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Parveen S, Akhtar N, Ghauri MA, Akhtar K. Conventional genetic manipulation of desulfurizing bacteria and prospects of using CRISPR-Cas systems for enhanced desulfurization activity. Crit Rev Microbiol 2020; 46:300-320. [PMID: 32530374 DOI: 10.1080/1040841x.2020.1772195] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Highly active and stable biocatalysts are the prerequisite for industrial scale application of the biodesulfurization process. Scientists are making efforts for increasing the desulfurizing activity of native strains by employing various genetic engineering approaches. Nevertheless, the achieved desulfurization rate is lower than the industrial requirements. Thus, there is a dire need to use efficient genetic tools for precise genome editing of desulfurizing bacteria for enhanced efficiency. In comparison to the previously used genetic engineering tools the newly developed CRISPR-Cas is a more efficient and simple genetic tool that has been successfully applied for targeted genome modification of eukaryotes as well as prokaryotes. In this paper, we have reviewed the approaches, previously used to enhance the biodesulfurization rates of the sulfur metabolizing microorganisms and have discussed the potential of CRISPR-Cas systems in engineering desulfurizing biocatalysts. We have also proposed a model to construct competent desulfurizing recombinants involving use of CRISPR-Cas technology. The model can be used to over-express the dsz genes under a constitutive promoter in a suitable heterologous host, to get a steady expression of desulfurization pathway. This may serve as an inducement to develop better performing desulfurizing recombinant strains using CRISPR-Cas systems, which can be helpful in increasing the rate of biodesulfurization in future.
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Affiliation(s)
- Sana Parveen
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Constituent College of Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
| | - Nasrin Akhtar
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Constituent College of Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
| | - Muhammad A Ghauri
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Constituent College of Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
| | - Kalsoom Akhtar
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Constituent College of Pakistan Institute of Engineering and Applied Sciences (PIEAS), Faisalabad, Pakistan
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Fujino Y, Goda S, Suematsu Y, Doi K. Development of a new gene expression vector for Thermus thermophilus using a silica-inducible promoter. Microb Cell Fact 2020; 19:126. [PMID: 32513169 PMCID: PMC7282064 DOI: 10.1186/s12934-020-01385-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/01/2020] [Indexed: 01/30/2023] Open
Abstract
Background Thermostable enzymes are commonly produced in mesophilic hosts for research and bioengineering purposes. However, these hosts do not overexpress the active forms of some biologically functional thermoenzymes. Therefore, an efficient thermophilic expression system is needed. Thermus thermophilus contains an easily manipulable genome and is therefore among the best candidate microbes for a “hot” expression system. We previously identified a strong and inducible promoter that was active in T. thermophilus under supersaturated silica conditions. Here, we report a new heterologous gene expression system based on a silica-inducible promoter in T. thermophilus. Results A Thermus sp. A4 gene encoding thermostable β-galactosidase was cloned as a reporter gene into the expression vector pSix1, which contains a selection marker that confers thermostable resistance to hygromycin and a 600 bp DNA region containing a putative silica-inducible promoter. β-galactosidase activity was 11-fold higher in the presence than in the absence of 10 mM silicic acid. SDS-PAGE revealed a prominent band corresponding to 73 kDa of β-galactosidase, and this enzyme was expressed as an active and soluble protein (yield: 27 mg/L) in Thermus but as an inclusion body in Escherichia coli. Truncation of the putative silica-inducible promoter region in Thermus expression vector improved the yield of the target protein, possibly by avoiding plasmid instability due to homologous recombination. Finally, we developed an expression vector containing the pSix1 backbone and a 100 bp DNA region corresponding to the silica-inducible promoter. We used this vector to successfully express the active form of glutamate dehydrogenase from Pyrobaculum islandicum (PisGDH) without additional treatment (yield: 9.5 mg/L), whereas the expression of active PisGDH in E. coli required heat treatment. Conclusion We successfully expressed the thermostable β-galactosidase and PisGDH in T. thermophilus as active and soluble forms and achieved with our system the highest known protein expression levels in this species. These thermoenzymes were expressed in active and soluble forms. Our results validate the use of our silica-inducible expression system as a novel strategy for the intracellular overexpression of thermostable proteins.
