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DeChellis A, Nemmaru B, Sammond D, Douglass J, Patil N, Reste O, Chundawat SPS. Supercharging carbohydrate-binding module alone enhances endocellulase thermostability, binding, and activity on cellulosic biomass. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.09.557007. [PMID: 37745483 PMCID: PMC10515785 DOI: 10.1101/2023.09.09.557007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Lignocellulosic biomass recalcitrance to enzymatic degradation necessitates high enzyme loadings incurring large processing costs for industrial-scale biofuels or biochemicals production. Manipulating surface charge interactions to minimize non-productive interactions between cellulolytic enzymes and plant cell wall components (e.g., lignin or cellulose) via protein supercharging has been hypothesized to improve biomass biodegradability, but with limited demonstrated success to date. Here we characterize the effect of introducing non-natural enzyme surface mutations and net charge on cellulosic biomass hydrolysis activity by designing a library of supercharged family-5 endoglucanase Cel5A and its native family-2a carbohydrate binding module (CBM) originally belonging to an industrially relevant thermophilic microbe Thermobifida fusca . A combinatorial library of 33 mutant constructs containing different CBM and Cel5A designs spanning a net charge range of -52 to 37 was computationally designed using Rosetta macromolecular modelling software. Activity for all mutants was rapidly characterized as soluble cell lysates and promising mutants (containing mutations either on the CBM, Cel5A catalytic domain, or both CBM and Cel5A domains) were then purified and systematically characterized. Surprisingly, often endocellulases with mutations on the CBM domain alone resulted in improved activity on cellulosic biomass, with three top-performing supercharged CBM mutants exhibiting between 2-5-fold increase in activity, compared to native enzyme, on both pretreated biomass enriched in lignin (i.e., corn stover) and isolated crystalline/amorphous cellulose. Furthermore, we were able to clearly demonstrate that endocellulase net charge can be selectively fine-tuned using protein supercharging protocol for targeting distinct substrates and maximizing biocatalytic activity. Additionally, several supercharged CBM containing endocellulases exhibited a 5-10 °C increase in optimal hydrolysis temperature, compared to native enzyme, which enabled further increase in hydrolytic yield at higher operational reaction temperatures. This study demonstrates the first successful implementation of enzyme supercharging of cellulolytic enzymes to increase hydrolytic activity towards complex lignocellulosic biomass derived substrates.
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Sun R, Fu M, Ma L, Zhou Y, Li Q. Iron reduction in composting environment synergized with quinone redox cycling drives humification and free radical production from humic substances. BIORESOURCE TECHNOLOGY 2023:129341. [PMID: 37343801 DOI: 10.1016/j.biortech.2023.129341] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
The aim of this paper was to investigate the influence of Fe (III) on humification and free radicals evolution. The experimental data showed that the experimental group (CT) with Fe2(SO4)3 had a better degree of humification than the control group (CK). The humic substances (HS) content was 10% higher in CT (23.94 mg·g-1) than in CK (21.54 mg·g-1) in the final. Fe (III) contributed significantly to the formation of free radicals in HS. The amount of H2O2 in CT increased to 74.8 mmol·kg-1, while CK was only 46.5 mmol·kg-1. The content of semiquinone free radical was 10.32×1011 spins/mm3 in CT, 5.11×1011 spins/mm3 in CK in the end. Several iron-reducing bacteria were detected in composting, among which Paenibacillus was dominant. The above findings suggested that the application of Fe2(SO4)3 enhanced the iron reduction synergistic quinone redox cycling and promoted the generation of free radicals during the humification of composting.
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Affiliation(s)
- Ru Sun
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Mengxin Fu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Liangcai Ma
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Yucheng Zhou
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Qunliang Li
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
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Thakur V, Singh D. A thermo-alkali stable and detergent compatible processive β-1,4-glucanase from Himalayan Bacillus sp. PCH94. Front Microbiol 2022; 13:1058249. [DOI: 10.3389/fmicb.2022.1058249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
Present study reports a novel and robust GH9 processive endoglucanase β-1,4-glucanase from Bacillus sp. PCH94 (EGaseBL) with thermo-alkali stable properties. The EGaseBL gene was cloned in pET-28b(+) and expressed in Escherichia coli BL21(DE3) cells. The recombinant protein was purified 94-fold with a yield of 67.8%. The biochemical characterization revealed an active enzyme at a wide pH (4.0–10.0) and temperature (4–100°C). It showed a Km and Vmax of 1.10 mg/ml and 208.24 IU/mg, respectively, using β-glucan as a substrate. The EGaseBL showed dual activities for endoglucanase (134.17 IU/mg) and exoglucanase (28.76 IU/mg), assayed using substrates β-glucan and Avicel, respectively. The enzyme is highly stable in neutral and alkaline pH and showed a half-life of 11.29 h, and 8.31 h in pH 7.0 and 9.0, respectively. The enzyme is also compatible with commercial detergents (Tide, Surf, Ghadi, Raj, and Healing tree) of the Indian market and retained > 85% enzyme activity. Concisely, robustness, extreme functionality, and detergent compatibility endorse EGaseBL as a potential bioresource for the detergent industry, in addition to its implications for the bioethanol industry.Highlights– Cloning, expression, and purification of putative novel GH9 family β-1,4-glucanase.– Processive endoglucanase with CBM3 domain and bi-functional (endo/exo) activity.– Broad pH-temperature active and stable enzyme.– Compatible with commercial detergent powders.
