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Pal P, Pramanik K, Ghosh SK, Mondal S, Mondal T, Soren T, Maiti TK. Molecular and eco-physiological responses of soil-borne lead (Pb 2+)-resistant bacteria for bioremediation and plant growth promotion under lead stress. Microbiol Res 2024; 287:127831. [PMID: 39079267 DOI: 10.1016/j.micres.2024.127831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 06/25/2024] [Accepted: 07/01/2024] [Indexed: 08/22/2024]
Abstract
Lead (Pb) is the 2nd known portentous hazardous substance after arsenic (As). Being highly noxious, widespread, non-biodegradable, prolonged environmental presence, and increasing accumulation, particularly in arable land, Pb pollution has become a serious global health concern requiring urgent remediation. Soil-borne, indigenous microbes from Pb-polluted sites have evolved diverse resistance strategies, involving biosorption, bioprecipitation, biomineralization, biotransformation, and efflux mechanisms, under continuous exposure to Pb in human-impacted surroundings. These strategies employ a wide range of functional bioligands to capture Pb and render it inaccessible for leaching. Recent breakthroughs in molecular technology and understanding of lead resistance mechanisms offer the potential for utilizing microbes as biological tools in environmental risk assessment. Leveraging the specific affinity and sensitivity of bacterial regulators to Pb2+ ions, numerous lead biosensors have been designed and deployed worldwide to monitor Pb bioavailability in contaminated sites, even at trace levels. Besides, the ongoing degradation of croplands due to Pb pollution poses a significant challenge to meet the escalating global food demands. The accumulation of Pb in plant tissues jeopardizes both food safety and security while severely impacting plant growth. Exploring Pb-resistant plant growth-promoting rhizobacteria (PGPR) presents a promising sustainable approach to agricultural practices. The active associations of PGPR with host plants have shown enhancements in plant biomass and stress alleviation under Pb influence. They thus serve a dual purpose for plants grown in Pb-contaminated areas. This review aims to offer a comprehensive understanding of the role played by Pb-resistant soil-borne indigenous bacteria in expediting bioremediation and improving the growth of Pb-challenged plants essential for potential field application, thus broadening prospects for future research and development.
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Affiliation(s)
- Priyanka Pal
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India
| | - Krishnendu Pramanik
- Department of Botany, Cooch Behar Panchanan Barma University, Panchanan Nagar, Vivekananda Street, Cooch Behar, West Bengal 736101, India
| | - Sudip Kumar Ghosh
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India
| | - Sayanta Mondal
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India
| | - Tanushree Mondal
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India
| | - Tithi Soren
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India
| | - Tushar Kanti Maiti
- Microbiology Laboratory, CAS, Department of Botany, Burdwan University, Burdwan, West Bengal 713104, India.
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Guo Y, Hu SY, Wu C, Gao CX, Hui CY. Biosynthesis of Indigo Dyes and Their Application in Green Chemical and Visual Biosensing for Heavy Metals. ACS OMEGA 2024; 9:33868-33881. [PMID: 39130558 PMCID: PMC11308077 DOI: 10.1021/acsomega.4c03613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 08/13/2024]
Abstract
Fermentative production of natural colorants using microbial strains has emerged as a cost-effective and sustainable alternative to chemical synthesis. Visual pigments are used as signal outputs in colorimetric bacterial biosensors, a promising method for monitoring environmental pollutants. In this study, we engineered four self-sufficient indigo-forming enzymes, including HbpAv, bFMO, cFMO, and rFPMO, in a model bacterium E. coli. TrxA-bFMO was chosen for its strong ability to produce indigo under T7 lac and mer promoters' regulation. The choice of bacterial hosts, the supplementation of substrate l-tryptophan, and ventilation were crucial factors affecting indigo production. The indigo reporter validated the biosensors for Hg(II), Pb(II), As(III), and Cd(II). The biosensors reported Hg(II) as low as 14.1 nM, Pb(II) as low as 1.5 nM, and As(III) as low as 4.5 nM but increased to 25 μM for Cd(II). The detection ranges for Hg(II), Pb(II), As(III), and Cd(II) were quantified from 14.1 to 225 nM, 1.5 to 24.4 nM, 4.5 to 73.2 nM, and 25 to 200 μM, respectively. The sensitivity, responsive concentration range, and selectivity are comparable to β-galactosidase and luciferase reporter enzymes. This study suggests that engineered enzymes for indigo production have great potential for green chemical synthesis. Additionally, heterologous biosynthesis of indigo production can lead to the development of novel, low-cost, and mini-equipment bacterial biosensors with zero background noise for visual monitoring of pollutant heavy metals.
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Affiliation(s)
- Yan Guo
- National
Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen 518020, China
| | - Shun-Yu Hu
- Department
of Pathology and Toxicology, Shenzhen Prevention
and Treatment Center for Occupational Diseases, Shenzhen 518020, China
- Department
of Toxicology, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Can Wu
- Department
of Pathology and Toxicology, Shenzhen Prevention
and Treatment Center for Occupational Diseases, Shenzhen 518020, China
- Department
of Environmental Health, School of Public Health, Southern Medical University, Guangzhou 510515, China
| | - Chao-Xian Gao
- Department
of Pathology and Toxicology, Shenzhen Prevention
and Treatment Center for Occupational Diseases, Shenzhen 518020, China
| | - Chang-Ye Hui
- Department
of Pathology and Toxicology, Shenzhen Prevention
and Treatment Center for Occupational Diseases, Shenzhen 518020, China
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Hui CY, Liu MQ, Guo Y. Synthetic bacteria designed using ars operons: a promising solution for arsenic biosensing and bioremediation. World J Microbiol Biotechnol 2024; 40:192. [PMID: 38709285 DOI: 10.1007/s11274-024-04001-2] [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: 03/18/2024] [Accepted: 04/22/2024] [Indexed: 05/07/2024]
Abstract
The global concern over arsenic contamination in water due to its natural occurrence and human activities has led to the development of innovative solutions for its detection and remediation. Microbial metabolism and mobilization play crucial roles in the global cycle of arsenic. Many microbial arsenic-resistance systems, especially the ars operons, prevalent in bacterial plasmids and genomes, play vital roles in arsenic resistance and are utilized as templates for designing synthetic bacteria. This review novelty focuses on the use of these tailored bacteria, engineered with ars operons, for arsenic biosensing and bioremediation. We discuss the advantages and disadvantages of using synthetic bacteria in arsenic pollution treatment. We highlight the importance of genetic circuit design, reporter development, and chassis cell optimization to improve biosensors' performance. Bacterial arsenic resistances involving several processes, such as uptake, transformation, and methylation, engineered in customized bacteria have been summarized for arsenic bioaccumulation, detoxification, and biosorption. In this review, we present recent insights on the use of synthetic bacteria designed with ars operons for developing tailored bacteria for controlling arsenic pollution, offering a promising avenue for future research and application in environmental protection.
