1
|
Ariaeenejad S, Gharechahi J, Foroozandeh Shahraki M, Fallah Atanaki F, Han JL, Ding XZ, Hildebrand F, Bahram M, Kavousi K, Hosseini Salekdeh G. Precision enzyme discovery through targeted mining of metagenomic data. NATURAL PRODUCTS AND BIOPROSPECTING 2024; 14:7. [PMID: 38200389 PMCID: PMC10781932 DOI: 10.1007/s13659-023-00426-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024]
Abstract
Metagenomics has opened new avenues for exploring the genetic potential of uncultured microorganisms, which may serve as promising sources of enzymes and natural products for industrial applications. Identifying enzymes with improved catalytic properties from the vast amount of available metagenomic data poses a significant challenge that demands the development of novel computational and functional screening tools. The catalytic properties of all enzymes are primarily dictated by their structures, which are predominantly determined by their amino acid sequences. However, this aspect has not been fully considered in the enzyme bioprospecting processes. With the accumulating number of available enzyme sequences and the increasing demand for discovering novel biocatalysts, structural and functional modeling can be employed to identify potential enzymes with novel catalytic properties. Recent efforts to discover new polysaccharide-degrading enzymes from rumen metagenome data using homology-based searches and machine learning-based models have shown significant promise. Here, we will explore various computational approaches that can be employed to screen and shortlist metagenome-derived enzymes as potential biocatalyst candidates, in conjunction with the wet lab analytical methods traditionally used for enzyme characterization.
Collapse
Affiliation(s)
- Shohreh Ariaeenejad
- Department of Systems and Synthetic Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Javad Gharechahi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mehdi Foroozandeh Shahraki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Fereshteh Fallah Atanaki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Jian-Lin Han
- Livestock Genetics Program, International Livestock Research, Institute (ILRI), Nairobi, 00100, Kenya
- CAAS-ILRI Joint Laboratory On Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - Xue-Zhi Ding
- Key Laboratory of Yak Breeding Engineering, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences (CAAS), Lanzhou, 730050, China
| | - Falk Hildebrand
- Gut Microbes and Health, Quadram Institute Bioscience, Norwich, Norfolk, UK
- Digital Biology, Earlham Institute, Norwich, Norfolk, UK
| | - Mohammad Bahram
- Department of Ecology, Swedish University of Agricultural Sciences, Ulls Väg 16, 756 51, Uppsala, Sweden
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, 40 Lai St, Tartu, Estonia
| | - Kaveh Kavousi
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
| | | |
Collapse
|
2
|
Pabbathi NPP, Velidandi A, Tavarna T, Gupta S, Raj RS, Gandam PK, Baadhe RR. Role of metagenomics in prospecting novel endoglucanases, accentuating functional metagenomics approach in second-generation biofuel production: a review. BIOMASS CONVERSION AND BIOREFINERY 2023; 13:1371-1398. [PMID: 33437563 PMCID: PMC7790359 DOI: 10.1007/s13399-020-01186-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/30/2020] [Accepted: 12/01/2020] [Indexed: 05/02/2023]
Abstract
As the fossil fuel reserves are depleting rapidly, there is a need for alternate fuels to meet the day to day mounting energy demands. As fossil fuel started depleting, a quest for alternate forms of fuel was initiated and biofuel is one of its promising outcomes. First-generation biofuels are made from edible sources like vegetable oils, starch, and sugars. Second-generation biofuels (SGB) are derived from lignocellulosic crops and the third-generation involves algae for biofuel production. Technical challenges in the production of SGB are hampering its commercialization. Advanced molecular technologies like metagenomics can help in the discovery of novel lignocellulosic biomass-degrading enzymes for commercialization and industrial production of SGB. This review discusses the metagenomic outcomes to enlighten the importance of unexplored habitats for novel cellulolytic gene mining. It also emphasizes the potential of different metagenomic approaches to explore the uncultivable cellulose-degrading microbiome as well as cellulolytic enzymes associated with them. This review also includes effective pre-treatment technology and consolidated bioprocessing for efficient biofuel production.
Collapse
Affiliation(s)
- Ninian Prem Prashanth Pabbathi
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Aditya Velidandi
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Tanvi Tavarna
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Shreyash Gupta
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Ram Sarvesh Raj
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Pradeep Kumar Gandam
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| | - Rama Raju Baadhe
- Integrated Biorefinery Research Lab, Department of Biotechnology, National Institute of Technology, Warangal, Telangana 506004 India
| |
Collapse
|
3
|
Liu Y, Angelov A, Feiler W, Baudrexl M, Zverlov V, Liebl W, Vanderhaeghen S. Arabinan saccharification by biogas reactor metagenome-derived arabinosyl hydrolases. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:121. [PMID: 36371193 PMCID: PMC9655821 DOI: 10.1186/s13068-022-02216-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Plant cell walls represent the most plentiful renewable organic resource on earth, but due to their heterogeneity, complex structure and partial recalcitrance, their use as biotechnological feedstock is still limited. RESULTS In order to identify efficient enzymes for polysaccharide breakdown, we have carried out functional screening of metagenomic fosmid libraries from biogas fermenter microbial communities grown on sugar beet pulp, an arabinan-rich agricultural residue, or other sources containing microbes that efficiently depolymerize polysaccharides, using CPH (chromogenic polysaccharide hydrogel) or ICB (insoluble chromogenic biomass) labeled polysaccharide substrates. Seventy-one depolymerase-encoding genes were identified from 55 active fosmid clones by using Illumina and Sanger sequencing and dbCAN CAZyme (carbohydrate-active enzyme) annotation. An around 56 kb assembled DNA fragment putatively originating from Xylanivirga thermophila strain or a close relative was analyzed in detail. It contained 48 ORFs (open reading frames), of which 31 were assigned to sugar metabolism. Interestingly, a large number of genes for enzymes putatively involved in degradation and utilization of arabinose-containing carbohydrates were found. Seven putative arabinosyl hydrolases from this DNA fragment belonging to glycoside hydrolase (GH) families GH51 and GH43 were biochemically characterized, revealing two with endo-arabinanase activity and four with exo-α-L-arabinofuranosidase activity but with complementary cleavage properties. These enzymes were found to act synergistically and can completely hydrolyze SBA (sugar beet arabinan) and DA (debranched arabinan). CONCLUSIONS We screened 32,776 fosmid clones from several metagenomic libraries with chromogenic lignocellulosic substrates for functional enzymes to advance the understanding about the saccharification of recalcitrant lignocellulose. Seven putative X. thermophila arabinosyl hydrolases were characterized for pectic substrate degradation. The arabinosyl hydrolases displayed maximum activity and significant long-term stability around 50 °C. The enzyme cocktails composed in this study fully degraded the arabinan substrates and thus could serve for arabinose production in food and biofuel industries.
Collapse
Affiliation(s)
- Yajing Liu
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: Chair of Chemistry of Biogenic Resources, Technical University of Munich, Schulgasse 16, 94315 Straubing, Germany
| | - Angel Angelov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: NGS Competence Center Tübingen, Universitätsklinikum Tübingen, Calwerstraße 7, 72076 Tübingen, Germany
| | - Werner Feiler
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Melanie Baudrexl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Vladimir Zverlov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Sonja Vanderhaeghen
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: IMGM Laboratories, Lochhamer Straße 29a, 82152 Planegg, Germany
| |
Collapse
|
4
|
Rafeeq H, Hussain A, Shabbir S, Ali S, Bilal M, Sher F, Iqbal HMN. Esterases as emerging biocatalysts: Mechanistic insights, genomic and metagenomic, immobilization, and biotechnological applications. Biotechnol Appl Biochem 2022; 69:2176-2194. [PMID: 34699092 DOI: 10.1002/bab.2277] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 10/20/2021] [Indexed: 02/05/2023]
Abstract
Esterase enzymes are a family of hydrolases that catalyze the breakdown and formation of ester bonds. Esterases have gained a prominent position in today's world's industrial enzymes market. Due to their unique biocatalytic attributes, esterases contribute to environmentally sustainable design approaches, including biomass degradation, food and feed industry, dairy, clothing, agrochemical (herbicides, insecticides), bioremediation, biosensor development, anticancer, antitumor, gene therapy, and diagnostic purposes. Esterases can be isolated by a diverse range of mammalian tissues, animals, and microorganisms. The isolation of extremophilic esterases increases the interest of researchers in the extraction and utilization of these enzymes at the industrial level. Genomic, metagenomic, and immobilization techniques have opened innovative ways to extract esterases and utilize them for a longer time to take advantage of their beneficial activities. The current study discusses the types of esterases, metagenomic studies for exploring new esterases, and their biomedical applications in different industrial sectors.