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Buta-Hubeny M, Korzeniewska E, Hubeny J, Zieliński W, Rolbiecki D, Harnisz M, Paukszto Ł. Structure of the manure resistome and the associated mobilome for assessing the risk of antimicrobial resistance transmission to crops. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152144. [PMID: 34864022 DOI: 10.1016/j.scitotenv.2021.152144] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 05/23/2023]
Abstract
In this study, the impact of bovine and poultry manure on the quantitative and qualitative composition of antibiotic resistance genes (ARGs) and the environmental mobilome associated with antimicrobial resistance in soil and crops was determined with the use of next generation sequencing methods. The aim of the study was to perform a metagenomic analysis of manure to estimate the risk of the transmission of ARGs and bacterial drug resistance carriers to fertilized soil and crops. The total copy number of ARGs was nearly four times higher in poultry manure (555 ppm) than in bovine manure (140 ppm), and this relationship was also noted in fertilized soil. Poultry manure induced a much greater increase in the concentrations of ARGs in the soil environment (196.4 ppm) than bovine manure (137.8 ppm) immediately after supplementation. The application of poultry manure led to the highest increase in the abundance of genes encoding resistance to tetracyclines (9%), aminoglycosides (3.5%), sulfonamides (3%), bacitracin (2%), chloramphenicol (2%), and macrolide-lincosamide-streptogramin antibiotics (1%). Heavy metals were stronger promoters of antibiotic resistance in the environment than antibiotics. Antibiotics exerted a greater influence on maintaining the diversity of ARGs than on increasing their abundance in soil. Large quantities of insertion sequences (IS), including those associated with the mobility of ARGs in the population of ESKAPEE pathogens, are introduced to soil with manure. These IS remain stable for up to several months, which indicates that manure, in particular poultry manure, significantly increases the risk of rapid ARG transfer to the environment. Manure also largely contributes to an increase in the diversity of the resistome and mobilome in the metagenome of bacteria isolated from crops. Bacteria of the phylum Proteobacteria appear to play a major role in the transmission of multiple ARGs in crops grown for human and animal consumption.
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Affiliation(s)
- Martyna Buta-Hubeny
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Ewa Korzeniewska
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland.
| | - Jakub Hubeny
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Wiktor Zieliński
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Damian Rolbiecki
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Monika Harnisz
- Department of Water Protection Engineering and Environmental Microbiology, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-720 Olsztyn, Poland
| | - Łukasz Paukszto
- Department of Plant Physiology, Genetics and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland
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Planifilum fulgidum Is the Dominant Functional Microorganism in Compost Containing Spent Mushroom Substrate. SUSTAINABILITY 2021. [DOI: 10.3390/su131810002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The extensive accumulation of spent mushroom substrate (SMS) owing to the large-scale production of edible fungi is causing environmental problems that cannot be ignored. Co-composting is a promising method for agricultural and animal husbandry waste disposal. In this study, the composition and function of microbial communities in the process of cattle manure–maize straw composting with SMS addition were compared through an integrated meta-omics approach. The results showed that irrespective of SMS addition, the predominant fungi were Ascomycota, while the dominant bacteria were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. High temperature promoted the evolution from Gram-negative bacteria (Bacteroides, Proteobacteria) to Gram-positive bacteria (Firmicutes, Actinomycetes). The composting process was accelerated by SMS addition, and the substrate was effectively degraded in 14 days. Metaproteomics results showed that the dominant microorganism, Planifilum fulgidum, secreted large amounts of S8, M17, and M32 proteases that could degrade macromolecular protein substrates in the presence of SMS. Planifilum fulgidum, along with Thermobifida fusca and Melanocarpus albomyces, synergistically degraded hemicellulose, cellulose, and protein. In addition, the dominant microorganisms related to the initial raw materials such as Pichia, Lactobacillus in the microbial agent and Hypsizygus in SMS could not adapt to the high-temperature environment (>60 °C) and were replaced by thermophilic bacteria after 5 days of composting.
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Phospholipid N-methyltransferases produce various methylated phosphatidylethanolamine derivatives in thermophilic bacteria. Appl Environ Microbiol 2021; 87:e0110521. [PMID: 34288711 DOI: 10.1128/aem.01105-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One of the most common pathways for the biosynthesis of the phospholipid phosphatidylcholine (PC) in bacteria is the successive three-fold N-methylation of phosphatidylethanolamine (PE) catalyzed by phospholipid N-methyltransferases (Pmts). Pmts with different activities have been described in a number of mesophilic bacteria. In the present study, we identified and characterized the substrate and product spectrum of four Pmts from thermophilic bacteria. Three of these enzymes were purified in an active form. The Pmts from Melghirimyces thermohalophilus, Thermochromogena staphylospora and Thermobifida fusca produce monomethyl-PE (MMPE) and dimethyl-PE (DMPE). T. fusca encodes two Pmt candidates, one is mutationally inactivated and the other is responsible for the accumulation of large amounts of MMPE. The Pmt enzyme from Rubellimicrobium thermophilum catalyzes all three methylation reactions to synthesize PC. Moreover, we show that PE, previously reported to be absent in R. thermophilum, is in fact produced and serves as precursor for the methylation pathway. In an alternative route, the strain is able to produce PC by the PC synthase pathway when choline is available. The activity of all purified thermophilic Pmt enzymes was stimulated by anionic lipids suggesting membrane recruitment of these cytoplasmic proteins via electrostatic interactions. Our study provides novel insights into the functional characteristics of phospholipid N-methyltransferases in a previously unexplored set of thermophilic environmental bacteria. Importance In recent years, the presence of phosphatidylcholine (PC) in bacterial membranes has gained increasing attention, partly due to its critical role in the interaction with eukaryotic hosts. PC biosynthesis via a three-step methylation of phosphatidylethanolamine, catalyzed by phospholipid N-methyltransferases (Pmts), has been described in a range of mesophilic bacteria. Here, we expand our knowledge on bacterial PC formation by the identification, purification and characterization of Pmts from phylogenetically diverse thermophilic bacteria, and thereby provide insights into the functional characteristics of Pmt enzymes in thermophilic actinomycetes and proteobacteria.