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Affiliation(s)
- Yasuhiro Fujino
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Shuichiro Goda
- Graduate School of Science and Engineering, Soka University, 1-236, Tangi-cho, Hachioji-shi, Tokyo, 192-8577, Japan
| | - Yuri Suematsu
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Katsumi Doi
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Loder AJ, Zeldes BM, Conway JM, Counts JA, Straub CT, Khatibi PA, Lee LL, Vitko NP, Keller MW, Rhaesa AM, Rubinstein GM, Scott IM, Lipscomb GL, Adams MW, Kelly RM. Extreme Thermophiles as Metabolic Engineering Platforms: Strategies and Current Perspective. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Andrew J. Loder
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Benjamin M. Zeldes
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Jonathan M. Conway
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - James A. Counts
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Christopher T. Straub
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Piyum A. Khatibi
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Laura L. Lee
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Nicholas P. Vitko
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Matthew W. Keller
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Amanda M. Rhaesa
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gabe M. Rubinstein
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Israel M. Scott
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gina L. Lipscomb
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Michael W.W. Adams
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Robert M. Kelly
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
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Kilbane JJ. Biodesulfurization: How to Make it Work? ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2016. [DOI: 10.1007/s13369-016-2269-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Polysaccharide-degrading thermophiles generated by heterologous gene expression in Geobacillus kaustophilus HTA426. Appl Environ Microbiol 2013; 79:5151-8. [PMID: 23793634 DOI: 10.1128/aem.01506-13] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thermophiles have important advantages over mesophiles as host organisms for high-temperature bioprocesses, functional production of thermostable enzymes, and efficient expression of enzymatic activities in vivo. To capitalize on these advantages of thermophiles, we describe here a new inducible gene expression system in the thermophile Geobacillus kaustophilus HTA426. Six promoter regions in the HTA426 genome were identified and analyzed for expression profiles using β-galactosidase reporter assay. This analysis identified a promoter region upstream of a putative amylose-metabolizing gene cluster that directed high-level expression of the reporter gene. The expression was >280-fold that without a promoter and was further enhanced 12-fold by maltose addition. In association with a multicopy plasmid, this promoter region was used to express heterologous genes. Several genes, including a gene whose product was insoluble when expressed in Escherichia coli, were successfully expressed as soluble proteins, with yields of 0.16 to 59 mg/liter, and conferred new functions to G. kaustophilus strains. Remarkably, cellulase and α-amylase genes conferred the ability to degrade cellulose paper and insoluble starch at high temperatures, respectively, generating thermophiles with the potential to degrade plant biomass. Our results demonstrate that this novel expression system expands the potential applications of G. kaustophilus.
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Taylor MP, van Zyl L, Tuffin IM, Leak DJ, Cowan DA. Genetic tool development underpins recent advances in thermophilic whole-cell biocatalysts. Microb Biotechnol 2011; 4:438-48. [PMID: 21310009 PMCID: PMC3815256 DOI: 10.1111/j.1751-7915.2010.00246.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The environmental value of sustainably producing bioproducts from biomass is now widely appreciated, with a primary target being the economic production of fuels such as bioethanol from lignocellulose. The application of thermophilic prokaryotes is a rapidly developing niche in this field, driven by their known catabolic versatility with lignocellulose-derived carbohydrates. Fundamental to the success of this work has been the development of reliable genetic and molecular systems. These technical tools are now available to assist in the development of other (hyper)thermophilic strains with diverse phenotypes such as hemicellulolytic and cellulolytic properties, branched chain alcohol production and other 'valuable bioproduct' synthetic capabilities. Here we present an insight into the historical limitations, recent developments and current status of a number of genetic systems for thermophiles. We also highlight the value of reliable genetic methods for increasing our knowledge of thermophile physiology. We argue that the development of robust genetic systems is paramount in the evolution of future thermophilic based bioprocesses and make suggestions for future approaches and genetic targets that will facilitate this process.
