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Jiang G, Wang C, Wang Y, Wang J, Xue Y, Lin Y, Hu X, Lv Y. Exogenous putrescine plays a switch-like influence on the pH stress adaptability of biofilm-based activated sludge. Appl Environ Microbiol 2024; 90:e0056924. [PMID: 38916292 PMCID: PMC11267902 DOI: 10.1128/aem.00569-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 06/04/2024] [Indexed: 06/26/2024] Open
Abstract
Microbial community adaptability to pH stress plays a crucial role in biofilm formation. This study aims to investigate the regulatory mechanisms of exogenous putrescine on pH stress, as well as enhance understanding and application for the technical measures and molecular mechanisms of biofilm regulation. Findings demonstrated that exogenous putrescine acted as a switch-like distributor affecting microorganism pH stress, thus promoting biofilm formation under acid conditions while inhibiting it under alkaline conditions. As pH decreases, the protonation degree of putrescine increases, making putrescine more readily adsorbed. Protonated exogenous putrescine could increase cell membrane permeability, facilitating its entry into the cell. Subsequently, putrescine consumed intracellular H+ by enhancing the glutamate-based acid resistance strategy and the γ-aminobutyric acid metabolic pathway to reduce acid stress on cells. Furthermore, putrescine stimulated ATPase expression, allowing for better utilization of energy in H+ transmembrane transport and enhancing oxidative phosphorylation activity. However, putrescine protonation was limited under alkaline conditions, and the intracellular H+ consumption further exacerbated alkali stress and inhibits cellular metabolic activity. Exogenous putrescine promoted the proportion of fungi and acidophilic bacteria under acidic stress and alkaliphilic bacteria under alkali stress while having a limited impact on fungi in alkaline biofilms. Increasing Bdellovibrio under alkali conditions with putrescine further aggravated the biofilm decomposition. This research shed light on the unclear relationship between exogenous putrescine, environmental pH, and pH stress adaptability of biofilm. By judiciously employing putrescine, biofilm formation could be controlled to meet the needs of engineering applications with different characteristics.IMPORTANCEThe objective of this study is to unravel the regulatory mechanism by which exogenous putrescine influences biofilm pH stress adaptability and understand the role of environmental pH in this intricate process. Our findings revealed that exogenous putrescine functioned as a switch-like distributor affecting the pH stress adaptability of biofilm-based activated sludge, which promoted energy utilization for growth and reproduction processes under acidic conditions while limiting biofilm development to conserve energy under alkaline conditions. This study not only clarified the previously ambiguous relationship between exogenous putrescine, environmental pH, and biofilm pH stress adaptability but also offered fresh insights into enhancing biofilm stability within extreme environments. Through the modulation of energy utilization, exerting control over biofilm growth and achieving more effective engineering goals could be possible.
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Affiliation(s)
- Guanyu Jiang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Can Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Yongchao Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Jiayi Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Yimei Xue
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Yuting Lin
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Xurui Hu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
| | - Yahui Lv
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, China
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Liang J, Zheng X, Ning T, Wang J, Wei X, Tan L, Shen F. Revealing the Viable Microbial Community of Biofilm in a Sewage Treatment System Using Propidium Monoazide Combined with Real-Time PCR and Metagenomics. Microorganisms 2024; 12:1508. [PMID: 39203351 PMCID: PMC11356008 DOI: 10.3390/microorganisms12081508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 07/16/2024] [Accepted: 07/19/2024] [Indexed: 09/03/2024] Open
Abstract
Microbial community composition, function, and viability are important for biofilm-based sewage treatment technologies. Most studies of microbial communities mainly rely on the total deoxyribonucleic acid (DNA) extracted from the biofilm. However, nucleotide materials released from dead microorganisms may interfere with the analysis of viable microorganisms and their metabolic potential. In this study, we developed a protocol to assess viability as well as viable community composition and function in biofilm in a sewage treatment system using propidium monoazide (PMA) coupled with real-time quantitative polymerase chain reaction (qPCR) and metagenomic technology. The optimal removal of PMA from non-viable cells was achieved by a PMA concentration of 4 μM, incubation in darkness for 5 min, and exposure for 5 min. Simultaneously, the detection limit can reach a viable bacteria proportion of 1%, within the detection concentration range of 102-108 CFU/mL (colony forming unit/mL), showing its effectiveness in removing interference from dead cells. Under the optimal conditions, the result of PMA-metagenomic sequencing revealed that 6.72% to 8.18% of non-viable microorganisms were influenced and the composition and relative abundance of the dominant genera were changed. Overall, this study established a fast, sensitive, and highly specific biofilm viability detection method, which could provide technical support for accurately deciphering the structural composition and function of viable microbial communities in sewage treatment biofilms.