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Aymé L, Hébert A, Henrissat B, Lombard V, Franche N, Perret S, Jourdier E, Heiss-Blanquet S. Characterization of three bacterial glycoside hydrolase family 9 endoglucanases with different modular architectures isolated from a compost metagenome. Biochim Biophys Acta Gen Subj 2021; 1865:129848. [PMID: 33460770 DOI: 10.1016/j.bbagen.2021.129848] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND Environmental bacteria express a wide diversity of glycoside hydrolases (GH). Screening and characterization of GH from metagenomic sources provides an insight into biomass degradation strategies of non-cultivated prokaryotes. METHODS In the present report, we screened a compost metagenome for lignocellulolytic activities and identified six genes encoding enzymes belonging to family GH9 (GH9a-f). Three of these enzymes (GH9b, GH9d and GH9e) were successfully expressed and characterized. RESULTS A phylogenetic analysis of the catalytic domain of pro- and eukaryotic GH9 enzymes suggested the existence of two major subgroups. Bacterial GH9s displayed a wide variety of modular architectures and those harboring an N-terminal Ig-like domain, such as GH9b and GH9d, segregated from the remainder. We purified and characterized GH9 endoglucanases from both subgroups and examined their stabilities, substrate specificities and product profiles. GH9e exhibited an original hydrolysis pattern, liberating an elevated proportion of oligosaccharides longer than cellobiose. All of the enzymes exhibited processive behavior and a synergistic action on crystalline cellulose. Synergy was also evidenced between GH9d and a GH48 enzyme identified from the same metagenome. CONCLUSIONS The characterized GH9 enzymes displayed different modular architectures and distinct substrate and product profiles. The presence of a cellulose binding domain was shown to be necessary for binding and digestion of insoluble cellulosic substrates, but not for processivity. GENERAL SIGNIFICANCE The identification of six GH9 enzymes from a compost metagenome and the functional variety of three characterized members highlight the importance of this enzyme family in bacterial biomass deconstruction.
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Affiliation(s)
- Laure Aymé
- IFP Energies Nouvelles, 1 - 4 avenue du Bois-Préau, 92852 Rueil-Malmaison, France
| | - Agnès Hébert
- IFP Energies Nouvelles, 1 - 4 avenue du Bois-Préau, 92852 Rueil-Malmaison, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, 163 avenue de Luminy, 13288 Aix Marseille Université, Marseille, France; INRAE, USC1408 Architecture et Fonction des Macromolécules Biologiques (AFMB), 163 avenue de Luminy, 13288 Marseille, France; Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Vincent Lombard
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, 163 avenue de Luminy, 13288 Aix Marseille Université, Marseille, France; INRAE, USC1408 Architecture et Fonction des Macromolécules Biologiques (AFMB), 163 avenue de Luminy, 13288 Marseille, France
| | - Nathalie Franche
- Aix Marseille Université, CNRS, LCB, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Stéphanie Perret
- Aix Marseille Université, CNRS, LCB, 31 Chemin Joseph Aiguier, 13009 Marseille, France
| | - Etienne Jourdier
- IFP Energies Nouvelles, 1 - 4 avenue du Bois-Préau, 92852 Rueil-Malmaison, France
| | - Senta Heiss-Blanquet
- IFP Energies Nouvelles, 1 - 4 avenue du Bois-Préau, 92852 Rueil-Malmaison, France.
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Shivaiah KK, Upton B, Nikolau BJ. Kinetic, Structural, and Mutational Analysis of Acyl-CoA Carboxylase From Thermobifida fusca YX. Front Mol Biosci 2021; 7:615614. [PMID: 33511159 PMCID: PMC7835884 DOI: 10.3389/fmolb.2020.615614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/07/2020] [Indexed: 11/13/2022] Open
Abstract
Acyl-CoA carboxylases (AcCCase) are biotin-dependent enzymes that are capable of carboxylating more than one short chain acyl-CoA substrate. We have conducted structural and kinetic analyses of such an AcCCase from Thermobifida fusca YX, which exhibits promiscuity in carboxylating acetyl-CoA, propionyl-CoA, and butyryl-CoA. The enzyme consists of two catalytic subunits (TfAcCCA and TfAcCCB) and a non-catalytic subunit, TfAcCCE, and is organized in quaternary structure with a A6B6E6 stoichiometry. Moreover, this holoenzyme structure appears to be primarily assembled from two A3 and a B6E6 subcomplexes. The role of the TfAcCCE subunit is to facilitate the assembly of the holoenzyme complex, and thereby activate catalysis. Based on prior studies of an AcCCase from Streptomyces coelicolor, we explored whether a conserved Asp residue in the TfAcCCB subunit may have a role in determining the substrate selectivity of these types of enzymes. Mutating this D427 residue resulted in alterations in the substrate specificity of the TfAcCCase, increasing proficiency for carboxylating acetyl-CoA, while decreasing carboxylation proficiency with propionyl-CoA and butyryl-CoA. Collectively these results suggest that residue D427 of AcCCB subunits is an important, but not sole determinant of the substrate specificity of AcCCase enzymes.