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Affiliation(s)
- M P Taylor
- Institute for Microbial Biotechnology and Metagenomics (IMBM), University of the Western Cape, Modderdam Road, Bellville 7535, Cape Town, South Africa
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Larentis AL, Sampaio HDCC, Martins OB, Rodrigues MI, Alves TLM. Influence of induction conditions on the expression of carbazole dioxygenase components (CarAa, CarAc, and CarAd) from Pseudomonas stutzeri in recombinant Escherichia coli using experimental design. J Ind Microbiol Biotechnol 2010; 38:1045-54. [PMID: 20953895 DOI: 10.1007/s10295-010-0879-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Accepted: 09/15/2010] [Indexed: 10/18/2022]
Abstract
Carbazole 1,9a-dioxygenase (CarA), the first enzyme in the carbazole degradation pathway used by Pseudomonas sp., was expressed in E. coli under different conditions defined by experimental design. This enzyme depends on the coexistence of three components containing [2Fe-2S] clusters: CarAa, CarAc, and CarAd. The catalytic site is present in CarAa. The genes corresponding to components of carbazole 1,9a-dioxygenase from P. stutzeri were cloned and expressed by salt induction in E. coli BL21-SI (a host that allows the enhancement of overexpressed proteins in the soluble fraction), using the vector pDEST™14. The expression of these proteins was performed under different induction conditions (cell concentration, temperature, and time), with the help of two-level factorial design. Cell concentration at induction (measured by absorbance at 600 nm) was tested at 0.5 and 0.8. After salt induction, expression was performed at 30 and 37°C, for 4 h and 24 h. Protein expression was evaluated by densitometry analysis. Expression of CarAa was enhanced by induction at a lower cell concentration and temperature and over a longer time, according to the analysis of the experimental design results. The results were validated at Abs (ind) = 0.3, 25°C, and 24 h, at which CarAa expression was three times higher than under the standard condition. The behavior of CarAc and CarAd was the inverse, with the best co-expression condition tested being the standard one (Abs (ind) = 0.5, T = 37°C, and t = 4 h). The functionality of the proteins expressed in E. coli was confirmed by the degradation of 20 ppm carbazole.
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Affiliation(s)
- Ariane Leites Larentis
- Laboratório de Bioprocessos, Universidade Federal do Rio de Janeiro-UFRJ, Centro de Tecnologia (CT), G115, Cidade Universitária, Ilha do Fundão, Caixa Postal 68502, Rio de Janeiro, RJ, 21945-970, Brazil.
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DUAN Y, CHEN T, CHEN X, Jingyu W, ZHAO X. Enhanced Riboflavin Production by Expressing Heterologous Riboflavin Operon from B. cereus ATCC14579 in Bacillus subtilis. Chin J Chem Eng 2010. [DOI: 10.1016/s1004-9541(08)60333-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Angelov A, Mientus M, Liebl S, Liebl W. A two-host fosmid system for functional screening of (meta)genomic libraries from extreme thermophiles. Syst Appl Microbiol 2009; 32:177-85. [PMID: 19285378 DOI: 10.1016/j.syapm.2008.01.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2007] [Revised: 01/24/2008] [Accepted: 01/27/2008] [Indexed: 11/24/2022]
Abstract
A new cloning system is described, which allows the construction of large-insert fosmid libraries in Escherichia coli and the transfer of the recombinant libraries to the extreme thermophile Thermus thermophilus via natural transformation. Libraries are established in the thermophilic host by site-specific chromosomal insertion of the recombinant fosmids via single crossover or double crossover recombination at the T. thermophilus pyr locus. Comparative screening of a fosmid library constructed from genomic DNA from the thermophilic spirochaete, Spirochaeta thermophila, for clones expressing thermoactive xylanase activity revealed that 50% of the fosmids that conferred xylanase activity upon the corresponding T. thermophilus transformants did not give rise to xylanase-positive E. coli clones, indicating that significantly more S. thermophila genes are functionally expressed in T. thermophilus than in E. coli. The novel T. thermophilus host/vector system may be of value for the construction and functional screening of recombinant DNA libraries from individual thermophilic or extremely thermophilic organisms as well as from complex metagenomes isolated from thermophilic microbial communities.