Collapse
Affiliation(s)
- Hamza Rafeeq
- Department of Biochemistry, Riphah International University, Faisalabad, Pakistan
| | - Asim Hussain
- Department of Biochemistry, Riphah International University, Faisalabad, Pakistan
| | - Sumaira Shabbir
- Department of Zoology, Wildlife, and Fisheries, University of Agriculture, Faisalabad, Pakistan
| | - Sabir Ali
- Department of Biochemistry, University of Agriculture, Faisalabad, Pakistan
| | - Muhammad Bilal
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, China
| | - Farooq Sher
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Hafiz M N Iqbal
- Tecnologico de Monterrey, School of Engineering and Sciences, Monterrey, Mexico
| |
Collapse
|
5
|
Lu M, Schneider D, Daniel R. Metagenomic Screening for Lipolytic Genes Reveals an Ecology-Clustered Distribution Pattern. Front Microbiol 2022; 13:851969. [PMID: 35756004 PMCID: PMC9226776 DOI: 10.3389/fmicb.2022.851969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/28/2022] [Indexed: 12/02/2022] Open
Abstract
Lipolytic enzymes are one of the most important enzyme types for application in various industrial processes. Despite the continuously increasing demand, only a small portion of the so far encountered lipolytic enzymes exhibit adequate stability and activities for biotechnological applications. To explore novel and/or extremophilic lipolytic enzymes, microbial consortia in two composts at thermophilic stage were analyzed using function-driven and sequence-based metagenomic approaches. Analysis of community composition by amplicon-based 16S rRNA genes and transcripts, and direct metagenome sequencing revealed that the communities of the compost samples were dominated by members of the phyla Actinobacteria, Proteobacteria, Firmicutes, Bacteroidetes, and Chloroflexi. Function-driven screening of the metagenomic libraries constructed from the two samples yielded 115 unique lipolytic enzymes. The family assignment of these enzymes was conducted by analyzing the phylogenetic relationship and generation of a protein sequence similarity network according to an integrated classification system. The sequence-based screening was performed by using a newly developed database, containing a set of profile Hidden Markov models, highly sensitive and specific for detection of lipolytic enzymes. By comparing the lipolytic enzymes identified through both approaches, we demonstrated that the activity-directed complements sequence-based detection, and vice versa. The sequence-based comparative analysis of lipolytic genes regarding diversity, function and taxonomic origin derived from 175 metagenomes indicated significant differences between habitats. Analysis of the prevalent and distinct microbial groups providing the lipolytic genes revealed characteristic patterns and groups driven by ecological factors. The here presented data suggests that the diversity and distribution of lipolytic genes in metagenomes of various habitats are largely constrained by ecological factors.
Collapse
Affiliation(s)
| | | | - Rolf Daniel
- Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg August University of Göttingen, Göttingen, Germany
| |
Collapse
|
6
|
Zhang L, Chen F, Zeng Z, Xu M, Sun F, Yang L, Bi X, Lin Y, Gao Y, Hao H, Yi W, Li M, Xie Y. Advances in Metagenomics and Its Application in Environmental Microorganisms. Front Microbiol 2022; 12:766364. [PMID: 34975791 PMCID: PMC8719654 DOI: 10.3389/fmicb.2021.766364] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/18/2021] [Indexed: 01/04/2023] Open
Abstract
Metagenomics is a new approach to study microorganisms obtained from a specific environment by functional gene screening or sequencing analysis. Metagenomics studies focus on microbial diversity, community constitute, genetic and evolutionary relationships, functional activities, and interactions and relationships with the environment. Sequencing technologies have evolved from shotgun sequencing to high-throughput, next-generation sequencing (NGS), and third-generation sequencing (TGS). NGS and TGS have shown the advantage of rapid detection of pathogenic microorganisms. With the help of new algorithms, we can better perform the taxonomic profiling and gene prediction of microbial species. Functional metagenomics is helpful to screen new bioactive substances and new functional genes from microorganisms and microbial metabolites. In this article, basic steps, classification, and applications of metagenomics are reviewed.
Collapse
Affiliation(s)
- Lu Zhang
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - FengXin Chen
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Zhan Zeng
- Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| | - Mengjiao Xu
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Fangfang Sun
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Liu Yang
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Xiaoyue Bi
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Yanjie Lin
- Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| | - YuanJiao Gao
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - HongXiao Hao
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Wei Yi
- Department of Gynecology and Obstetrics, Beijing Ditan Hospital, Capital Medical University, Beijing, China
| | - Minghui Li
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China.,Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| | - Yao Xie
- Department of Hepatology Division 2, Beijing Ditan Hospital, Capital Medical University, Beijing, China.,Department of Hepatology Division 2, Peking University Ditan Teaching Hospital, Beijing, China
| |
Collapse
|
7
|
Exploring the Diversity and Biotechnological Potential of Cultured and Uncultured Coral-Associated Bacteria. Microorganisms 2021; 9:microorganisms9112235. [PMID: 34835361 PMCID: PMC8622030 DOI: 10.3390/microorganisms9112235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/20/2021] [Accepted: 10/24/2021] [Indexed: 11/17/2022] Open
Abstract
Coral-associated microbes are crucial for the biology of their hosts, contributing to nutrient cycling, adaptation, mitigation of toxic compounds, and biological control of pathogens. Natural products from coral-associated micro-organisms (CAM) may possess unique traits. Despite this, the use of CAM for biotechnological purposes has not yet been adequately explored. Here, we investigated the production of commercially important enzymes by 37 strains of bacteria isolated from the coral species Mussismilia braziliensis, Millepora alcicornis, and Porites astreoides. In-vitro enzymatic assays showed that up to 56% of the isolates produced at least one of the seven enzymes screened (lipase, caseinase, keratinase, cellulase, chitinase, amylase, and gelatinase); one strain, identified as Bacillus amyloliquefaciens produced all these enzymes. Additionally, coral species-specific cultured and uncultured microbial communities were identified. The phylum Firmicutes predominated among the isolates, including the genera Exiguobacterium, Bacillus, and Halomonas, among others. Next-generation sequencing and bacteria culturing produced similar but also complementary data, with certain genera detected only by one or the other method. Our results demonstrate the importance of exploring different coral species as sources of specific micro-organisms of biotechnological and industrial interest, at the same time reinforcing the economic and ecological importance of coral reefs as reservoirs of such diversity.
Collapse
|
8
|
Crofts TS, McFarland AG, Hartmann EM. Mosaic Ends Tagmentation (METa) Assembly for Highly Efficient Construction of Functional Metagenomic Libraries. mSystems 2021; 6:e0052421. [PMID: 34184912 PMCID: PMC8269240 DOI: 10.1128/msystems.00524-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 11/20/2022] Open
Abstract
Functional metagenomic libraries, physical bacterial libraries which allow the high-throughput capture and expression of microbiome genes, have been instrumental in the sequence-naive and cultivation-independent exploration of metagenomes. However, preparation of these libraries is often limited by their high DNA input requirement and their low cloning efficiency. Here, we describe a new method, mosaic ends tagmentation (METa) assembly, for highly efficient functional metagenomic library preparation. We applied tagmentation to metagenomic DNA from soil and gut microbiomes to prepare DNA inserts for high-throughput cloning into functional metagenomic libraries. The presence of mosaic end sequences in the resulting DNA fragments synergized with homology-based assembly cloning to result in a 300-fold increase in cloning efficiency compared to traditional blunt-cloning-based protocols. We show that compared to published libraries prepared by state-of-the-art protocols, METa assembly is on average ca. 20- to 200-fold more efficient and can prepare gigabase-sized libraries with as little as 200 ng of input DNA. We show the usefulness of METa assembly first by using a normative 5-μg mass of soil metagenomic DNA to prepare a 700-Gb library that allowed us to discover novel nourseothricin resistance genes and a potentially new mode of resistance to this antibiotic and second by using only 300 ng of goose fecal metagenomic DNA to prepare a 27-Gb library that captured numerous tetracycline and colistin resistance genes. METa assembly provides a streamlined, flexible, and efficient method for preparing functional metagenomic libraries, enabling new avenues of genetic and biochemical research into low-biomass or scarce microbiomes. IMPORTANCE Medically and industrially important genes can be recovered from microbial communities by high-throughput sequencing, but precise annotation is often limited to characterized genes and their relatives. Cloning a metagenome en masse into an expression host to produce a functional metagenomic library, directly connecting genes to functions, is a sequence-naive and cultivation-independent method to discover novel genes. The process of preparing these libraries is DNA greedy and inefficient, however. Here, we describe a library preparation method that is an order of magnitude more efficient and less DNA greedy. This method is consistently efficient across libraries prepared from cultures, a soil microbiome, and a goose fecal microbiome and allowed us to discover new antibiotic resistance genes and mechanisms. This library preparation method will potentially allow the functional metagenomic exploration of microbiomes that were previously off limits due to their rarity or low microbial biomass, such as biomedical swabs or exotic samples.
Collapse
Affiliation(s)
- Terence S. Crofts
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
| | - Alexander G. McFarland
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| | - Erica M. Hartmann
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| |
Collapse
|
9
|
Mongui A, Lozano GL, Handelsman J, Restrepo S, Junca H. Design and validation of a transposon that promotes expression of genes in episomal DNA. J Biotechnol 2020; 310:1-5. [PMID: 31954761 DOI: 10.1016/j.jbiotec.2020.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 01/15/2020] [Indexed: 01/20/2023]
Abstract
Functional metagenomics, or the cloning and expression of DNA isolated directly from environmental samples, represents a source of novel compounds with biotechnological potential. However, attempts to identify such compounds in metagenomic libraries are generally inefficient in part due to lack of expression of heterologous DNA. In this research, the TnC_T7 transposon was developed to supply transcriptional machinery during functional analysis of metagenomic libraries. TnC_T7 contains bidirectional T7 promoters, the gene encoding the T7 RNA polymerase (T7RNAP), and a kanamycin resistance gene. The T7 RNA polymerase gene is regulated by the inducible arabinose promoter (PBAD), thereby facilitating inducible expression of genes adjacent to the randomly integrating transposon. The high processivity of T7RNAP should make this tool particularly useful for obtaining gene expression in long inserts. TnC_T7 functionality was validated by conducting in vitro transposition of pKR-C12 or fosmid pF076_GFPmut3*, carrying metagenomic DNA from soil. We identified transposon insertions that enhanced GFP expression in both vectors, including insertions in which the promoter delivered by the transposon was located as far as 8.7 kb from the GFP gene, indicating the power of the high processivity of the T7 polymerase. The results gathered in this research demonstrate the potential of TnC_T7 to enhance gene expression in functional metagenomic studies.