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Affiliation(s)
- Chang-Ye Hui
- Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China.
| | - Ming-Qi Liu
- Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
- School of Public Health, Guangdong Medical University, Dongguan, China
| | - Yan Guo
- Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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Muñoz-Muñoz PLA, Terán-Ramírez C, Mares-Alejandre RE, Márquez-González AB, Madero-Ayala PA, Meléndez-López SG, Ramos-Ibarra MA. Surface Engineering of Escherichia coli to Display Its Phytase (AppA) and Functional Analysis of Enzyme Activities. Curr Issues Mol Biol 2024; 46:3424-3437. [PMID: 38666945 PMCID: PMC11048855 DOI: 10.3390/cimb46040215] [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: 03/18/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Escherichia coli phytase (AppA) is widely used as an exogenous enzyme in monogastric animal feed mainly because of its ability to degrade phytic acid or its salt (phytate), a natural source of phosphorus. Currently, successful recombinant production of soluble AppA has been achieved by gene overexpression using both bacterial and yeast systems. However, some methods for the biomembrane immobilization of phytases (including AppA), such as surface display on yeast cells and bacterial spores, have been investigated to avoid expensive enzyme purification processes. This study explored a homologous protein production approach for displaying AppA on the cell surface of E. coli by engineering its outer membrane (OM) for extracellular expression. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of total bacterial lysates and immunofluorescence microscopy of non-permeabilized cells revealed protein expression, whereas activity assays using whole cells or OM fractions indicated functional enzyme display, as evidenced by consistent hydrolytic rates on typical substrates (i.e., p-nitrophenyl phosphate and phytic acid). Furthermore, the in vitro results obtained using a simple method to simulate the gastrointestinal tract of poultry suggest that the whole-cell biocatalyst has potential as a feed additive. Overall, our findings support the notion that biomembrane-immobilized enzymes are reliable for the hydrolysis of poorly digestible substrates relevant to animal nutrition.
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Affiliation(s)
- Patricia L. A. Muñoz-Muñoz
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
| | - Celina Terán-Ramírez
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
- Biochemical Sciences Graduate Program (Doctorate Studies), National Autonomous University of Mexico, Cuernavaca 62210, MOR, Mexico
| | - Rosa E. Mares-Alejandre
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
| | - Ariana B. Márquez-González
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
- Biological and Biomedical Sciences Graduate Program (Doctorate Studies), University of North Carolina, Chapel Hill, NC 27599, USA
| | - Pablo A. Madero-Ayala
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
- Science and Engineering Graduate Program (Doctorate Studies), Autonomous University of Baja California, Tijuana 22390, BCN, Mexico
| | - Samuel G. Meléndez-López
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
| | - Marco A. Ramos-Ibarra
- Biotechnology and Biosciences Research Group, School of Chemical Sciences and Engineering, Autonomous University of Baja California, Tijuana 22390, BCN, Mexico; (P.L.A.M.-M.); (C.T.-R.); (R.E.M.-A.); (A.B.M.-G.); (P.A.M.-A.); (S.G.M.-L.)
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Hui CY, Ma BC, Hu SY, Wu C. Tailored bacteria tackling with environmental mercury: Inspired by natural mercuric detoxification operons. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:123016. [PMID: 38008253 DOI: 10.1016/j.envpol.2023.123016] [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: 08/01/2023] [Revised: 10/30/2023] [Accepted: 11/19/2023] [Indexed: 11/28/2023]
Abstract
Mercury (Hg) and its inorganic and organic compounds significantly threaten the ecosystem and human health. However, the natural and anthropogenic Hg environmental inputs exceed 5000 metric tons annually. Hg is usually discharged in elemental or ionic forms, accumulating in surface water and sediments where Hg-methylating microbes-mediated biotransformation occurs. Microbial genetic factors such as the mer operon play a significant role in the complex Hg biogeochemical cycle. Previous reviews summarize the fate of environmental Hg, its biogeochemistry, and the mechanism of bacterial Hg resistance. This review mainly focuses on the mer operon and its components in detecting, absorbing, bioaccumulating, and detoxifying environmental Hg. Four components of the mer operon, including the MerR regulator, divergent mer promoter, and detoxification factors MerA and MerB, are rare bio-parts for assembling synthetic bacteria, which tackle pollutant Hg. Bacteria are designed to integrate synthetic biology, protein engineering, and metabolic engineering. In summary, this review highlights that designed bacteria based on the mer operon can potentially sense and bioremediate pollutant Hg in a green and low-cost manner.