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Affiliation(s)
- Jiayin Liang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
| | - Xiangqun Zheng
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Institute of Environment and Sustainable Development in Agriculture, No.12 Zhongguancun South Street, Haidian District, Beijing 100081, China
| | - Tianyang Ning
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
| | - Jiarui Wang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
| | - Xiaocheng Wei
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
| | - Lu Tan
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
| | - Feng Shen
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China; (J.L.); (X.Z.); (T.N.); (J.W.); (F.S.)
- Key Laboratory of Rural Toilet and Sewage Treatment Technology, Ministry of Agriculture and Rural Affairs, No. 31 Fukang Road, Nankai District, Tianjin 300191, China
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Fu Y, Wu J, Wu Y, Yang B, Wang X, Xu R, Meng F. Development of a novel membrane-based quorum-quenching microbial isolator for biofouling control: Process performance and microbial mechanism. BIORESOURCE TECHNOLOGY 2024; 402:130817. [PMID: 38723725 DOI: 10.1016/j.biortech.2024.130817] [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: 03/19/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/14/2024]
Abstract
Quorum quenching (QQ) can mitigate biofouling in membrane bioreactors (MBRs) by inhibiting cell-to-cell communication. However, it is difficult to maintain long-term QQ activity. Here, a novel microbial isolator composed of tubular microfiltration membranes was developed to separate QQ bacteria (Rhodococcus sp. BH4) from sludge. The time to reach a transmembrane pressure of 50 kPa was delayed by 69.55 % (p = 0.002, Student's t test) in MBR with QQ microbial isolator (MBR-Q), compared to that in the control MBR (MBR-C) during stable operation. The concentration of proteins in the extracellular polymeric substances of sludge was reduced by 20.61 % in MBR-Q relative to MBR-C. The results of the bacterial community analyses indicated less enrichment of fouling-associated bacteria (e.g., Acinetobacter) but a higher abundance of QQ enzymes in MBR-Q than in MBR-C. This environmentally friendly technique can decrease the cleaning frequency and increase the membrane lifespan, thus improving the sustainability of MBR technology.
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Affiliation(s)
- Yue Fu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Jiajie Wu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Yingxin Wu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Boyi Yang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Xiaolong Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
| | - Ronghua Xu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China.
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou 510275, PR China
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Hirakata Y, Mei R, Morinaga K, Katayama T, Tamaki H, Meng XY, Watari T, Yamaguchi T, Hatamoto M, Nobu MK. Identification and cultivation of anaerobic bacterial scavengers of dead cells. THE ISME JOURNAL 2023; 17:2279-2289. [PMID: 37872273 PMCID: PMC10689501 DOI: 10.1038/s41396-023-01538-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
The cycle of life and death and Earth's carbon cycle(s) are intimately linked, yet how bacterial cells, one of the largest pools of biomass on Earth, are recycled back into the carbon cycle remains enigmatic. In particular, no bacteria capable of scavenging dead cells in oxygen-depleted environments have been reported thus far. In this study, we discover the first anaerobes that scavenge dead cells and the two isolated strains use distinct strategies. Based on live-cell imaging, transmission electron microscopy, and hydrolytic enzyme assays, one strain (designated CYCD) relied on cell-to-cell contact and cell invagination for degrading dead food bacteria where as the other strain (MGCD) degraded dead food bacteria via excretion of lytic extracellular enzymes. Both strains could degrade dead cells of differing taxonomy (bacteria and archaea) and differing extents of cell damage, including those without artificially inflicted physical damage. In addition, both depended on symbiotic metabolic interactions for maximizing cell degradation, representing the first cultured syntrophic Bacteroidota. We collectively revealed multiple symbiotic bacterial decomposition routes of dead prokaryotic cells, providing novel insight into the last step of the carbon cycle.