Collapse
Affiliation(s)
- Alvaro Mongui
- Molecular Biotechnology, Corporación CorpoGen, Bogotá, Colombia; Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.
| | - Gabriel L Lozano
- Wisconsin Institute for Discovery and Department of Plant Pathology, University of Wisconsin, Madison, WI, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Jo Handelsman
- Wisconsin Institute for Discovery and Department of Plant Pathology, University of Wisconsin, Madison, WI, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Silvia Restrepo
- Laboratory of Mycology and Plant Diseases, Universidad de los Andes, Bogotá, Colombia
| | - Howard Junca
- RG Microbial Ecology: Metabolism, Genomics & Evolution, Microbiomas Foundation, Chía, Colombia
| |
Collapse
|
10
|
Alves LDF, Borelli TC, Westmann CA, Silva-Rocha R, Guazzaroni ME. Boundaries in metagenomic screenings using lacZα-based vectors. Genet Mol Biol 2020; 43:e20180252. [PMID: 31429862 PMCID: PMC7198016 DOI: 10.1590/1678-4685-gmb-2018-0252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/28/2019] [Indexed: 11/21/2022] Open
Abstract
Metagenomics approaches have been of high relevance for providing enzymes used in
diverse industrial applications. In the current study, we have focused on the
prospection of protease and glycosyl hydrolase activities from a soil sample by
using the lacZα -based plasmid pSEVA232. For
this, we used a functional screen based on skimmed milk agar and a pH indicator
dye for detection of both enzymes, as previously reported in literature.
Although we effectively identified positive clones in the screenings, subsequent
experiments revealed that this phenotype was not because of the hydrolytic
activity encoded in the metagenomic fragments, but rather due to the insertion
of small metagenomic DNA fragments in frame within the coding
region of the lacZ gene present in the original vector.
Analyses of the thermodynamic stability of mRNA secondary structures indicated
that recovering of positive clones was probably due to higher expression levels
of the chimeric lacZα-genes in respect to the original from empty vector. We
concluded that this method has a higher tendency for recovery false positive
clones, when used in combination with a
lacZα-based vector. As these vectors are
massively used in functional metagenomic screenings, we highlight the importance
of reporting boundaries in established metagenomic screenings methodologies.
Collapse
|
11
|
Chao L, Jongkees S. High-Throughput Approaches in Carbohydrate-Active Enzymology: Glycosidase and Glycosyl Transferase Inhibitors, Evolution, and Discovery. Angew Chem Int Ed Engl 2019; 58:12750-12760. [PMID: 30913359 PMCID: PMC6771893 DOI: 10.1002/anie.201900055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/05/2019] [Indexed: 01/13/2023]
Abstract
Carbohydrates are attached and removed in living systems through the action of carbohydrate-active enzymes such as glycosyl transferases and glycoside hydrolases. The molecules resulting from these enzymes have many important roles in organisms, such as cellular communication, structural support, and energy metabolism. In general, each carbohydrate transformation requires a separate catalyst, and so these enzyme families are extremely diverse. To make this diversity manageable, high-throughput approaches look at many enzymes at once. Similarly, high-throughput approaches can be a powerful way of finding inhibitors that can be used to tune the reactivity of these enzymes, either in an industrial, a laboratory, or a medicinal setting. In this review, we provide an overview of how these enzymes and inhibitors can be sought using techniques such as high-throughput natural product and combinatorial library screening, phage and mRNA display of (glyco)peptides, fluorescence-activated cell sorting, and metagenomics.
Collapse
Affiliation(s)
- Lemeng Chao
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3581AG, Utrecht, The Netherlands
| | - Seino Jongkees
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3581AG, Utrecht, The Netherlands
| |
Collapse
|
12
|
Chao L, Jongkees S. High‐Throughput Approaches in Carbohydrate‐Active Enzymology: Glycosidase and Glycosyl Transferase Inhibitors, Evolution, and Discovery. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Lemeng Chao
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences Utrecht University Universiteitsweg 99 3581AG Utrecht The Netherlands
| | - Seino Jongkees
- Department of Chemical Biology and Drug Discovery Utrecht Institute for Pharmaceutical Sciences Utrecht University Universiteitsweg 99 3581AG Utrecht The Netherlands
| |
Collapse
|
13
|
Calderon D, Peña L, Suarez A, Villamil C, Ramirez-Rojas A, Anzola JM, García-Betancur JC, Cepeda ML, Uribe D, Del Portillo P, Mongui A. Recovery and functional validation of hidden soil enzymes in metagenomic libraries. Microbiologyopen 2019; 8:e00572. [PMID: 30851083 PMCID: PMC6460280 DOI: 10.1002/mbo3.572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 11/01/2017] [Accepted: 11/09/2017] [Indexed: 11/10/2022] Open
Abstract
The vast microbial diversity on the planet represents an invaluable source for identifying novel activities with potential industrial and therapeutic application. In this regard, metagenomics has emerged as a group of strategies that have significantly facilitated the analysis of DNA from multiple environments and has expanded the limits of known microbial diversity. However, the functional characterization of enzymes, metabolites, and products encoded by diverse microbial genomes is limited by the inefficient heterologous expression of foreign genes. We have implemented a pipeline that combines NGS and Sanger sequencing as a way to identify fosmids within metagenomic libraries. This strategy facilitated the identification of putative proteins, subcloning of targeted genes and preliminary characterization of selected proteins. Overall, the in silico approach followed by the experimental validation allowed us to efficiently recover the activity of previously hidden enzymes derived from agricultural soil samples. Therefore, the methodology workflow described herein can be applied to recover activities encoded by environmental DNA from multiple sources.
Collapse
Affiliation(s)
- Dayana Calderon
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia
| | - Luis Peña
- Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Friedrich-Schiller Universität, Jena, Germany
| | - Angélica Suarez
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia
| | - Carolina Villamil
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia
| | - Adan Ramirez-Rojas
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia
| | - Juan M Anzola
- Computational Biology, Corporación CorpoGen, Bogotá, Colombia
| | | | - Martha L Cepeda
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia
| | - Daniel Uribe
- Biotechnology Institute, Universidad Nacional de Colombia, Bogotá, Colombia
| | | | - Alvaro Mongui
- Molecular Biotechnology Research Group, Corporación CorpoGen, Bogotá, Colombia.,Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| |
Collapse
|
14
|
Lu M, Dukunde A, Daniel R. Biochemical profiles of two thermostable and organic solvent-tolerant esterases derived from a compost metagenome. Appl Microbiol Biotechnol 2019; 103:3421-3437. [PMID: 30809711 DOI: 10.1007/s00253-019-09695-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 12/15/2022]
Abstract
Owing to the functional versatility and potential applications in industry, interest in lipolytic enzymes tolerant to organic solvents is increasing. In this study, functional screening of a compost soil metagenome resulted in identification of two lipolytic genes, est1 and est2, encoding 270 and 389 amino acids, respectively. The two genes were heterologously expressed and characterized. Est1 and Est2 are thermostable enzymes with optimal enzyme activities at 80 and 70 °C, respectively. A second-order rotatable design, which allows establishing the relationship between multiple variables with the obtained responses, was used to explore the combined effects of temperature and pH on esterase stability. The response curve indicated that Est1, and particularly Est2, retained high stability within a broad range of temperature and pH values. Furthermore, the effects of organic solvents on Est1 and Est2 activities and stabilities were assessed. Notably, Est2 activity was significantly enhanced (two- to tenfold) in the presence of ethanol, methanol, isopropanol, and 1-propanol over a concentration range between 6 and 30% (v/v). For the short-term stability (2 h of incubation), Est2 exhibited high tolerance against 60% (v/v) of ethanol, methanol, isopropanol, DMSO, and acetone, while Est1 activity resisted these solvents only at lower concentrations (below 30%, v/v). Est2 also displayed high stability towards some water-immiscible organic solvents, such as ethyl acetate, diethyl ether, and toluene. With respect to long-term stability, Est2 retained most of its activity after 26 days of incubation in the presence of 30% (v/v) ethanol, methanol, isopropanol, DMSO, or acetone. All of these features indicate that Est1 and Est2 possess application potential.
Collapse
Affiliation(s)
- Mingji Lu
- Department of Genomic and Applied Microbiology, Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany
| | - Amélie Dukunde
- Department of Genomic and Applied Microbiology, Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University of Göttingen, Grisebachstraße 8, 37077, Göttingen, Germany.
| |
Collapse
|
15
|
Microbial Community Dynamics During the Composting Process of Animal Manure as Analyzed by Molecular Biological Methods. ADVANCES IN ENVIRONMENTAL MICROBIOLOGY 2019. [DOI: 10.1007/978-3-030-10777-2_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
16
|
Ranjan R, Yadav MK, Suneja G, Sharma R. Discovery of a diverse set of esterases from hot spring microbial mat and sea sediment metagenomes. Int J Biol Macromol 2018; 119:572-581. [PMID: 30059741 DOI: 10.1016/j.ijbiomac.2018.07.170] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 11/18/2022]
Abstract
Esterases are an important group of biocatalysts for synthetic organic chemistry. Functional metagenomics allows discovery of novel biocatalysts by providing access to the gene pool of the microbial community of a habitat. Two metagenomic libraries representing the gene pool of sea sediment and hot spring microbial mat were constructed. Functional screening of these libraries resulted in the isolation of total 8 clones with tributyrin hydrolytic activity. Sequence analysis revealed 10 putative lipolytic proteins with 42-99% homology to the protein sequences in the databases, nine of which represented six known esterase families. Four of the encoded proteins represented Family V and amongst others, one each represented the Family VIII, pectin acetylesterase, enterobactin esterase, G-D-S-L family and OsmC domain containing esterase. One unusual lipolytic protein possessed poly-(3-hydroxybutyrate) depolymerase domain fused to lipase/esterase domain. Two phylogenetically related esterases (MLC3 and SLC5) belonging to family V were expressed and purified to homogeneity. The enzymes exhibited environment-adapted temperature optimum and thermostability. MLC3 was able to stereoselectively hydrolyze R-methyl mandelate to produce R-mandelic acid, an important chiral building block, which suggests MLC3 has potential commercial application.
