1
|
Wang D, Liu N, Qiao M, Xu C. Gallic acid as biofilm inhibitor can improve transformation efficiency of Ruminiclostridium papyrosolvens. Biotechnol Lett 2024:10.1007/s10529-024-03522-y. [PMID: 39162860 DOI: 10.1007/s10529-024-03522-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/26/2024] [Accepted: 08/03/2024] [Indexed: 08/21/2024]
Abstract
Ruminiclostridium papyrosolvens is an anaerobic, mesophilic, and cellulolytic clostridia, promising consolidated bioprocessing (CBP) candidate for producing renewable green chemicals from cellulose, but its genetic transformation has been severely impeded by extracellular biofilm. Here, we analyzed the effects of five different inhibitors with gradient concentrations on R. papyrosolvens growth and biofilm formation. Gallic acid was proved to be a potent inhibitor of biofilm synthesis of R. papyrosolvens. Furthermore, the transformation efficiency of R. papyrosolvens was significantly increased when the cells were treated by the gallic acid, and the mutant strain was successfully obtained by the improved transformation method. Thus, inhibition of biofilm formation of R. papyrosolvens by using gallic acid will contribute to its genetic transformation and efficient metabolic engineering.
Collapse
Affiliation(s)
- Duodong Wang
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China
- College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang Province, China
| | - Na Liu
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Mingqiang Qiao
- School of Life Science, Shanxi University, Taiyuan, 030006, Shanxi, China.
| | - Chenggang Xu
- College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang Province, China.
| |
Collapse
|
2
|
Xiao Y, Dong S, Liu YJ, You C, Feng Y, Cui Q. Key roles of β-glucosidase BglA for the catabolism of both laminaribiose and cellobiose in the lignocellulolytic bacterium Clostridium thermocellum. Int J Biol Macromol 2023; 250:126226. [PMID: 37558019 DOI: 10.1016/j.ijbiomac.2023.126226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/31/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023]
Abstract
The thermophilic bacterium Clostridium thermocellum efficiently degrades polysaccharides into oligosaccharides. The metabolism of β-1,4-linked cello-oligosaccharides is initiated by three enzymes, i.e., the cellodextrin phosphorylase (Cdp), the cellobiose phosphorylase (Cbp), and the β-glucosidase A (BglA), in C. thermocellum. In comparison, how the oligosaccharides containing other kinds of linkage are utilized is rarely understood. In this study, we found that BglA could hydrolyze the β-1,3-disaccharide laminaribiose with much higher activity than that against the β-1,4-disaccharide cellobiose. The structural basis of the substrate specificity was analyzed by crystal structure determination and molecular docking. Genetic deletions of BglA and Cbp, respectively, and enzymatic analysis of cell extracts demonstrated that BglA is the key enzyme responsible for laminaribiose metabolism. Furthermore, the deletion of BglA can suppress the expression of Cbp and the deletion of Cbp can up-regulate the expression of BglA, indicating that BglA and Cbp have cross-regulation and BglA is also critical for cellobiose metabolism. These insights pave the way for both a fundamental understanding of metabolism and regulation in C. thermocellum and emphasize the importance of the degradation and utilization of polysaccharides containing β-1,3-linked glycosidic bonds in lignocellulose biorefinery.
Collapse
Affiliation(s)
- Yan Xiao
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; Dalian National Laboratory for Clean Energy, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; Dalian National Laboratory for Clean Energy, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Ya-Jun Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; Dalian National Laboratory for Clean Energy, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Chun You
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; Dalian National Laboratory for Clean Energy, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China; Shandong Energy Institute, Qingdao, China; Qingdao New Energy Shandong Laboratory, Qingdao, China; Dalian National Laboratory for Clean Energy, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
3
|
Hocq R, Bottone S, Gautier A, Pflügl S. A fluorescent reporter system for anaerobic thermophiles. Front Bioeng Biotechnol 2023; 11:1226889. [PMID: 37476481 PMCID: PMC10355840 DOI: 10.3389/fbioe.2023.1226889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/23/2023] [Indexed: 07/22/2023] Open
Abstract
Owing to their inherent capacity to make invisible biological processes visible and quantifiable, fluorescent reporter systems have numerous applications in biotechnology. For classical fluorescent protein systems (i.e., GFP and derivatives), chromophore maturation is O2-dependent, restricting their applications to aerobic organisms. In this work, we pioneered the use of the oxygen-independent system FAST (Fluorescence Activating and absorption Shifting tag) in the thermophilic anaerobe Thermoanaerobacter kivui. We developed a modular cloning system that was used to easily clone a library of FAST expression cassettes in an E. coli-Thermoanaerobacter shuttle plasmid. FAST-mediated fluorescence was then assessed in vivo in T. kivui, and we observed bright green and red fluorescence for cells grown at 55°C. Next, we took advantage of this functional reporter system to characterize a set of homologous and heterologous promoters by quantifying gene expression, expanding the T. kivui genetic toolbox. Low fluorescence at 66°C (Topt for T. kivui) was subsequently investigated at the single-cell level using flow cytometry and attributed to plasmid instability at higher temperatures. Adaptive laboratory evolution circumvented this issue and drastically enhanced fluorescence at 66°C. Whole plasmid sequencing revealed the evolved strain carried functional plasmids truncated at the Gram-positive origin of replication, that could however not be linked to the increased fluorescence displayed by the evolved strain. Collectively, our work demonstrates the applicability of the FAST fluorescent reporter systems to T. kivui, paving the way for further applications in thermophilic anaerobes.
Collapse
Affiliation(s)
- Rémi Hocq
- Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Vienna, Austria
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Vienna, Austria
| | - Sara Bottone
- Laboratoire des Biomolécules (LBM), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, École Normale Supérieure, Université PSL, Paris, France
- Institut Universitaire de France, Paris, France
| | - Arnaud Gautier
- Laboratoire des Biomolécules (LBM), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, École Normale Supérieure, Université PSL, Paris, France
- Institut Universitaire de France, Paris, France
| | - Stefan Pflügl
- Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Vienna, Austria
- Christian Doppler Laboratory for Optimized Expression of Carbohydrate-Active Enzymes, Institute of Chemical, Environmental and Bioscience Engineering, Technische Universität Wien, Vienna, Austria
| |
Collapse
|
4
|
Wang N, Li P, Cheng Y, Song H, Xu C. Stem-loop structures control mRNA processing of the cellulosomal cip-cel operon in Ruminiclostridium cellulolyticum. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:106. [PMID: 37386549 DOI: 10.1186/s13068-023-02357-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 06/11/2023] [Indexed: 07/01/2023]
Abstract
BACKGROUND Anaerobic, mesophilic, and cellulolytic Ruminiclostridium cellulolyticum produces an efficient cellulolytic extracellular complex named cellulosome, which consist of a non-catalytic multi-functional integrating subunit, organizing the various catalytic subunits into the complex. Main components of cellulosome were encoded by the cip-cel operon in R. cellulolyticum, and their stoichiometry is controlled by the mechanism of selective RNA processing and stabilization, which allows to confer each processed RNA portion from the cip-cel mRNA on different fates due to their stability and resolve the potential contradiction between the equimolar stoichiometry of transcripts with a within a transcription unit and the non-equimolar stoichiometry of subunits. RESULTS In this work, RNA processing events were found to occur at six intergenic regions (IRs) harboring stem-loop structures in cip-cel operon. These stem-loops not only stabilize processed transcripts at their both ends, but also act as cleavage signals specifically recognized by endoribonucleases. We further demonstrated that cleavage sites were often located downstream or 3' end of their associated stem-loops that could be classified into two types, with distinct GC-rich stems being required for RNA cleavage. However, the cleavage site in IR4 was found to be located upstream of the stem-loop, as determined by the bottom AT-pair region of this stem-loop, together with its upstream structure. Thus, our findings reveal the structural requirements for processing of cip-cel transcripts, which can be potentially used to control the stoichiometry of gene expression in an operon. CONCLUSIONS Our findings reveal that stem-loop structures acting as RNA cleavage signals not only can be recognized by endoribonucleases and determine the location of cleavage sites but also determine the stoichiometry of their flanking processed transcripts by controlling stability in cip-cel operon. These features represent a complexed regulation of cellulosome in the post-transcriptional level, which can be exploited for designing synthetic elements to control gene expression.
Collapse
Affiliation(s)
- Na Wang
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, China-Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Ping Li
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Ying Cheng
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Houhui Song
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, China-Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
| | - Chenggang Xu
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, China-Australia Joint Laboratory for Animal Health Big Data Analytics, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, College of Animal Science and Technology & College of Veterinary Medicine, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006, Shanxi, China.
| |
Collapse
|
5
|
Development of an efficient ClosTron system for gene disruption in Ruminiclostridium papyrosolvens. Appl Microbiol Biotechnol 2023; 107:1801-1812. [PMID: 36808278 DOI: 10.1007/s00253-023-12427-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/17/2023] [Accepted: 02/07/2023] [Indexed: 02/20/2023]
Abstract
Ruminiclostridium papyrosolvens is an anaerobic, mesophilic, and cellulolytic clostridia, promising consolidated bioprocessing (CBP) candidate for producing renewable green chemicals from cellulose, but its metabolic engineering is limited by lack of genetic tools. Here, we firstly employed the endogenous xylan-inducible promoter to control ClosTron system for gene disruption of R. papyrosolvens. The modified ClosTron can be easily transformed into R. papyrosolvens and specifically disrupt targeting genes. Furthermore, a counter selectable system based on uracil phosphoribosyl-transferase (Upp) was successfully established and introduced into the ClosTron system, which resulted in plasmid curing rapidly. Thus, the combination of xylan-inducible ClosTron and upp-based counter selectable system makes the gene disruption more efficient and convenient for successive gene disruption in R. papyrosolvens. KEY POINTS: • Limiting expression of LtrA enhanced the transformation of ClosTron plasmids in R. papyrosolvens. • DNA targeting specificity can be improved by precise management of the expression of LtrA. • Curing of ClosTron plasmids was achieved by introducing the upp-based counter selectable system.
