, and machine learning, we identified emergent community-level life-history strategies that aligned with increasing disturbance. These strategies were reflected in functional trade-offs, shifts in community composition, and genomic trait distributions. A simulation-based approach was used to generate a CSR classification of metagenome-assembled genomes, which was consistent with patterns observed in other microbial ecosystems. Our results demonstrate that life-history frameworks can capture predictable dynamics in microbial communities across disturbance regimes. This strategy provides a unifying tool for linking microbial structure, function, and traits across scales, helping to reconcile ecological theory with microbial resource management. More broadly, our findings support the integration of classical ecological theory with microbial genomics to uncover the trait-based principles that govern microbiome function and stability in both natural and engineered ecosystems.

ecology↗
bioRxiv2025

Enhanced Resistance and Resilience of Anaerobic Digestion Microbiome after Single and Dual Short-Term Disturbances

Anaerobic digesters are operated at high solids retention times (SRTs) of 20 d or longer to mitigate accidental substrate overloading. However, the long-term effects of such disturbances on digester performance and microbiome remain unclear. This study investigates whether short-term pulse disturbances (temporary SRT reductions) can enhance microbial resilience and accelerate recovery from sustained overloading conditions. We explored the feasibility of anaerobic digestion at shorter SRTs by introducing one or two pulse SRT disturbances (SRT reduction from 15 to 5 d) in four mesophilic anaerobic digesters treating wastewater sludge, followed by sustained operation (press disturbance) 5 d SRT. Dual pulse disturbances showed faster process recovery compared to digesters receiving a single pulse disturbance (60 d vs 104 d) with reduced volatile fatty acids levels during the subsequent press disturbance periods. Microbial community redundancy and resilience, with shifts between the slow-growing, resource-efficient taxa (K-strategists) and fast-growing, opportunistic taxa (r-strategists), were crucial in ensuring minimal disruptions during disturbance and recovery periods. Overall, pulse disturbances may serve as a practical tool for enhancing microbiome resilience in anaerobic digestion, enabling stable performance under fluctuating substrate loading conditions. SYNOPSISControlled pulse disturbances enhance anaerobic digestion resilience by priming microbial communities, enabling stable performance at short solids retention times and high organic loading conditions.

microbiology↗
bioRxiv2025

Synchronization of the collective air-breathing behavior in juvenile Arapaima gigas

Animal collectives are capable of performing behaviors with high degrees of synchrony though their members might differ consistently and substantially in the focal behavior when alone. It is thus not entirely understood how these consistent differences in behavior at the individual level can be (socially) integrated into synchronized behaviors at the collective level. Here we show an unprecedented synchronized behavior in fish - the collective air-breathing of juvenile Arapaima gigas. Individuals of this obligate air-breathing fish from South America differed in their time between consecutive breaths when recorded alone in an aquaculture facility. However, when together in a shoal of about 200 same aged individuals, breathing is executed by a substantial portion of the shoal - within the same second. Our analysis of the individual and collective breathing patterns supported by stochastic individual-based simulations of inherently non-periodic coupled oscillators revealed that this degree of collective synchronization could be achieved by having some kind of assortative interaction rules where individuals respond towards one cluster/subgroup members stronger than to other cluster/subgroup members. By integrating this cluster synchrony rule we could successfully simulate highly synchronized collective behavior with varying proportions of otherwise diverse individuals taking part, matching our experimental observations and providing a mechanism to synchronize agents that differ consistently in the behavior in focus when in isolation.

animal behavior and cognition↗
bioRxiv2024

MicroEcoTools: an R package for comprehensive theoretical microbial ecology analysis