Collapse
Affiliation(s)
- Ravi Ranjan
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Mathura Road, New Delhi 110025, India
| | - Manish Kumar Yadav
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Mathura Road, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Mathura Road, New Delhi 110025, India
| | - Garima Suneja
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Mathura Road, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Mathura Road, New Delhi 110025, India
| | - Rakesh Sharma
- CSIR-Institute of Genomics and Integrative Biology, Council of Scientific and Industrial Research, Mathura Road, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Mathura Road, New Delhi 110025, India.
| |
Collapse
|
17
|
Pessoa TBA, Rezende RP, Marques EDLS, Pirovani CP, Dos Santos TF, Dos Santos Gonçalves AC, Romano CC, Dotivo NC, Freitas ACO, Salay LC, Dias JCT. Metagenomic alkaline protease from mangrove sediment. J Basic Microbiol 2017; 57:962-973. [PMID: 28804942 DOI: 10.1002/jobm.201700159] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 06/29/2017] [Accepted: 07/07/2017] [Indexed: 11/09/2022]
Abstract
Functional screening of metagenomic libraries is an important tool for the discovery of new molecules. The metabolic diversity of microorganisms enables survival in harsh environments and is related to the production of enzymes. In this study, we identified a protease-producing clone from a metagenomic library derived from mangrove sediment. The protease was purified by ammonium sulphate precipitation and gel filtration chromatography, with a yield of 77.27% and a specific activity of 8.57 U μg-1 . It had a molecular weight of approximately 70 kDa. MS/MS in ESI-Q-TOF revealed nine peptides similar to a peptidase of Bacillus safensis. The aligned partial sequence showed 47.48% identity and 82.74% similarity to the conserved domains of a glutamyl aminopeptidase from the human gut metagenome and 32.12% total coverage. The protease had an optimal pH of 8.5 and optimal activity at 60°C. At pH 9-12, its activity was greater than 80%. It had moderate thermotolerance and thermostability at temperatures of 40 and 50 °C. The KM and Vmax values were estimated to be 0.92 mg ml-1 , and 13.15 mmol min-1 for azocasein. Substrate specificity analysis showed that PR4A3 was active on gelatin, blood, egg yolk, and milk. These results support the potential use of PR4A3 in biotechnological applications.
Collapse
Affiliation(s)
- Tharcilla B A Pessoa
- State University of Feira de Santana, Program in Biotechnology, Feira de Santana, Bahia, Brazil
| | - Rachel P Rezende
- Department of Biological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| | | | - Carlos P Pirovani
- Department of Biological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| | | | | | - Carla C Romano
- Department of Biological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| | - Natielle C Dotivo
- State University of Santa Cruz, Undergraduate in Biomedicine, Ilheus, Bahia, Brazil
| | - Ana C O Freitas
- Department of Biological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| | - Luiz C Salay
- Department of Exact and Technological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| | - João C T Dias
- Department of Biological Sciences, State University of Santa Cruz, Ilheus, Bahia, Brazil
| |
Collapse
|
18
|
Yousofian-Varzaneh H, Namazian M, Zare HR, Jahanbani S, Benvidi A. Determination of acidic constants of tetrafluoro-p-hydroquinone. J Fluor Chem 2017. [DOI: 10.1016/j.jfluchem.2016.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
19
|
Khan M, Kumar A. Computational modelling and protein-ligand interaction studies of SMlipA lipase cloned from forest metagenome. J Mol Graph Model 2016; 70:212-225. [DOI: 10.1016/j.jmgm.2016.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 09/06/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022]
|
20
|
Uria AR, Zilda DS. Metagenomics-Guided Mining of Commercially Useful Biocatalysts from Marine Microorganisms. ADVANCES IN FOOD AND NUTRITION RESEARCH 2016; 78:1-26. [PMID: 27452163 DOI: 10.1016/bs.afnr.2016.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Marine microorganisms are a rich reservoir of highly diverse and unique biocatalysts that offer potential applications in food, pharmaceutical, fuel, and cosmetic industries. The fact that only less than 1% of microbes in any marine habitats can be cultured under standard laboratory conditions has hampered access to their extraordinary biocatalytic potential. Metagenomics has recently emerged as a powerful and well-established tool to investigate the vast majority of hidden uncultured microbial diversity for the discovery of novel industrially relevant enzymes from different types of environmental samples, such as seawater, marine sediment, and symbiotic microbial consortia. We discuss here in this review about approaches and methods in metagenomics that have been used and can potentially be used to mine commercially useful biocatalysts from uncultured marine microbes.
Collapse
Affiliation(s)
- A R Uria
- Research and Development Center for Marine and Fisheries Product Processing and Biotechnology, Central Jakarta, Indonesia.
| | - D S Zilda
- Research and Development Center for Marine and Fisheries Product Processing and Biotechnology, Central Jakarta, Indonesia
| |
Collapse
|
21
|
Baweja M, Nain L, Kawarabayasi Y, Shukla P. Current Technological Improvements in Enzymes toward Their Biotechnological Applications. Front Microbiol 2016; 7:965. [PMID: 27379087 PMCID: PMC4909775 DOI: 10.3389/fmicb.2016.00965] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/03/2016] [Indexed: 01/07/2023] Open
Abstract
Enzymes from extremophiles are creating interest among researchers due to their unique properties and the enormous power of catalysis at extreme conditions. Since community demands are getting more intensified, therefore, researchers are applying various approaches viz. metagenomics to increase the database of extremophilic species. Furthermore, the innovations are being made in the naturally occurring enzymes utilizing various tools of recombinant DNA technology and protein engineering, which allows redesigning of the enzymes for its better fitment into the process. In this review, we discuss the biochemical constraints of psychrophiles during survival at the lower temperature. We summarize the current knowledge about the sources of such enzymes and their in vitro modification through mutagenesis to explore their biotechnological potential. Finally, we recap the microbial cell surface display to enhance the efficiency of the process in cost effective way.
Collapse
Affiliation(s)
- Mehak Baweja
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak India
| | - Lata Nain
- Division of Microbiology, Indian Agricultural Research Institute, New Delhi India
| | - Yutaka Kawarabayasi
- National Institute of Advanced Industrial Science and Technology, Tsukuba Japan
| | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak India
| |
Collapse
|
22
|
Gao W, Wu K, Chen L, Fan H, Zhao Z, Gao B, Wang H, Wei D. A novel esterase from a marine mud metagenomic library for biocatalytic synthesis of short-chain flavor esters. Microb Cell Fact 2016; 15:41. [PMID: 26892801 PMCID: PMC4758151 DOI: 10.1186/s12934-016-0435-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/01/2016] [Indexed: 11/13/2022] Open
Abstract
Background Marine mud is an abundant and largely unexplored source of enzymes with unique properties that may be useful for industrial and biotechnological purposes. However, since most microbes cannot be cultured in the laboratory, a cultivation-independent metagenomic approach would be advantageous for the identification of novel enzymes. Therefore, with the objective of screening novel lipolytic enzymes, a metagenomic library was constructed using the total genomic DNA extracted from marine mud. Results Based on functional heterologous expression, 34 clones that showed lipolytic activity were isolated. The five clones with the largest halos were identified, and the corresponding genes were successfully overexpressed in Escherichia coli. Molecular analysis revealed that these encoded proteins showed 48–79 % similarity with other proteins in the GenBank database. Multiple sequence alignment and phylogenetic tree analysis classified these five protein sequences as new members of known families of bacterial lipolytic enzymes. Among them, EST4, which has 316 amino acids with a predicted molecular weight of 33.8 kDa, was further studied in detail due to its strong hydrolytic activity. Characterization of EST4 indicated that it is an alkaline esterase that exhibits highest hydrolytic activity towards p-nitrophenyl butyrate (specific activity: 1389 U mg−1) at 45 °C and pH 8.0. The half-life of EST4 is 55 and 46 h at 40 and 45 °C, respectively, indicating a relatively high thermostability. EST4 also showed remarkable stability in organic solvents, retaining 90 % of its initial activity when incubated for 12 h in the presence of hydrophobic alkanes. Furthermore, EST4 was used as an efficient whole-cell biocatalyst for the synthesis of short-chain flavor esters, showing high conversion rate and good tolerance for high substrate concentrations (up to 3.0 M). These results demonstrate a promising potential for industrial scaling-up to produce short-chain flavor esters at high substrate concentrations in non-aqueous media. Conclusions This manuscript reports unprecedented alcohol tolerance and conversion of an esterase biocatalyst identified from a marine mud metagenomic library. The high organic solvent tolerance and thermostability of EST4 suggest that it has great potential as a biocatalyst. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0435-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Wenyuan Gao
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Kai Wu
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Lifeng Chen
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Haiyang Fan
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Zhiqiang Zhao
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Bei Gao
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Hualei Wang
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| | - Dongzhi Wei
- State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
| |
Collapse
|
23
|
Maruthamuthu M, Jiménez DJ, Stevens P, van Elsas JD. A multi-substrate approach for functional metagenomics-based screening for (hemi)cellulases in two wheat straw-degrading microbial consortia unveils novel thermoalkaliphilic enzymes. BMC Genomics 2016; 17:86. [PMID: 26822785 PMCID: PMC4730625 DOI: 10.1186/s12864-016-2404-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/18/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Functional metagenomics is a promising strategy for the exploration of the biocatalytic potential of microbiomes in order to uncover novel enzymes for industrial processes (e.g. biorefining or bleaching pulp). Most current methodologies used to screen for enzymes involved in plant biomass degradation are based on the use of single substrates. Moreover, highly diverse environments are used as metagenomic sources. However, such methods suffer from low hit rates of positive clones and hence the discovery of novel enzymatic activities from metagenomes has been hampered. RESULTS Here, we constructed fosmid libraries from two wheat straw-degrading microbial consortia, denoted RWS (bred on untreated wheat straw) and TWS (bred on heat-treated wheat straw). Approximately 22,000 clones from each library were screened for (hemi)cellulose-degrading enzymes using a multi-chromogenic substrate approach. The screens yielded 71 positive clones for both libraries, giving hit rates of 1:440 and 1:1,047 for RWS and TWS, respectively. Seven clones (NT2-2, T5-5, NT18-17, T4-1, 10BT, NT18-21 and T17-2) were selected for sequence analyses. Their inserts revealed the presence of 18 genes encoding enzymes belonging to twelve different glycosyl hydrolase families (GH2, GH3, GH13, GH17, GH20, GH27, GH32, GH39, GH53, GH58, GH65 and GH109). These encompassed several carbohydrate-active gene clusters traceable mainly to Klebsiella related species. Detailed functional analyses showed that clone NT2-2 (containing a beta-galactosidase of ~116 kDa) had highest enzymatic activity at 55 °C and pH 9.0. Additionally, clone T5-5 (containing a beta-xylosidase of ~86 kDa) showed > 90% of enzymatic activity at 55 °C and pH 10.0. CONCLUSIONS This study employed a high-throughput method for rapid screening of fosmid metagenomic libraries for (hemi)cellulose-degrading enzymes. The approach, consisting of screens on multi-substrates coupled to further analyses, revealed high hit rates, as compared with recent other studies. Two clones, 10BT and T4-1, required the presence of multiple substrates for detectable activity, indicating a new avenue in library activity screening. Finally, clones NT2-2, T5-5 and NT18-17 were found to encode putative novel thermo-alkaline enzymes, which could represent a starting point for further biotechnological applications.
