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Hu W, Zhang H, Lin X, Liu R, Bartlam M, Wang Y. Characteristics, Biodiversity, and Cultivation Strategy of Low Nucleic Acid Content Bacteria. Front Microbiol 2022; 13:900669. [PMID: 35783413 PMCID: PMC9240426 DOI: 10.3389/fmicb.2022.900669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
Low nucleic acid content (LNA) bacteria are ubiquitous and estimated to constitute 20%–90% of the total bacterial community in marine and freshwater environment. LNA bacteria with unique physiological characteristics, including small cell size and small genomes, can pass through 0.45-μm filtration. The researchers came up with different terminologies for low nucleic acid content bacteria based on different research backgrounds, such as: filterable bacteria, oligotrophic bacteria, and low-DNA bacteria. LNA bacteria have an extremely high level of genetic diversity and play an important role in material circulation in oligotrophic environment. However, the majority of LNA bacteria in the environment remain uncultivated. Thus, an important challenge now is to isolate more LNA bacteria from oligotrophic environments and gain insights into their unique metabolic mechanisms and ecological functions. Here, we reviewed LNA bacteria in aquatic environments, focusing on their characteristics, community structure and diversity, functions, and cultivation strategies. Exciting future prospects for LNA bacteria are also discussed.
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Affiliation(s)
- Wei Hu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Hui Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Xiaowen Lin
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Ruidan Liu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
| | - Yingying Wang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai International Advanced Research Institute (Shenzhen Futian), Nankai University, Tianjin, China
- *Correspondence: Yingying Wang,
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Exploiting Aerobic Carboxydotrophic Bacteria for Industrial Biotechnology. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2021; 180:1-32. [PMID: 34894287 DOI: 10.1007/10_2021_178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Aerobic carboxydotrophic bacteria are a group of microorganisms which possess the unique trait to oxidize carbon monoxide (CO) as sole energy source with molecular oxygen (O2) to produce carbon dioxide (CO2) which subsequently is used for biomass formation via the Calvin-Benson-Bassham cycle. Moreover, most carboxydotrophs are also able to oxidize hydrogen (H2) with hydrogenases to drive the reduction of carbon dioxide in the absence of CO. As several abundant industrial off-gases contain significant amounts of CO, CO2, H2 as well as O2, these bacteria come into focus for industrial application to produce chemicals and fuels from such gases in gas fermentation approaches. Since the group of carboxydotrophic bacteria is rather unknown and not very well investigated, we will provide an overview about their lifestyle and the underlying metabolic characteristics, introduce promising members for industrial application, and give an overview of available genetic engineering tools. We will point to limitations and discuss challenges, which have to be overcome to apply metabolic engineering approaches and to utilize aerobic carboxydotrophs in the industrial environment.
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Liu J, Li B, Wang Y, Zhang G, Jiang X, Li X. Passage and community changes of filterable bacteria during microfiltration of a surface water supply. ENVIRONMENT INTERNATIONAL 2019; 131:104998. [PMID: 31330365 DOI: 10.1016/j.envint.2019.104998] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/06/2019] [Accepted: 07/07/2019] [Indexed: 06/10/2023]
Abstract
The omnipresence of filterable bacteria that can pass through 0.22-μm membrane filters demands a change in the sterile filtration practice. In this study, we identified that filterable bacteria enriched from a surface water are members of the Bacteroidetes, Proteobacteria, Spirochaetae, Firmicutes, and Actinobacteria. Filterable bacteria displayed superior filterability during the entire bacterial growth phase, especially at the exponential phase. Maximal passage percentages were comparable at different cell densities, and achieved earlier at high cell density. Furthermore, filter retention for the investigated bacteria is independent of liquid temperature. However, cultivation temperature could affect the growth of some specific filterable bacteria and lead to variability in the passage percentage. Additionally, membrane materials, pore size and filtering flux greatly affected the passage of filterable bacteria. The majority of filterable Hylemonella and SAR324 could pass through 0.1-μm polyvinylidene fluoride and polyethersulfone filters but could not pass through 0.1-μm polycarbonate and mixed cellulose esters filters. Taken together, our results demonstrated that the ultra-small size of filterable bacteria, membrane characteristics and filtration operational conditions could challenge the validity of the 0.22/0.1-μm sterilizing grade filters in providing bio-safety barriers.
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Affiliation(s)
- Jie Liu
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, China
| | - Bing Li
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, China.
| | - Yingying Wang
- College of Environmental Science and Engineering, Nankai University, China
| | - Guijuan Zhang
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, China
| | - Xiaotao Jiang
- Environmental Biotechnology Laboratory, The University of Hong Kong, Hong Kong, China
| | - Xiaoyan Li
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, China; Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, China.