BackgroundEcological theory aids in understanding how disturbances affect ecosystems. However, experimental data are often complex, with multiple post-disturbance theories potentially applying simultaneously to the same ecosystem. This emphasizes the need for tools to experimentally test these theoretical predictions. ResultsWe introduce MicroEcoTools, an R package designed to test ecological framework predictions using microbial community data. It assesses microbial diversity and evaluates the relative impacts of stochastic and deterministic assembly mechanisms through a taxa-based null model approach for replicated designs. Specifically, the package allows application of Grimes trait-based life-history categories--competitor, stress-tolerant, and ruderal (CSR)-- to taxa, functional traits, and ecosystem functions within microbial communities. MicroEcoTools also includes relevant statistical tests, numeric simulations, and publicly available datasets for demonstration. ConclusionsIn conclusion, MicroEcoTools facilitates the application of ecological frameworks, including community assembly mechanisms, diversity analysis, and life-history strategies, to microbial ecosystems under disturbance. This R package, along with its source code, can be freely accessed on GitHub at https://www.github.com/Soheil-A-Neshat/MicroEcoTools.

ecology↗
bioRxiv2024

The haplotype-resolved Prymnesium parvum (type B) microalga genome reveals the genetic basis of its fish-killing toxins

The catastrophic loss of aquatic life in the Central European Oder River in 2022, caused by a toxic bloom of the haptophyte microalga Prymnesium parvum (in a wide sense, s.l.), underscores the need to improve our understanding of the genomic basis of the toxin. Previous morphological, phylogenetic, and genomic studies have revealed cryptic diversity within P. parvum s.l. and uncovered three clade-specific (types A, B, C) prymnesin toxins. Here, we used state-of-the-art long-read sequencing and assembled the first haplotype-resolved diploid genome of a P. parvum type B, the strain responsible for the Oder disaster. Comparative analyses with type A genomes uncovered a genome-size expansion driven by repetitive elements in type B. We also found conserved chromosomal synteny but divergent evolution in several polyketide synthase (PKS) genes, which are known to underlie toxin production in combination with environmental cues. We identified a specific, approximately 20 kilobase pair comprising deletion in the largest PKS gene of type B that we link to differences of the chemical structure of types A and B prymnesins. Electron-microscopy and flow cytometry confirmed diploidy in the Oder River strain and differences to closely related strains in morphology and ploidy. Our results provide unprecedented resolution of strain diversity in P. parvum and a better understanding of the genomic basis of toxin variability in haptophytes. The reference-quality genome will help to understand changes to microbial diversity in the face of increasing environmental pressures, and provides a basis for strain-level monitoring of invasive Prymnesium in the future.

genomics↗
bioRxiv2023

Multi-genome comparisons reveal gain-and-loss evolution of the anti-Mullerian hormone receptor type 2 gene, an old master sex determining gene, in Percidae

The Percidae family comprises many fish species of major importance for aquaculture and fisheries. Based on three new chromosome-scale assemblies in Perca fluviatilis, Perca schrenkii and Sander vitreus along with additional percid fish reference genomes, we provide an evolutionary and comparative genomic analysis of their sex-determination systems. We explored the fate of a duplicated anti-Mullerian hormone receptor type-2 gene (amhr2bY), previously suggested to be the master sex determining (MSD) gene in P. flavescens. Phylogenetically related and structurally similar amhr2 duplications (amhr2b) were found in P. schrenkii and Sander lucioperca, potentially dating this duplication event to their last common ancestor around 19-27 Mya. In P. fluviatilis and S. vitreus, this amhr2b duplicate has been lost while it was subject to amplification in S. lucioperca. Analyses of the amhr2b locus in P. schrenkii suggest that this duplication could be also male-specific as it is in P. flavescens. In P. fluviatilis, a relatively small (100 kb) non-recombinant sex-determining region (SDR) was characterized on chromosome-18 using population-genomics approaches. This SDR is characterized by many male-specific single-nucleotide variants (SNVs) and no large duplication/insertion event, suggesting that P. fluviatilis has a male heterogametic sex determination system (XX/XY), generated by allelic diversification. This SDR contains six annotated genes, including three (c18h1orf198, hsdl1, tbc1d32) with higher expression in testis than ovary. Together, our results provide a new example of the highly dynamic sex chromosome turnover in teleosts and provide new genomic resources for Percidae, including sex-genotyping tools for all three known Perca species.