Collapse
Affiliation(s)
- Mukil Maruthamuthu
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Diego Javier Jiménez
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Patricia Stevens
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| |
Collapse
|
24
|
ExoMeg1: a new exonuclease from metagenomic library. Sci Rep 2016; 6:19712. [PMID: 26815639 PMCID: PMC4750427 DOI: 10.1038/srep19712] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/27/2015] [Indexed: 01/18/2023] Open
Abstract
DNA repair mechanisms are responsible for maintaining the integrity of DNA and are essential to life. However, our knowledge of DNA repair mechanisms is based on model organisms such as Escherichia coli, and little is known about free living and uncultured microorganisms. In this study, a functional screening was applied in a metagenomic library with the goal of discovering new genes involved in the maintenance of genomic integrity. One clone was identified and the sequence analysis showed an open reading frame homolog to a hypothetical protein annotated as a member of the Exo_Endo_Phos superfamily. This novel enzyme shows 3′-5′ exonuclease activity on single and double strand DNA substrates and it is divalent metal-dependent, EDTA-sensitive and salt resistant. The clone carrying the hypothetical ORF was able to complement strains deficient in recombination or base excision repair, suggesting that the new enzyme may be acting on the repair of single strand breaks with 3′ blockers, which are substrates for these repair pathways. Because this is the first report of an enzyme obtained from a metagenomic approach showing exonuclease activity, it was named ExoMeg1. The metagenomic approach has proved to be a useful tool for identifying new genes of uncultured microorganisms.
Collapse
|
25
|
Contemporary molecular tools in microbial ecology and their application to advancing biotechnology. Biotechnol Adv 2015; 33:1755-73. [DOI: 10.1016/j.biotechadv.2015.09.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 09/19/2015] [Accepted: 09/20/2015] [Indexed: 12/30/2022]
|
26
|
Use of Substrate-Induced Gene Expression in Metagenomic Analysis of an Aromatic Hydrocarbon-Contaminated Soil. Appl Environ Microbiol 2015; 82:897-909. [PMID: 26590287 DOI: 10.1128/aem.03306-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/16/2015] [Indexed: 11/20/2022] Open
Abstract
Metagenomics allows the study of genes related to xenobiotic degradation in a culture-independent manner, but many of these studies are limited by the lack of genomic context for metagenomic sequences. This study combined a phenotypic screen known as substrate-induced gene expression (SIGEX) with whole-metagenome shotgun sequencing. SIGEX is a high-throughput promoter-trap method that relies on transcriptional activation of a green fluorescent protein (GFP) reporter gene in response to an inducing compound and subsequent fluorescence-activated cell sorting to isolate individual inducible clones from a metagenomic DNA library. We describe a SIGEX procedure with improved library construction from fragmented metagenomic DNA and improved flow cytometry sorting procedures. We used SIGEX to interrogate an aromatic hydrocarbon (AH)-contaminated soil metagenome. The recovered clones contained sequences with various degrees of similarity to genes (or partial genes) involved in aromatic metabolism, for example, nahG (salicylate oxygenase) family genes and their respective upstream nahR regulators. To obtain a broader context for the recovered fragments, clones were mapped to contigs derived from de novo assembly of shotgun-sequenced metagenomic DNA which, in most cases, contained complete operons involved in aromatic metabolism, providing greater insight into the origin of the metagenomic fragments. A comparable set of contigs was generated using a significantly less computationally intensive procedure in which assembly of shotgun-sequenced metagenomic DNA was directed by the SIGEX-recovered sequences. This methodology may have broad applicability in identifying biologically relevant subsets of metagenomes (including both novel and known sequences) that can be targeted computationally by in silico assembly and prediction tools.
Collapse
|
27
|
Masuch T, Kusnezowa A, Nilewski S, Bautista JT, Kourist R, Leichert LI. A combined bioinformatics and functional metagenomics approach to discovering lipolytic biocatalysts. Front Microbiol 2015; 6:1110. [PMID: 26528261 PMCID: PMC4602143 DOI: 10.3389/fmicb.2015.01110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/25/2015] [Indexed: 11/30/2022] Open
Abstract
The majority of protein sequence data published today is of metagenomic origin. However, our ability to assign functions to these sequences is often hampered by our general inability to cultivate the larger part of microbial species and the sheer amount of sequence data generated in these projects. Here we present a combination of bioinformatics, synthetic biology, and Escherichia coli genetics to discover biocatalysts in metagenomic datasets. We created a subset of the Global Ocean Sampling dataset, the largest metagenomic project published to date, by removing all proteins that matched Hidden Markov Models of known protein families from PFAM and TIGRFAM with high confidence (E-value > 10-5). This essentially left us with proteins with low or no homology to known protein families, still encompassing ~1.7 million different sequences. In this subset, we then identified protein families de novo with a Markov clustering algorithm. For each protein family, we defined a single representative based on its phylogenetic relationship to all other members in that family. This reduced the dataset to ~17,000 representatives of protein families with more than 10 members. Based on conserved regions typical for lipases and esterases, we selected a representative gene from a family of 27 members for synthesis. This protein, when expressed in E. coli, showed lipolytic activity toward para-nitrophenyl (pNP) esters. The Km-value of the enzyme was 66.68 μM for pNP-butyrate and 68.08 μM for pNP-palmitate with kcat/Km values at 3.4 × 106 and 6.6 × 105 M-1s-1, respectively. Hydrolysis of model substrates showed enantiopreference for the R-form. Reactions yielded 43 and 61% enantiomeric excess of products with ibuprofen methyl ester and 2-phenylpropanoic acid ethyl ester, respectively. The enzyme retains 50% of its maximum activity at temperatures as low as 10°C, its activity is enhanced in artificial seawater and buffers with higher salt concentrations with an optimum osmolarity of 3,890 mosmol/l.
Collapse
Affiliation(s)
- Thorsten Masuch
- Department of Microbial Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum Bochum, Germany
| | - Anna Kusnezowa
- Department of Microbial Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum Bochum, Germany
| | - Sebastian Nilewski
- Department of Microbial Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum Bochum, Germany
| | - José T Bautista
- Junior Research Group for Microbial Biotechnology - Department for Biology and Biotechnology, Ruhr University Bochum Bochum, Germany
| | - Robert Kourist
- Junior Research Group for Microbial Biotechnology - Department for Biology and Biotechnology, Ruhr University Bochum Bochum, Germany
| | - Lars I Leichert
- Department of Microbial Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum Bochum, Germany
| |
Collapse
|
28
|
López-López O, Cerdán ME, González Siso MI. New extremophilic lipases and esterases from metagenomics. Curr Protein Pept Sci 2015; 15:445-55. [PMID: 24588890 PMCID: PMC4093774 DOI: 10.2174/1389203715666140228153801] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 01/21/2014] [Accepted: 02/25/2014] [Indexed: 11/22/2022]
Abstract
Lipolytic enzymes catalyze the hydrolysis of ester bonds in the presence of water. In media with low water content or in organic solvents, they can catalyze synthetic reactions such as esterification and transesterification. Lipases and esterases, in particular those from extremophilic origin, are robust enzymes, functional under the harsh conditions of industrial processes owing to their inherent thermostability and resistance towards organic solvents, which combined with their high chemo-, regio- and enantioselectivity make them very attractive biocatalysts for a variety of industrial applications. Likewise, enzymes from extremophile sources can provide additional features such as activity at extreme temperatures, extreme pH values or high salinity levels, which could be interesting for certain purposes. New lipases and esterases have traditionally been discovered by the isolation of microbial strains producing lipolytic activity. The Genome Projects Era allowed genome mining, exploiting homology with known lipases and esterases, to be used in the search for new enzymes. The Metagenomic Era meant a step forward in this field with the study of the metagenome, the pool of genomes in an environmental microbial community. Current molecular biology techniques make it possible to construct total environmental DNA libraries, including the genomes of unculturable organisms, opening a new window to a vast field of unknown enzymes with new and unique properties. Here, we review the latest advances and findings from research into new extremophilic lipases and esterases, using metagenomic approaches, and their potential industrial and biotechnological applications.