Collapse
|
6
|
Rostain W, Zaplana T, Boutard M, Baum C, Tabuteau S, Sanitha M, Ramya M, Guss A, Ettwiller L, Tolonen AC. Tuning of Gene Expression in Clostridium phytofermentans Using Synthetic Promoters and CRISPRi. ACS Synth Biol 2022; 11:4077-4088. [PMID: 36427328 PMCID: PMC9765743 DOI: 10.1021/acssynbio.2c00385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Indexed: 11/27/2022]
Abstract
Control of gene expression is fundamental to cell engineering. Here we demonstrate a set of approaches to tune gene expression in Clostridia using the model Clostridium phytofermentans. Initially, we develop a simple benchtop electroporation method that we use to identify a set of replicating plasmids and resistance markers that can be cotransformed into C. phytofermentans. We define a series of promoters spanning a >100-fold expression range by testing a promoter library driving the expression of a luminescent reporter. By insertion of tet operator sites upstream of the reporter, its expression can be quantitatively altered using the Tet repressor and anhydrotetracycline (aTc). We integrate these methods into an aTc-regulated dCas12a system with which we show in vivo CRISPRi-mediated repression of reporter and fermentation genes in C. phytofermentans. Together, these approaches advance genetic transformation and experimental control of gene expression in Clostridia.
Collapse
Affiliation(s)
- William Rostain
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Tom Zaplana
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Magali Boutard
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Chloé Baum
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
- New
England Biolabs, Inc., 240 County Road, Ipswich, Massachusetts 01938, United States
| | - Sibylle Tabuteau
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| | - Mary Sanitha
- Molecular
Genetics Laboratory, Department of Genetic Engineering, College of
Engineering and Technology, SRM Institute
of Science and Technology, SRM Nagar, Kattankulathur-603 203, TN, India
| | - Mohandass Ramya
- Molecular
Genetics Laboratory, Department of Genetic Engineering, College of
Engineering and Technology, SRM Institute
of Science and Technology, SRM Nagar, Kattankulathur-603 203, TN, India
| | - Adam Guss
- Biosciences
Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6038, United States
| | - Laurence Ettwiller
- New
England Biolabs, Inc., 240 County Road, Ipswich, Massachusetts 01938, United States
| | - Andrew C. Tolonen
- Génomique
Métabolique, Genoscope, Institut François Jacob, CEA,
CNRS, Univ Evry, Université Paris-Saclay, 91057 Évry, France
| |
Collapse
|
7
|
Deciphering Cellodextrin and Glucose Uptake in Clostridium thermocellum. mBio 2022; 13:e0147622. [PMID: 36069444 PMCID: PMC9601137 DOI: 10.1128/mbio.01476-22] [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] [Indexed: 11/29/2022] Open
Abstract
Sugar uptake is of great significance in industrially relevant microorganisms. Clostridium thermocellum has extensive potential in lignocellulose biorefineries as an environmentally prominent, thermophilic, cellulolytic bacterium. The bacterium employs five putative ATP-binding cassette transporters which purportedly take up cellulose hydrolysates. Here, we first applied combined genetic manipulations and biophysical titration experiments to decipher the key glucose and cellodextrin transporters. In vivo gene inactivation of each transporter and in vitro calorimetric and nuclear magnetic resonance (NMR) titration of each putative sugar-binding protein with various saccharides supported the conclusion that only transporters A and B play the roles of glucose and cellodextrin transport, respectively. To gain insight into the structural mechanism of the transporter specificities, 11 crystal structures, both alone and in complex with appropriate saccharides, were solved for all 5 putative sugar-binding proteins, thus providing detailed specific interactions between the proteins and the corresponding saccharides. Considering the importance of transporter B as the major cellodextrin transporter, we further identified its cryptic, hitherto unknown ATPase-encoding gene as clo1313_2554, which is located outside the transporter B gene cluster. The crystal structure of the ATPase was solved, showing that it represents a typical nucleotide-binding domain of the ATP-binding cassette (ABC) transporter. Moreover, we determined that the inducing effect of cellobiose (G2) and cellulose on cellulosome production could be eliminated by deletion of transporter B genes, suggesting the coupling of sugar transport and regulation of cellulosome components. This study provides key basic information on the sugar uptake mechanism of C. thermocellum and will promote rational engineering of the bacterium for industrial application.
Collapse
|
8
|
Development of fluorescence-xBased nucleic acid blot hybridization method using Cy5.5 labeled DNA probes. J Microbiol Methods 2022; 197:106479. [DOI: 10.1016/j.mimet.2022.106479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 12/27/2022]
|
9
|
Internal Transcription Terminators Control Stoichiometry of ABC Transporters in Cellulolytic Clostridia. Microbiol Spectr 2022; 10:e0165621. [PMID: 35286151 PMCID: PMC9045158 DOI: 10.1128/spectrum.01656-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The extracellular substrate-binding proteins (SBPs) of ATP-binding cassette (ABC) importers tend to be expressed in excess relative to their cognate translocators, but how the stoichiometry of ABC transporters is controlled remains unclear. Here, we elucidated a mechanism contributing to differential gene expression in operons encoding ABC importers by employing cellulolytic Clostridia species, specifically Ruminiclostridium cellulolyticum. We found that there were usually stem-loop structures downstream of SBP genes, which could prematurely terminate the transcription of ABC importers and were putative internal intrinsic terminators, resulting in high transcript levels of upstream SBP genes and low transcript levels of downstream cognate translocator genes. This was determined by their termination efficiencies. Internal terminators had a lower U content in their 3′ U-rich tracts and longer GC-rich stems, which distinguishes them from canonical terminators and potentially endows them with special termination efficiencies. The pairing of U-rich tracts and the formation of unpaired regions in these internal terminators contributed to their folding energies, affecting the stability of their upstream SBP transcripts. Our findings revealed a strategy of internal transcriptional terminators controlling in vivo stoichiometry of their flanking transcripts. IMPORTANCE Operons encoding protein complexes or metabolic pathways usually require fine-tuned gene expression ratios to create and maintain the appropriate stoichiometry for biological functions. In this study, a strategy for controlling differential expression of genes in an operon was proposed by utilizing ABC importers from Ruminiclostridium cellulolyticum. We found that a stem-loop structure is introduced into the intergenic regions of operons encoding ABC importers as the putative internal terminator, which results in the premature termination of transcription. Consequently, the stoichiometric ratio of genes flanking terminators is precisely determined by their termination efficiencies and folding energies at the transcriptional level. Thus, it can be utilized as a promising synthetic biology tool to control the differential expression of genes in an operon.
Collapse
|
10
|
Synergy of Cellulase Systems between Acetivibrio thermocellus and Thermoclostridium stercorarium in Consolidated-Bioprocessing for Cellulosic Ethanol. Microorganisms 2022; 10:microorganisms10030502. [PMID: 35336078 PMCID: PMC8951355 DOI: 10.3390/microorganisms10030502] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/18/2022] Open
Abstract
Anaerobes harbor some of the most efficient biological machinery for cellulose degradation, especially thermophilic bacteria, such as Acetivibrio thermocellus and Thermoclostridium stercorarium, which play a fundamental role in transferring lignocellulose into ethanol through consolidated bioprocessing (CBP). In this study, we compared activities of two cellulase systems under varying kinds of hemicellulose and cellulose. A. thermocellus was identified to contribute specifically to cellulose hydrolysis, whereas T. stercorarium contributes to hemicellulose hydrolysis. The two systems were assayed in various combinations to assess their synergistic effects using cellulose and corn stover as the substrates. Their maximum synergy degrees on cellulose and corn stover were, respectively, 1.26 and 1.87 at the ratio of 3:2. Furthermore, co-culture of these anaerobes on the mixture of cellulose and xylan increased ethanol concentration from 21.0 to 40.4 mM with a high cellulose/xylan-to-ethanol conversion rate of up to 20.7%, while the conversion rates of T. stercorarium and A. thermocellus monocultures were 19.3% and 15.2%. The reason is that A. thermocellus had the ability to rapidly degrade cellulose while T. stercorarium co-utilized both pentose and hexose, the metabolites of cellulose degradation, to produce ethanol. The synergistic effect of cellulase systems and metabolic pathways in A. thermocellus and T. stercorarium provides a novel strategy for the design, selection, and optimization of ethanol production from cellulosic biomass through CBP.
Collapse
|
11
|
Cheng Y, Jiang Y, Ren Z, Fu Y, Xu C. Development of an in vivo methylation system for transformation of Ruminiclostridium cellulolyticum. J Appl Microbiol 2021; 132:1926-1935. [PMID: 34787948 DOI: 10.1111/jam.15367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/06/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022]
Abstract
AIMS Ruminiclostridium cellulolyticum, an anaerobic cellulolytic bacterium producing an efficient cellulolytic extracellular complex named cellulosome, is a promising host for biofuel production from lignocellulose. This study aims to develop a rapid transformation method for R. cellulolyticum avoiding its restriction system. METHODS AND RESULTS The CceI restriction system is a major barrier to introduction of foreign DNA into R. cellulolyticum cells. To improve the transformation efficiency of R. cellulolyticum, the gene encoding CceI methyltransferase (M.CceI) of R. cellulolyticum H10 was functionally expressed in Escherichia coli, resulting in an in vivo methylation system for transformation of R. cellulolyticum. The electrotransformation experiments of R. cellulolyticum H10 with the E. coli-Clostridium shuttle plasmid pMTC6 showed that the transformation efficiency reached up to 2.6 × 103 ±0.23 × 103 CFU per μg plasmid DNA. The results demonstrated that the system is able to confer the M.CceI-specific DNA methylation pattern to its resident plasmid, which makes the plasmid resistant to the CceI restriction and efficiently transferred into R. cellulolyticum. CONCLUSIONS In this study, we generated an in vivo methylation system of R. cellulolyticum, allowing interspecies DNA transfer and improving transformation efficiency. SIGNIFICANCE AND IMPACT OF THE STUDY This research result will greatly facilitate the metabolic engineering of R. cellulolyticum for biofuel production directly from cellulose.