genomics↗
bioRxiv2023

Microbial community-based bacterial protein from soybean-processing wastewater as a value-added alternative fish feed ingredient for Asian sea bass (Lates calcarifer)

As the global demand for food increases, aquaculture plays a key role as the fastest growing animal protein sector. However, existing aquafeeds contain protein ingredients that are not sustainable under current production systems. We evaluated the use of microbial community-based single cell protein (SCP), produced from soybean processing wastewater, as a partial fishmeal protein substitute in juvenile Asian seabass (Lates calcarifer). A 24-day feeding trial was conducted with a control fishmeal diet and a 50% fishmeal replacement with microbial community-based SCP as an experimental group, in triplicate tanks containing 20 fish each. Both diets met the protein, essential amino acids (except for lysine), and fat requirements for juvenile Asian sea bass. The microbial composition of the SCP was dominated by the genera Acidipropionibacterium and Propioniciclava, which have potential as probiotics and producers of valuable metabolites. The growth performance in terms of percent weight gain, feed conversion ratio (FCR), specific growth rate (SGR), and survival were not significantly different between groups after 24 days. The experimental group had less variability in terms of weight gain and FCR than the control group. Overall, microbial community-based protein produced from soybean processing wastewater has potential as a value-added feed ingredient for sustainable aquaculture feeds.

microbiology↗
bioRxiv2022

CRISPR-Cas phage defense systems and prophages in Candidatus Accumulibacter

Candidatus Accumulibacter is a key genus of polyphosphate-accumulating organisms (PAOs) found in laboratory- and full-scale wastewater treatment systems, mediating enhanced biological phosphorus removal (EBPR). However, little is known about their ability to resist phage infection. We conducted a systematic analysis of the occurrence and characteristics of clustered regularly interspaced short palindromic repeats and associated proteins (CRISPR-Cas) systems and prophages in diverse Ca. Accumulibacter taxa (43 in total, including 10 newly recovered genomes). Fourty complete CRISPR loci were identified in 28 genomes, falling into 6 subtypes. The occurrence and distribution of CRISPR-Cas systems did not follow a vertical evolutionary relationship. Phylogenetic analyses of the cas genes and direct repeats (DRs) suggested that the CRISPR-Cas systems were likely acquired via horizontal gene transfer, with acquisition rates higher than those of speciation, rendering different Ca. Accumulibacter distinct adaptivity to phage predations. 2448 spacers were identified, 67 of them matched to known phages. Major differences were observed among the numbers of spacers for different Ca. Accumulibacter, showing unique phages that could be resisted by different members. A comparison of the spacers in genomes having the same cas gene but from distinct geographical locations indicated that habitat isolation may have resulted in the acquisition of different spacers by different Ca. Accumulibacter. Metagenomic analysis allowed the identification of 26 viral contigs (18 are Caudovirales members) in 6 metagenomic datasets from three lab-scale enrichment reactors, matching to 73 spacers in 10 Ca. Accumulibacter genomes in these reactors, showing the specific immunity of these Ca. Accumulibacter. Metatranscriptomic analyses showed the activity of the CRISPR-Cas system under both anaerobic and aerobic conditions. Extra efforts were made to identify prophages in Ca. Accumulibacter genomes. In total, 133 prophage regions were identified. Twenty-seven of them were classified as potentially active prophages. Three prophages (all are Caudovirales members, in DS2011, SCELSE-7IIH and SCELSE-5IIH, respectively) are readily activable. Differences in the occurrence of CRISPR-Cas systems and prophages in Ca. Accumulibacter will lead to their distinct responses under phage predation. This study represents the first systematic analysis of CRISPR-Cas systems and prophages with combined experimental and bioinformatic methods in the Ca. Accumulibacter lineage, providing new perspectives on the potential impacts of phages on Ca. Accumulibacter and EBPR systems.

bioinformatics↗
bioRxiv2022

Microbial community-based production of single cell protein from soybean-processing wastewater of variable chemical composition