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Affiliation(s)
- Kiran-Kumar Shivaiah
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States.,Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,Center for Metabolic Biology, Iowa State University, Ames, IA, United States
| | - Bryon Upton
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States.,Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,Center for Metabolic Biology, Iowa State University, Ames, IA, United States
| | - Basil J Nikolau
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States.,Center for Biorenewable Chemicals (CBiRC), Iowa State University, Ames, IA, United States.,Center for Metabolic Biology, Iowa State University, Ames, IA, United States
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Ghosh S, Godoy L, Anchang KY, Achilonu CC, Gryzenhout M. Fungal Cellulases: Current Research and Future Challenges. Fungal Biol 2021. [DOI: 10.1007/978-3-030-85603-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shi Z, Han C, Zhang X, Tian L, Wang L. Novel Synergistic Mechanism for Lignocellulose Degradation by a Thermophilic Filamentous Fungus and a Thermophilic Actinobacterium Based on Functional Proteomics. Front Microbiol 2020; 11:539438. [PMID: 33042052 PMCID: PMC7518101 DOI: 10.3389/fmicb.2020.539438] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/24/2020] [Indexed: 11/13/2022] Open
Abstract
Effective artificial microbial consortia containing microorganisms with desired biological functions have the potential to optimize the lignocellulose-based bioindustry. Thermobifida fusca was a dominant actinobacterium in high-temperature corn stalk composts, but it was unable to grow alone in corn stalk solid medium. Interestingly, T. fusca showed good growth and secreted enzymes when cocultured with Thermomyces lanuginosus. T. lanuginosus grew firstly during the initial stage, whereas T. fusca dominated the system subsequently during cocultivation. The secretome indicated that T. lanuginosus mainly degraded xylan by expressing a GH11 xylanase (g4601.t1, GenBank AAB94633.1; with relative secretion of 4.95 ± 0.65%). T. fusca was induced by xylan mainly to secrete a xylanase from GH11 family (W8GGR4, GenBank AHK22788.1; with relative secretion of 8.71 ± 3.83%) which could rapidly degrade xylan to xylo-oligosaccharide (XOS) and xylose within 2 min, while high concentrations (>0.5%, w/v) of XOS or xylose suppressed the growth of T. fusca; which may be the reason why T. fusca unable to grow alone in corn stalk solid medium. However, T. lanuginosus could utilize the XOS and xylose produced by xylanases secreted by T. fusca. During the synergistic degradation of lignocellulose by T. lanuginosus and T. fusca, xylan was rapidly consumed by T. lanuginosus, the residual cellulose could specifically induced T. fusca to express a GH10 xylanase with a CBM2 domain (Q47KR6, GenBank AAZ56956.1; with relative secretion of 5.03 ± 1.33%) and 6 cellulases (2 exocellulases and 4 endocellulases). Moreover, T. lanuginosus increased the secretion of cellulases from T. fusca by 19-25%. The order of T. lanuginosus and T. fusca was consistent with the multilayered structures of lignocellulose and could be regulated by different concentrations of XOS and xylose. The novel synergism of T. lanuginosus and T. fusca gave a new sight for revealing more synergetic relationships in natural environments and exploring efficient microbial inoculants and enzyme cocktails for lignocellulose degradation.
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Affiliation(s)
- Zelu Shi
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Chao Han
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Xiujun Zhang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Li Tian
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
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Enhanced Thermostability and Enzymatic Activity of Cel6A Variants from Thermobifida fusca by Empirical Domain Engineering (Short Title: Domain Engineering of Cel6A). BIOLOGY 2020; 9:biology9080214. [PMID: 32784797 PMCID: PMC7464639 DOI: 10.3390/biology9080214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 02/07/2023]
Abstract
Cellulases are a set of lignocellulolytic enzymes, capable of producing eco-friendly low-cost renewable bioethanol. However, low stability and hydrolytic activity limit their wide-scale applicability at the industrial scale. In this work, we report the domain engineering of endoglucanase (Cel6A) of Thermobifida fusca to improve their catalytic activity and thermal stability. Later, enzymatic activity and thermostability of the most efficient variant named as Cel6A.CBC was analyzed by molecular dynamics simulations. This variant demonstrated profound activity against soluble and insoluble cellulosic substrates like filter paper, alkali-treated bagasse, regenerated amorphous cellulose (RAC), and bacterial microcrystalline cellulose. The variant Cel6A.CBC showed the highest catalysis of carboxymethyl cellulose (CMC) and other related insoluble substrates at a pH of 6.0 and a temperature of 60 °C. Furthermore, a sound rationale was observed between experimental findings and molecular modeling of Cel6A.CBC which revealed thermostability of Cel6A.CBC at 26.85, 60.85, and 74.85 °C as well as structural flexibility at 126.85 °C. Therefore, a thermostable derivative of Cel6A engineered in the present work has enhanced biological performance and can be a useful construct for the mass production of bioethanol from plant biomass.
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Rodriguez Buitrago JA, Klünemann T, Blankenfeldt W, Schallmey A. Expression, purification and crystal structure determination of a ferredoxin reductase from the actinobacterium Thermobifida fusca. Acta Crystallogr F Struct Biol Commun 2020; 76:334-340. [PMID: 32744244 PMCID: PMC7397466 DOI: 10.1107/s2053230x2000922x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/06/2020] [Indexed: 11/10/2022] Open
Abstract
The ferredoxin reductase FdR9 from Thermobifida fusca, a member of the oxygenase-coupled NADH-dependent ferredoxin reductase (FNR) family, catalyses electron transfer from NADH to its physiological electron acceptor ferredoxin. It forms part of a putative three-component cytochrome P450 monooxygenase system in T. fusca comprising CYP222A1 and the [3Fe-4S]-cluster ferredoxin Fdx8 as well as FdR9. Here, FdR9 was overexpressed and purified and its crystal structure was determined at 1.9 Å resolution. The overall structure of FdR9 is similar to those of other members of the FNR family and is composed of an FAD-binding domain, an NAD-binding domain and a C-terminal domain. Activity measurements with FdR9 confirmed a strong preference for NADH as the cofactor. Comparison of the FAD- and NAD-binding domains of FdR9 with those of other ferredoxin reductases revealed the presence of conserved sequence motifs in the FAD-binding domain as well as several highly conserved residues involved in FAD and NAD cofactor binding. Moreover, the NAD-binding site of FdR9 contains a modified Rossmann-fold motif, GxSxxS, instead of the classical GxGxxG motif.
