1
|
Sui Y, Cui YW, Huang JL, Xu MJ. Feast/famine ratio regulates the succession of heterotrophic nitrification-aerobic denitrification and autotrophic ammonia oxidizing bacteria in halophilic aerobic granular sludge treating saline wastewater. BIORESOURCE TECHNOLOGY 2024; 393:129995. [PMID: 37951552 DOI: 10.1016/j.biortech.2023.129995] [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: 07/31/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
Heterotrophic nitrification-aerobic denitrification (HN-AD) shows innovation potential of wastewater treatment process in a single tank. However, how to enrich HN-AD bacteria in activated sludge to enhance their contribution remained unknown. This study explored the impact of the feast/famine (F/F) ratio on the succession of autotrophic ammonia oxidizing bacteria (AOB) and HN-AD bacteria in a halophilic aerobic granular sludge (HAGS) system. As the F/F ratio decreased from 1/9 to 1/15, the total inorganic nitrogen (TIN) removal performance significantly decreased. The proportion of heterotrophic bacteria was dropped from 79.0 % to 33 %. Accordingly, the relative abundance of Paracoccus decreased from 70.8 % to 25.4 %, and the copy number of the napA gene was reduced from 2.2 × 1010 copies/g HAGS to 8.1 × 109 copies/g HAGS. It found the F/F ratio regulated the population succession of autotrophic AOB and HN-AD bacteria, thereby providing a solution to achieve the enrichment of HN-AD bacteria in HAGS.
Collapse
Affiliation(s)
- Yuan Sui
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - You-Wei Cui
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Ji-Lin Huang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Meng-Jiao Xu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| |
Collapse
|
2
|
Zhou Y, Liu Z, Wen J, Zhou Y, Lin H. The inhibitory effect of berberine chloride hydrate on Streptococcus mutans biofilm formation at different pH values. Microbiol Spectr 2023; 11:e0217023. [PMID: 37747238 PMCID: PMC10580975 DOI: 10.1128/spectrum.02170-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/01/2023] [Indexed: 09/26/2023] Open
Abstract
Streptococcus mutans (S. mutans) is one of the major cariogenic bacteria of dental caries owing to its ability to adhere to tooth surfaces and biofilm formation. Berberine chloride hydrate (BH), a quaternary ammonium salt alkaloid, has diverse pharmacological efforts against microorganisms. However, the effect of BH on S. mutans biofilm has not been reported. Considering that berberine is a quaternary ammonium salt alkaloid, which needs to adapt to a large variation in pH values and the acid resistance of S. mutans, we employed three groups including pH 5 (acidic), pH 8 (alkaline), and unprocessed group (neutral) to examine the antibiofilm activities of BH against S. mutans during different pH values. In this study, we found BH effectively suppresses S. mutans biofilm formation as well as its cariogenic virulence including acid production and EPS synthesis significantly, and the inhibitory effort was reduced under acidic condition whereas elevated under alkaline condition. In addition, we preliminarily explored the influence of pH values on the structural stability and biosafety of BHas well as the underlying mechanism of inhibition of S. mutans biofilm formation with BH. Our study showed BH could maintain a good structural stability and low toxicity to erythrocytes at different pH values. And BH could downregulate the expression of srtA, spaP, and gbpC, which play critical roles in the adhesion process, promoting bacterial colonization and biofilm formation. Furthermore, comX and ldh expression levels were downregulated in BH-treated group, which might explain its inhibitory effect on acid production.IMPORTANCEDental caries is a common chronic detrimental disease, which could cause a series of oral problem including oral pain, difficulties in eating, and so on. Recently, many natural products have been considered as fundamental sources of therapeutic drugs to prevent caries. Berberine as a plant extract showed good antibiofilm abilities against microorganism. Our study focuses on its antibiofilm abilities against S. mutans, which was defined as major cariogenic bacterium and explored the role of pH values and possible underlying mechanisms in the inhibitory effect of BH on S. mutans biofilm formation. This study demonstrated a promising prospect for BH as an adjuvant drug in the prevention and management of dental caries.