The use of food-processing wastewaters to produce microbial biomass-derived single cell protein (SCP) is a sustainable way to meet the global food demand. Yet, despite the potential benefits of lower costs and greater resource recovery compared to pure cultures, bioconversion processes relying on microbial community-based approaches to SCP production have received scarce attention. Here, we evaluated SCP production from soybean-processing wastewaters under controlled reactor conditions using the existent microbial communities in these wastewaters. Six sequencing batch reactors of 4.5-L working volume were operated at 30 {square} for 34 d in cycles consisting of 3-h anaerobic and 9-h aerobic phases. Four reactors received no microbial inoculum and the remaining two were amended with a 1.5 L of mixed culture from a prior microbial community-based SCP production. Microbial characterization was done via 16S rRNA gene metabarcoding. Influent wastewater batches had variable chemical characteristics but a similar microbial composition. Reactors produced more SCP when fed with wastewaters of higher soluble total Kjeldahl nitrogen (sTKN) content and a lower carbon-to-nitrogen ratio (sCOD:sTKN). The biomass protein yield ranged from 0.24 to 3.13 g protein/g sTKN, with a maximum protein content of 50%. An average of 92% of sCOD and 73% of sTN removal was achieved. Distinct microbial communities were enriched in all six bioreactors after 34 d, where the prevailing genera included Azospirillum, Rhodobacter, Lactococcus, Novosphingobium, and Acidipropionibacterium. In contrast, the microbial community of influent wastewaters was dominated by Lactococcus and Weissella. We showed that constituents in soybean wastewater can be converted to SCP through microbial community-based growth processes and demonstrated the effect of variable influent wastewater composition on SCP production.

microbiology↗
bioRxiv2021

Recovery of high quality metagenome-assembled genomes from full-scale activated sludge microbial communities in a tropical climate using longitudinal metagenome sampling

Analysis of metagenome data based on the recovery of draft genomes (so called metagenome-assembled genomes, or MAG) have assumed an increasingly central role in microbiome research in recent years. Microbial communities underpinning the operation of wastewater treatment plants are particularly challenging targets for MAG analysis due to their high ecological complexity, and remain important, albeit understudied, microbial communities that play a key role in mediating interactions between human and natural ecosystems. In this paper, we consider strategies for recovery of MAG sequence from time series metagenome surveys of full-scale activated sludge microbial communities. We generate MAG catalogues from this set of data using several different strategies, including the use of multiple individual sample assemblies, two variations on multi-sample co-assembly and a recently published MAG recovery workflow using deep learning. We obtain a total of just under 9,100 draft genomes, which collapse to around 3,100 non-redundant genomic clusters. We examine the strengths and weaknesses of these approaches in relation to MAG yield and quality, showing the co-assembly offers clear advantages over single-sample assembly. Around 1000 MAGs were candidates for being considered high quality, based on single-copy marker gene occurrence statistics, however only 58 MAG formally meet the MIMAG criteria for being high quality draft genomes. These findings carry broader implications for performing genome-resolved metagenomics on highly complex communities, the design and implementation of genome recoverability strategies, MAG decontamination and the search for better binning methodology.

genomics↗
bioRxiv2021

Microbiome assembly predictably shapes diversity across a range of disturbance frequencies

Diversity is frequently linked to the functional stability of ecological communities. However, its association with assembly mechanisms remains largely unknown, particularly under fluctuating disturbances. Here, we subjected complex bacterial communities in bioreactor microcosms to different frequencies of organic loading shocks, tracking temporal dynamics in their assembly, structure and function. Null modelling revealed a stronger role of stochasticity at intermediate disturbance frequencies, preceding the formation of a peak in -diversity. Communities at extreme ends of the disturbance range had the lowest -diversity and highest within-treatment similarity in terms of {beta}-diversity, with stronger deterministic assembly. Stochasticity prevailed during the initial successional stages, coinciding with better specialized function (nitrogen removal). In contrast, general functions (carbon removal and microbial aggregate settleability) benefited from stronger deterministic processes. We showed that changes in assembly processes predictably precede changes in diversity under a gradient of disturbance frequencies, advancing our understanding of the mechanisms behind disturbance-diversity-function relationships.