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Park JW, Lee YJ, Meyer AS, Douterelo I, Maeng SK. Bacterial growth through microfiltration membranes and NOM characteristics in an MF-RO integrated membrane system: Lab-scale and full-scale studies. WATER RESEARCH 2018; 144:36-45. [PMID: 30014977 DOI: 10.1016/j.watres.2018.07.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 07/07/2018] [Accepted: 07/10/2018] [Indexed: 06/08/2023]
Abstract
Biofilm formation on membrane surfaces causes many operational problems such as a decrease in permeate flux and an increase in hydraulic resistance. In this study, the ability of bacteria to pass through microfiltration (MF) membranes and the growth potential of microfilterable bacteria were investigated in order to understand biofouling in MF-reverse osmosis (RO) integrated membrane systems. Growth of microfilterable bacteria in MF permeate was observed, indicating that not all MF membranes can guarantee the total rejection of bacteria. Changes in natural organic matter (NOM) characteristics and growth potential of bacteria during the treatment process are important factors in the occurrence of biofilm development in water treatment systems. Analysis of protein-like and humic-like substances in NOM of two successive RO stages revealed an increase in the concentrations of both biopolymers and humic substances of RO concentrates. Unexpectedly, the use of antiscalants was seen to enhance the growth of bacteria in the RO feed water in this study. Bacterial 16s rRNA pyrosequencing revealed that passing source water through the MF membranes dramatically changed bacterial community structure. The bacterial communities that passed through the MF steps primarily belonged to the family Comamonadaceae. However, several bacteria groups including Flavobacteriaceae, Sphingobacteriaceae and Sphingomonadaceae selectively composed the biofilm community formed on the RO membranes. Thus, understanding the selectivity and filterability of MF towards microorganisms involved in biofouling on RO membrane surfaces is crucial for the improvement of membrane-related operational processes.
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Affiliation(s)
- Ji Won Park
- Department of Civil and Environmental Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea
| | - Young Joo Lee
- K-water Convergence Institute, 125 Yuseong-daero 1689 beon-gil, Yuseong-gu, Deajeon, 34045, Republic of Korea
| | - Anne S Meyer
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Isabel Douterelo
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - Sung Kyu Maeng
- Department of Civil and Environmental Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, Republic of Korea.
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Baron JL, Peters T, Shafer R, MacMurray B, Stout JE. Field evaluation of a new point-of-use faucet filter for preventing exposure to Legionella and other waterborne pathogens in health care facilities. Am J Infect Control 2014; 42:1193-6. [PMID: 25234046 DOI: 10.1016/j.ajic.2014.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Opportunistic waterborne pathogens (eg, Legionella, Pseudomonas) may persist in water distribution systems despite municipal chlorination and secondary disinfection and can cause health care-acquired infections. Point-of-use (POU) filtration can limit exposure to pathogens; however, their short maximum lifetime and membrane clogging have limited their use. METHODS A new faucet filter rated at 62 days was evaluated at a cancer center in Northwestern Pennsylvania. Five sinks were equipped with filters, and 5 sinks served as controls. Hot water was collected weekly for 17 weeks and cultured for Legionella, Pseudomonas, and total bacteria. RESULTS Legionella was removed from all filtered samples for 12 weeks. One colony was recovered from 1 site at 13 weeks; however, subsequent tests were negative through 17 weeks of testing. Total bacteria were excluded for the first 2 weeks, followed by an average of 1.86 log reduction in total bacteria compared with controls. No Pseudomonas was recovered from filtered or control faucets. CONCLUSION This next generation faucet filter eliminated Legionella beyond the 62 day manufacturers' recommended maximum duration of use. These new POU filters will require fewer change-outs than standard filters and could be a cost-effective method for preventing exposure to Legionella and other opportunistic waterborne pathogens in hospitals with high-risk patients.
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Affiliation(s)
- Julianne L Baron
- Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA; Special Pathogens Laboratory, Pittsburgh, PA
| | | | | | | | - Janet E Stout
- Special Pathogens Laboratory, Pittsburgh, PA; Department of Civil and Environmental Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA.
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Evidence for grow-through penetration of 0.2-μm-pore-size filters by Serratia marcescens and Brevundimonas diminuta. ACTA ACUST UNITED AC 2013; 40:327-34. [DOI: 10.1007/s10295-013-1232-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 01/17/2013] [Indexed: 11/27/2022]
Abstract
Abstract
We find that both Brevundimonas diminuta and Serratia marcescens can grow through sterilizing grade filter membranes of different membrane polymer compositions. Although this passage does not occur on a consistent basis, generation of “grow-through positive” results indicate that grow-through can occur stochastically at basal levels. This observation argues that the following risk mitigation strategies during pharmaceutical aseptic processing are warranted: minimization of processing times, and monitoring, minimizing and characterizing pre–filter bioburden.
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