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Affiliation(s)
- Jhon Alexander Rodriguez Buitrago
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Thomas Klünemann
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Wulf Blankenfeldt
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Anett Schallmey
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
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Hefferon K, Cantero-Tubilla B, Badar U, Wilson DW. Plant-Based Cellulase Assay Systems as Alternatives for Synthetic Substrates. Appl Biochem Biotechnol 2020; 192:1318-1330. [PMID: 32734581 DOI: 10.1007/s12010-020-03395-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/16/2020] [Indexed: 11/25/2022]
Abstract
Dissociative enzymes such as cellulases are greatly desired for a variety of applications in the food, fuel, and fiber industries. Cellulases and other cell wall-degrading enzymes are currently being engineered with improved traits for application in the breakdown of lignocellulosic biomass. Biochemical assays using these "designer" enzymes have traditionally been carried out using synthetic substrates such as crystalline bacterial microcellulose (BMCC). However, the use of synthetic substrates may not reflect the actual action of these cellulases on real plant biomass. We examined the potential of suspension cell walls from several plant species as possible alternatives for synthetic cellulose substrates. Suspension cells grow synchronously; hence, their cell walls are more uniform than those derived from mature plants. This work will help to establish a new assay system that is more genuine than using synthetic substrates. In addition to this, we have demonstrated that it is feasible to produce cellulases inexpensively and at high concentrations and activities in plants using a recombinant plant virus expression system. Our long-term goals are to use this system to develop tailored cocktails of cellulases that have been engineered to function optimally for specific tasks (i.e., the conversion of biomass into biofuel or the enhancement of nutrients available in livestock feed). The broad impact would be to provide a facile and economic system for generating industrial enzymes that offer green solutions to valorize biomass in industrialized communities and specifically in developing countries.
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Affiliation(s)
- Kathleen Hefferon
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA.
| | - Borja Cantero-Tubilla
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Uzma Badar
- Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - David W Wilson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14850, USA
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14
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Wang W, Archbold T, Lam JS, Kimber MS, Fan MZ. A processive endoglucanase with multi-substrate specificity is characterized from porcine gut microbiota. Sci Rep 2019; 9:13630. [PMID: 31541154 PMCID: PMC6754456 DOI: 10.1038/s41598-019-50050-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 09/05/2019] [Indexed: 02/08/2023] Open
Abstract
Cellulases play important roles in the dietary fibre digestion in pigs, and have multiple industrial applications. The porcine intestinal microbiota display a unique feature in rapid cellulose digestion. Herein, we have expressed a cellulase gene, p4818Cel5_2A, which singly encoded a catalytic domain belonging to glycoside hydrolase family 5 subfamily 2, and was previously identified from a metagenomic expression library constructed from porcine gut microbiome after feeding grower pigs with a cellulose-supplemented diet. The activity of purified p4818Cel5_2A was maximal at pH 6.0 and 50 °C and displayed resistance to trypsin digestion. This enzyme exhibited activities towards a wide variety of plant polysaccharides, including cellulosic substrates of avicel and solka-Floc®, and the hemicelluloses of β-(1 → 4)/(1 → 3)-glucans, xyloglucan, glucomannan and galactomannan. Viscosity, reducing sugar distribution and hydrolysis product analyses further revealed that this enzyme was a processive endo-β-(1 → 4)-glucanase capable of hydrolyzing cellulose into cellobiose and cellotriose as the primary end products. These catalytic features of p4818Cel5_2A were further explored in the context of a three-dimensional homology model. Altogether, results of this study report a microbial processive endoglucanase identified from the porcine gut microbiome, and it may be tailored as an efficient biocatalyst candidate for potential industrial applications.
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Affiliation(s)
- Weijun Wang
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Tania Archbold
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Joseph S Lam
- Department of Cellular and Molecular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Matthew S Kimber
- Department of Cellular and Molecular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Ming Z Fan
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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15
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A highly thermostable crude endoglucanase produced by a newly isolated Thermobifida fusca strain UPMC 901. Sci Rep 2019; 9:13526. [PMID: 31537863 PMCID: PMC6753106 DOI: 10.1038/s41598-019-50126-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/06/2019] [Indexed: 01/22/2023] Open
Abstract
A thermophilic Thermobifida fusca strain UPMC 901, harboring highly thermostable cellulolytic activity, was successfully isolated from oil palm empty fruit bunch compost. Its endoglucanase had the highest activity at 24 hours of incubation in carboxymethyl-cellulose (CMC) and filter paper. A maximum endoglucanase activity of 0.9 U/mL was achieved at pH 5 and 60 °C using CMC as a carbon source. The endoglucanase properties were further characterized using crude enzyme preparations from the culture supernatant. Thermal stability indicated that the endoglucanase activity was highly stable at 70 °C for 24 hours. Furthermore, the activity was found to be completely maintained without any loss at 50 °C and 60 °C for 144 hours, making it the most stable than other endoglucanases reported in the literature. The high stability of the endoglucanase at an elevated temperature for a prolonged period of time makes it a suitable candidate for the biorefinery application.