Collapse
Affiliation(s)
- Ying Cheng
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Yuanyuan Jiang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Zhenxing Ren
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi Province, China
| | - Yuejun Fu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| | - Chenggang Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, Shanxi Province, China
| |
Collapse
|
12
|
Qi K, Chen C, Yan F, Feng Y, Bayer EA, Kosugi A, Cui Q, Liu YJ. Coordinated β-glucosidase activity with the cellulosome is effective for enhanced lignocellulose saccharification. BIORESOURCE TECHNOLOGY 2021; 337:125441. [PMID: 34182347 DOI: 10.1016/j.biortech.2021.125441] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Consolidated bio-saccharification (CBS) technology employs cellulosome-producing bacterial cells, rather than fungal cellulases, as biocatalysts for cost-effective production of lignocellulosic sugars. Extracellular β-glucosidase (BGL) expression in the whole-cell arsenal is indispensable, due to severe cellobiose inhibition of the cellulosome. However, high-level BGL expression in Clostridium thermocellum is challenging, and the optimal BGL production level for efficient cellulose saccharification is currently unknown. Herein, we obtained new CBS biocatalysts by transforming BGL-expressing plasmids into C. thermocellum, which produced abundant BGL proteins and hydrolyzed cellulose effectively. The optimal ratio of extracellular BGL-to-cellulosome activity was determined to be in a range of 5.5 to 21.6. Despite the critical impact of BGL, both excessive BGL expression and its assembly on the cellulosome via type I cohesin-dockerin interaction led to reduced cellulosomal activity, which further confirmed the importance of coordinated BGL expression with the cellulosome. This study will further promote industrial CBS application in lignocellulose conversion.
Collapse
Affiliation(s)
- Kuan Qi
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chao Chen
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Fei Yan
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel; Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8499000, Israel
| | - Akihiko Kosugi
- Biological Resources and Post-Harvest Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Ya-Jun Liu
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Engineering Laboratory for Single Cell Oil, Qingdao Engineering Laboratory for Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Dalian National Laboratory for Clean Energy, Qingdao 266101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| |
Collapse
|
13
|
Anaerobic fluorescent reporters for cell identification, microbial cell biology and high-throughput screening of microbiota and genomic libraries. Curr Opin Biotechnol 2021; 71:151-163. [PMID: 34375813 DOI: 10.1016/j.copbio.2021.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/08/2021] [Indexed: 11/23/2022]
Abstract
The lack of real-time reporters in obligate anaerobes has limited studies in gene expression, promoter characterization, library screening, population dynamics, and cell biology in these organisms. While the use of enzymatic, colorimetric, and luminescent reporters has been reported, the need for reliable anaerobic fluorescent proteins is widely acknowledged. Recently, the fluorescent proteins HaloTag, SNAP-tag and FAST have been established as reliable reporters in Clostridium spp., thus suggesting that these reporters can be adopted widely for many obligate anaerobes. With a multitude of labeling options, these anaerobic fluorescent proteins hold a great potential for screening promoters, terminators, and RBS sites, tracking population dynamics in complex multi-species co-cultures, such as microbiomes, screening libraries, and in cell biology studies of protein localization and interactions using high-resolution microscopy.
Collapse
|
14
|
Bhaskar Y, Su X, Xu C, Xu J. Predicting Selective RNA Processing and Stabilization Operons in Clostridium spp. Front Microbiol 2021; 12:673349. [PMID: 34177856 PMCID: PMC8219983 DOI: 10.3389/fmicb.2021.673349] [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: 02/27/2021] [Accepted: 04/28/2021] [Indexed: 11/29/2022] Open
Abstract
In selective RNA processing and stabilization (SRPS) operons, stem–loops (SLs) located at the 3′-UTR region of selected genes can control the stability of the corresponding transcripts and determine the stoichiometry of the operon. Here, for such operons, we developed a computational approach named SLOFE (stem–loop free energy) that identifies the SRPS operons and predicts their transcript- and protein-level stoichiometry at the whole-genome scale using only the genome sequence via the minimum free energy (ΔG) of specific SLs in the intergenic regions within operons. As validated by the experimental approach of differential RNA-Seq, SLOFE identifies genome-wide SRPS operons in Clostridium cellulolyticum with 80% accuracy and reveals that the SRPS mechanism contributes to diverse cellular activities. Moreover, in the identified SRPS operons, SLOFE predicts the transcript- and protein-level stoichiometry, including those encoding cellulosome complexes, ATP synthases, ABC transporter family proteins, and ribosomal proteins. Its accuracy exceeds those of existing in silico approaches in C. cellulolyticum, Clostridium acetobutylicum, Clostridium thermocellum, and Bacillus subtilis. The ability to identify genome-wide SRPS operons and predict their stoichiometry via DNA sequence in silico should facilitate studying the function and evolution of SRPS operons in bacteria.
Collapse
Affiliation(s)
- Yogendra Bhaskar
- Single-Cell Center and CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoquan Su
- Single-Cell Center and CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Chenggang Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Jian Xu
- Single-Cell Center and CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
15
|
Yan F, Wei R, Cui Q, Bornscheuer UT, Liu Y. Thermophilic whole-cell degradation of polyethylene terephthalate using engineered Clostridium thermocellum. Microb Biotechnol 2021; 14:374-385. [PMID: 32343496 PMCID: PMC7936307 DOI: 10.1111/1751-7915.13580] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/03/2022] Open
Abstract
Polyethylene terephthalate (PET) is a mass-produced synthetic polyester contributing remarkably to the accumulation of solid plastics waste and plastics pollution in the natural environments. Recently, bioremediation of plastics waste using engineered enzymes has emerged as an eco-friendly alternative approach for the future plastic circular economy. Here we genetically engineered a thermophilic anaerobic bacterium, Clostridium thermocellum, to enable the secretory expression of a thermophilic cutinase (LCC), which was originally isolated from a plant compost metagenome and can degrade PET at up to 70°C. This engineered whole-cell biocatalyst allowed a simultaneous high-level expression of LCC and conspicuous degradation of commercial PET films at 60°C. After 14 days incubation of a batch culture, more than 60% of the initial mass of a PET film (approximately 50 mg) was converted into soluble monomer feedstocks, indicating a markedly higher degradation performance than previously reported whole-cell-based PET biodegradation systems using mesophilic bacteria or microalgae. Our findings provide clear evidence that, compared to mesophilic species, thermophilic microbes are a more promising synthetic microbial chassis for developing future biodegradation processes of PET waste.
Collapse
Affiliation(s)
- Fei Yan
- CAS Key Laboratory of BiofuelsShandong Provincial Key Laboratory of Synthetic BiologyQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao266101China
- Dalian National Laboratory for Clean EnergyQingdao266101China
- University of Chinese Academy of SciencesChinese Academy of SciencesBeijing100049China
| | - Ren Wei
- Department of Biotechnology and Enzyme CatalysisInstitute of BiochemistryGreifswald UniversityFelix-Hausdorff-Str. 4D-17487GreifswaldGermany
| | - Qiu Cui
- CAS Key Laboratory of BiofuelsShandong Provincial Key Laboratory of Synthetic BiologyQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao266101China
- Dalian National Laboratory for Clean EnergyQingdao266101China
- University of Chinese Academy of SciencesChinese Academy of SciencesBeijing100049China
| | - Uwe T. Bornscheuer
- Department of Biotechnology and Enzyme CatalysisInstitute of BiochemistryGreifswald UniversityFelix-Hausdorff-Str. 4D-17487GreifswaldGermany
| | - Ya‐Jun Liu
- CAS Key Laboratory of BiofuelsShandong Provincial Key Laboratory of Synthetic BiologyQingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao266101China
- Dalian National Laboratory for Clean EnergyQingdao266101China
- University of Chinese Academy of SciencesChinese Academy of SciencesBeijing100049China
| |
Collapse
|
16
|
Jiang Y, Fu Y, Ren Z, Gou H, Xu C. Screening and application of inducible promoters in Ruminiclostridium papyrosolvens. Lett Appl Microbiol 2020; 71:428-436. [PMID: 32649779 DOI: 10.1111/lam.13352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/05/2020] [Accepted: 07/06/2020] [Indexed: 11/27/2022]
Abstract
Ruminiclostridium papyrosolvens is a promising candidate for producing renewable green chemicals from cellulose due to its cellulolytic and ethanologenic capabilities. It is of significance to screen effective, and convenient-to-use inducible promoters that can be used for regulating the gene expression in R. papyrosolvens. We characterized two endogenous inducible promoters and investigated another two exogenous ones on the adaptability in R. papyrosolvens. Both of the endogenous xylan-inducible promoter Pxyl and exogenous lactose-inducible promoter Plac are found of high specificity and stringency. Pxyl has a short time to be induced while Plac has a low concentration of inducer. With these findings, a mazF-based counter selectable system has been constructed for promoting the efficiency of mutant screening via plasmid curing. The inducible gene expression systems provided novel tools for enhancing the capability of genetic manipulation in engineering R. papyrosolvens. SIGNIFICANCE AND IMPACT OF THE STUDY: Four inducible promoters from Clostridia were characterized in R. papyrosolvens. Xylan-inducible promoter Pxyl was found of a short time while lactose-inducible promoter Plac needs a low concentration of inducer to induce. Employing them, we successfully construct a mazF-based counter selectable system, which would be used to increase the mutant screening efficiency via induction of plasmid curing. The inducible gene expression systems provided novel tools for enhancing the capability of genetic manipulation in engineering R. papyrosolvens.
