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Aqeel H, Brei E, Allen DG, Liss SN. Distribution of extracellular adhesins in environmental biofilms and flocs: Reimagining the microbial structure. CHEMOSPHERE 2024; 363:142928. [PMID: 39048048 DOI: 10.1016/j.chemosphere.2024.142928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 07/20/2024] [Accepted: 07/21/2024] [Indexed: 07/27/2024]
Abstract
Extracellular cellular adhesins facilitate microbial aggregation; however, most of the information about extracellular adhesins is based on pure culture studies. In this study, we characterized the hydrophobic characteristics and distribution of the extracellular adhesins in environmental biofilms and flocs. The hydrophobic characteristics of the extracellular adhesins were studied by sonicating the microbial aggregates to disperse the cells and by fractionating them using the microbial adhesion to the hydrocarbon method. Furthermore, we probed environmental biofilms and flocs using immunohistochemistry coupled with confocal laser scanning microscopy for reimaging the microbial aggregates based on extracellular adhesins. Small flocs have a relatively dispersed distribution of extracellular adhesins (flagella, fimbriae, pili, and amyloid adhesins). The stratified distribution of extracellular adhesins was observed in environmental biofilms. It was observed that the pili and amyloid adhesins were predominantly present in the core of biofilms, whereas flagella and fimbriae were present in the outer layer of the microbial aggregates. The dispersion of microbial aggregates is one of the limiting factors that challenge the sustainable application of wastewater treatment processes. Greater attention to the components of extracellular protein (such as the adhesins) is required to understand the aggregation of dispersible environmental microbial aggregates.
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Affiliation(s)
- Hussain Aqeel
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada
| | - Elena Brei
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - D Grant Allen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Steven N Liss
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada; School of Environmental Studies, Queen's University, Kingston, Canada; Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
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Wu Y, Niu J, Yuan X, Liu Y, Zhai S, Zhao Y. Polydopamine and calcium functionalized fiber carrier for enhancing microbial attachment and Cr(VI) resistance. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166626. [PMID: 37643709 DOI: 10.1016/j.scitotenv.2023.166626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/25/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
The formation of biofilm determines the performance and stability of biofilm system. Increasing the hydrophilicity of the carrier surface could efficiently accelerate the attachment and growth of microorganisms. Here, the surface of polypropylene (PP) fiber carrier was modified with polydopamine (PDA) and calcium (Ca(II)) to enhance microbial attachment and toxicity resistance. The results of surface characteristic confirmed the self-polymerization of PDA and the chelation mechanism of Ca(II). Subsequently, the biofilm formation experiments were conducted in sequencing batch biofilm reactors using both normal and chromium-containing wastewater. The biofilm on the surface of the modified carrier exhibited better nitrogen removal and Cr(VI) reduction ability. The biomass of the modified carrier was significantly increased, and the maximum microbial attachment amounts in normal wastewater and chrome-containing wastewater were 1153.34 and 511.78 mg/g carrier, respectively. Furthermore, the confocal laser scanning microscope (CLSM) indicated that the modified carrier coated with PDA and Ca(II) were both biocompatible, and the cell activity was significantly increased. 16S rRNA sequencing results showed that the modified carrier efficiently enriched both denitrification bacteria (Thauera and Flavobacterium) and chrome-reducing bacteria (Simplicispira and Arenimonas) to improve system stability and Cr(VI) resistance. Microbial phenotype prediction based on BugBase analysis further verified the enrichment effect of modified carriers on microorganisms responsible for biofilm formation and oxidative stress resistance. Overall, this work proposed a novel functional carrier that could provide references for advancing the application of biofilm systems in wastewater treatment.