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Affiliation(s)
- Chang-Ye Hui
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen, 518020, China.
| | - Bing-Chan Ma
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen, 518020, China; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, China
| | - Shun-Yu Hu
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen, 518020, China; Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, 510515, China
| | - Can Wu
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen, 518020, China; Department of Toxicology, School of Public Health, Southern Medical University, Guangzhou, 510515, China
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Hui CY, Ma BC, Wang YQ, Yang XQ, Cai JM. Designed bacteria based on natural pbr operons for detecting and detoxifying environmental lead: A mini-review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 267:115662. [PMID: 37939554 DOI: 10.1016/j.ecoenv.2023.115662] [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: 09/30/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 11/10/2023]
Abstract
Lead (Pb), a naturally occurring element, is redistributed in the environment mainly due to anthropogenic activities. Pb pollution is a crucial public health problem worldwide due to its adverse effects. Environmental bacteria have evolved various protective mechanisms against high levels of Pb. The pbr operon, first identified in Cupriavidus metallidurans CH34, encodes a unique Pb(II) resistance mechanism involving transport, efflux, sequestration, biomineralization, and precipitation. Similar pbr operons are gradually found in diverse bacterial strains. This review focuses on the pbr-encoded Pb(II) resistance system. It summarizes various whole-cell biosensors harboring artificially designed pbr operons for Pb(II) biomonitoring with fluorescent, luminescent, and colorimetric signal output. Optimization of genetic circuits, employment of pigment-based reporters, and screening of host cells are promising in improving the sensitivity, selectivity, and response range of whole-cell biosensors. Engineered bacteria displaying Pb(II) binding and sequestration proteins, including PbrR and its derivatives, PbrR2 and PbrD, for adsorption are involved. Although synthetic bacteria show great potential in determining and removing Pb at the nanomolar level for environmental protection and food safety, some challenges must be addressed to meet demanding application requirements.
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Affiliation(s)
- Chang-Ye Hui
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen 518020, China.
| | - Bing-Chan Ma
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen 518020, China; School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan 430030, China
| | - Yong-Qiang Wang
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen 518020, China
| | - Xue-Qin Yang
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen 518020, China
| | - Jin-Min Cai
- Shenzhen Prevention and Treatment Center for Occupational Diseases, 2019 Buxin Road, Shenzhen 518020, China
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Lin Y, Shi J, Feng W, Yue J, Luo Y, Chen S, Yang B, Jiang Y, Hu H, Zhou C, Shi F, Prominski A, Talapin DV, Xiong W, Gao X, Tian B. Periplasmic biomineralization for semi-artificial photosynthesis. SCIENCE ADVANCES 2023; 9:eadg5858. [PMID: 37478187 PMCID: PMC10361601 DOI: 10.1126/sciadv.adg5858] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 06/21/2023] [Indexed: 07/23/2023]
Abstract
Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the periplasmic space, characterized by its confinement and the presence of numerous enzymes and peptidoglycans, offers additional opportunities for biomineralization, allowing for nongenetic modulation interfaces. We demonstrate semiconductor nanocluster precipitation containing single- and multiple-metal elements within the periplasm, as observed through various electron- and x-ray-based imaging techniques. The periplasmic semiconductors are metastable and display defect-dominant fluorescent properties. Unexpectedly, the defect-rich (i.e., the low-grade) semiconductor nanoclusters produced in situ can still increase adenosine triphosphate levels and malate production when coupled with photosensitization. We expand the sustainability levels of the biohybrid system to include reducing heavy metals at the primary level, building living bioreactors at the secondary level, and creating semi-artificial photosynthesis at the tertiary level. The biomineralization-enabled periplasmic biohybrids have the potential to serve as defect-tolerant platforms for diverse sustainable applications.
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Affiliation(s)
- Yiliang Lin
- The James Franck Institute, University of Chicago, Chicago, IL 60637, USA
| | - Jiuyun Shi
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Wei Feng
- Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, and Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518000, China
| | - Jiping Yue
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Yanqi Luo
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Si Chen
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Bin Yang
- Bioscience Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Yuanwen Jiang
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Huicheng Hu
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Chenkun Zhou
- The James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Fengyuan Shi
- Electron Microscopy Core, University of Illinois Chicago, Chicago, IL 60607, USA
| | | | - Dmitri V. Talapin
- The James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Wei Xiong
- Bioscience Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Xiang Gao
- The James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, and Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518000, China
| | - Bozhi Tian
- The James Franck Institute, University of Chicago, Chicago, IL 60637, USA
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
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Thai TD, Lim W, Na D. Synthetic bacteria for the detection and bioremediation of heavy metals. Front Bioeng Biotechnol 2023; 11:1178680. [PMID: 37122866 PMCID: PMC10133563 DOI: 10.3389/fbioe.2023.1178680] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 05/02/2023] Open
Abstract
Toxic heavy metal accumulation is one of anthropogenic environmental pollutions, which poses risks to human health and ecological systems. Conventional heavy metal remediation approaches rely on expensive chemical and physical processes leading to the formation and release of other toxic waste products. Instead, microbial bioremediation has gained interest as a promising and cost-effective alternative to conventional methods, but the genetic complexity of microorganisms and the lack of appropriate genetic engineering technologies have impeded the development of bioremediating microorganisms. Recently, the emerging synthetic biology opened a new avenue for microbial bioremediation research and development by addressing the challenges and providing novel tools for constructing bacteria with enhanced capabilities: rapid detection and degradation of heavy metals while enhanced tolerance to toxic heavy metals. Moreover, synthetic biology also offers new technologies to meet biosafety regulations since genetically modified microorganisms may disrupt natural ecosystems. In this review, we introduce the use of microorganisms developed based on synthetic biology technologies for the detection and detoxification of heavy metals. Additionally, this review explores the technical strategies developed to overcome the biosafety requirements associated with the use of genetically modified microorganisms.