Collapse
Affiliation(s)
- Y Jiang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Y Fu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| | - Z Ren
- Institute of Applied Chemistry, Shanxi University, Taiyuan, China
| | - H Gou
- Shenzhen Digital Life Institute, Shenzhen, China
| | - C Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, China
| |
Collapse
|
17
|
Zhang J, Hong W, Guo L, Wang Y, Wang Y. Enhancing plasmid transformation efficiency and enabling CRISPR-Cas9/Cpf1-based genome editing in Clostridium tyrobutyricum. Biotechnol Bioeng 2020; 117:2911-2917. [PMID: 32437010 DOI: 10.1002/bit.27435] [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] [Received: 04/03/2020] [Revised: 04/30/2020] [Accepted: 05/19/2020] [Indexed: 12/16/2022]
Abstract
Clostridium tyrobutyricum ATCC 25755 is known as a natural hyper-butyrate producer with great potentials as an excellent platform to be engineered for valuable biochemical production from renewable resources. However, limited transformation efficiency and the lack of genetic manipulation tools have hampered the broader applications of this micro-organism. In this study, the effects of Type I restriction-modification system and native plasmid on conjugation efficiency of C. tyrobutyricum were investigated through gene deletion. The deletion of Type I restriction endonuclease resulted in a 3.7-fold increase in conjugation efficiency, while the additional elimination of the native plasmid further enhanced conjugation efficiency to 6.05 ± 0.75 × 103 CFU/ml-donor, which was 15.3-fold higher than the wild-type strain. Fermentation results indicated that the deletion of those two genetic elements did not significantly influence the end-products production in the resultant mutant ΔRMIΔNP. Thanks to the increased conjugation efficiency, the CRISPR-Cas9/Cpf1 systems, which previously could not be implemented in C. tyrobutyricum, were successfully employed for genome editing in ΔRMIΔNP with an efficiency of 12.5-25%. Altogether, approaches we developed herein offer valuable guidance for establishing efficient DNA transformation methods in nonmodel micro-organisms. The ΔRMIΔNP mutant can serve as a great chassis to be engineered for diverse valuable biofuel and biochemical production.
Collapse
Affiliation(s)
- Jie Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama.,Key Laboratory for Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Hong
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama.,Key Laboratory of Endemic and Ethnic Diseases, Guizhou Medical University, Ministry of Education, Guiyang, China
| | - Liang Guo
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China
| | - Yifen Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, Alabama
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, Alabama
| |
Collapse
|
18
|
Kwon SW, Paari KA, Malaviya A, Jang YS. Synthetic Biology Tools for Genome and Transcriptome Engineering of Solventogenic Clostridium. Front Bioeng Biotechnol 2020; 8:282. [PMID: 32363182 PMCID: PMC7181999 DOI: 10.3389/fbioe.2020.00282] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 03/17/2020] [Indexed: 12/18/2022] Open
Abstract
Strains of Clostridium genus are used for production of various value-added products including fuels and chemicals. Development of any commercially viable production process requires a combination of both strain and fermentation process development strategies. The strain development in Clostridium sp. could be achieved by random mutagenesis, and targeted gene alteration methods. However, strain improvement in Clostridium sp. by targeted gene alteration method was challenging due to the lack of efficient tools for genome and transcriptome engineering in this organism. Recently, various synthetic biology tools have been developed to facilitate the strain engineering of solventogenic Clostridium. In this review, we consolidated the recent advancements in toolbox development for genome and transcriptome engineering in solventogenic Clostridium. Here we reviewed the genome-engineering tools employing mobile group II intron, pyrE alleles exchange, and CRISPR/Cas9 with their application for strain development of Clostridium sp. Next, transcriptome engineering tools such as untranslated region (UTR) engineering and synthetic sRNA techniques were also discussed in context of Clostridium strain engineering. Application of any of these discussed techniques will facilitate the metabolic engineering of clostridia for development of improved strains with respect to requisite functional attributes. This might lead to the development of an economically viable butanol production process with improved titer, yield and productivity.
Collapse
Affiliation(s)
- Seong Woo Kwon
- Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Institute of Agriculture & Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| | | | - Alok Malaviya
- Applied and Industrial Biotechnology Laboratory (AIBL), Department of Life Sciences, CHRIST (Deemed to be University), Bengaluru, India
| | - Yu-Sin Jang
- Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Institute of Agriculture & Life Science (IALS), Gyeongsang National University, Jinju, South Korea
| |
Collapse
|
19
|
Tao X, Xu T, Kempher ML, Liu J, Zhou J. Precise promoter integration improves cellulose bioconversion and thermotolerance in Clostridium cellulolyticum. Metab Eng 2020; 60:110-118. [PMID: 32294528 DOI: 10.1016/j.ymben.2020.03.013] [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] [Received: 01/03/2020] [Revised: 03/22/2020] [Accepted: 03/30/2020] [Indexed: 11/15/2022]
Abstract
Lignocellulose has been used for production of sustainable biofuels and value-added chemicals. However, the low-efficiency bioconversion of lignocellulose greatly contributes to a high production cost. Here, we employed CRISPR-Cas9 editing to improve cellulose degradation efficiency by editing a regulatory element of the cip-cel gene cluster in Clostridium cellulolyticum. Insertion of a synthetic promoter (P4) and an endogenous promoter (P2) in the mspI-deficient parental strain (Δ2866) created chromosomal integrants, P4-2866 and P2-2866, respectively. Both engineered strains increased the transcript abundance of downstream polycistronic genes and enhanced in vitro cellulolytic activities of isolated cellulosomes. A high cellulose load of 20 g/L suppressed cellulose degradation in the parental strain in the first 150 h fermentation; whereas P4-2866 and P2-2866 hydrolyzed 29% and 53% of the cellulose, respectively. Both engineered strains also demonstrated a greater growth rate and a higher cell biomass yield. Interestingly, the Δ2866 parental strain demonstrated better thermotolerance than the wildtype strain, and promoter insertion further enhanced thermotolerance. Similar improvements in cell growth and cellulose degradation were reproduced by promoter insertion in the wildtype strain and a lactate production-defective mutant (LM). P2 insertion in LM increased ethanol titer by 65%. Together, the editing of regulatory elements of catabolic gene clusters provides new perspectives on improving cellulose bioconversion in microbes.
Collapse
Affiliation(s)
- Xuanyu Tao
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Tao Xu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Section on Pathophysiology and Molecular Pharmacology, Joslin Diabetes Center, Boston, MA, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.
| | - Megan L Kempher
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jiantao Liu
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, USA; Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
| |
Collapse
|
20
|
Abstract
Clostridia are a group of Gram-positive anaerobic bacteria of medical and industrial importance for which limited genetic methods are available. Here, we demonstrate an approach to make large genomic deletions and insertions in the model Clostridium phytofermentans by combining designed group II introns (targetrons) and Cre recombinase. We apply these methods to delete a 50-gene prophage island by programming targetrons to position markerless lox66 and lox71 sites, which mediate deletion of the intervening 39-kb DNA region using Cre recombinase. Gene expression and growth of the deletion strain showed that the prophage genes contribute to fitness on nonpreferred carbon sources. We also inserted an inducible fluorescent reporter gene into a neutral genomic site by recombination-mediated cassette exchange (RMCE) between genomic and plasmid-based tandem lox sites bearing heterospecific spacers to prevent intracassette recombination. These approaches generally enable facile markerless genome engineering in clostridia to study their genome structure and regulation.IMPORTANCE Clostridia are anaerobic bacteria with important roles in intestinal and soil microbiomes. The inability to experimentally modify the genomes of clostridia has limited their study and application in biotechnology. Here, we developed a targetron-recombinase system to efficiently make large targeted genomic deletions and insertions using the model Clostridium phytofermentans We applied this approach to reveal the importance of a prophage to host fitness and introduce an inducible reporter by recombination-mediated cassette exchange.
Collapse
|
21
|
Wen Z, Lu M, Ledesma-Amaro R, Li Q, Jin M, Yang S. TargeTron Technology Applicable in Solventogenic Clostridia: Revisiting 12 Years' Advances. Biotechnol J 2019; 15:e1900284. [PMID: 31475782 DOI: 10.1002/biot.201900284] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/20/2019] [Indexed: 12/11/2022]
Abstract
Clostridium has great potential in industrial application and medical research. But low DNA repair capacity and plasmids transformation efficiency severely delay development and application of genetic tools based on homologous recombination (HR). TargeTron is a gene editing technique dependent on the mobility of group II introns, rather than homologous recombination, which makes it very suitable for gene disruption of Clostridium. The application of TargeTron technology in solventogenic Clostridium is academically reported in 2007 and this tool has been introduced in various clostridia as it is easy to operate, time saving, and reliable. TargeTron has made great progress in solventogenic Clostridium in the aspects of acetone-butanol-ethanol (ABE) fermentation pathway modification, important functional genes identification, and xylose metabolic pathway analysis and reconstruction. In the review, 12 years' advances of TargeTron technology applicable in solventogenic Clostridium, including its principle, technical characteristics, application, and efforts to expand its capabilities, or to avoid potential drawbacks, are revisisted. Some other technologies as putative competitors or collaborators are also discussed. It is believed that TargeTron combined with CRISPR/Cas-assisted gene/base editing and gene-expression regulation system will make a better future for clostridial genetic modification.
Collapse
Affiliation(s)
- Zhiqiang Wen
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China
| | - Minrui Lu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China
| | | | - Qi Li
- College of Life Sciences, Sichuan Normal University, Longquan, Chengdu, 610101, China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing, 210094, China
| | - Sheng Yang
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.,Huzhou Center of Industrial Biotechnology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Zhejiang, 313000, China
| |
Collapse
|
22
|
Development of a shuttle plasmid without host restriction sites for efficient transformation and heterologous gene expression in Clostridium cellulovorans. Appl Microbiol Biotechnol 2019; 103:5391-5400. [DOI: 10.1007/s00253-019-09882-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/16/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
|
23
|
Charubin K, Bennett RK, Fast AG, Papoutsakis ET. Engineering Clostridium organisms as microbial cell-factories: challenges & opportunities. Metab Eng 2018; 50:173-191. [DOI: 10.1016/j.ymben.2018.07.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 11/25/2022]
|
24
|
An optogenetic toolbox of LOV-based photosensitizers for light-driven killing of bacteria. Sci Rep 2018; 8:15021. [PMID: 30301917 PMCID: PMC6177443 DOI: 10.1038/s41598-018-33291-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 09/26/2018] [Indexed: 01/04/2023] Open
Abstract
Flavin-binding fluorescent proteins (FPs) are genetically encoded in vivo reporters, which are derived from microbial and plant LOV photoreceptors. In this study, we comparatively analyzed ROS formation and light-driven antimicrobial efficacy of eleven LOV-based FPs. In particular, we determined singlet oxygen (1O2) quantum yields and superoxide photosensitization activities via spectroscopic assays and performed cell toxicity experiments in E. coli. Besides miniSOG and SOPP, which have been engineered to generate 1O2, all of the other tested flavoproteins were able to produce singlet oxygen and/or hydrogen peroxide but exhibited remarkable differences in ROS selectivity and yield. Accordingly, most LOV-FPs are potent photosensitizers, which can be used for light-controlled killing of bacteria. Furthermore, the two variants Pp2FbFP and DsFbFP M49I, exhibiting preferential photosensitization of singlet oxygen or singlet oxygen and superoxide, respectively, were shown to be new tools for studying specific ROS-induced cell signaling processes. The tested LOV-FPs thus further expand the toolbox of optogenetic sensitizers usable for a broad spectrum of microbiological and biomedical applications.