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Affiliation(s)
- Yichen Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Jiaojiao Niu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Xin Yuan
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yinuo Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Siyuan Zhai
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
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Aqeel H, Asefa B, Liss SN. Nitrospira dominant pin-point flocs with granule-like settleability in stirred tank reactors with oxic/hypoxic/oxic zones. Front Microbiol 2023; 14:1307727. [PMID: 38111639 PMCID: PMC10726125 DOI: 10.3389/fmicb.2023.1307727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 11/16/2023] [Indexed: 12/20/2023] Open
Abstract
The characteristics of biomass and microbial community dynamics, in relation to autotrophic nitrification, were studied in two 20 L stirred tank reactors (STR) with oxic/hypoxic/oxic zones. The bioreactors were fed with synthetic wastewater with stepwise increasing ammonia concentrations (50-200 N mg/L) without organic substrate in the first phase (autotrophic phase) for 35 days (R1) and 15 days (R2), followed by a heterotrophic phase (with supplementation of organic substrate). The settling properties of the biomass, represented by pin-point flocs, gradually improved in both reactors during the autotrophic phase. The pin-point flocs of R1 exhibited granule-like settling properties. The SVI30 in RI gradually improved to 29 mL/g MLSS, and the corresponding SVI30/ SVI10 gradually improved to 0.88 during the autotrophic phase. The settling properties of the biomass deteriorated in both bioreactors during the heterotrophic phase. The protein to polysaccharide ratio (PN:PS ratio) gradually increased in the extracted EPS (in both, loosely bound (LB) and tightly bound (TB) EPS) during the autotrophic phase, in both bioreactors. The TB:LB EPS ratio was higher when the pin-point flocs of R1 showed granule-like settling properties, followed by a decline in TB:LB EPS ratio during the heterotrophic phase. A combination of molecular approaches (droplet digital-PCR (dd-PCR) and 16S rRNA gene sequencing) revealed that Nitrospira were the predominant nitrifying bacteria in the pin-point flocs that show granular sludge-like settling properties during autotrophic phase in R1. Comammox Nitrospira was the dominant ammonia oxidizer in seed biomass and at low ammonia concentrations in both bioreactors. The relative abundance of canonical ammonia-oxidizing bacteria increased with an increase in influent-ammonia concentrations.
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Affiliation(s)
- Hussain Aqeel
- Chemistry and Biology, Toronto Metropolitan University, Toronto, ON, Canada
| | - Bruke Asefa
- Chemistry and Biology, Toronto Metropolitan University, Toronto, ON, Canada
| | - Steven N. Liss
- Chemistry and Biology, Toronto Metropolitan University, Toronto, ON, Canada
- School of Environmental Studies, Queen’s University, Kingston, ON, Canada
- Department of Microbiology, Stellenbosch University, Stellenbosch, Western Cape, South Africa
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Maza-Márquez P, Gallardo-Altamirano MJ, Osorio F, Pozo C, Rodelas B. Microbial indicators of efficient performance in an anaerobic/anoxic/aerobic integrated fixed-film activated sludge (A2O-IFAS) and a two-stage mesophilic anaerobic digestion process. CHEMOSPHERE 2023; 335:139164. [PMID: 37295687 DOI: 10.1016/j.chemosphere.2023.139164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/15/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
An analysis of the community structure, diversity and population dynamics of Bacteria and Archaea in the suspended and attached biomass fractions of a pilot-scale anaerobic/anoxic/aerobic integrated fixed-film activated sludge (A2O-IFAS) was executed. Along with this, the effluents of the acidogenic (AcD) and methanogenic (MD) digesters of a two-stage mesophilic anaerobic (MAD) system treating the primary sludge (PS) and waste activated sludge (WAS) generated by the A2O-IFAS were also analyzed. Non-metric multidimensional scaling (MDS) and Biota-environment (BIO-ENV) multivariate analyses were performed to link population dynamics of Bacteria and Archaea to operating parameters and removal efficiencies of organic matter and nutrients, in search of microbial indicators associated with optimal performance. In all samples analyzed, Proteobacteria, Bacteroidetes and Chloroflexi were the most abundant phyla, while the hydrogenotrophic methanogens Methanolinea, Methanocorpusculum and Methanobacterium were the predominant archaeal genera. BIO-ENV analysis disclosed strong correlations between the population shifts observed in the suspended and attached bacterial communities of the A2O-IFAS and the removal rates of organic matter, N and P. It is noteworthy that the incorporation of carriers combined with a short sludge retention time (SRT = 4.0 ± 1.0 days) enhanced N removal performance of the A2O by favoring the enrichment of bacterial genera able to denitrify (Bosea, Dechloromonas, Devosia, Hyphomicrobium, Rhodobacter, Rhodoplanes, Rubrivivax, and Sulfuritalea) in the attached biomass fraction. In addition, operation at short SRT enabled the generation of a highly biodegradable WAS, which enhanced the biogas and methane yields in the two-stage MAD. An increase in the relative abundance of Acetobacteroides (uncultured Blvii28 wastewater-sludge group of Rikenellaceae family) correlated positively with the volatile solids removal rate (%VSR), CH4 recovery rate and %CH4 in the biogas (r > 0.8), supporting their relevance for an efficient methanogenesis in two-stage systems.