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Brandenberg OF, Schubert OT, Kruglyak L. Towards synthetic PETtrophy: Engineering Pseudomonas putida for concurrent polyethylene terephthalate (PET) monomer metabolism and PET hydrolase expression. Microb Cell Fact 2022; 21:119. [PMID: 35717313 PMCID: PMC9206389 DOI: 10.1186/s12934-022-01849-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Biocatalysis offers a promising path for plastic waste management and valorization, especially for hydrolysable plastics such as polyethylene terephthalate (PET). Microbial whole-cell biocatalysts for simultaneous PET degradation and growth on PET monomers would offer a one-step solution toward PET recycling or upcycling. We set out to engineer the industry-proven bacterium Pseudomonas putida for (i) metabolism of PET monomers as sole carbon sources, and (ii) efficient extracellular expression of PET hydrolases. We pursued this approach for both PET and the related polyester polybutylene adipate co-terephthalate (PBAT), aiming to learn about the determinants and potential applications of bacterial polyester-degrading biocatalysts. RESULTS P. putida was engineered to metabolize the PET and PBAT monomer terephthalic acid (TA) through genomic integration of four tphII operon genes from Comamonas sp. E6. Efficient cellular TA uptake was enabled by a point mutation in the native P. putida membrane transporter MhpT. Metabolism of the PET and PBAT monomers ethylene glycol and 1,4-butanediol was achieved through adaptive laboratory evolution. We then used fast design-build-test-learn cycles to engineer extracellular PET hydrolase expression, including tests of (i) the three PET hydrolases LCC, HiC, and IsPETase; (ii) genomic versus plasmid-based expression, using expression plasmids with high, medium, and low cellular copy number; (iii) three different promoter systems; (iv) three membrane anchor proteins for PET hydrolase cell surface display; and (v) a 30-mer signal peptide library for PET hydrolase secretion. PET hydrolase surface display and secretion was successfully engineered but often resulted in host cell fitness costs, which could be mitigated by promoter choice and altering construct copy number. Plastic biodegradation assays with the best PET hydrolase expression constructs genomically integrated into our monomer-metabolizing P. putida strains resulted in various degrees of plastic depolymerization, although self-sustaining bacterial growth remained elusive. CONCLUSION Our results show that balancing extracellular PET hydrolase expression with cellular fitness under nutrient-limiting conditions is a challenge. The precise knowledge of such bottlenecks, together with the vast array of PET hydrolase expression tools generated and tested here, may serve as a baseline for future efforts to engineer P. putida or other bacterial hosts towards becoming efficient whole-cell polyester-degrading biocatalysts.
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Affiliation(s)
- Oliver F Brandenberg
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
| | - Olga T Schubert
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.,Department of Environmental Microbiology, EAWAG, 8600, Dübendorf, Switzerland.,Department of Environmental Systems Science, ETH Zurich, 8092, Zürich, Switzerland
| | - Leonid Kruglyak
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
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Hui CY, Guo Y, Li H, Chen YT, Yi J. Differential Detection of Bioavailable Mercury and Cadmium Based on a Robust Dual-Sensing Bacterial Biosensor. Front Microbiol 2022; 13:846524. [PMID: 35495723 PMCID: PMC9043898 DOI: 10.3389/fmicb.2022.846524] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/17/2022] [Indexed: 11/22/2022] Open
Abstract
Genetically programmed biosensors have been widely used to monitor bioavailable heavy metal pollutions in terms of their toxicity to living organisms. Most bacterial biosensors were initially designed to detect specific heavy metals such as mercury and cadmium. However, most available biosensors failed to distinguish cadmium from various heavy metals, especially mercury. Integrating diverse sensing elements into a single genetic construct or a single host strain has been demonstrated to quantify several heavy metals simultaneously. In this study, a dual-sensing construct was assembled by employing mercury-responsive regulator (MerR) and cadmium-responsive regulator (CadR) as the separate sensory elements and enhanced fluorescent protein (eGFP) and mCherry red fluorescent protein (mCherry) as the separate reporters. Compared with two corresponding single-sensing bacterial sensors, the dual-sensing bacterial sensor emitted differential double-color fluorescence upon exposure to 0–40 μM toxic Hg(II) and red fluorescence upon exposure to toxic Cd(II) below 200 μM. Bioavailable Hg(II) could be quantitatively determined using double-color fluorescence within a narrow concentration range (0–5 μM). But bioavailable Cd(II) could be quantitatively measured using red fluorescence over a wide concentration range (0–200 μM). The dual-sensing biosensor was applied to detect bioavailable Hg(II) and Cd(II) simultaneously. Significant higher red fluorescence reflected the predominant pollution of Cd(II), and significant higher green fluorescence suggested the predominant pollution of Hg(II). Our findings show that the synergistic application of various sensory modules contributes to an efficient biological device that responds to concurrent heavy metal pollutants in the environment.
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Affiliation(s)
- Chang-Ye Hui
- Department of Pathology and Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Han Li
- College of Lab Medicine, Hebei North University, Zhangjiakou, China
| | - Yu-Ting Chen
- Department of Pathology and Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Juan Yi
- Department of Pathology and Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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11
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Detection of environmental pollutant cadmium in water using a visual bacterial biosensor. Sci Rep 2022; 12:6898. [PMID: 35477977 PMCID: PMC9046199 DOI: 10.1038/s41598-022-11051-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/18/2022] [Indexed: 11/10/2022] Open
Abstract
Cadmium (Cd) contamination in water and soil is considered an environmental pollutant. Food crops can absorb and accumulate bioavailable Cd. Continuous monitoring of Cd levels in the environment can minimize exposure and harm to humans. Visual pigments have been demonstrated to have great potential in the development of minimal-equipment biosensors. In the present study, a metabolically engineered bacterium was employed to produce blue-purple pigment violacein responsive to toxic Cd(II). The high stability of the bisindole pigment contributed to determining the violacein at wavelengths of 578 nm. Visual and quantifiable signals could be captured after a 1.5-h Cd(II) exposure. This novel biosensor showed significantly stronger responses to Cd(II) than to other heavy metals including Pb(II), Zn(II), and Hg(II). A significant increase in pigment signal was found to respond to as low as 0.049 μM Cd(II). The naked eye can detect the color change when violacein-based biosensor is exposed to 25 μM Cd(II). A high-throughput method for rapid determination of soluble Cd(II) in environmental water was developed using a colorimetric microplate.