Collapse
Affiliation(s)
- Yang Zhou
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Zhuoying Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Jie Wen
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Yan Zhou
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Huancai Lin
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| |
Collapse
|
3
|
Yuan Q, Jia Z, Roots P, Wells G. A strategy for fast anammox biofilm formation under mainstream conditions. CHEMOSPHERE 2023; 318:137955. [PMID: 36702412 DOI: 10.1016/j.chemosphere.2023.137955] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/11/2023] [Accepted: 01/22/2023] [Indexed: 06/18/2023]
Abstract
One of the bottlenecks to applying anaerobic ammonium oxidation (Anammox) is the long start-up time, especially under mainstream conditions. This study proposed a strategy for fast anammox biofilm formation under mainstream conditions. By first cultivating an aerobic heterotrophic biofilm, and then transferring to anoxic conditions, a pre-cultivated heterotrophic biofilm can be formed in 12 days. The pre-cultivated heterotrophic biofilm then functions as a "glue" to accelerate anammox bacteria adhesion and biofilm formation. Secondary settled effluent with externally added 15-30 mg-N·L-1 ammonium and nitrite was applied as reactor influent. With a single inoculation of suspended growth anammox-laden biomass and no bioaugmentation, an anammox-enriched biofilm formed after 5 months of operation under uncontrolled temperature of 15-20 °C. Both the nitrogen removal rate and specific anammox activity exponentially increased over the course of study, corresponding to an estimated anammox doubling time of 10.8 days. The biofilm thickness on primed carriers was 2-3 times higher than on the non-primed carriers over the first 5 months of operation, and the hszA gene copy number in primed biofilms revealed was consistently 1 to 2 times higher than the non-primed carrier biofilm, indicating that biofil m carrier priming via selection for a pre-cultivated heterotrophic biofilm base can effectively improve the anammox enrichment rate at early stages of reactor operation. Time, rather than the type of biofilm (primed versus non-primed), had a stronger influence on microbial community structure over the full 230 days of reactor operation. Candidatus Brocadia was the only detected anammox bacteria genus. Overall, pre-cultivation of heterotrophs on biofilm carriers provides a simple route to accelerate anammox-enriched biofilm formation under mainstream conditions.
Collapse
Affiliation(s)
- Quan Yuan
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, China; Department of Civil & Environmental Engineering, Northwestern University, Evanston, USA
| | - Zhen Jia
- Department of Civil & Environmental Engineering, Northwestern University, Evanston, USA
| | - Paul Roots
- Department of Civil & Environmental Engineering, Northwestern University, Evanston, USA
| | - George Wells
- Department of Civil & Environmental Engineering, Northwestern University, Evanston, USA.
| |
Collapse
|
4
|
Ramos P, Honda R, Hoek EMV, Mahendra S. Carbon/nitrogen ratios determine biofilm formation and characteristics in model microbial cultures. CHEMOSPHERE 2023; 313:137628. [PMID: 36565767 DOI: 10.1016/j.chemosphere.2022.137628] [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: 11/02/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
The influence of growth medium water chemistry, specifically carbon/nitrogen (C/N) molar ratios, on the characteristics and development of biofilms of the model microorganism Pseudomonas aeruginosa was investigated. C/N = 9 had a unique effect on biofilm composition as well as quorum sensing (QS) pathways, with higher concentrations of carbohydrates and proteins in the biofilm and a significant upregulation of the QS gene lasI in planktonic cells. The effect of C/N ratio on total attached biomass was negligible. Principal component analysis revealed a different behavior of most outputs such as carbohydrates and QS chemicals at C/N = 9, and pointed to correlations between parameters of biofilm formation and steady state distribution of cells and extracellular components. C/N ratio was also shown to influence organic compound utilization by both planktonic and sessile organisms, with a maximum chemical oxygen demand (COD) removal of 83% achieved by biofilms at C/N = 21. Planktonic cells achieved higher COD removal rates, but greater overall rates after six days occurred in biofilms. The development of a dual-species biofilm of P. aeruginosa and Nitrobacter winogradskyi was also influenced by C/N, with increase in the relative abundance of the slower-growing N. winogradskyi above C/N = 9. These results indicate that altering operational parameters related to C/N would be relevant for mitigating or promoting biofilm formation and function depending on the desired industrial application or treatment configuration.