Collapse
Affiliation(s)
| | | | - Maria I González Siso
- University of A Coruna, Faculty of Sciences, Department of Cellular and Molecular Biology, Biochemistry and Molecular Biology Area. Campus A Zapateira s/n, 15071, A Coruna, Spain.
| |
Collapse
|
29
|
Butera G, Ferraro C, Alonzo G, Colazza S, Quatrini P. The gut microbiota of the wood-feeding termite Reticulitermes lucifugus (Isoptera; Rhinotermitidae). ANN MICROBIOL 2015. [DOI: 10.1007/s13213-015-1101-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
30
|
Alnoch RC, Martini VP, Glogauer A, Costa ACDS, Piovan L, Muller-Santos M, de Souza EM, de Oliveira Pedrosa F, Mitchell DA, Krieger N. Immobilization and characterization of a new regioselective and enantioselective lipase obtained from a metagenomic library. PLoS One 2015; 10:e0114945. [PMID: 25706996 PMCID: PMC4338019 DOI: 10.1371/journal.pone.0114945] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 11/16/2014] [Indexed: 11/19/2022] Open
Abstract
In previous work, a new lipase and its cognate foldase were identified and isolated from a metagenomic library constructed from soil samples contaminated with fat. This new lipase, called LipG9, is a true lipase that shows specific activities that are comparable to those of well-known industrially-used lipases with high activity against long-chain triglycerides. In the present work, LipG9 was co-expressed and co-immobilized with its foldase, on an inert hydrophobic support (Accurel MP1000). We studied the performance of this immobilized LipG9 (Im-LipG9) in organic media, in order to evaluate its potential for use in biocatalysis. Im-LipG9 showed good stability, maintaining a residual activity of more than 70% at 50 °C after incubation in n-heptane (log P 4.0) for 8 h. It was also stable in polar organic solvents such as ethanol (log P -0.23) and acetone (log P -0.31), maintaining more than 80% of its original activity after 8 h incubation at 30 °C. The synthesis of ethyl esters was tested with fatty acids of different chain lengths in n-heptane at 30 °C. The best conversions (90% in 3 h) were obtained for medium and long chain saturated fatty acids (C8, C14 and C16), with the maximum specific activity, 29 U per gram of immobilized preparation, being obtained with palmitic acid (C16). Im-LipG9 was sn-1,3-specific. In the transesterification of the alcohol (R,S)-1-phenylethanol with vinyl acetate and the hydrolysis of the analogous ester, (R,S)-1-phenylethyl acetate, Im-LipG9 showed excellent enantioselectivity for the R-isomer of both substrates (E> 200), giving an enantiomeric excess (ee) of higher than 95% for the products at 49% conversion. The results obtained in this work provide the basis for the development of applications of LipG9 in biocatalysis.
Collapse
Affiliation(s)
- Robson Carlos Alnoch
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | | | - Arnaldo Glogauer
- Agência Tecpar de Inovação, Instituto de Tecnologia do Paraná—Tecpar, Curitiba 81350–010, Paraná, Brazil
| | - Allen Carolina dos Santos Costa
- Departamento de Química, Universidade Federal do Paraná, Cx. P. 19081 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - Leandro Piovan
- Departamento de Química, Universidade Federal do Paraná, Cx. P. 19081 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - Marcelo Muller-Santos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - Emanuel Maltempi de Souza
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - Fábio de Oliveira Pedrosa
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - David Alexander Mitchell
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| | - Nadia Krieger
- Departamento de Química, Universidade Federal do Paraná, Cx. P. 19081 Centro Politécnico, Curitiba 81531–980, Paraná, Brazil
| |
Collapse
|
31
|
Gu X, Wang S, Wang S, Zhao LX, Cao M, Feng Z. Identification and Characterization of Two Novel Esterases from a Metagenomic Library. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2015. [DOI: 10.3136/fstr.21.649] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Xinqi Gu
- College of Food Science and Technology, Nanjing Agricultural University
| | - Shilin Wang
- College of Food Science and Technology, Nanjing Agricultural University
| | - Shaochen Wang
- College of Food Science and Technology, Nanjing Agricultural University
| | - Li-Xing Zhao
- Key Laboratory of Medicinal chemistry for Natural Resource, Ministry of Education, School of Chemical Science and Technology, Yunnan University
| | - Mingming Cao
- College of Food Science and Technology, Nanjing Agricultural University
| | - Zhiyang Feng
- College of Food Science and Technology, Nanjing Agricultural University
| |
Collapse
|
32
|
Martini VP, Glogauer A, Müller-Santos M, Iulek J, de Souza EM, Mitchell DA, Pedrosa FO, Krieger N. First co-expression of a lipase and its specific foldase obtained by metagenomics. Microb Cell Fact 2014; 13:171. [PMID: 25510188 PMCID: PMC4305245 DOI: 10.1186/s12934-014-0171-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 11/20/2014] [Indexed: 11/10/2022] Open
Abstract
Background Metagenomics is a useful tool in the search for new lipases that might have characteristics that make them suitable for application in biocatalysis. This paper reports the cloning, co-expression, purification and characterization of a new lipase, denominated LipG9, and its specific foldase, LifG9, from a metagenomic library derived from a fat-contaminated soil. Results Within the metagenomic library, the gene lipg9 was cloned jointly with the gene of the foldase, lifg9. LipG9 and LifG9 have 96% and 84% identity, respectively, with the corresponding proteins of Aeromonas veronii B565. LipG9 and LifG9 were co-expressed, both in N-truncated form, in Escherichia coli BL21(DE3), using the vectors pET28a(+) and pT7-7, respectively, and then purified by affinity chromatography using a Ni2+ column (HiTrap Chelating HP). The purified enzyme eluted from the column complexed with its foldase. The molecular masses of the N-truncated proteins were 32 kDa for LipG9, including the N-terminal His-tag with 6 residues, and 23 kDa for LifG9, which did not have a His-tag. The biochemical and kinetic characteristics of the purified lipase-foldase preparation were investigated. This preparation was active and stable over a wide range of pH values (6.5-9.5) and temperatures (10-40°C), with the highest specific activity, of 1500 U mg−1, being obtained at pH 7.5 at 30°C. It also had high specific activities against tributyrin, tricaprylin and triolein, with values of 1852, 1566 and 817 U mg−1, respectively. A phylogenetic analysis placed LipG9 in the lipase subfamily I.1. A comparison of the sequence of LipG9 with those of other bacterial lipases in the Protein Data Bank showed that LipG9 contains not only the classic catalytic triad (Ser103, Asp250, His272), with the catalytic Ser occurring within a conserved pentapeptide, Gly-His-Ser-His-Gly, but also a conserved disulfide bridge and a conserved calcium binding site. The homology-modeled structure presents a canonical α/β hydrolase folding type I. Conclusions This paper is the first to report the successful co-expression of a lipase and its associated foldase from a metagenomic library. The high activity and stability of Lip-LifG9 suggest that it has a good potential for use in biocatalysis. Electronic supplementary material The online version of this article (doi:10.1186/s12934-014-0171-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Viviane Paula Martini
- Departamento de Química, Universidade Federal do Paraná, Cx. P. 19081 Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil. .,Instituto Federal do Paraná - Campus Irati, Rua Pedro Koppe, 100, Irati, 84500-000, Paraná, Brazil.
| | - Arnaldo Glogauer
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046, Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil. .,Agência Tecpar de Inovação, Instituto de Tecnologia do Paraná - Tecpar, Curitiba, 81350-010, Paraná, Brazil.
| | - Marcelo Müller-Santos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046, Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil.
| | - Jorge Iulek
- Departamento de Química, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, Ponta Grossa, 84070-900, Paraná, Brazil.
| | - Emanuel Maltempi de Souza
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046, Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil.
| | - David Alexander Mitchell
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046, Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil.
| | - Fabio Oliveira Pedrosa
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx. P. 19046, Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil.
| | - Nadia Krieger
- Departamento de Química, Universidade Federal do Paraná, Cx. P. 19081 Centro Politécnico, Curitiba, 81531-980, Paraná, Brazil.
| |
Collapse
|
33
|
Vester JK, Glaring MA, Stougaard P. Improved cultivation and metagenomics as new tools for bioprospecting in cold environments. Extremophiles 2014; 19:17-29. [PMID: 25399309 PMCID: PMC4272415 DOI: 10.1007/s00792-014-0704-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 10/28/2014] [Indexed: 11/28/2022]
Abstract
Only a small minority of microorganisms from an environmental sample can be cultured in the laboratory leaving the enormous bioprospecting potential of the uncultured diversity unexplored. This resource can be accessed by improved cultivation methods in which the natural environment is brought into the laboratory or through metagenomic approaches where culture-independent DNA sequence information can be combined with functional screening. The coupling of these two approaches circumvents the need for pure, cultured isolates and can be used to generate targeted information on communities enriched for specific activities or properties. Bioprospecting in extreme environments is often associated with additional challenges such as low biomass, slow cell growth, complex sample matrices, restricted access, and problematic in situ analyses. In addition, the choice of vector system and expression host may be limited as few hosts are available for expression of genes with extremophilic properties. This review summarizes the methods developed for improved cultivation as well as the metagenomic approaches for bioprospecting with focus on the challenges faced by bioprospecting in cold environments.
Collapse
Affiliation(s)
- Jan Kjølhede Vester
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark,
| | | | | |
Collapse
|
34
|
Yang G, Ding Y. Recent advances in biocatalyst discovery, development and applications. Bioorg Med Chem 2014; 22:5604-12. [DOI: 10.1016/j.bmc.2014.06.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 12/25/2022]
|
35
|
Culligan EP, Sleator RD, Marchesi JR, Hill C. Metagenomic identification of a novel salt tolerance gene from the human gut microbiome which encodes a membrane protein with homology to a brp/blh-family β-carotene 15,15'-monooxygenase. PLoS One 2014; 9:e103318. [PMID: 25058308 PMCID: PMC4110020 DOI: 10.1371/journal.pone.0103318] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/29/2014] [Indexed: 12/30/2022] Open
Abstract
The human gut microbiome consists of at least 3 million non-redundant genes, 150 times that of the core human genome. Herein, we report the identification and characterisation of a novel stress tolerance gene from the human gut metagenome. The locus, assigned brpA, encodes a membrane protein with homology to a brp/blh-family β-carotene monooxygenase. Cloning and heterologous expression of brpA in Escherichia coli confers a significant salt tolerance phenotype. Furthermore, when cultured in the presence of exogenous β-carotene, cell pellets adopt a red/orange pigmentation indicating the incorporation of carotenoids in the cell membrane.