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12
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Hui CY, Guo Y, Liu L, Yi J. Recent advances in bacterial biosensing and bioremediation of cadmium pollution: a mini-review. World J Microbiol Biotechnol 2021; 38:9. [PMID: 34850291 DOI: 10.1007/s11274-021-03198-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/23/2021] [Indexed: 12/27/2022]
Abstract
Cadmium (Cd) pollution has become a global environmental issue because Cd gets easily accumulated and translocated in the food chain, threatening human health. Considering the detrimental effects and non-biodegradability of environmental Cd, this is an urgent issue that needs to be addressed through the development of robust, cost-effective, and eco-friendly green routes for monitoring and remediating toxic levels of Cd. This article attempts to review various bacterial approaches toward biosensing and bioremediation of Cd in the environment. This review focuses on the recent development of bacterial cell-based biosensors for the detection of bioavailable Cd and the bioremediation of toxic Cd by natural or genetically-engineered bacteria. The present limitations and future perspectives of these available bacterial approaches are outlined. New trends for integrating synthetic biology and metabolic engineering into the design of bacterial biosensors and bioadsorbers are additionally highlighted.
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Affiliation(s)
- Chang-Ye Hui
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China.
| | - Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Lisa Liu
- Lewis Katz School of Medicine, Temple University, Pennsylvania, USA
| | - Juan Yi
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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13
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Hui CY, Guo Y, Wu J, Liu L, Yang XQ, Guo X, Xie Y, Yi J. Detection of Bioavailable Cadmium by Double-Color Fluorescence Based on a Dual-Sensing Bioreporter System. Front Microbiol 2021; 12:696195. [PMID: 34603225 PMCID: PMC8481780 DOI: 10.3389/fmicb.2021.696195] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/18/2021] [Indexed: 01/04/2023] Open
Abstract
Cadmium (Cd) is carcinogenic to humans and can accumulate in the liver, kidneys, and bones. There is widespread presence of cadmium in the environment as a consequence of anthropogenic activities. It is important to detect cadmium in the environment to prevent further exposure to humans. Previous whole-cell biosensor designs were focused on single-sensing constructs but have had difficulty in distinguishing cadmium from other metal ions such as lead (Pb) and mercury (Hg). We developed a dual-sensing bacterial bioreporter system to detect bioavailable cadmium by employing CadC and CadR as separate metal sensory elements and eGFP and mCherry as fluorescent reporters in one genetic construct. The capability of this dual-sensing biosensor was proved to simultaneously detect bioavailable cadmium and its toxic effects using two sets of sensing systems while still maintaining similar specificity and sensitivity of respective signal-sensing biosensors. The productions of double-color fluorescence were directly proportional to the exposure concentration of cadmium, thereby serving as an effective quantitative biosensor to detect bioavailable cadmium. This novel dual-sensing biosensor was then validated to respond to Cd(II) spiked in environmental water samples. This is the first report of the development of a novel dual-sensing, whole-cell biosensor for simultaneous detection of bioavailable cadmium. The application of two biosensing modules provides versatile biosensing signals and improved performance that can make a significant impact on monitoring high concentration of bioavailable Cd(II) in environmental water to reduce human exposure to the harmful effects of cadmium.
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Affiliation(s)
- Chang-ye Hui
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Jian Wu
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Lisa Liu
- Lewis Katz School of Medicine, Temple University, Ambler, PA, United States
| | - Xue-qin Yang
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Xiang Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Ying Xie
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Juan Yi
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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14
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Hui CY, Guo Y, Li LM, Liu L, Chen YT, Yi J, Zhang NX. Indigoidine biosynthesis triggered by the heavy metal-responsive transcription regulator: a visual whole-cell biosensor. Appl Microbiol Biotechnol 2021; 105:6087-6102. [PMID: 34291315 DOI: 10.1007/s00253-021-11441-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/22/2021] [Accepted: 07/03/2021] [Indexed: 10/20/2022]
Abstract
During the last few decades, whole-cell biosensors have attracted increasing attention for their enormous potential in monitoring bioavailable heavy metal contaminations in the ecosystem. Visual and measurable output signals by employing natural pigments have been demonstrated to offer another potential choice to indicate the existence of bioavailable heavy metals in recent years. The biosynthesis of the blue pigment indigoidine has been achieved in E. coli following heterologous expression of both BpsA (a single-module non-ribosomal peptide synthetase) and PcpS (a PPTase to activate apo-BpsA). Moreover, we demonstrated herein the development of the indigoidine-based whole-cell biosensors to detect bioavailable Hg(II) and Pb(II) in water samples by employing metal-responsive transcriptional regulator MerR and PbrR as the sensory elements, and the indigoidine biosynthesis gene cluster as a reporter element. The resulting indigoidine-based biosensors presented a good selectivity and high sensitivity to target metal ions. High concentration of target metal exposure could be clearly recognized by the naked eye due to the color change by the secretion of indigoidine, and quantified by measuring the absorbance of the culture supernatants at 600 nm. Dose-response relationships existed between the exposure concentrations of target heavy metals and the production of indigoidine. Although fairly good linear relationships were obtained in a relatively limited concentration range of the concentrations of heavy metal ions, these findings suggest that genetically controlled indigoidine biosynthesis triggered by the MerR family transcriptional regulator can enable a sensitive, visual, and qualitative whole-cell biosensor for bioindicating the presence of bioaccessible heavy metal in environmental water samples. KEY POINTS: • Biosynthesis pathway of indigoidine reconstructed in a high copy number plasmid in E. coli. • Visual and colorimetric detection of Hg(II) and Pb(II) by manipulation of indigoidine biosynthesis through MerR family metalloregulator. •Enhanced detection sensitivity toward Hg(II) and Pb(II) achieved using novel pigment-based whole-cell biosensors.