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Affiliation(s)
- P Maza-Márquez
- Environmental Microbiology Group, Institute of Water Research, University of Granada, C/ Ramón y Cajal, nº4, 18071, Granada, Spain; Department of Microbiology, University of Granada, 18071, Granada, Spain
| | - M J Gallardo-Altamirano
- Environmental Microbiology Group, Institute of Water Research, University of Granada, C/ Ramón y Cajal, nº4, 18071, Granada, Spain; Department of Chemical Engineering, University of Granada, 18071, Granada, Spain.
| | - F Osorio
- Environmental Microbiology Group, Institute of Water Research, University of Granada, C/ Ramón y Cajal, nº4, 18071, Granada, Spain; Department of Civil Engineering, University of Granada, 18071, Granada, Spain
| | - C Pozo
- Environmental Microbiology Group, Institute of Water Research, University of Granada, C/ Ramón y Cajal, nº4, 18071, Granada, Spain; Department of Microbiology, University of Granada, 18071, Granada, Spain
| | - B Rodelas
- Environmental Microbiology Group, Institute of Water Research, University of Granada, C/ Ramón y Cajal, nº4, 18071, Granada, Spain; Department of Microbiology, University of Granada, 18071, Granada, Spain
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Zhu Q, Hu J, Liu B, Liang S, Xiao K, Yu W, Yuan S, Yang J, Hou H. Potassium channel blocker selectively enriched Geobacter from mixed-cultured electroactive biofilm: Insights from microbial community, functional prediction and gene expressions. BIORESOURCE TECHNOLOGY 2022; 364:128109. [PMID: 36244602 DOI: 10.1016/j.biortech.2022.128109] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
This study investigated the effects of electrical signaling disruption induced by adding tetraethylammonium (TEA, a potassium channel blocker) on the formation of mixed-cultured electroactive biofilms, especially the relative abundance of Geobacter over time. Results showed that TEA addition decelerated the biofilm formation, but selectively enriched Geobacter over time (45.8% on Day 32, 67.7% on Day 60 and 78.1% on Day 90), thus resulting in higher final extracellular electron transfer (EET) efficiency. Redundancy analysis (RDA) confirmed that TEA and operation time were significant factors for the selective enrichment of Geobacter. Moreover, increase in cellular processes and signal processing by PICRUSt analysis indicated adaptive responses of electrogenic biofilms to electrical signaling disruption. Furthermore, qRT-PCR indicated the compensatory roles of key cytochromes and pilA in electrochemical communication, which induced Geobacter enrichment. This work provided a broader understanding of electroactive biofilm regulation and potential applications for electricity generation and biosensor in the future.
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Affiliation(s)
- Qian Zhu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Jingping Hu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Bingchuan Liu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Sha Liang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Keke Xiao
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Wenbo Yu
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Shushan Yuan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Jiakuan Yang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Huijie Hou
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hubei Provincial Engineering Laboratory of Solid Waste Treatment, Disposal and Recycling, 1037 Luoyu Road, Wuhan, Hubei 430074, China.
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Charles CJ, Rout SP, Jackson BR, Boxall SA, Akbar S, Humphreys PN. The evolution of alkaliphilic biofilm communities in response to extreme alkaline pH values. Microbiologyopen 2022; 11:e1309. [PMID: 36031955 PMCID: PMC9380404 DOI: 10.1002/mbo3.1309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 11/25/2022] Open
Abstract
Extremes of pH present a challenge to microbial life and our understanding of survival strategies for microbial consortia, particularly at high pH, remains limited. The utilization of extracellular polymeric substances within complex biofilms allows micro-organisms to obtain a greater level of control over their immediate environment. This manipulation of the immediate environment may confer a survival advantage in adverse conditions to biofilms. Within the present study alkaliphilic biofilms were created at pH 11.0, 12.0, or 13.0 from an existing alkaliphilic community. In each pH system, the biofilm matrix provided pH buffering, with the internal pH being 1.0-1.5 pH units lower than the aqueous environment. Increasing pH resulted in a reduced removal of substrate and standing biomass associated with the biofilm. At the highest pH investigated (pH 13.0), the biofilms matrix contained a greater degree of eDNA and the microbial community was dominated by Dietzia sp. and Anaerobranca sp.
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Affiliation(s)
- Christopher J. Charles
- Department of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
- Present address:
Sulaimani Polytechnic UniversitySulaimaniIraq
| | - Simon P. Rout
- Department of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
| | - Brian R. Jackson
- Genesis BiosciencesUnit P1Capital Business Park, Capital PointParkwayCardiffUK
| | - Sally A. Boxall
- Genesis BiosciencesUnit P1Capital Business Park, Capital PointParkwayCardiffUK
| | - Sirwan Akbar
- Bio‐imaging Facility, School of Molecular and Cellular BiologyFaculty of Biological Sciences, University of LeedsLeedsUK
| | - Paul N. Humphreys
- Department of Biological and Geographical Sciences, School of Applied SciencesUniversity of HuddersfieldHuddersfieldUK
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