Collapse
Affiliation(s)
- Pia Ramos
- Department of Civil and Environmental Engineering, University of California Los Angeles, 5732 Boelter Hall, Los Angeles, CA, 90095, USA
| | - Ryo Honda
- Faculty of Geoscience and Civil Engineering, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Eric M V Hoek
- Department of Civil and Environmental Engineering, University of California Los Angeles, 5732 Boelter Hall, Los Angeles, CA, 90095, USA; UCLA California NanoSystems Institute, Los Angeles, CA, 90095, USA; UCLA Institute of the Environment & Sustainability, Los Angeles, CA, 90095, USA
| | - Shaily Mahendra
- Department of Civil and Environmental Engineering, University of California Los Angeles, 5732 Boelter Hall, Los Angeles, CA, 90095, USA; UCLA California NanoSystems Institute, Los Angeles, CA, 90095, USA; UCLA Institute of the Environment & Sustainability, Los Angeles, CA, 90095, USA.
| |
Collapse
|
5
|
Yang Y, Li M, Zheng X, Ma H, Nerenberg R, Chai H. Extracellular DNA plays a key role in the structural stability of sulfide-based denitrifying biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155822. [PMID: 35561912 DOI: 10.1016/j.scitotenv.2022.155822] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Sulfide-based biofilm processes are increasingly used for wastewater denitrification, yet little is known about the extracellular polymeric substance (EPS) composition of sulfide-oxidizing biofilms. This can have an important impact on biofilm mechanical strength and stability. In this research, the properties and roles of EPS components in biofilm stability were investigated. Weak biofilm stability characterized by high roughness and numerous "needle" structures was visualized by optical coherence tomography (OCT) and microscopy. A high abundance of extracellular DNA (eDNA) and a low protein to polysaccharide ratio were found in the biofilm. The roles of eDNA, protein and polysaccharide in biofilm cohesion and adhesion were identified through enzyme treatment and atomic force microscopy (AFM). The enzymatic hydrolysis of eDNA increased the elastic modulus of biofilms by 57 times and reduced the adhesion energy by 96%. The hydrolysis of proteins led to an increase of elastic modulus by 27 times and a loss of adhesion energy by 95.5%. The enzymatic hydrolysis of polysaccharides caused minimal changes in elastic modulus and adhesion energy. These results suggest that eDNA was the key EPS component for biofilm cohesion and adhesion, possibly because it provided special binding sites and can form strong cross-linking with magnesium or other multivalent cations. This study provided new insights into the role of eDNA in biofilm stability and shed light on the development of sulfide-based denitrifying biofilms.
Collapse
Affiliation(s)
- Yan Yang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China; Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haiyuan Ma
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Hongxiang Chai
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
| |
Collapse
|
6
|
Kunapongkiti P, Rongsayamanont C, Mhuantong W, Pornkulwat P, Charanaipayuk N, Limpiyakorn T. Substrate loading rates conducive to nitritation in entrapped cell reactors: performance and microbial community structure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:37722-37736. [PMID: 35072882 DOI: 10.1007/s11356-022-18632-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
This study aimed to elucidate the boundaries of ammonia and organic loading rates that allow for nitritation in continuous flow phosphorylated-polyvinyl alcohol entrapped cell reactors and to clarify the community structure of microorganisms involving nitrogen transformation in the gel bead matrices. At operating bulk dissolved oxygen concentration of 2 mg/L, nitritation was accomplished when the total ammonia nitrogen (TAN) loading rate was ≥ 0.3 kgN/m3/d. At TAN loading rates of ≤ 0.2 kgN/m3 /d, complete oxidation of ammonia to nitrate took place. Nitritation performance dropped with increased chemical oxygen demand (COD) loading rates indicating limitation of nitritation reactor operation at some COD loading conditions. 16S rRNA gene amplicon sequencing revealed that the uncultured Cytophagaceae bacterium, Arenimonas, Truepera, Nitrosomonas, Comamonas, unclassified Soil Crenarchaeotic Group, and uncultured Chitinophagaceae bacterium were highly abundant taxa in the reactors' gel bead matrices. qPCR with specific primers targeting amoA genes demonstrated the coexistence of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea, and Comammox in the gel bead matrices. AOB was likely the main functioning ammonia-oxidizing microorganisms due to the amoA gene being of highest abundance in most of the studied conditions. Nitrite-oxidizing microorganisms presented in less relative abundance than ammonia-oxidizing microorganisms, with Nitrobacter rather than Nitrospira dominating in the group. Results obtained from this study are expected to further the application of nitritation entrapped cell reactors to real wastewater treatment processes.