ecology↗
bioRxiv2021

Metagenomics and Metatranscriptomics Reveal Pathway of 3-Chloroaniline Degradation in Wastewater Reactors

Biological wastewater treatment systems are often affected by major shifts in influent quality, including the input of various toxic chemicals. Yet the mechanisms underlying adaptation of activated sludge process performance when challenged with a sustained toxin input are rarely studied in a controlled and replicated experimental setting. Three replicate bench-scale bioreactors were subjected to a chemical disturbance in the form of 3-chloroaniline (3-CA) over 132 days, after an acclimation period of 58 days, while three control reactors received no 3-CA input. Nitrification was initially affected by 3-CA but the microbial communities in all three treatment reactors adapted to biologically degrade 3-CA within three weeks of the experiment, resulting in partial nitrification recovery. Combining process and microbial community data from amplicon sequencing with potential functions gleaned from assembled metagenomics and metatranscriptomics data, two putative degradation pathways for 3-CA were identified. The first pathway proceeds via a phenol monooxygenase followed by ortho-cleavage of the aromatic ring, and the second one involves a benzoate dioxygenase and subsequent meta-cleavage of the aromatic ring. The genera Gemmatimonas, OLB8, and Taibaiella correlated significantly with 3-CA degradation. Metagenome-assembled genome data also showed the genus OLB8 to be differentially enriched in treatment reactors, making it a strong candidate as 3-CA degrader. Using replicated reactors, this study has demonstrated the impact of a sustained stress on the activated sludge community and processes carried out by its members, followed by process recovery. By a combination of techniques, we showed that microbial communities can develop degradative capacity following a sustained xenobiotic input, and that targeted culture-independent approaches can suggest plausible mechanisms for 3-CA degradation and identify the taxa potentially contributing to it.

microbiology↗
bioRxiv2021

Factors Shaping Young and Mature Bacterial Biofilm Communities in Two Drinking Water Distribution Networks

The presence of biofilms in drinking water distribution systems (DWDS) can affect both water quality and system integrity; yet these systems remain poorly studied due to lack of accessibility. We established two independent full-scale DWDS Testbeds (A and B) on two different campuses situated in a tropical urban environment and equipped them with online sensors. Testbed B experienced higher levels of monochloramine and lower water age than Testbed A within the campus. Based on long amplicon-sequencing of bacterial 16S rRNA genes extracted from the mature biofilms (MPB) growing on pipes and young biofilms (YSB) growing on the sensors, a core community was identified in the two testbeds. The relative abundances of operational taxonomic units at the family level, including Mycobacteriaceae, Methylobacteriaceae, Rhodospirillaceae, Nitrosomonadaceae, and Moraxellaceae, were consistent for MPB and YSB on each campus. The MPB community was found to be influenced by conductivity, sample age, and pipe diameter as determined by both canonical correlation analysis and fuzzy set ordination. MPB displayed higher -diversity based on Hill numbers than YSB; in general, second order Hill numbers correlated positively with conductivity and sample age, but negatively with ORP and nitrite. Pseudomonas spp. together with Bacillus spp. likely initiated biofilm formation of YSB on Testbed A under conditions of reduced monochloramine and high water age. Significant levels of orthophosphate were detected in YSB samples at two stations and associated with higher levels of stagnation based on long-term differential turbidity measurement (DTM). Orthophosphate and DTM may act as indicators of the biofilm growth potential within DWDS. Highlights- Established two testbeds to study biofilms in full-scale distribution system - Biofilms on pipes and sensors had core community - Temporal effect and higher -diversity for biofilms on pipes - Water chemistry was related to biofilm community differences O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/434709v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@c392aforg.highwire.dtl.DTLVardef@1d355eborg.highwire.dtl.DTLVardef@1addf37org.highwire.dtl.DTLVardef@19cc22_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

ecology↗