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Affiliation(s)
- Yuga Hirakata
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
| | - Ran Mei
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Kana Morinaga
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Taiki Katayama
- Geomicrobiology Research Group, Research Institute for Geo-Resources and Environment, Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8567, Japan
| | - Hideyuki Tamaki
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Xian-Ying Meng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Takahiro Watari
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, Nagaoka, 940-2188, Japan
| | - Takashi Yamaguchi
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, Nagaoka, 940-2188, Japan
- Department of Science of Technology Innovation, Nagaoka University of Technology, Nagaoka, 940-2188, Japan
| | - Masashi Hatamoto
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, Nagaoka, 940-2188, Japan
| | - Masaru K Nobu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
- Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, 237-0061, Japan.
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Xiao K, Wang K, Yu S, Yuan Y, Qin Y, An Y, Zhao X, Zhou Z. Membrane fouling behavior in membrane bioreactors for nitrogen-deficient wastewater pretreated by ammonium ion exchange. J Memb Sci 2023. [DOI: 10.1016/j.memsci.2022.121087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Miwa T, Takimoto Y, Mizuta Y, Hatamoto M, Watari T, Yamaguchi T. An increase in sludge loading rate induces gel fouling in membrane bioreactors treating real sewage. CHEMOSPHERE 2022; 309:136557. [PMID: 36185000 DOI: 10.1016/j.chemosphere.2022.136557] [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: 06/27/2022] [Revised: 08/29/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
The main objective of this study was to investigate the cause of gel fouling in membrane bioreactors (MBRs) treating real sewage in terms of soluble microbial products (SMPs) and microbial aspects. Two anoxic/oxic-MBRs were operated as the control reactor (S1) and the sludge loading rate increased reactor (S2). The reactors were operated under low-temperature around 11 °C conditions. Membrane permeability substantially decreased in S2, and gel layer biofilm was formed on membrane surface. In contrast, the permeability of S1 gradually decreased and cake layer formed. When gel fouling occurred, the protein and polysaccharide of SMP in S2 were 47 and 23 mg L-1, which were significantly lower than those recorded in S1 accounted for 118 and 68 mg L-1, respectively. Furthermore, the total organic carbon concentration of SMPs was 24 mg L-1, which was lower than the influent in S2, accounted for 62 mg L-1. Finally, Campylobacteraceae which exists in sewage and uncultured OD1, dominated the gel layer biofilm in S2, unlike the cake layer biofilm in S1. These results indicated that the gel layer biofilm might be composed of influent substances, demonstrating the importance of influent decomposition in MBR for gel fouling mitigation.
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Affiliation(s)
- Toru Miwa
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Yuya Takimoto
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Yuki Mizuta
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Masashi Hatamoto
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan.
| | - Takahiro Watari
- Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
| | - Takashi Yamaguchi
- Department of Science of Technology Innovation, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan; Department of Civil and Environmental Engineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, 940-2188, Japan
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Liao G, Bin L, Tang B, Li P, Qiu B, Huang Z, Huang S, Fu F. Insights into the fouling layer of flat-sheet membrane and its development in an integrated oxidation ditch-membrane bioreactor. BIORESOURCE TECHNOLOGY 2022; 345:126466. [PMID: 34864179 DOI: 10.1016/j.biortech.2021.126466] [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: 10/29/2021] [Revised: 11/22/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
This work revealed the characteristics of fouling layer on the flat-sheet membranes and its development in an integrated oxidation-ditch membrane bioreactor. During the operation period (130 days), the reactor performed very well in removing pollutants. As the operation proceeded, membrane fouling occurred on the flat-sheet membranes and trans-membrane pressure showed a cyclical variation. The experimental results showed that the process of membrane fouling appeared successively in two different structures: biofilm (BF) and sludge fouling (SF). The substances causing membrane fouling were mainly organic foulants and a small amount of inorganic metal compounds, especially the protein-like and fulvic acid-like substances in loosely bound extracellular polymeric substances (LB-EPS). The analysis of microbial communities revealed that SF and BF had very different microbial properties. Although most membrane foulants could be removed by physical and chemical cleaning methods, the protein-like and fulvic acid-like substances in BF were contribute much to causing irreversible membrane fouling.
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Affiliation(s)
- Guohao Liao
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Liying Bin
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Ping Li
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Bangqiao Qiu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Zhaole Huang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Shaosong Huang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
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