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16
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Lee S, Kang M, Bae JH, Sohn JH, Sung BH. Bacterial Valorization of Lignin: Strains, Enzymes, Conversion Pathways, Biosensors, and Perspectives. Front Bioeng Biotechnol 2019; 7:209. [PMID: 31552235 PMCID: PMC6733911 DOI: 10.3389/fbioe.2019.00209] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/19/2019] [Indexed: 12/17/2022] Open
Abstract
Lignin, an aromatic polymer found in plants, has been studied for years in many biological fields. Initially, when biofuel was produced from lignocellulosic biomass, lignin was regarded as waste generated by the biorefinery and had to be removed, because of its inhibitory effects on fermentative bacteria. Although it has since proven to be a natural resource for bio-products with considerable potential, its utilization is confined by its complex structure. Hence, the microbial degradation of lignin has attracted researchers' interest to overcome this problem. From this perspective, the studies have primarily focused on fungal systems, such as extracellular peroxidase and laccase from white- and brown-rot fungi. However, recent reports have suggested that bacteria play an increasing role in breaking down lignin. This paper, therefore, reviews the role of bacteria in lignin and lignin-related research. Several reports on bacterial species in soil that can degrade lignin and their enzymes are included. In addition, a cellulolytic anaerobic bacterium capable of solubilizing lignin and carbohydrate simultaneously has recently been identified, even though the enzyme involved has not been discovered yet. The assimilation of lignin-derived small molecules and their conversion to renewable chemicals by bacteria, such as muconic acid and polyhydroxyalkanoates, including genetic modification to enhance their capability was discussed. This review also covers the indirect use of bacteria for lignin degradation, which is concerned with whole-cell biosensors designed to detect the aromatic chemicals released from lignin transformation.
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Affiliation(s)
- Siseon Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Minsik Kang
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, Korea University of Science and Technology, Daejeon, South Korea
| | - Jung-Hoon Bae
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Jung-Hoon Sohn
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, Korea University of Science and Technology, Daejeon, South Korea
| | - Bong Hyun Sung
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
- Department of Biosystems and Bioengineering, Korea University of Science and Technology, Daejeon, South Korea
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17
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Hefferon KL, Cantero‐Tubilla B, Brady J, Wilson D. Aromatic residues surrounding the active site tunnel of TfCel48A influence activity, processivity, and synergistic interactions with other cellulases. Biotechnol Bioeng 2019; 116:2463-2472. [DOI: 10.1002/bit.27086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/29/2019] [Accepted: 06/02/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Kathleen L. Hefferon
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - Borja Cantero‐Tubilla
- Robert Frederick Smith School of Chemical and Biomolecular EngineeringCornell University Ithaca New York
| | - John Brady
- Department of Food Science and TechnologyCornell University Ithaca New York
| | - David Wilson
- Department of Cellular and Molecular GeneticsCornell University Ithaca New York
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18
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Schmidt JA, McGrath JM, Hanson MR, Long SP, Ahner BA. Field-grown tobacco plants maintain robust growth while accumulating large quantities of a bacterial cellulase in chloroplasts. NATURE PLANTS 2019; 5:715-721. [PMID: 31285558 DOI: 10.1038/s41477-019-0467-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 06/04/2019] [Indexed: 06/09/2023]
Abstract
High accumulation of heterologous proteins expressed from the plastid genome has sometimes been reported to result in compromised plant phenotypes. Comparisons of transplastomic plants to wild-type (WT) are typically made in environmentally controlled chambers with relatively low light; little is known about the performance of such plants under field conditions. Here, we report on two plastid-engineered tobacco lines expressing the bacterial cellulase Cel6A. Field-grown plants producing Cel6A at ~20% of total soluble protein exhibit no loss in biomass or Rubisco content and only minor reductions in photosynthesis compared to WT. These experiments demonstrate that, when grown in the field, tobacco possesses sufficient metabolic flexibility to accommodate high levels of recombinant protein by increasing total protein synthesis and accumulation and/or by reallocating unneeded endogenous proteins. Based on current tobacco cultivation practices and readily achievable recombinant protein yields, we estimate that specific proteins could be obtained from field-grown transgenic tobacco plants at costs three orders of magnitude less than current cell culture methods.
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Affiliation(s)
- Jennifer A Schmidt
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - Justin M McGrath
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL, USA
| | - Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Stephen P Long
- Department of Plant Biology, University of Illinois, Urbana-Champaign, Urbana, IL, USA
- Department of Crop Sciences, University of Illinois, Urbana-Champaign, Urbana, IL, USA
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Beth A Ahner
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA.
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19
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Cloning, expression, and characterization of novel GH5 endoglucanases from Thermobifida alba AHK119. J Biosci Bioeng 2019; 127:554-562. [DOI: 10.1016/j.jbiosc.2018.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 10/13/2018] [Accepted: 10/16/2018] [Indexed: 01/01/2023]
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20
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Hamre AG, Kaupang A, Payne CM, Väljamäe P, Sørlie M. Thermodynamic Signatures of Substrate Binding for Three Thermobifida fusca Cellulases with Different Modes of Action. Biochemistry 2019; 58:1648-1659. [PMID: 30785271 DOI: 10.1021/acs.biochem.9b00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzymatic breakdown of recalcitrant polysaccharides is achieved by synergistic enzyme cocktails of glycoside hydrolases (GHs) and accessory enzymes. Many GHs are processive, meaning that they stay bound to the substrate between subsequent catalytic interactions. Cellulases are GHs that catalyze the hydrolysis of cellulose [β-1,4-linked glucose (Glc)]. Here, we have determined the relative subsite binding affinity for a glucose moiety as well as the thermodynamic signatures for (Glc)6 binding to three of the seven cellulases produced by the bacterium Thermobifida fusca. TfCel48A is exo-processive, TfCel9A endo-processive, and TfCel5A endo-nonprocessive. Initial hydrolysis of (Glc)5 and (Glc)6 was performed in H218O enabling the incorporation of an 18O atom at the new reducing end anomeric carbon. A matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the products reveals the intensity ratios of otherwise identical 18O- and 16O-containing products to provide insight into how the substrate is placed during productive binding. The two processive cellulases have significant binding affinity in subsites where products dissociate during processive hydrolysis, aligned with a need to have a pushing potential to remove obstacles on the substrate. Moreover, we observed a correlation between processive ability and favorable binding free energy, as previously postulated. Upon ligand binding, the largest contribution to the binding free energy is desolvation for all three cellulases as determined by isothermal titration calorimetry. The two endo-active cellulases show a more favorable solvation entropy change compared to the exo-active cellulase, while the two processive cellulases have less favorable changes in binding enthalpy compared to the nonprocessive TfCel5A.