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Affiliation(s)
- Chang-Ye Hui
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China.
| | - Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Li-Mei Li
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Lisa Liu
- Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Yu-Ting Chen
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Juan Yi
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Nai-Xing Zhang
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China.
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15
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Guo Y, Hui CY, Liu L, Chen MP, Huang HY. Development of a bioavailable Hg(II) sensing system based on MerR-regulated visual pigment biosynthesis. Sci Rep 2021; 11:13516. [PMID: 34188121 PMCID: PMC8242042 DOI: 10.1038/s41598-021-92878-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/14/2021] [Indexed: 12/02/2022] Open
Abstract
Engineered microorganisms have proven to be a highly effective and robust tool to specifically detect heavy metals in the environment. In this study, a highly specific pigment-based whole-cell biosensor has been investigated for the detection of bioavailable Hg(II) based on an artificial heavy metal resistance operon. The basic working principle of biosensors is based on the violacein biosynthesis under the control of mercury resistance (mer) promoter and mercury resistance regulator (MerR). Engineered biosensor cells have been demonstrated to selectively respond to Hg(II), and the specific response was not influenced by interfering metal ions. The response of violacein could be recognized by the naked eye, and the time required for the maximum response of violacein (5 h) was less than that of enhanced green fluorescence protein (eGFP) (8 h) in the single-signal output constructs. The response of violacein was almost unaffected by the eGFP in a double-promoter controlled dual-signals output construct. However, the response strength of eGFP was significantly decreased in this genetic construct. Exponentially growing violacein-based biosensor detected concentrations as low as 0.39 μM Hg(II) in a colorimetric method, and the linear relationship was observed in the concentration range of 0.78-12.5 μM. Non-growing biosensor cells responded to concentrations as low as 0.006 μM Hg(II) in a colorimetric method and in a Hg(II) containing plate sensitive assay, and the linear relationship was demonstrated in a very narrow concentration range. The developed biosensor was finally validated for the detection of spiked bioavailable Hg(II) in environmental water samples.
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Affiliation(s)
- Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Chang-Ye Hui
- Department of Pathology and Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China.
| | - Lisa Liu
- Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Min-Peng Chen
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Hong-Ying Huang
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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16
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Zhang NX, Guo Y, Li H, Yang XQ, Gao CX, Hui CY. Versatile artificial mer operons in Escherichia coli towards whole cell biosensing and adsorption of mercury. PLoS One 2021; 16:e0252190. [PMID: 34038487 PMCID: PMC8153442 DOI: 10.1371/journal.pone.0252190] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/11/2021] [Indexed: 01/17/2023] Open
Abstract
Mercury exists naturally and mainly as a man-made pollutant in the environment, where it exerts adverse effects on local ecosystems and living organisms. It is important to develop an appropriate synthetic biological device that recognizes, detects and removes the bioavailable fraction of environmental mercury. Both single-signal and double-signal output mercury biosensors were assembled using a natural mer operon as a template. Selectivity and sensitivity of whole-cell biosensors based on artificial mer operons were determined. Three whole-cell biosensors were highly stable at very high concentrations of mercuric chloride, and could detect bioavailable Hg(II) in the concentration range of 6.25-200 μM HgCl2. A novel Hg(II) bioadsorption coupled with biosensing artificial mer operon was assembled. This would allow Hg(II)-induced Hg(II) binding protein cell surface display and green fluorescence emission to be achieved simultaneously while retaining the linear relationship between fluorescent signal and Hg(II) exposure concentration. The present study provides an innovative way to simultaneously detect, quantify, and remove bioavailable heavy metal ions using an artificially reconstructed heavy metal resistance operon.
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Affiliation(s)
- Nai-xing Zhang
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Hui Li
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Xue-Qin Yang
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Chao-xian Gao
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Chang-ye Hui
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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17
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Chen X, Yang J, Ling Z, Zhou T, Zhou B, Wang H, Li X, Liu P. Gut Escherichia coli expressing Pb 2+-adsorption protein reduces lead accumulation in grass carp, Ctenopharyngodon idellus. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116634. [PMID: 33592445 DOI: 10.1016/j.envpol.2021.116634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Lead (Pb2+) is easy to accumulate in fish which become a major source of Pb2+ exposure to humans. In this study, a recombinant Escherichia coli strain expressing Pb2+-specific surface-binding protein anchored by the ice nucleation protein was introduced into grass carp (Ctenopharyngodon idellus) gut to investigate its protective effect against dietary Pb2+ exposure. Pb2+ mostly precipitated on the surface of the engineered strain through Pb2+-specific surface-binding protein, with a maximum adsorption efficiency of 73% and an adsorption capacity of 163 μmol/g dry cells. The Pb2+ concentration in engineered bacteria-fed grass carp was reduced significantly, and the residual level of Pb2+ in feces was increased by 76%, compared with the control group. Meantime, the engineered bacteria were able to mitigate the oxidative stress and histological alterations of intestines and dysbiosis of gut microbiota induced by Pb2+exposure. Thus, the engineered bacterium that can effectively reduce Pb2+ residue in grass carp might be a useful tool for decontamintion of lead in aquatic organisms.
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Affiliation(s)
- Xiao Chen
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China
| | - Jinfeng Yang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China
| | - Zhenmin Ling
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China
| | - Tuoyu Zhou
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China
| | - Bojian Zhou
- Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, PR China
| | - Haoyang Wang
- McMaster University, 303-2, 1100 Main Street West, Hamilton, Ontario, Canada
| | - Xiangkai Li
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China
| | - Pu Liu
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, 222 South Tianshui Rd, Lanzhou, Gansu, 730000, PR China.