Collapse
Affiliation(s)
- Pattaraporn Kunapongkiti
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand
| | - Chaiwat Rongsayamanont
- Environmental Assessment and Technology for Hazardous Waste Management Research Center, Faculty of Environmental Management, Prince of Songkla University, Songkhla, Thailand
- Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, Thailand
| | - Wuttichai Mhuantong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathumthani, Thailand
| | - Preeyaporn Pornkulwat
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand
| | - Nampetch Charanaipayuk
- Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, Thailand
- International Program in Hazardous Substance and Environmental Management, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Tawan Limpiyakorn
- Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
- Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, Thailand.
- Research Unit Control of Emerging Micropollutants in Environment, Chulalongkorn University, Bangkok, Thailand.
- Research Network of NANOTEC-CU on Environment, Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand.
| |
Collapse
|
7
|
Effect of biofilm media application on biomass characteristics and membrane permeability in the biological spatiotemporal phase-separation process. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
8
|
Wang J, Jiang Z, Wang W, Wang H, Zhang Y, Wang Y. The connection between aeration regimes and EPS composition in nitritation biofilm. CHEMOSPHERE 2021; 265:129141. [PMID: 33272669 DOI: 10.1016/j.chemosphere.2020.129141] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
The effects of aeration regimes (intermittent and continuous aeration) on nitritation performance and biofilm EPS composition were evaluated in moving bed biofilm reactors (MBBRs), and a hypothesis that the aeration regimes affect EPS composition by affecting the microbial activity and sludge discharge content was proposed. The effluent NO2-/NH4+ ratio corresponded to that of an anammox reaction (1.07 ± 0.20) for the MBBR with continuous aeration (MBBRcon.), while that in the MBBR with intermittent aeration (20 min on/15 min off) (MBBRint.) was relatively lower (0.75 ± 0.19). Furthermore, the activity of ammonia-oxidizing bacteria in MBBRcon. was 0.4-7.9 mg-N·L-1·h-1 more than that in MBBRint., which was consistent with the lower proportion of dead cells in MBBRcon. compared with MBBRint. (9.4% vs. 31.8%). The higher microbial activity in MBBRcon. led to more sludge discharge than MBBRint., which was reflected in the higher biofilm detachment rate in MBBRcon. compared with MBBRint. (0.15 ± 0.02 vs. 0.11 ± 0.02 g m-2·d-1). The ratio of humic substances to polysaccharides in the EPS was high (0.96 ± 0.08) in the detachment biomass, while the ratios in the nitritation biofilm on carriers from MBBRcon. and MBBRint. were 0.52 ± 0.13 and 0.72 ± 0.16, respectively. We hypothesized that biofilm matrix with high ratios of humic substances to polysaccharides are structurally unstable and prone to fall off. In addition, the higher proportion of dead cells in MBBRint. made the proportion of humic substances in EPS high. Meanwhile, less sludge discharge in MBBRint. than MBBRcon. caused more humic substances to accumulate in the biofilm. These was responsible for the higher ratio of humic substances to polysaccharides in MBBRint. compared with MBBRcon. The findings elucidate the connection between aeration regimes and biofilm EPS composition, and guide the choice of aeration regimes in the design of biofilm reactors for partial nitritation.