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Affiliation(s)
- Anne Grethe Hamre
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Anita Kaupang
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
| | - Christina M Payne
- Department of Chemical and Materials Engineering , University of Kentucky , 177 F. Paul Anderson Tower , Lexington , Kentucky 40506 , United States
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology , University of Tartu , 50090 Tartu , Estonia
| | - Morten Sørlie
- Department of Chemistry, Biotechnology and Food Science , Norwegian University of Life Sciences , P.O. Box 5003, N-1432 Ås , Norway
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21
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Kahn A, Moraïs S, Galanopoulou AP, Chung D, Sarai NS, Hengge N, Hatzinikolaou DG, Himmel ME, Bomble YJ, Bayer EA. Creation of a functional hyperthermostable designer cellulosome. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:44. [PMID: 30858881 PMCID: PMC6394049 DOI: 10.1186/s13068-019-1386-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/20/2019] [Indexed: 05/28/2023]
Abstract
BACKGROUND Renewable energy has become a field of high interest over the past decade, and production of biofuels from cellulosic substrates has a particularly high potential as an alternative source of energy. Industrial deconstruction of biomass, however, is an onerous, exothermic process, the cost of which could be decreased significantly by use of hyperthermophilic enzymes. An efficient way of breaking down cellulosic substrates can also be achieved by highly efficient enzymatic complexes called cellulosomes. The modular architecture of these multi-enzyme complexes results in substrate targeting and proximity-based synergy among the resident enzymes. However, cellulosomes have not been observed in hyperthermophilic bacteria. RESULTS Here, we report the design and function of a novel hyperthermostable "designer cellulosome" system, which is stable and active at 75 °C. Enzymes from Caldicellulosiruptor bescii, a highly cellulolytic hyperthermophilic anaerobic bacterium, were selected and successfully converted to the cellulosomal mode by grafting onto them divergent dockerin modules that can be inserted in a precise manner into a thermostable chimaeric scaffoldin by virtue of their matching cohesins. Three pairs of cohesins and dockerins, selected from thermophilic microbes, were examined for their stability at extreme temperatures and were determined stable at 75 °C for at least 72 h. The resultant hyperthermostable cellulosome complex exhibited the highest levels of enzymatic activity on microcrystalline cellulose at 75 °C, compared to those of previously reported designer cellulosome systems and the native cellulosome from Clostridium thermocellum. CONCLUSION The functional hyperthermophilic platform fulfills the appropriate physico-chemical properties required for exothermic processes. This system can thus be adapted for other types of thermostable enzyme systems and could serve as a basis for a variety of cellulolytic and non-cellulolytic industrial objectives at high temperatures.
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Affiliation(s)
- Amaranta Kahn
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001 Rehovot, Israel
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, 8499000 Beer-Sheva, Israel
| | - Anastasia P. Galanopoulou
- Microbiology Group, Faculty of Biology, National and Kapodistrian University of Athens, Zografou Campus, 15784 Athens, Greece
| | - Daehwan Chung
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Nicholas S. Sarai
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
- Present Address: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 USA
| | - Neal Hengge
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Dimitris G. Hatzinikolaou
- Microbiology Group, Faculty of Biology, National and Kapodistrian University of Athens, Zografou Campus, 15784 Athens, Greece
| | - Michael E. Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Yannick J. Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO USA
| | - Edward A. Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001 Rehovot, Israel
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22
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Cellulose as Potential Feedstock for Cellulase Enzyme Production: Versatility and Properties of Various Cellulosic Biomass – Part II. Fungal Biol 2019. [DOI: 10.1007/978-3-030-14726-6_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Yin YR, Sang P, Xian WD, Li X, Jiao JY, Liu L, Hozzein WN, Xiao M, Li WJ. Expression and Characteristics of Two Glucose-Tolerant GH1 β-glucosidases From Actinomadura amylolytica YIM 77502 T for Promoting Cellulose Degradation. Front Microbiol 2018; 9:3149. [PMID: 30619214 PMCID: PMC6305311 DOI: 10.3389/fmicb.2018.03149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/04/2018] [Indexed: 01/25/2023] Open
Abstract
The bioconversion of lignocellulose in various industrial processes, such as biofuel production, requires the degradation of cellulose. Actinomadura amylolytica YIM 77502T is an aerobic, Gram-positive actinomycete that can efficiently degrade crystalline cellulose by extracellular cellulases. Genomic analysis of A. amylolytica identified 9 cellulase and 11 β-glucosidase genes that could potentially encode proteins that digest cellulose. Extracellular proteome characterization of A. amylolytica cell-free culture supernatant by liquid chromatography tandem mass spectrometry analysis revealed that 4 of these cellulases and 2 of these β-glucosidases functioned during cellulose hydrolysis. Thin-layer chromatography analysis revealed extracellular β-glucosidases play a major role in carboxyl methyl cellulose (CMC) degradation of products in culture supernatants. In this study, 2 of the identified secreted β-glucosidases, AaBGL1 and AaBGL2, were functionally expressed in Escherichia coli and found to have β-glucosidase activity with wide substrate specificities, including for p-nitrophenyl β-D-glucopyranoside (pNPG), p-nitrophenyl-beta-D-cellobioside (pNPC), and cellobiose. Moreover, AaBGL1 and AaBGL2 had high tolerances for glucose. After adding these β-glucosidases to commercial cellulases, the degradation rates of CMC, Avicel, birch sawdust, and corncob powder increased by 37, 42, 33, and 9%, respectively. Overall, this work identifies an alternative potential source of β-glucosidases with potential applications in commercial cellulose utilization and the bioenergy industry.