Collapse
Affiliation(s)
- Eamonn P. Culligan
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - Roy D. Sleator
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
- * E-mail: (CH); (RDS); (JRM)
| | - Julian R. Marchesi
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
- Department of Hepatology and Gastroenterology, Imperial College London, London, United Kingdom
- * E-mail: (CH); (RDS); (JRM)
| | - Colin Hill
- Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
- * E-mail: (CH); (RDS); (JRM)
| |
Collapse
|
36
|
Discovery of novel enzymes with industrial potential from a cold and alkaline environment by a combination of functional metagenomics and culturing. Microb Cell Fact 2014; 13:72. [PMID: 24886068 PMCID: PMC4035831 DOI: 10.1186/1475-2859-13-72] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/13/2014] [Indexed: 02/01/2023] Open
Abstract
Background The use of cold-active enzymes has many advantages, including reduced energy consumption and easy inactivation. The ikaite columns of SW Greenland are permanently cold (4-6°C) and alkaline (above pH 10), and the microorganisms living there and their enzymes are adapted to these conditions. Since only a small fraction of the total microbial diversity can be cultured in the laboratory, a combined approach involving functional screening of a strain collection and a metagenomic library was undertaken for discovery of novel enzymes from the ikaite columns. Results A strain collection with 322 cultured isolates was screened for enzymatic activities identifying a large number of enzyme producers, with a high re-discovery rate to previously characterized strains. A functional expression library established in Escherichia coli identified a number of novel cold-active enzymes. Both α-amylases and β-galactosidases were characterized in more detail with respect to temperature and pH profiles and one of the β-galactosidases, BGalI17E2, was able to hydrolyze lactose at 5°C. A metagenome sequence of the expression library indicated that the majority of enzymatic activities were not detected by functional expression. Phylogenetic analysis showed that different bacterial communities were targeted with the culture dependent and independent approaches and revealed the bias of multiple displacement amplification (MDA) of DNA isolated from complex microbial communities. Conclusions Many cold- and/or alkaline-active enzymes of industrial relevance were identified in the culture based approach and the majority of the enzyme-producing isolates were closely related to previously characterized strains. The function-based metagenomic approach, on the other hand, identified several enzymes (β-galactosidases, α-amylases and a phosphatase) with low homology to known sequences that were easily expressed in the production host E. coli. The β-galactosidase BGalI17E2 was able to hydrolyze lactose at low temperature, suggesting a possibly use in the dairy industry for this enzyme. The two different approaches complemented each other by targeting different microbial communities, highlighting the usefulness of combining methods for bioprospecting. Finally, we document here that ikaite columns constitute an important source of cold- and/or alkaline-active enzymes with industrial application potential.
Collapse
|
37
|
Culligan EP, Sleator RD, Marchesi JR, Hill C. Metagenomics and novel gene discovery: promise and potential for novel therapeutics. Virulence 2014; 5:399-412. [PMID: 24317337 PMCID: PMC3979868 DOI: 10.4161/viru.27208] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/21/2013] [Accepted: 11/14/2013] [Indexed: 02/06/2023] Open
Abstract
Metagenomics provides a means of assessing the total genetic pool of all the microbes in a particular environment, in a culture-independent manner. It has revealed unprecedented diversity in microbial community composition, which is further reflected in the encoded functional diversity of the genomes, a large proportion of which consists of novel genes. Herein, we review both sequence-based and functional metagenomic methods to uncover novel genes and outline some of the associated problems of each type of approach, as well as potential solutions. Furthermore, we discuss the potential for metagenomic biotherapeutic discovery, with a particular focus on the human gut microbiome and finally, we outline how the discovery of novel genes may be used to create bioengineered probiotics.
Collapse
Affiliation(s)
- Eamonn P Culligan
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
| | - Roy D Sleator
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork, Ireland
| | - Julian R Marchesi
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- Cardiff School of Biosciences; Cardiff University; Cardiff, UK
- Department of Hepatology and Gastroenterology; Imperial College London; London, UK
| | - Colin Hill
- Alimentary Pharmabiotic Centre; University College Cork; Cork, Ireland
- School of Microbiology; University College Cork; Cork, Ireland
| |
Collapse
|
38
|
Kimura N. Metagenomic approaches to understanding phylogenetic diversity in quorum sensing. Virulence 2014; 5:433-42. [PMID: 24429899 DOI: 10.4161/viru.27850] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Quorum sensing, a form of cell-cell communication among bacteria, allows bacteria to synchronize their behaviors at the population level in order to control behaviors such as luminescence, biofilm formation, signal turnover, pigment production, antibiotics production, swarming, and virulence. A better understanding of quorum-sensing systems will provide us with greater insight into the complex interaction mechanisms used widely in the Bacteria and even the Archaea domain in the environment. Metagenomics, the use of culture-independent sequencing to study the genomic material of microorganisms, has the potential to provide direct information about the quorum-sensing systems in uncultured bacteria. This article provides an overview of the current knowledge of quorum sensing focused on phylogenetic diversity, and presents examples of studies that have used metagenomic techniques. Future technologies potentially related to quorum-sensing systems are also discussed.
Collapse
Affiliation(s)
- Nobutada Kimura
- Bioproduction Research Institute; National Institute of Advanced Industrial Science and Technology (AIST); Tsukuba, Ibaraki Japan
| |
Collapse
|
39
|
Abstract
The genomic revolution promises great advances in the search for useful biocatalysts. Function-based metagenomic approaches have identified several enzymes with properties that make them useful candidates for a variety of bioprocesses. As DNA sequencing costs continue to decline, the volume of genomic data, along with their corresponding predicted protein sequences, will continue to increase dramatically, necessitating new approaches to leverage this information for gene-based bioprospecting efforts. Additionally, as new functions are discovered and correlated with this sequence information, the knowledge of the often complex relationship between a protein's sequence and function will improve. This in turn will lead to better gene-based bioprospecting approaches and facilitate the tailoring of desired properties through protein engineering projects. In this chapter, we discuss a number of recent advances in bioprospecting within the context of the genomic age.
Collapse
Affiliation(s)
- Michael A Hicks
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Kristala L J Prather
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA; Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
| |
Collapse
|
40
|
Garst A, Lynch M, Evans R, Gill RT. Strategies for the multiplex mapping of genes to traits. Microb Cell Fact 2013; 12:99. [PMID: 24171944 PMCID: PMC3842685 DOI: 10.1186/1475-2859-12-99] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/20/2013] [Indexed: 12/19/2022] Open
Abstract
Rewiring and optimization of metabolic networks to enable the production of commercially valuable chemicals is a central goal of metabolic engineering. This prospect is challenged by the complexity of metabolic networks, lack of complete knowledge of gene function(s), and the vast combinatorial genotype space that is available for exploration and optimization. Various approaches have thus been developed to aid in the efficient identification of genes that contribute to a variety of different phenotypes, allowing more rapid design and engineering of traits desired for industrial applications. This review will highlight recent technologies that have enhanced capabilities to map genotype-phenotype relationships on a genome wide scale and emphasize how such approaches enable more efficient design and engineering of complex phenotypes.
Collapse
Affiliation(s)
| | | | | | - Ryan T Gill
- Department of Chemical and Biological Engineering, University of Colorado, Campus Box 592, Boulder, CO 80303, USA.
| |
Collapse
|
41
|
Zarraonaindia I, Smith DP, Gilbert JA. Beyond the genome: community-level analysis of the microbial world. BIOLOGY & PHILOSOPHY 2013; 28:261-282. [PMID: 23482824 PMCID: PMC3585761 DOI: 10.1007/s10539-012-9357-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 11/29/2012] [Indexed: 05/10/2023]
Abstract
The development of culture-independent strategies to study microbial diversity and function has led to a revolution in microbial ecology, enabling us to address fundamental questions about the distribution of microbes and their influence on Earth's biogeochemical cycles. This article discusses some of the progress that scientists have made with the use of so-called "omic" techniques (metagenomics, metatranscriptomics, and metaproteomics) and the limitations and major challenges these approaches are currently facing. These 'omic methods have been used to describe the taxonomic structure of microbial communities in different environments and to discover new genes and enzymes of industrial and medical interest. However, microbial community structure varies in different spatial and temporal scales and none of the 'omic techniques are individually able to elucidate the complex aspects of microbial communities and ecosystems. In this article we highlight the importance of a spatiotemporal sampling design, together with a multilevel 'omic approach and a community analysis strategy (association networks and modeling) to examine and predict interacting microbial communities and their impact on the environment.
Collapse
Affiliation(s)
- Iratxe Zarraonaindia
- Argonne National Laboratory, Institute for Genomic and Systems Biology, 9700 South Cass Avenue, Argonne, IL 60439 USA
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| | - Daniel P. Smith
- Argonne National Laboratory, Institute for Genomic and Systems Biology, 9700 South Cass Avenue, Argonne, IL 60439 USA
| | - Jack A. Gilbert
- Argonne National Laboratory, Institute for Genomic and Systems Biology, 9700 South Cass Avenue, Argonne, IL 60439 USA
- Department of Ecology and Evolution, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 USA
| |
Collapse
|
42
|
Heterologous viral expression systems in fosmid vectors increase the functional analysis potential of metagenomic libraries. Sci Rep 2013; 3:1107. [PMID: 23346364 PMCID: PMC3551230 DOI: 10.1038/srep01107] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/08/2013] [Indexed: 01/26/2023] Open
Abstract
The extraordinary potential of metagenomic functional analyses to identify activities of interest present in uncultured microorganisms has been limited by reduced gene expression in surrogate hosts. We have developed vectors and specialized E. coli strains as improved metagenomic DNA heterologous expression systems, taking advantage of viral components that prevent transcription termination at metagenomic terminators. One of the systems uses the phage T7 RNA-polymerase to drive metagenomic gene expression, while the other approach uses the lambda phage transcription anti-termination protein N to limit transcription termination. A metagenomic library was constructed and functionally screened to identify genes conferring carbenicillin resistance to E. coli. The use of these enhanced expression systems resulted in a 6-fold increase in the frequency of carbenicillin resistant clones. Subcloning and sequence analysis showed that, besides β-lactamases, efflux pumps are not only able contribute to carbenicillin resistance but may in fact be sufficient by themselves to convey carbenicillin resistance.