Collapse
Affiliation(s)
- Junjie Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Zhuwu Jiang
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, 350108, PR China.
| | - Weigang Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Han Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Yao Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering, Tongji University, Siping Road, Shanghai, 200092, PR China.
| |
Collapse
|
9
|
Gu YQ, Li TT, Li HQ. Biofilm formation monitored by confocal laser scanning microscopy during startup of MBBR operated under different intermittent aeration modes. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.08.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
10
|
Barker LK, Giska JR, Radniecki TS, Semprini L. Effects of short- and long-term exposure of silver nanoparticles and silver ions to Nitrosomonas europaea biofilms and planktonic cells. CHEMOSPHERE 2018; 206:606-614. [PMID: 29778938 DOI: 10.1016/j.chemosphere.2018.05.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
The increasing use of silver nanoparticles (AgNPs) in consumer products, and their resulting influx into wastewater, may pose a threat to biological nutrient removal in wastewater treatment plants. Planktonic ammonia-oxidizing bacteria (AOB), which convert ammonia to nitrite in the first step of nitrification, are highly sensitive to AgNPs and their released silver ions (Ag+), but the sensitivity of AOB biofilms to AgNPs and Ag+ is less clear. This study demonstrated that biofilms of Nitrosomonas europaea, a model AOB, were more resistant to both short-term and long-term exposure to AgNP and Ag+ than planktonic cells. The increased resistance of N. europaea biofilms was attributed primarily to the increased biomass and slower growth rates present in the biofilm. Similar inhibition mechanisms were observed for AgNPs and Ag+ in both planktonic cells and biofilms with enzymatic inhibition observed at lower concentrations and cell lysis observed at higher concentrations. Long-term continuous exposure to AgNPs lowered the inhibitory concentration by 1-2 orders of magnitude below that required by short-term exposures. Although the total AgNP load was similar between the short and long-term exposure scenarios, the long-term exposure resulted in an order of magnitude more silver being associated in the biofilms and is the primary reason for the increased sensitivity observed. This suggests that short-term batch toxicity assays may greatly underestimate the sensitivity of biofilm treatment systems to long-term exposures of low concentrations of AgNPs and Ag+.
Collapse
Affiliation(s)
- L K Barker
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - J R Giska
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - T S Radniecki
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA.
| | - L Semprini
- School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA
| |
Collapse
|
11
|
Sun Y, Guan Y, Wang D, Liang K, Wu G. Potential roles of acyl homoserine lactone based quorum sensing in sequencing batch nitrifying biofilm reactors with or without the addition of organic carbon. BIORESOURCE TECHNOLOGY 2018; 259:136-145. [PMID: 29549833 DOI: 10.1016/j.biortech.2018.03.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/04/2018] [Accepted: 03/05/2018] [Indexed: 05/03/2023]
Abstract
Two lab-scale nitrifying sequencing batch biofilm reactors, with (SBBR_CN) or without the addition of organics (SBBR_N), were operated to investigate potential roles of acyl homoserine lactone (AHL) based quorum sensing. AHLs of N-[(RS)-3-Hydroxybutyryl]-L-homoserine lactone, N-hexanoyl-L-homoserine lactone (C6-HSL) and N-octanoyl-L-homoserine lactone (C8-HSL) were detected in both reactors. C6-HSL and C8-HSL were also detected in batch experiments, especially with stimulated nitrite oxidizing bacteria activities. Quorum sensing affected biofilm formation mainly through the regulation of extracellular protein production. By the metagenomics analysis, many identified genera and species could participate in quorum sensing, quorum quenching and extracellular polymeric substances (EPS) production. A high quorum quenching activity was obtained in SBBR_CN, whereas a high quorum sensing activity in SBBR_N. Nitrosomonas-like ammonia oxidizing bacteria, Nitrospira-like nitrite oxidizing bacteria and Comammox harbored genes for AHL synthesis and EPS production. Possible relationships among AHLs synthesis, biofilm formation and nitrifiers activity were proposed.