Collapse
|
25
|
Li R, Feng Y, Liu S, Qi K, Cui Q, Liu YJ. Inducing effects of cellulosic hydrolysate components of lignocellulose on cellulosome synthesis in Clostridium thermocellum. Microb Biotechnol 2018; 11:905-916. [PMID: 29943510 PMCID: PMC6116742 DOI: 10.1111/1751-7915.13293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/25/2018] [Accepted: 06/04/2018] [Indexed: 02/06/2023] Open
Abstract
Cellulosome is a highly efficient supramolecular machine for lignocellulose degradation, and its substrate‐coupled regulation requires soluble transmembrane signals. However, the inducers for cellulosome synthesis and the inducing effect have not been clarified quantitatively. Values of cellulosome production capacity (CPC) and estimated specific activity (eSA) were calculated based on the primary scaffoldin ScaA to define the stimulating effects on the cellulosome synthesis in terms of quantity and quality respectively. The estimated cellulosome production of Clostridium thermocellum on glucose was at a low housekeeping level. Both Avicel and cellobiose increased CPCs of the cells instead of the eSAs of the cellulosome. The CPC of Avicel‐grown cells was over 20‐fold of that of glucose‐grown cells, while both Avicel‐ and glucose‐derived cellulosomes showed similar eSA. The CPC of cellobiose‐grown cells was also over three times higher than glucose‐grown cells, but the eSA of cellobiose‐derived cellulosome was 16% lower than that of the glucose‐derived cellulosome. Our results indicated that cello‐oligosaccharides played the key roles in inducing the synthesis of the cellulosome, but non‐cellulosic polysaccharides showed no inducing effects.
Collapse
Affiliation(s)
- Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kuan Qi
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| |
Collapse
|
26
|
Wang S, Hong W, Dong S, Zhang ZT, Zhang J, Wang L, Wang Y. Genome engineering of Clostridium difficile using the CRISPR-Cas9 system. Clin Microbiol Infect 2018; 24:1095-1099. [PMID: 29604353 DOI: 10.1016/j.cmi.2018.03.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/22/2017] [Accepted: 01/14/2018] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Clostridium difficile is a notorious pathogenic species that can cause severe gastrointestinal infections in humans and animals. C. difficile infection (CDI) results in thousands of deaths worldwide every year. The elucidation of related mechanisms of CDI and exploration of potential therapeutic strategies are largely delayed due to the lack of efficient genetic engineering tools for C. difficile strains. METHODS Plasmids carrying the CRISPR-Cas9 system were constructed and transformed into C. difficile through conjugation. Mutants were identified using colony PCR with primers annealing to the regions flanking the target gene deletion/integration locus. Heat-survival assay was used to compare the sporulation frequency between the mutant with spo0A deletion and the wild type strain. The fluorescence in the mutant with the insertion of the green fluorescent protein (GFP) gene was inspected under a fluorescent microscope. RESULTS An efficient genome editing tool was developed for C. difficile based on the CRISPR-Cas9 system. With this tool, spo0A was deleted with a 100% mutation efficiency. Conversely, an anaerobic GFP gene was successfully inserted into the C. difficile chromosome (with a mutation efficiency of 80%). CONCLUSIONS The developed CRISPR-Cas9-based genome engineering tool will facilitate functional genomic studies in C. difficile as well as the elucidation of mechanisms related to host-bacteria interaction and pathogenesis of CDI. This will be highly beneficial for the development of innovative strategies for CDI diagnostics and therapies.
Collapse
Affiliation(s)
- S Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA
| | - W Hong
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA; Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University), Ministry of Education, Guiyang, People's Republic of China
| | - S Dong
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA
| | - Z-T Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA
| | - J Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA
| | - L Wang
- Department of Animal Sciences, Auburn University, Auburn, AL, USA
| | - Y Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.
| |
Collapse
|
27
|
Zou X, Ren Z, Wang N, Cheng Y, Jiang Y, Wang Y, Xu C. Function analysis of 5'-UTR of the cellulosomal xyl- doc cluster in Clostridium papyrosolvens. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:43. [PMID: 29467821 PMCID: PMC5815224 DOI: 10.1186/s13068-018-1040-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 02/02/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Anaerobic, mesophilic, and cellulolytic Clostridium papyrosolvens produces an efficient cellulolytic extracellular complex named cellulosome that hydrolyzes plant cell wall polysaccharides into simple sugars. Its genome harbors two long cellulosomal clusters: cip-cel operon encoding major cellulosome components (including scaffolding) and xyl-doc gene cluster encoding hemicellulases. Compared with works on cip-cel operon, there are much fewer studies on xyl-doc mainly due to its rare location in cellulolytic clostridia. Sequence analysis of xyl-doc revealed that it harbors a 5' untranslated region (5'-UTR) which potentially plays a role in the regulation of downstream gene expression. Here, we analyzed the function of 5'-UTR of xyl-doc cluster in C. papyrosolvens in vivo via transformation technology developed in this study. RESULTS In this study, we firstly developed an electrotransformation method for C. papyrosolvens DSM 2782 before the analysis of 5'-UTR of xyl-doc cluster. In the optimized condition, a field with an intensity of 7.5-9.0 kV/cm was applied to a cuvette (0.2 cm gap) containing a mixture of plasmid and late cell suspended in exponential phase to form a 5 ms pulse in a sucrose-containing buffer. Afterwards, the putative promoter and the 5'-UTR of xyl-doc cluster were determined by sequence alignment. It is indicated that xyl-doc possesses a long conservative 5'-UTR with a complex secondary structure encompassing at least two perfect stem-loops which are potential candidates for controlling the transcriptional termination. In the last step, we employed an oxygen-independent flavin-based fluorescent protein (FbFP) as a quantitative reporter to analyze promoter activity and 5'-UTR function in vivo. It revealed that 5'-UTR significantly blocked transcription of downstream genes, but corn stover can relieve its suppression. CONCLUSIONS In the present study, our results demonstrated that 5'-UTR of the cellulosomal xyl-doc cluster blocks the transcriptional activity of promoter. However, some substrates, such as corn stover, can relieve the effect of depression of 5'-UTR. Thus, it is speculated that 5'-UTR of xyl-doc was a putative riboswitch to regulate the expression of downstream cellulosomal genes, which is helpful to understand the complex regulation of cellulosome.
Collapse
Affiliation(s)
- Xia Zou
- Research Center for Harmful Algae and Marine Biology, College of Life Science and Technology, Jinan University, Guangzhou, 510632 Guangdong Province China
| | - Zhenxing Ren
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006 Shanxi Province China
| | - Na Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006 Shanxi Province China
| | - Yin Cheng
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006 Shanxi Province China
| | - Yuanyuan Jiang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006 Shanxi Province China
| | - Yan Wang
- Research Center for Harmful Algae and Marine Biology, College of Life Science and Technology, Jinan University, Guangzhou, 510632 Guangdong Province China
| | - Chenggang Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan, 030006 Shanxi Province China
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and BioProcess Technology, Chinese Academy of Sciences, Qingdao, 266101 Shandong Province China
| |
Collapse
|
28
|
Wang Y, Okugawa K, Kunitake E, Sakka M, Kimura T, Sakka K. Development of an efficient host-vector system of Ruminiclostridium josui. J Basic Microbiol 2018; 58:448-458. [PMID: 29388680 DOI: 10.1002/jobm.201700620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/23/2017] [Accepted: 12/30/2017] [Indexed: 01/22/2023]
Abstract
Although Ruminiclostridium josui (formerly Clostridium josui), a strictly anaerobic mesophilic cellulolytic bacterium, is a promising candidate for biomass utilization via consolidated bioprocessing, its host-vector system has not yet been established. The existence of a restriction and modification system is a significant barrier to the transformation of R. josui. Here, we partially purified restriction endonuclease RjoI from R. josui cell extract using column chromatography. Further characterization showed that RjoI is an isoschizomer of DpnI, recognizing the sequence 5'-Gmet ATC-3', where the A nucleotide is Dam-methylated. RjoI cleaved the recognition sequence between the A and T nucleotides, producing blunt ends. We then successfully introduced plasmids prepared from Escherichia coli C2925 (dam- /dcm- ) into R. josui by electroporation. The highest transformation efficiency of 6.6 × 103 transformants/μg of DNA was obtained using a square-wave pulse (750 V, 1 ms). When the R. josui cel48A gene, devoid of the dockerin-encoding region, cloned into newly developed plasmid pKKM801 was introduced into R. josui, a truncated form of RjCel48A, RjCel48AΔdoc, was detected in the culture supernatant but not in the intracellular fraction. This is the first report on the establishment of fundamental technology for molecular breeding of R. josui.