Collapse
|
43
|
|
44
|
Ouyang LM, Liu JY, Qiao M, Xu JH. Isolation and biochemical characterization of two novel metagenome-derived esterases. Appl Biochem Biotechnol 2012; 169:15-28. [PMID: 23117418 DOI: 10.1007/s12010-012-9949-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/25/2012] [Indexed: 10/27/2022]
Abstract
Environmental DNA from soil and water samples was extracted to construct a plasmid library and a fosmid library containing 19,500 and 20,400 clones, respectively. Two esterases (EstP2K and EstF4K) were finally isolated from each library based on activity screening, and both of them were characterized in this study. The esterase EstF4K consists of 396 amino acids with an SMTK motif which belongs to family VIII esterase/lipase. The amino acid sequence of EstF4K showed 83 % identity with that of EstA3, a reported esterase isolated from uncultured organisms of soil. EstP2K is composed of 224 amino acids in size and shows only 37 % identity with a putative lipase of Neisseria elongata subsp. The purified EstF4K was optimally active at pH 8.0 and 50 °C. It was remarkably active and very stable in the presence of 30 % dimethyl sulfoxide. Activity fingerprint of EstF4K displayed a higher level of activity toward short-chain fatty acid p-nitrophenyl (pNP) esters, while EstP2K preferred bias for pNP caprylate ester. The optimum reaction temperature and pH for EstP2K are 45 °C and 7.5, respectively, and the enzyme exhibited strong tolerance in the presence of 30 % methanol. EstF4K and EstP2K showed opposite enantioselectivity for methyl 3-phenylglycidate, a chiral synthon for the synthesis of Taxol® side chain.
Collapse
Affiliation(s)
- Li-Ming Ouyang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People's Republic of China.
| | | | | | | |
Collapse
|
45
|
Xing MN, Zhang XZ, Huang H. Application of metagenomic techniques in mining enzymes from microbial communities for biofuel synthesis. Biotechnol Adv 2012; 30:920-9. [DOI: 10.1016/j.biotechadv.2012.01.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
46
|
Delavat F, Phalip V, Forster A, Plewniak F, Lett MC, Lièvremont D. Amylases without known homologues discovered in an acid mine drainage: significance and impact. Sci Rep 2012; 2:354. [PMID: 22482035 PMCID: PMC3319935 DOI: 10.1038/srep00354] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/08/2012] [Indexed: 12/25/2022] Open
Abstract
Acid Mine Drainages (AMDs) are extreme environments characterized by acidic and oligotrophic conditions and by metal contaminations. A function-based screening of an AMD-derived metagenomic library led to the discovery and partial characterization of two non-homologous endo-acting amylases sharing no sequence similarity with any known amylase nor glycosidase. None carried known amylolytic domains, nor could be assigned to any GH-family. One amylase displayed no similarity with any known protein, whereas the second one was similar to TraC proteins involved in the bacterial type IV secretion system. According to the scarce similarities with known proteins, 3D-structure modelling using I-TASSER was unsuccessful. This study underlined the utility of a function-driven metagenomic approach to obtain a clearer image of the bacterial community enzymatic landscape. More generally, this work points out that screening for microorganisms or biomolecules in a priori incongruous environments could provide unconventional and new exciting ways for bioprospecting.
Collapse
|
47
|
Sharma N, Tanksale H, Kapley A, Purohit HJ. Mining the metagenome of activated biomass of an industrial wastewater treatment plant by a novel method. Indian J Microbiol 2012; 52:538-43. [PMID: 24293707 DOI: 10.1007/s12088-012-0263-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/01/2012] [Indexed: 12/01/2022] Open
Abstract
Metagenomic libraries herald the era of magnifying the microbial world, tapping into the vast metabolic potential of uncultivated microbes, and enhancing the rate of discovery of novel genes and pathways. In this paper, we describe a method that facilitates the extraction of metagenomic DNA from activated sludge of an industrial wastewater treatment plant and its use in mining the metagenome via library construction. The efficiency of this method was demonstrated by the large representation of the bacterial genome in the constructed metagenomic libraries and by the functional clones obtained. The BAC library represented 95.6 times the bacterial genome, while, the pUC library represented 41.7 times the bacterial genome. Twelve clones in the BAC library demonstrated lipolytic activity, while four clones demonstrated dioxygenase activity. Four clones in pUC library tested positive for cellulase activity. This method, using FTA cards, not only can be used for library construction, but can also store the metagenome at room temperature.
Collapse
Affiliation(s)
- Nandita Sharma
- Environmental Genomics Division, National Environmental Engineering Research Institute, CSIR, Nehru Marg, Nagpur, 440020 Maharashtra India
| | | | | | | |
Collapse
|
48
|
Jeong YS, Na HB, Kim SK, Kim YH, Kwon EJ, Kim J, Yun HD, Lee JK, Kim H. Characterization of Xyn10J, a Novel Family 10 Xylanase from a Compost Metagenomic Library. Appl Biochem Biotechnol 2012; 166:1328-39. [DOI: 10.1007/s12010-011-9520-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Accepted: 12/21/2011] [Indexed: 11/29/2022]
|
49
|
Ekkers DM, Cretoiu MS, Kielak AM, van Elsas JD. The great screen anomaly--a new frontier in product discovery through functional metagenomics. Appl Microbiol Biotechnol 2011; 93:1005-20. [PMID: 22189864 PMCID: PMC3264863 DOI: 10.1007/s00253-011-3804-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 11/27/2011] [Accepted: 11/29/2011] [Indexed: 11/25/2022]
Abstract
Functional metagenomics, the study of the collective genome of a microbial community by expressing it in a foreign host, is an emerging field in biotechnology. Over the past years, the possibility of novel product discovery through metagenomics has developed rapidly. Thus, metagenomics has been heralded as a promising mining strategy of resources for the biotechnological and pharmaceutical industry. However, in spite of innovative work in the field of functional genomics in recent years, yields from function-based metagenomics studies still fall short of producing significant amounts of new products that are valuable for biotechnological processes. Thus, a new set of strategies is required with respect to fostering gene expression in comparison to the traditional work. These new strategies should address a major issue, that is, how to successfully express a set of unknown genes of unknown origin in a foreign host in high throughput. This article is an opinionating review of functional metagenomic screening of natural microbial communities, with a focus on the optimization of new product discovery. It first summarizes current major bottlenecks in functional metagenomics and then provides an overview of the general metagenomic assessment strategies, with a focus on the challenges that are met in the screening for, and selection of, target genes in metagenomic libraries. To identify possible screening limitations, strategies to achieve optimal gene expression are reviewed, examining the molecular events all the way from the transcription level through to the secretion of the target gene product.
Collapse
Affiliation(s)
- David Matthias Ekkers
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Mariana Silvia Cretoiu
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Anna Maria Kielak
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| |
Collapse
|
50
|
Gao M, Wang L, Chen SF. Metagenome cloning and functional analysis of Na⁺/H⁺ antiporter genes from Keke Salt Lake in China. Curr Microbiol 2011; 64:179-84. [PMID: 22101456 DOI: 10.1007/s00284-011-0053-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/07/2011] [Indexed: 11/24/2022]
Abstract
Na⁺/H⁺ antiporters are ubiquitous membrane proteins and play a central role in cell homeostasis including pH regulation, osmoregulation, and Na⁺/Li⁺ tolerance in bacteria. The microbial communities in extremely hypersaline soil are an important resource for isolating Na⁺/H⁺ antiporter genes. A metagenomic library containing 35,700 clones was constructed by using genomic DNA obtained from the hypersaline soil samples of Keke Salt Lake in Northwest of China. Two Na⁺/H⁺ antiporters, K1-NhaD, and K2-NhaD belonging to NhaD family, were screened and cloned from this metagenome by complementing the triple mutant Escherichia coli strain KNabc (nhaA⁻, nhaB⁻, chaA⁻) in medium containing 0.2 M NaCl. K1-NhaD and K2-NhaD have 75.5% identity at the predicted amino acid sequence. K1-NhaD has 78% identity with Na⁺/H⁺ antiporter NhaD from Halomonas elongate at the predicted amino acid sequence. The predicted K1-NhaD is a 53.5 kDa protein (487 amino acids) with 13 transmembrane helices. K2-NhaD has 73% identity with Alkalimonas amylolytica NhaD. The predicted K2-NhaD is a 55 kDa protein (495 amino acids) with 12 transmembrane helices. Both K1-NhaD and K2-NhaD could make the triple mutant E. coli KNabc (nhaA⁻, nhaB⁻, chaA⁻) grow in the LBK medium containing 0.2-0.6 M Na⁺ or with 0.05-0.4 M Li⁺. Everted membrane vesicles prepared from E. coli KNabc cells carrying K1-NhaD or K2-NhaD exhibited Na⁺/H⁺ and Li⁺/H⁺ antiporter activities which were pH-dependent with the highest activity at pH 9.5. Little K⁺/H⁺ antiporter activity was also detected in vesicles form E. coli KNabc carrying K1-NhaD or K2-NhaD.
Collapse
Affiliation(s)
- Maio Gao
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, People's Republic of China
| | | | | |
Collapse
|