Collapse
Affiliation(s)
- Yuepeng Sun
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Yuntao Guan
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Dan Wang
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Kai Liang
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Guangxue Wu
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| |
Collapse
|
12
|
Wang J, Zhang Z, Qian F, Shen Y, Qi Z, Ji X, Kajamisso EML. Rapid start-up of a nitritation granular reactor using activated sludge as inoculum at the influent organics/ammonium mass ratio of 2/1. BIORESOURCE TECHNOLOGY 2018; 256:170-177. [PMID: 29438917 DOI: 10.1016/j.biortech.2018.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
Partial oxidation of ammonium to nitrite is a pre- and crucial step to achieve shortcut biological nitrogen removal from ammonium-rich wastewater. In the present study, a nitritation granular reactor using activated sludge as inoculum was started up in a sequencing batch reactor (SBR) at a fixed influent C/N ratio of 2:1. Variations in the reactor performance, functional bacteria activities, sludge morphology and bacterial community structure were investigated. Results showed the formation of compact granules was achieved in 55 days, and a stable nitrite accumulation rate of 0.68 kg N·m-3·d-1 was maintained in the following period. With a rapid growth of granular size, the total nitrogen removal by simultaneous nitritation/denitritation was progressively increased to 50%. In sludge granulation, the significant enrichment of r-strategist ammonium oxidizing bacteria (Nitrosomonas) was identified. Additionally, both high free ammonia concentration and extra nitrite competition by heterotrophic denitrifiers were critical to suppress nitrite oxidizing bacteria effectively.
Collapse
Affiliation(s)
- Jianfang Wang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Zeyu Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Feiyue Qian
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China.
| | - Yaoliang Shen
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Zekun Qi
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Xiaoqing Ji
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| | - Emma Marcello Lagu Kajamisso
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, 215009 Suzhou, People's Republic of China
| |
Collapse
|
13
|
Petrovich M, Wu CY, Rosenthal A, Chen KF, Packman AI, Wells GF. Nitrosomonas europaea biofilm formation is enhanced by Pseudomonas aeruginosa. FEMS Microbiol Ecol 2017; 93:3106320. [DOI: 10.1093/femsec/fix047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 04/05/2017] [Indexed: 11/15/2022] Open
|
14
|
Chen L, Bu Q, Xu H, Liu Y, She P, Tan R, Wu Y. The effect of berberine hydrochloride on Enterococcus faecalis biofilm formation and dispersion in vitro. Microbiol Res 2016; 186-187:44-51. [PMID: 27242142 DOI: 10.1016/j.micres.2016.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 02/19/2016] [Accepted: 03/08/2016] [Indexed: 01/29/2023]
Abstract
Enterococcus faecalis (E. faecalis) is one of the major causes of biofilm infections. Berberine hydrochloride (BBH) has diverse pharmacological effects; however, the effects and mechanisms of BBH on E. faecalis biofilm formation and dispersion have not been reported. In this study, 99 clinical isolates from the urine samples of patients with urinary tract infections (UTIs) were collected and identified. Ten strains of E. faecalis with biofilm formation ability were studied. BBH inhibited E. faecalis biofilm formation and promoted the biofilm dispersion of E. faecalis. In addition, sortase A and esp expression levels were elevated during early E. faecalis biofilm development, whereas BBH significantly reduced their expression levels. The results of this study indicated that BBH effectively prevents biofilm formation and promotes biofilm dispersion in E. faecalis, most likely by inhibiting the expressions of sortase A and esp.
Collapse
Affiliation(s)
- Lihua Chen
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Qianqian Bu
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Huan Xu
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Yuan Liu
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Pengfei She
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Ruichen Tan
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China
| | - Yong Wu
- Department of Medicine Clinical Laboratory, the Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, PR China.
| |
Collapse
|
15
|
Vannecke TPW, Bernet N, Winkler MKH, Santa-Catalina G, Steyer JP, Volcke EIP. Influence of process dynamics on the microbial diversity in a nitrifying biofilm reactor: Correlation analysis and simulation study. Biotechnol Bioeng 2016; 113:1962-74. [DOI: 10.1002/bit.25952] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/03/2016] [Accepted: 02/08/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Thomas P. W. Vannecke
- Department of Biosystems Engineering; Ghent University, Coupure links 653; 9000 Ghent Belgium
| | - Nicolas Bernet
- Laboratoire de Biotechnologie de l'Environnement; INRA, UR0050; Narbonne France
| | - Mari K. H. Winkler
- Department of Biosystems Engineering; Ghent University, Coupure links 653; 9000 Ghent Belgium
| | | | | | - Eveline I. P. Volcke
- Department of Biosystems Engineering; Ghent University, Coupure links 653; 9000 Ghent Belgium
| |
Collapse
|