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18
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Guo Y, Hui CY, Zhang NX, Liu L, Li H, Zheng HJ. Development of Cadmium Multiple-Signal Biosensing and Bioadsorption Systems Based on Artificial Cad Operons. Front Bioeng Biotechnol 2021; 9:585617. [PMID: 33644011 PMCID: PMC7902519 DOI: 10.3389/fbioe.2021.585617] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 01/22/2021] [Indexed: 02/04/2023] Open
Abstract
The development of genetic engineering, especially synthetic biology, greatly contributes to the development of novel metal biosensors. The cad operon encoding cadmium resistance was previously characterized from Pseudomonas putida. In this study, single-, dual-, and triple-signal output Cd(II) biosensors were successfully developed using artificial translationally coupled cad operons. Sensitivity, selectivity, and response toward Cd(II) and Hg(II), of three biosensors were all determined. Reporter signals of three biosensors all increased within the range 0.1-3.125 μM Cd(II). Three biosensors responded strongly to Cd(II), and weakly to Hg(II). However, the detection ranges of Cd(II) and Hg(II) do not overlap in all three biosensors. Next, novel Cd(II) biosensing coupled with bioadsorptive artificial cad operons were assembled for the first time. Cd(II)-induced fluorescence emission, enzymatic indication, and Cd(II) binding protein surface display can be achieved simultaneously. This study provides an example of one way to realize multiple signal outputs and bioadsorption based on the redesigned heavy metal resistance operons, which may be a potential strategy for biodetection and removal of toxic metal in the environment, facilitating the study of the mechanism and dynamics of bioremediation.
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Affiliation(s)
- Yan Guo
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Chang-ye Hui
- Department of Pathology and Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Nai-xing Zhang
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Lisa Liu
- Institute of Translational Medicine, Shenzhen Second People's Hospital, Shenzhen, China
| | - Hui Li
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Hong-ju Zheng
- National Key Clinical Specialty of Occupational Diseases, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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19
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Liu J, Zhu N, Zhang Y, Ren T, Shao C, Shi R, Li X, Ju M, Ma T, Yu Q. Transcription profiling-guided remodeling of sulfur metabolism in synthetic bacteria for efficiently capturing heavy metals. JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123638. [PMID: 32805554 DOI: 10.1016/j.jhazmat.2020.123638] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/30/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Heavy metal contamination is becoming a global problem threatening human health. Heavy metal removal by engineered microbes by cellular adsorption and uptake is a promising strategy for treatment of heavy metal contamination. However, this strategy is confronted with limited heavy metal-capturing elements. In this study, we performed a transcription profiling-guided strategy for construction of heavy metal-capturing synthetic bacteria. Transcription profiling of a heavy metal-tolerating Cupriavidus taiwanensis strain revealed up-regulation of sulfur metabolism-related operons (e.g., iscSAU and moaEDAB) by Pb2+ and Cd2+. A synthetic Escherichia coli strain, EcSSMO, was constructed by design of a synthetic sulfur metabolism operon (SSMO) based on iscSAU/moaEDAB. Biochemical analysis and X-ray photoelectron spectroscopy (XPS) revealed that the synthetic bacteria had remodeled sulfur metabolism and enhanced heavy metal-tolerating capacity, with higher surviving EcSSMO cells than the surviving control cells Ec0 (not containing SSMO) at 50 mg/L of Pb2+ and Cd2+ (>92 % versus <10 %). Moreover, EcSSMO exhibited much higher heavy metal-capturing capacity than Ec0, removing>90 % of Pb2+ and Cd2+ at 5 mg/L of Pb2+ and Cd2+, and >40 % of both heavy metals even at 50 mg/L of Pb2+ and Cd2+. This study reveals emphasizes feasibility of transcription profiling-guided construction of synthetic organisms by large-scale remodeling metabolic network.
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Affiliation(s)
- Jinpeng Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Youjun Zhang
- Tianjin North China Geological Exploration Bureau, 67, Guang-rui-xi-lu Rd., Tianjin, 300170, China; School of Environmental Science and Engineering, Tianjin University, 92, Weijin Rd., Nankai District, 300350, China
| | - Tongtong Ren
- Beijing Institute of Biological Products Company, Beijing, China
| | - Chaofeng Shao
- National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Rongguang Shi
- Agro-environmental Protection Institute Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
| | - Xiaohua Li
- Rural Energy & Environment Agency, Ministry of Agriculture and Rural Affairs, Beijing, 100125, China
| | - Meiting Ju
- National & Local Joint Engineering Research Center on Biomass Resource Utilization, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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20
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Wang Y, Selvamani V, Yoo IK, Kim TW, Hong SH. A Novel Strategy for the Microbial Removal of Heavy Metals: Cell-surface Display of Peptides. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-020-0218-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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21
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Jia X, Li Y, Xu T, Wu K. Display of lead-binding proteins on Escherichia coli surface for lead bioremediation. Biotechnol Bioeng 2020; 117:3820-3834. [PMID: 32740905 DOI: 10.1002/bit.27525] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 07/29/2020] [Accepted: 07/31/2020] [Indexed: 12/21/2022]
Abstract
Cell surface display of heavy metal-binding proteins has been used to enhance the adsorption capacity of heavy metals and the engineered microbial cells can be potentially used for the bioremediation of heavy metals. In this study, the proteins PbrR, PbrR691, and PbrD from the Cupriavidus metallidurans strain CH34 were displayed on the extracellular membrane of Escherichia coli BL21 cells, with the N-domain of ice-nucleation protein as the anchor protein to achieve specific adsorption of lead ions (Pb2+ ) and bioremediation of lead in the soil. The localization of fusion proteins was confirmed by western blot analysis. We investigated the effects of fusion pattern, expression level, heavy metal concentration, and the presence of other heavy metal ions on the adsorption of Pb2+ by these engineered bacteria, and the optimal linker peptide (flexible linker) and inducer concentration (0.5 mM) were obtained. The engineered bacteria showed specific selectivity and strong adsorption capacity for Pb2+ . The maximum Pb2+ adsorption capacity of strains displaying the three proteins (PbrR, PbrR691, and PbrD) were 942.1-, 754.3-, and 864.8-μmol/g cell dry weight, respectively, which was the highest reported to date. The engineered E. coli bacteria were also applied to Pb2+ -contaminated soil and the detoxification effects were observed via the seed germination test and the growth of Nicotiana benthamiana in comparison with the control BL21, which provides the proof-of-concept for in situ remediations of Pb2+ -contaminated water or soil.