Collapse
Affiliation(s)
- Yayun Wang
- Graduate School of Bioresources, Mie University, Mie, Japan
| | - Kei Okugawa
- Graduate School of Bioresources, Mie University, Mie, Japan
| | - Emi Kunitake
- Graduate School of Bioresources, Mie University, Mie, Japan
| | - Makiko Sakka
- Graduate School of Bioresources, Mie University, Mie, Japan
| | - Tetsuya Kimura
- Graduate School of Bioresources, Mie University, Mie, Japan
| | - Kazuo Sakka
- Graduate School of Bioresources, Mie University, Mie, Japan
| |
Collapse
|
29
|
Liu YJ, Liu S, Dong S, Li R, Feng Y, Cui Q. Determination of the native features of the exoglucanase Cel48S from Clostridium thermocellum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:6. [PMID: 29344087 PMCID: PMC5766998 DOI: 10.1186/s13068-017-1009-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/29/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Clostridium thermocellum is considered one of the most efficient natural cellulose degraders because of its cellulosomal system. As the major exoglucanase of cellulosome in C. thermocellum, Cel48S plays key roles and influences the activity and features of cellulosome to a great extent. Thus, it is of great importance to reveal the enzymatic features of Cel48S. However, Cel48S has not been well performed due to difficulties in purifying either recombinant or native Cel48S proteins. RESULTS We observed that the soluble fraction of the catalytic domain of Cel48S (Cel48S_CD) obtained by heterologous expression in Escherichia coli and denaturation-refolding treatment contained a large portion of incorrectly folded proteins with low activity. Using a previously developed seamless genome-editing system for C. thermocellum, we achieved direct purification of Cel48S_CD from the culture supernatant of C. thermocellum DSM1313 by inserting a sequence encoding 12 successive histidine residues and a TAA stop codon immediately behind the GH domain of Cel48S. Based on the fully active protein, biochemical and structural analyses were performed to reveal its innate characteristics. The native Cel48S_CD showed high activity of 117.61 ± 2.98 U/mg and apparent substrate preference for crystalline cellulose under the assay conditions. The crystal structure of the native GH48 protein revealed substrate-coupled changes in the residue conformation, indicating induced-fit effects between Cel48S_CD and substrates. Mass spectrum and crystal structural analyses suggested no significant posttranslational modification in the native Cel48S_CD protein. CONCLUSION Our results confirmed that the high activity and substrate specificity of Cel48S_CD from C. thermocellum were consistent with its importance in the cellulosome. The structure of the native Cel48S_CD protein revealed evidence of conformational changes during substrate binding. In addition, our study provided a reliable method for in situ purification of cellulosomal and other secretive proteins from C. thermocellum.
Collapse
Affiliation(s)
- Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Sheng Dong
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| |
Collapse
|
30
|
Fermentative hydrogen production from Jerusalem artichoke by Clostridium tyrobutyricum expressing exo-inulinase gene. Sci Rep 2017; 7:7940. [PMID: 28801602 PMCID: PMC5554141 DOI: 10.1038/s41598-017-07207-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/23/2017] [Indexed: 12/01/2022] Open
Abstract
Clostridium tyrobutyricum ATCC25755 has been reported as being able to produce significant quantities of hydrogen. In this study, the exo-inulinase encoding gene cloned from Paenibacillus polymyxa SC-2 was into the expression plasmid pSY6 and expressed in the cells of C. tyrobutyricum. The engineered C. tyrobutyricum strain efficiently fermented the inulin-type carbohydrates from Jerusalem artichoke, without any pretreatment being necessary for the production of hydrogen. A comparatively high hydrogen yield (3.7 mol/mol inulin-type sugar) was achieved after 96 h in a batch process with simultaneous saccharification and fermentation (SSF), with an overall volumetric productivity rate of 620 ± 60 mL/h/L when the initial total sugar concentration of the inulin extract was increased to 100 g/L. Synthesis of inulinase in the batch SSF culture was closely associated with strain growth until the end of the exponential phase, reaching a maximum activity of 28.4 ± 0.26 U/mL. The overall results show that the highly productive and abundant biomass crop Jerusalem artichoke can be a good substrate for hydrogen production, and that the application of batch SSF for its conversion has the potential to become a cost-effective process in the near future.
Collapse
|
31
|
Zhang J, Liu S, Li R, Hong W, Xiao Y, Feng Y, Cui Q, Liu YJ. Efficient whole-cell-catalyzing cellulose saccharification using engineered Clostridium thermocellum. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:124. [PMID: 28507596 PMCID: PMC5429504 DOI: 10.1186/s13068-017-0796-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/19/2017] [Indexed: 05/26/2023]
Abstract
BACKGROUND Cost-efficient saccharification is one of the main bottlenecks for industrial lignocellulose conversion. Clostridium thermocellum naturally degrades lignocellulose efficiently using the cellulosome, a multiprotein supermolecular complex, and thus can be potentially used as a low-cost catalyst for lignocellulose saccharification. The industrial use of C. thermocellum is restrained due largely to the inhibition of the hydrolysate cellobiose to its cellulosome. Although the supplementation of beta-glucosidase may solve the problem, the production of the enzymes greatly complicates the process and may also increase the cost of saccharification. RESULTS To conquer the feedback inhibition and establish an efficient whole-cell catalyst for highly efficient cellulose saccharification, we constructed a recombinant strain of C. thermocellum ∆pyrF::CaBglA which produced a secretory exoglucanase CelS-bearing heterologous BGL using a newly developed seamless genome editing system. Without the extra addition of enzymes, the relative saccharification level of ∆pyrF::CaBglA was stimulated by over twofolds compared to its parent strain ∆pyrF through a two-stage saccharification process with 100 g/L Avicel as the carbon source. The production of reducing sugars and the relative saccharification level were further enhanced to 490 mM and 79.4%, respectively, with increased cell density. CONCLUSIONS The high cellulose-degrading ability and sugar productivity suggested that the whole-cell-catalysis strategy for cellulose saccharification is promising, and the C. thermocellum strain ∆pyrF::CaBglA could be potentially used as an efficient whole-cell catalyst for industrial cellulose saccharification.
Collapse
Affiliation(s)
- Jie Zhang
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Shiyue Liu
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Renmin Li
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100049 People’s Republic of China
| | - Wei Hong
- Key Laboratory of Endemic and Ethnic Diseases (Guizhou Medical University), Ministry of Education, Guiyang, 550000 People’s Republic of China
| | - Yan Xiao
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| | - Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
- Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101 People’s Republic of China
| |
Collapse
|
32
|
Heijstra BD, Leang C, Juminaga A. Gas fermentation: cellular engineering possibilities and scale up. Microb Cell Fact 2017; 16:60. [PMID: 28403896 PMCID: PMC5389167 DOI: 10.1186/s12934-017-0676-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 04/04/2017] [Indexed: 12/11/2022] Open
Abstract
Low carbon fuels and chemicals can be sourced from renewable materials such as biomass or from industrial and municipal waste streams. Gasification of these materials allows all of the carbon to become available for product generation, a clear advantage over partial biomass conversion into fermentable sugars. Gasification results into a synthesis stream (syngas) containing carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2) and nitrogen (N2). Autotrophy-the ability to fix carbon such as CO2 is present in all domains of life but photosynthesis alone is not keeping up with anthropogenic CO2 output. One strategy is to curtail the gaseous atmospheric release by developing waste and syngas conversion technologies. Historically microorganisms have contributed to major, albeit slow, atmospheric composition changes. The current status and future potential of anaerobic gas-fermenting bacteria with special focus on acetogens are the focus of this review.
Collapse
Affiliation(s)
| | - Ching Leang
- LanzaTech, Inc., 8045 Lamon Ave, Suite 400, Skokie, IL USA
| | - Alex Juminaga
- LanzaTech, Inc., 8045 Lamon Ave, Suite 400, Skokie, IL USA
| |
Collapse
|
33
|
Zhang SC, Lai QH, Lu Y, Liu ZD, Wang TM, Zhang C, Xing XH. Enhanced biohydrogen production from corn stover by the combination of Clostridium cellulolyticum and hydrogen fermentation bacteria. J Biosci Bioeng 2016; 122:482-7. [DOI: 10.1016/j.jbiosc.2016.03.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/25/2016] [Accepted: 03/18/2016] [Indexed: 12/16/2022]
|
34
|
Minton NP, Ehsaan M, Humphreys CM, Little GT, Baker J, Henstra AM, Liew F, Kelly ML, Sheng L, Schwarz K, Zhang Y. A roadmap for gene system development in Clostridium. Anaerobe 2016; 41:104-112. [PMID: 27234263 PMCID: PMC5058259 DOI: 10.1016/j.anaerobe.2016.05.011] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/19/2016] [Accepted: 05/21/2016] [Indexed: 01/18/2023]
Abstract
Clostridium species are both heroes and villains. Some cause serious human and animal diseases, those present in the gut microbiota generally contribute to health and wellbeing, while others represent useful industrial chassis for the production of chemicals and fuels. To understand, counter or exploit, there is a fundamental requirement for effective systems that may be used for directed or random genome modifications. We have formulated a simple roadmap whereby the necessary gene systems maybe developed and deployed. At its heart is the use of ‘pseudo-suicide’ vectors and the creation of a pyrE mutant (a uracil auxotroph), initially aided by ClosTron technology, but ultimately made using a special form of allelic exchange termed ACE (Allele-Coupled Exchange). All mutants, regardless of the mutagen employed, are made in this host. This is because through the use of ACE vectors, mutants can be rapidly complemented concomitant with correction of the pyrE allele and restoration of uracil prototrophy. This avoids the phenotypic effects frequently observed with high copy number plasmids and dispenses with the need to add antibiotic to ensure plasmid retention. Once available, the pyrE host may be used to stably insert all manner of application specific modules. Examples include, a sigma factor to allow deployment of a mariner transposon, hydrolases involved in biomass deconstruction and therapeutic genes in cancer delivery vehicles. To date, provided DNA transfer is obtained, we have not encountered any clostridial species where this technology cannot be applied. These include, Clostridium difficile, Clostridium acetobutylicum, Clostridium beijerinckii, Clostridium botulinum, Clostridium perfringens, Clostridium sporogenes, Clostridium pasteurianum, Clostridium ljungdahlii, Clostridium autoethanogenum and even Geobacillus thermoglucosidasius. A simple roadmap for the development and deployment of gene systems in clostridia. Allelic exchange using pyrE alleles and pseudo-suicide vectors. Knock-out and knock-in using allele-coupled exchange (ACE). Complementation studies through genome insertion. Genome insertion of application specific modules.