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Affiliation(s)
- Angel Angelov
- Institut f. Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, D-37077 Goettingen, Germany
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Thermus thermophilus as biological model. Extremophiles 2009; 13:213-31. [DOI: 10.1007/s00792-009-0226-6] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 12/31/2008] [Indexed: 10/21/2022]
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Enzymatic analysis of a thermostabilized mutant of an Escherichia coli hygromycin B phosphotransferase. Biosci Biotechnol Biochem 2008; 72:2467-71. [PMID: 18776672 DOI: 10.1271/bbb.80285] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An Escherichia coli hygromycin B phosphotransferase (HPH) and its thermostabilized mutant protein, HPH5, containing five amino acid substitutions, D20G, A118V, S225P, Q226L, and T246A (Nakamura et al., J. Biosci. Bioeng., 100, 158-163 (2005)), obtained by an in vivo directed evolution procedure in Thermus thermophilus, were produced and purified from E. coli recombinants, and enzymatic comparisons were performed. The optimum temperatures for enzyme activity were 50 and 55 degrees C for HPH and HPH5 respectively, but the thermal stability of the enzyme activity and the temperature for protein denaturation of HPH5 increased, from 36 and 37.2 degrees C of HPH to 53 and 58.8 degrees C respectively. Specific activities and steady-state kinetics measured at 25 degrees C showed only slight differences between the two enzymes. From these results we concluded that HPH5 was thermostabilized at the protein level, and that the mutations introduced did not affect its enzyme activity, at least under the assay conditions.
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Bjornsdottir SH, Fridjonsson OH, Kristjansson JK, Eggertsson G. Cloning and expression of heterologous genes in Rhodothermus marinus. Extremophiles 2006; 11:283-93. [PMID: 17124556 DOI: 10.1007/s00792-006-0037-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 10/01/2006] [Indexed: 10/23/2022]
Abstract
The construction of a shuttle cloning system for Rhodothermus marinus and Escherichia coli is described. It is based on the shuttle vector pRM3000, which contains a multiple cloning site as well as the shuttle marker trpB and TrpB(-) recipients of both species. The vector is stable and in 25 +/- 2 and 91 +/- 3 copies in R. marinus SB-1 and E. coli SDH-1, respectively. Three different R. marinus regulatory sequences of the dnaJ, dnaK and recA genes were integrated into pRM3000 to make the expression vectors pRM5100, pRM5200 and pRM5300, respectively. Genes encoding alpha- and beta-galactosidase (agaT and bgaT) from Thermus brockianus were cloned in R. marinus. Expression of both recombinant genes in R. marinus was demonstrated. The agaT gene was used as a reporter to study transcription from the expression vectors. Induced expression by ten- and twentyfold was observed from the dnaK and dnaJ regulatory sequences, respectively, after a temperature shift from 63 to 77 degrees C. This is the first report of cloning and expression of heterologous genes in R. marinus and the first study of promoter activity in the species.
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Kilbane JJ. Microbial biocatalyst developments to upgrade fossil fuels. Curr Opin Biotechnol 2006; 17:305-14. [PMID: 16678400 DOI: 10.1016/j.copbio.2006.04.005] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 03/25/2006] [Accepted: 04/26/2006] [Indexed: 11/26/2022]
Abstract
Steady increases in the average sulfur content of petroleum and stricter environmental regulations concerning the sulfur content have promoted studies of bioprocessing to upgrade fossil fuels. Bioprocesses can potentially provide a solution to the need for improved and expanded fuel upgrading worldwide, because bioprocesses for fuel upgrading do not require hydrogen and produce far less carbon dioxide than thermochemical processes. Recent advances have demonstrated that biodesulfurization is capable of removing sulfur from hydrotreated diesel to yield a product with an ultra-low sulfur concentration that meets current environmental regulations. However, the technology has not yet progressed beyond laboratory-scale testing, as more efficient biocatalysts are needed. Genetic studies to obtain improved biocatalysts for the selective removal of sulfur and nitrogen from petroleum provide the focus of current research efforts.