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Affiliation(s)
- Xiaoqiang Jia
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Frontier Science Center for Synthetic Biology, Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
| | - Ying Li
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Tao Xu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Kang Wu
- Department of Chemical Engineering, University of New Hampshire, Durham, New Hampshire
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22
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Guo Y, Hui CY, Liu L, Zheng HQ, Wu HM. Improved Monitoring of Low-Level Transcription in Escherichia coli by a β-Galactosidase α-Complementation System. Front Microbiol 2019; 10:1454. [PMID: 31297105 PMCID: PMC6607957 DOI: 10.3389/fmicb.2019.01454] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 06/11/2019] [Indexed: 01/02/2023] Open
Abstract
Genetically encoded reporter proteins are important and widely used tools for the identification and capture of a promoter, tracking the dynamic behavior of transcription, and the quantification of promoter activity. The sensitivity of the reporter gene is a critical factor for an ideal reporter system because weak transcriptional signal has usually failed to be detected using classical reporters. In this study, we present a novel reporter system for improved monitoring of transcription in E. coli based on β-galactosidase α-complementation. In this reporter system, the β-galactosidase activity resulting from the assembly of a reporter lacZα and an existing α-acceptor in advance serves as a measure of transcriptional activity in vivo. To validate the potential of the lacZα-derived reporter system, a series of artificial operons were constructed, and the moderately strong lac promoter, ara promoter, and weak pbr promoter were chosen as the detection promoters. The response profiles of lacZα was similar to that of wild type lacZ in artificial lac operons. Due to its small size and efficient expression profile, the detection sensitivity of a lacZα-derived reporter system was significantly higher than that of the traditional full-length β-galactosidase and the fluorescent protein mCherry reporter system in artificial ara operons. As expected, the response sensitivity of the lacZα-derived reporter system was also demonstrated to be significantly higher than that of the β-galactosidase and mCherry reporter systems in lead-sensitive artificial pbr operons. The lacZα-derived reporter system may prove to be a valuable tool for detecting promoter activity, especially low-level transcription in vivo.
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Affiliation(s)
- Yan Guo
- Department of Science & Education, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Chang-Ye Hui
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Lisa Liu
- Institute of Translational Medicine, Shenzhen Second People's Hospital, Shenzhen, China
| | - Hao-Qu Zheng
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
| | - Hong-Min Wu
- Department of Pathology & Toxicology, Shenzhen Prevention and Treatment Center for Occupational Diseases, Shenzhen, China
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Zhu B, Chen Y, Wei N. Engineering Biocatalytic and Biosorptive Materials for Environmental Applications. Trends Biotechnol 2019; 37:661-676. [DOI: 10.1016/j.tibtech.2018.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 10/27/2022]
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Development of a novel bacterial surface display system using truncated OmpT as an anchoring motif. Biotechnol Lett 2019; 41:763-777. [PMID: 31025146 DOI: 10.1007/s10529-019-02676-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 04/22/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVES An efficient bacterial surface display system based on the anchoring motif derived from Escherichia coli (E. coli) outer membrane protease OmpT was developed in this study. RESULTS Referring to the classical Lpp-OmpA (LOA) display system, the signal peptide and nine amino acids of mature Lpp were fused to the transmembrane domain comprising five β-strands of truncated OmpT to generate a novel Lpp-OmpT (LOT) display system. The C-terminal fusion strategy was used to fuse a small peptide (His tag) and red fluorescent protein (mCherry) to the C-terminus of LOT. Cell surface exposure of His tag and mCherry were compared between the LOA and LOT display systems. E. coli expressing LOT-His tag adsorbed more Cu2+ than E. coli expressing LOA-His tag. E. coli expressing both LOT-mCherry-His tag and LOA-mCherry-His tag adhered to Cu2+ chelating sepharose beads, and adhered cells could be dissociated from the beads after excess Cu2+ treatment. More importantly, compared with the LOA system, a higher amount of LOT-mCherry-His tag hybrid protein was demonstrated to be localized at the outer membrane by both fluorescence spectrophotometric determination of cell fractions and cell-surface immunofluorescence assay. CONCLUSIONS These results suggest that genetically modified OmpT can be used as a potential anchoring motif to efficiently and stably display polypeptides and proteins, and that the LOT system could be used in a variety of biotechnological and industrial processes.
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Hui CY, Guo Y, Zhang W, Huang XQ. Rapid monitoring of the target protein expression with a fluorescent signal based on a dicistronic construct in Escherichia coli. AMB Express 2018; 8:81. [PMID: 29785487 PMCID: PMC5962521 DOI: 10.1186/s13568-018-0612-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/12/2018] [Indexed: 01/02/2023] Open
Abstract
Real-time quantification of recombinant proteins is important in studies on fermentation engineering, cell engineering, etc. Measurement of the expression level of heterologous proteins in bacterial fermentation broth has traditionally relied on time-consuming and labor-intensive procedures, such as polyacrylamide gel electrophoresis, immunoblot analysis, and biological activity assays. We describe a simple, fast, and high sensitive assay for detecting heterologous proteins production in bacteria either at the overall level (fluorescence spectrophotometry) or at the individual level (fluorescence microscopic image) in this study. Based on a dicistronic model, the translation of target gene in the upstream open reading frame (ORF) was coupled with the synthesis of the mCherry reporter in the downstream ORF in E. coli cells, and subsequently this demonstrated a positive correlation between the expression of target gene and mCherry. Although a time lag exists between the expression of target protein and mCherry reporter, the method described here allows facile monitoring of dynamic changes in target protein expression, relying on indirect determination of the fluorescence intensity of mCherry during fermentation in real-time models. Additionally, the performance of a single bacterial cell factory could be checked under the fluorescence microscope field.
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