Collapse
Affiliation(s)
- Nigel P Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK; Nottingham Digestive Disease Centre, NIHR Biomedical Research Unit, The University of Nottingham, University Park, Nottingham, UK.
| | - Muhammad Ehsaan
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Christopher M Humphreys
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Gareth T Little
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan Baker
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Anne M Henstra
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Fungmin Liew
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Michelle L Kelly
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK; Nottingham Digestive Disease Centre, NIHR Biomedical Research Unit, The University of Nottingham, University Park, Nottingham, UK
| | - Lili Sheng
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Katrin Schwarz
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Ying Zhang
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| |
Collapse
|
35
|
Liew F, Martin ME, Tappel RC, Heijstra BD, Mihalcea C, Köpke M. Gas Fermentation-A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks. Front Microbiol 2016; 7:694. [PMID: 27242719 PMCID: PMC4862988 DOI: 10.3389/fmicb.2016.00694] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/26/2016] [Indexed: 12/13/2022] Open
Abstract
There is an immediate need to drastically reduce the emissions associated with global fossil fuel consumption in order to limit climate change. However, carbon-based materials, chemicals, and transportation fuels are predominantly made from fossil sources and currently there is no alternative source available to adequately displace them. Gas-fermenting microorganisms that fix carbon dioxide (CO2) and carbon monoxide (CO) can break this dependence as they are capable of converting gaseous carbon to fuels and chemicals. As such, the technology can utilize a wide range of feedstocks including gasified organic matter of any sort (e.g., municipal solid waste, industrial waste, biomass, and agricultural waste residues) or industrial off-gases (e.g., from steel mills or processing plants). Gas fermentation has matured to the point that large-scale production of ethanol from gas has been demonstrated by two companies. This review gives an overview of the gas fermentation process, focusing specifically on anaerobic acetogens. Applications of synthetic biology and coupling gas fermentation to additional processes are discussed in detail. Both of these strategies, demonstrated at bench-scale, have abundant potential to rapidly expand the commercial product spectrum of gas fermentation and further improve efficiencies and yields.
Collapse
|
36
|
|
37
|
Zhou X, Chen J, Chen J, Wu W, Wang X, Wang Y. The beneficial effects of betaine on dysfunctional adipose tissue and N6-methyladenosine mRNA methylation requires the AMP-activated protein kinase α1 subunit. J Nutr Biochem 2015; 26:1678-84. [DOI: 10.1016/j.jnutbio.2015.08.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 08/05/2015] [Accepted: 08/08/2015] [Indexed: 12/12/2022]
|
38
|
Restriction modification system analysis and development of in vivo methylation for the transformation of Clostridium cellulovorans. Appl Microbiol Biotechnol 2015; 100:2289-99. [PMID: 26590584 DOI: 10.1007/s00253-015-7141-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 12/11/2022]
Abstract
Clostridium cellulovorans, a cellulolytic bacterium producing butyric and acetic acids as main fermentation products, is a promising host for biofuel production from cellulose. However, the transformation method of C. cellulovorans was not available, hindering its genetic engineering. To overcome this problem, its restriction modification (RM) systems were analyzed and a novel in vivo methylation was established for its successful transformation in the present study. Specifically, two RM systems, Cce743I and Cce743II, were determined. R. Cce743I has the same specificity as LlaJI, recognizing 5'-GACGC-3' and 5'-GCGTC-3', while M. Cce743I methylates the external cytosine in the strand (5'-GACG(m)C-3'). R. Cce743II, has the same specificity as LlaI, recognizing 5'-CCAGG-3' and 5'-CCTGG-3', while M. Cce743II methylates the external cytosine of both strands. An in vivo methylation system, expressing M. Cce743I and M. Cce743II from C. cellulovorans in Escherichia coli, was then established to protect plasmids used in electrotransformation. Transformants expressing an aldehyde/alcohol dehydrogenase (adhE2), which converted butyryl-CoA to n-butanol and acetyl-CoA to ethanol, were obtained. For the first time, an effective transformation method was developed for metabolic engineering of C. cellulovorans for biofuel production directly from cellulose.
Collapse
|
39
|
Tan Y, Liu ZY, Liu Z, Li FL. Characterization of an acetoin reductase/2,3-butanediol dehydrogenase from Clostridium ljungdahlii DSM 13528. Enzyme Microb Technol 2015; 79-80:1-7. [DOI: 10.1016/j.enzmictec.2015.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/10/2015] [Accepted: 06/12/2015] [Indexed: 11/24/2022]
|
40
|
Chen C, Cui Z, Song X, Liu YJ, Cui Q, Feng Y. Integration of bacterial expansin-like proteins into cellulosome promotes the cellulose degradation. Appl Microbiol Biotechnol 2015; 100:2203-12. [DOI: 10.1007/s00253-015-7071-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/02/2015] [Accepted: 10/07/2015] [Indexed: 01/24/2023]
|
41
|
Teng L, Wang K, Xu J, Xu C. Flavin mononucleotide (FMN)-based fluorescent protein (FbFP) as reporter for promoter screening in Clostridium cellulolyticum. J Microbiol Methods 2015; 119:37-43. [PMID: 26427827 DOI: 10.1016/j.mimet.2015.09.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 09/28/2015] [Accepted: 09/28/2015] [Indexed: 12/13/2022]
Abstract
Conventional methods for screening promoters in anaerobic bacteria are generally based on detection of enzymatic reactions and thus usually complicated or strain specific. Therefore a more efficient and universal method will be valuable. Here, using cellulolytic bacteria Clostridium cellulolyticum H10 as a model, we employed an oxygen-independent flavin-based fluorescent protein (FbFP) derived from Pseudomonas putida as a quantitative reporter for the screening of promoter via monitoring fluorescence intensity. The stability and reliability of FbFP fluorescence were proven by the high correlation (R(2)=0.87) between fluorescence intensity and abundance of FbFP. Moreover, two endogenous promoters with exceptional performance were identified and characterized, including a constitutive promoter p3398 and an inducible promoter p1133. Compared to the existing reporter systems widely used in clostridia, this FbFP-based method is more rapid, intuitive and versatile, and the endogenous promoters reported here should enrich the synthetic biology toolbox for this and related organisms.
Collapse
Affiliation(s)
- Lin Teng
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kun Wang
- Key Laboratory of Horticulture Science for Southern Mountainous Region, Ministry of Education, College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400716, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.
| | - Chenggang Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.
| |
Collapse
|
42
|
Efficient Genome Editing in Clostridium cellulolyticum via CRISPR-Cas9 Nickase. Appl Environ Microbiol 2015; 81:4423-31. [PMID: 25911483 DOI: 10.1128/aem.00873-15] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/16/2015] [Indexed: 02/01/2023] Open
Abstract
The CRISPR-Cas9 system is a powerful and revolutionary genome-editing tool for eukaryotic genomes, but its use in bacterial genomes is very limited. Here, we investigated the use of the Streptococcus pyogenes CRISPR-Cas9 system in editing the genome of Clostridium cellulolyticum, a model microorganism for bioenergy research. Wild-type Cas9-induced double-strand breaks were lethal to C. cellulolyticum due to the minimal expression of nonhomologous end joining (NHEJ) components in this strain. To circumvent this lethality, Cas9 nickase was applied to develop a single-nick-triggered homologous recombination strategy, which allows precise one-step editing at intended genomic loci by transforming a single vector. This strategy has a high editing efficiency (>95%) even using short homologous arms (0.2 kb), is able to deliver foreign genes into the genome in a single step without a marker, enables precise editing even at two very similar target sites differing by two bases preceding the seed region, and has a very high target site density (median interval distance of 9 bp and 95.7% gene coverage in C. cellulolyticum). Together, these results establish a simple and robust methodology for genome editing in NHEJ-ineffective prokaryotes.
Collapse
|
43
|
Xu C, Huang R, Teng L, Jing X, Hu J, Cui G, Wang Y, Cui Q, Xu J. Cellulosome stoichiometry in Clostridium cellulolyticum is regulated by selective RNA processing and stabilization. Nat Commun 2015; 6:6900. [PMID: 25908225 PMCID: PMC4423207 DOI: 10.1038/ncomms7900] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 03/11/2015] [Indexed: 01/23/2023] Open
Abstract
The mechanism, physiological relevance and evolutionary implication of selective RNA processing and stabilization (SRPS) remain elusive. Here we report the genome-wide maps of transcriptional start sites (TSs) and post-transcriptional processed sites (PSs) for Clostridium cellulolyticum. The PS-associated genes are preferably associated with subunits of heteromultimeric protein complexes, and the intergenic PSs (iPSs) are enriched in operons exhibiting highly skewed transcript-abundance landscape. Stem-loop structures associated with those iPSs located at 3′ termini of highly transcribed genes exhibit folding free energy negatively correlated with transcript-abundance ratio of flanking genes. In the cellulosome-encoding cip-cel operon, iPSs and stem-loops precisely regulate structure and abundance of the subunit-encoding transcripts processed from a primary polycistronic RNA, quantitatively specifying cellulosome stoichiometry. Moreover, cellulosome evolution is shaped by the number, position and biophysical nature of TSs, iPSs and stem-loops. Our findings unveil a genome-wide RNA-encoded strategy controlling in vivo stoichiometry of protein complexes. Selective RNA processing and stabilization (SRPS) can regulate bacterial operons, but the process is not well understood. Here, the authors show that the stoichiometry of cellulosome, a 12-subunit protein complex expressed from an operon in Gram-positive Clostridium cellullolyticum, is regulated by SRPS.
Collapse
Affiliation(s)
- Chenggang Xu
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Ranran Huang
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin Teng
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyan Jing
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Jianqiang Hu
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guzhen Cui
- CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Yilin Wang
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Jian Xu
- Single-Cell Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.,CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| |
Collapse
|
44
|
Liu YJ, Zhang J, Cui GZ, Cui Q. Current progress of targetron technology: Development, improvement and application in metabolic engineering. Biotechnol J 2015; 10:855-65. [DOI: 10.1002/biot.201400716] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/22/2015] [Accepted: 01/29/2015] [Indexed: 01/10/2023]
|
45
|
Tan Y, Liu ZY, Liu Z, Zheng HJ, Li FL. Comparative transcriptome analysis between csrA-disruption Clostridium acetobutylicum and its parent strain. MOLECULAR BIOSYSTEMS 2015; 11:1434-42. [DOI: 10.1039/c4mb00600c] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This study represented the first attempt to investigate the global regulation of CsrA through transcriptome analysis in Gram-positive bacteria.