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Lyngberg OK, Solheid C, Charaniya S, Ma Y, Thiagarajan V, Scriven LE, Flickinger MC. Permeability and reactivity of Thermotoga maritima in latex bimodal blend coatings at 80°C: a model high temperature biocatalytic coating. Extremophiles 2005; 9:197-207. [PMID: 15778817 DOI: 10.1007/s00792-005-0434-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Accepted: 01/07/2005] [Indexed: 11/26/2022]
Abstract
Thermostable polymers cast as thin, porous coatings or membranes may be useful for concentrating and stabilizing hyperthermophilic microorganisms as biocatalysts. Hydrogel matrices can be unstable above 65 degrees C. Therefore a 55-microm thick, two layer (cell coat + polymer top coat) bimodal, adhesive latex coating of partially coalesced polystyrene particles was investigated at 80 degrees C using Thermotoga maritima as a model hyperthermophile. Coating permeability (pore structure) was critical for maintaining T. maritima viability. The permeability of bimodal coatings generated from 0.8 v/v of a suspension of non-film-forming 800 nm polystyrene particles with high glass transition temperature (T(g) = 94 degrees C, 26.9% total solids) blended with 0.2 v/v of a suspension of film-forming 158 nm polyacrylate/styrene particles (T(g) approximately -5 degrees C, 40.9% total solids) with 0.3 g sucrose/g latex was measured in a KNO3 diffusion cell. Diffusivity ratio remained above 0.04 (D(eff)/D) when incubated at 80 degrees C in artificial seawater (ASW) for 5 days. KNO3 permeability was corroborated by cryogenic-SEM images of the pore structure. In contrast, the permeability of a mono-dispersed acrylate/vinyl acetate latex Rovace SF091 (T(g) approximately 10 degrees C) rapidly decreased and became impermeable after 2 days incubation in ASW at 80 degrees C. Thermotoga maritima were entrapped in these coatings at a cell density of 49 g cell wet weight/liter of coating volume, 25-fold higher than the density in liquid culture. Viable T. maritima were released from single-layer coatings at 80 degrees C but accurate measurement of the percentage of viable entrapped cells by plate counting was not successful. Metabolic activity could be measured in bilayer coatings by utilization of glucose and maltose, which was identical for latex-entrapped and suspended cells. Starch was hydrolyzed for 200 h by latex-entrapped cells due to the slow diffusion of starch through the polymer top coat compared to only 24 h by suspended T. maritima. The observed reactivity and stability of these coatings was surprising since cryo-SEM images suggested that the smaller low T(g) polyacrylate/styrene particles preferentially bound to the T. maritima toga-sheath during coat formation. This model system may be useful for concentrating, entrapment and stabilization of metabolically active hyperthermophiles at 80 degrees C.
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Affiliation(s)
- Olav K Lyngberg
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA
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Moreno R, Haro A, Castellanos A, Berenguer J. High-level overproduction of His-tagged Tth DNA polymerase in Thermus thermophilus. Appl Environ Microbiol 2005; 71:591-3. [PMID: 15640243 PMCID: PMC544263 DOI: 10.1128/aem.71.1.591-593.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new plasmid for the overexpression of His-tagged thermozymes in Thermus thermophilus was developed. With this plasmid, soluble and active histidine-tagged DNA polymerase from T. thermophilus was overproduced in larger amounts in the thermophile than in Escherichia coli. The protein purified from the thermophile was active in PCR.
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Affiliation(s)
- Renata Moreno
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, Campus de Cantoblanco, 28049 Madrid, Spain
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