Collapse
Affiliation(s)
- Yang Tan
- Key Laboratory of Biofuels
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao 266101
- China
| | - Zi-Yong Liu
- Key Laboratory of Biofuels
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao 266101
- China
| | - Zhen Liu
- Key Laboratory of Biofuels
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao 266101
- China
| | - Hua-Jun Zheng
- Shanghai-MOST Key Laboratory of Health and Disease Genomics
- Chinese National Human Genome Center at Shanghai
- Shanghai 201203
- China
| | - Fu-Li Li
- Key Laboratory of Biofuels
- Qingdao Institute of Bioenergy and Bioprocess Technology
- Chinese Academy of Sciences
- Qingdao 266101
- China
| |
Collapse
|
46
|
Zhang J, Liu YJ, Cui GZ, Cui Q. A novel arabinose-inducible genetic operation system developed for Clostridium cellulolyticum. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:36. [PMID: 25763107 PMCID: PMC4355141 DOI: 10.1186/s13068-015-0214-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/29/2015] [Indexed: 05/07/2023]
Abstract
BACKGROUND Clostridium cellulolyticum and other cellulolytic Clostridium strains are natural producers of lignocellulosic biofuels and chemicals via the consolidated bioprocessing (CBP) route, and systems metabolic engineering is indispensable to meet the cost-efficient demands of industry. Several genetic tools have been developed for Clostridium strains, and an efficient and stringent inducible genetic operation system is still required for the precise regulation of the target gene function. RESULTS Here, we provide a stringent arabinose-inducible genetic operation (ARAi) system for C. cellulolyticum, including an effective gene expression platform with an oxygen-independent fluorescent reporter, a sensitive MazF-based counterselection genetic marker, and a precise gene knock-out method based on an inducible ClosTron system. A novel arabinose-inducible promoter derived from Clostridium acetobutylicum is employed in the ARAi system to control the expression of the target gene, and the gene expression can be up-regulated over 800-fold with highly induced stringency. The inducible ClosTron method of the ARAi system decreases the off-target frequency from 100% to 0, which shows the precise gene targeting in C. cellulolyticum. The inducible effect of the ARAi system is specific to a universal carbon source L-arabinose, implying that the system could be used widely for clostridial strains with various natural substrates. CONCLUSIONS The inducible genetic operation system ARAi developed in this study, containing both controllable gene expression and disruption tools, has the highest inducing activity and stringency in Clostridium by far. Thus, the ARAi system will greatly support the efficient metabolic engineering of C. cellulolyticum and other mesophilic Clostridium strains for lignocellulose bioconversion.
Collapse
Affiliation(s)
- Jie Zhang
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />University of Chinese Academy of Sciences, Chinese Academy of Sciences, 19, Yuquan Road, Beijing, 100049 People’s Republic of China
| | - Ya-Jun Liu
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
| | - Gu-Zhen Cui
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
| | - Qiu Cui
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
- />Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189, Songling Road, Qingdao, 266101 People’s Republic of China
| |
Collapse
|
47
|
Hong W, Zhang J, Feng Y, Mohr G, Lambowitz AM, Cui GZ, Liu YJ, Cui Q. The contribution of cellulosomal scaffoldins to cellulose hydrolysis by Clostridium thermocellum analyzed by using thermotargetrons. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:80. [PMID: 24955112 PMCID: PMC4045903 DOI: 10.1186/1754-6834-7-80] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 05/13/2014] [Indexed: 05/23/2023]
Abstract
BACKGROUND Clostridium thermocellum is a thermophilic anaerobic bacterium that degrades cellulose by using a highly effective cellulosome, a macromolecular complex consisting of multiple cellulose degrading enzymes organized and attached to the cell surface by non-catalytic scaffoldins. However, due largely to lack of efficient methods for genetic manipulation of C. thermocellum, it is still unclear how the different scaffoldins and their functional modules contribute to cellulose hydrolysis. RESULTS We constructed C. thermocellum mutants with the primary scaffoldin CipA (cellulosome-integrating protein A) truncated at different positions or lacking four different secondary scaffoldins by using a newly developed thermotargetron system, and we analyzed cellulose hydrolysis, cellulosome formation, and cellulose binding of the mutants. A CipA truncation that deletes six type I cohesin modules, which bind cellulolytic enzymes, decreased cellulose hydrolysis rates by 46%, and slightly longer truncations that also delete the carbohydrate binding module decreased rates by 89 to 92%, indicating strong cellulosome-substrate synergy. By contrast, a small CipA truncation that deletes only the C-terminal type II dockerin (XDocII) module detached cellulosomes from the cells, but decreased cellulose hydrolysis rates by only 9%, suggesting a relatively small contribution of cellulosome-cell synergy. Disruptants lacking any of four different secondary scaffoldins (OlpB, 7CohII, Orf2p, or SdbA) showed moderately decreased cellulose hydrolysis rates, suggesting additive contributions. Surprisingly, the CipA-ΔXDocII mutant, which lacks cell-associated polycellulosomes, adheres to cellulose almost as strongly as wild-type cells, revealing an alternate, previously unknown cellulose-binding mechanism. CONCLUSIONS Our results emphasize the important role of cellulosome-substrate synergy in cellulose degradation, demonstrate a contribution of secondary scaffoldins, and suggest a previously unknown, non-cellulosomal system for binding insoluble cellulose. Our findings provide new insights into cellulosome function and impact genetic engineering of microorganisms to enhance bioconversions of cellulose substrates.
Collapse
Affiliation(s)
- Wei Hong
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, P R China
| | - Jie Zhang
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, P R China
| | - Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
| | - Georg Mohr
- Departments of Molecular Biosciences and Chemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Alan M Lambowitz
- Departments of Molecular Biosciences and Chemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Gu-Zhen Cui
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
| | - Ya-Jun Liu
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
- Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, P R China
| |
Collapse
|
48
|
Pyne ME, Bruder M, Moo-Young M, Chung DA, Chou CP. Technical guide for genetic advancement of underdeveloped and intractable Clostridium. Biotechnol Adv 2014; 32:623-41. [DOI: 10.1016/j.biotechadv.2014.04.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/10/2014] [Accepted: 04/15/2014] [Indexed: 02/04/2023]
|
49
|
Drepper T, Gensch T, Pohl M. Advanced in vivo applications of blue light photoreceptors as alternative fluorescent proteins. Photochem Photobiol Sci 2014; 12:1125-34. [PMID: 23660639 DOI: 10.1039/c3pp50040c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ultimate ambition in cell biology, microbiology and biomedicine is to unravel complex physiological and pathophysiological processes within living organisms. To conquer this challenge, fluorescent proteins (FPs) are used as versatile in vivo reporters and biosensors to study gene regulation as well as the synthesis, localization and function of proteins in living cells. The most widely used FPs are the green fluorescent protein (GFP) and its derivatives and relatives. Their use as in vivo reporter proteins, however, is sometimes restricted by different environmental and cellular factors. Consequently, a whole range of alternative, cofactor-dependent reporter proteins have been developed recently. In this perspective, we summarize the advantages and limitations of the novel class of cyan-green fluorescent flavoproteins in comparison to members of the GFP family and discuss some correlated consequences for the use of FPs as in vivo reporters.
Collapse
Affiliation(s)
- Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich-Heine-University Duesseldorf, Forschungszentrum Jülich, 52425 Juelich, Germany.
| | | | | |
Collapse
|
50
|
Enyeart PJ, Mohr G, Ellington AD, Lambowitz AM. Biotechnological applications of mobile group II introns and their reverse transcriptases: gene targeting, RNA-seq, and non-coding RNA analysis. Mob DNA 2014; 5:2. [PMID: 24410776 PMCID: PMC3898094 DOI: 10.1186/1759-8753-5-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/19/2013] [Indexed: 12/21/2022] Open
Abstract
Mobile group II introns are bacterial retrotransposons that combine the activities of an autocatalytic intron RNA (a ribozyme) and an intron-encoded reverse transcriptase to insert site-specifically into DNA. They recognize DNA target sites largely by base pairing of sequences within the intron RNA and achieve high DNA target specificity by using the ribozyme active site to couple correct base pairing to RNA-catalyzed intron integration. Algorithms have been developed to program the DNA target site specificity of several mobile group II introns, allowing them to be made into ‘targetrons.’ Targetrons function for gene targeting in a wide variety of bacteria and typically integrate at efficiencies high enough to be screened easily by colony PCR, without the need for selectable markers. Targetrons have found wide application in microbiological research, enabling gene targeting and genetic engineering of bacteria that had been intractable to other methods. Recently, a thermostable targetron has been developed for use in bacterial thermophiles, and new methods have been developed for using targetrons to position recombinase recognition sites, enabling large-scale genome-editing operations, such as deletions, inversions, insertions, and ‘cut-and-pastes’ (that is, translocation of large DNA segments), in a wide range of bacteria at high efficiency. Using targetrons in eukaryotes presents challenges due to the difficulties of nuclear localization and sub-optimal magnesium concentrations, although supplementation with magnesium can increase integration efficiency, and directed evolution is being employed to overcome these barriers. Finally, spurred by new methods for expressing group II intron reverse transcriptases that yield large amounts of highly active protein, thermostable group II intron reverse transcriptases from bacterial thermophiles are being used as research tools for a variety of applications, including qRT-PCR and next-generation RNA sequencing (RNA-seq). The high processivity and fidelity of group II intron reverse transcriptases along with their novel template-switching activity, which can directly link RNA-seq adaptor sequences to cDNAs during reverse transcription, open new approaches for RNA-seq and the identification and profiling of non-coding RNAs, with potentially wide applications in research and biotechnology.
Collapse
Affiliation(s)
| | | | | | - Alan M Lambowitz
- Departments of Molecular Biosciences and Chemistry, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
| |
Collapse
|