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Affiliation(s)
- Yi-Rui Yin
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Peng Sang
- College of Agriculture and Biological Science, Dali University, Dali, China
| | - Wen-Dong Xian
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xin Li
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Lan Liu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wael N Hozzein
- Bioproducts Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.,Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Min Xiao
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
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24
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Takenaka M, Lee JM, Kahar P, Ogino C, Kondo A. Efficient and Supplementary Enzyme Cocktail from Actinobacteria and Plant Biomass Induction. Biotechnol J 2018; 14:e1700744. [PMID: 29981210 DOI: 10.1002/biot.201700744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 06/28/2018] [Indexed: 11/08/2022]
Abstract
Actinobacteria plays a key role in the cycling of organic matter in soils. They secret biomass-degrading enzymes that allow it to produce the unique metabolites that originate in plant biomass. Although past studies have focused on these unique metabolites, a large-scale screening of Actinobacteria is yet to be reported to focus on their biomass-degrading ability. In the present study, a rapid and simple method is constructed for a large-scale screening, and the novel resources that form the plant biomass-degrading enzyme cocktail are identified from 850 isolates of Actinobacteria. As a result, Nonomuraea fastidiosa secretes a biomass degrading enzyme cocktail with the highest enzyme titer, although cellulase activities are lower than a commercially available enzyme. So the rich accessory enzymes are suggested to contribute to the high enzyme titer for a pretreated bagasse with a synergistic effect. Additionally, an optimized cultivation method of biomass induction caused to produce the improved enzyme cocktail indicated strong enzyme titers and a strong synergistic effect. Therefore, the novel enzyme cocktails are selected via the optimized method for large-scale screening, and then the enzyme cocktail can be improved via the optimized production with biomass-induction.
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Affiliation(s)
- Musashi Takenaka
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Jae M Lee
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Prihardi Kahar
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Chiaki Ogino
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
| | - Akihiko Kondo
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho 1-1, 657-8501 Kobe, Japan
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25
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Fu Y, Yeom SJ, Kwon KK, Hwang J, Kim H, Woo EJ, Lee DH, Lee SG. Structural and functional analyses of the cellulase transcription regulator CelR. FEBS Lett 2018; 592:2776-2785. [PMID: 30062758 DOI: 10.1002/1873-3468.13206] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/05/2018] [Accepted: 07/19/2018] [Indexed: 11/10/2022]
Abstract
CelR is a transcriptional regulator that controls the expression of cellulases catalyzing cellulose hydrolysis. However, the structural mechanism of its regulation has remained unclear. Here, we report the first structure of CelR, in this case with cellobiose bound. CelR consists of a DNA-binding domain (DBD) and a regulatory domain (RD), and homodimerizes with each monomer bound to cellobiose. A hinge region (HR) in CelR connects the DBD with the RD, and Leu59 in the HR acts as a 'leucine lever' that transduces a transcriptional activation signal. Furthermore, an α4 helix mediates the ligand-binding signal for transcriptional activation. Tyr84 and Gln301 can potentially alter the ligand specificity of CelR. This study provides a pivotal step toward understanding transcription of the cellulases.
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Affiliation(s)
- Yaoyao Fu
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.,The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, Jiangsu Normal University, China
| | - Soo-Jin Yeom
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Kil Koang Kwon
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Jungwon Hwang
- Infection and Immunity Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Haseong Kim
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, Korea
| | - Eui-Jeon Woo
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.,Department of Bio-Analytical Science, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon, Korea
| | - Dae-Hee Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, Korea
| | - Seung-Goo Lee
- Synthetic Biology and Bioengineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.,Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, Korea
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Yan Q, Fong SS. Cloning and characterization of a chitinase from Thermobifida fusca reveals Tfu_0580 as a thermostable and acidic endochitinase. ACTA ACUST UNITED AC 2018; 19:e00274. [PMID: 30094208 PMCID: PMC6070660 DOI: 10.1016/j.btre.2018.e00274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 11/17/2022]
Abstract
A Thermobifida fusca chitinase Tfu_0580 is characterized for its function. Tfu_0580 is the first reported as a functional chitinase that can degrade colloidal chitin. Enzymatic characterization shows Tfu_0580 as a thermostable and acidic endochitinase.
Being capable of hydrolyzing chitin, chitinases have various applications such as production of N-acetylchitooligosaccharides (COSs) and N-acetylglucosamine (GlcNAc), degrading chitin as a consolidated bioprocessing, and bio-control of fungal phytopathogens. Here, a putative chitinase in Thermobifida fusca, Tfu_0580, is characterized. Tfu_0580 was purified by homogeneity with a molecular weight of 44.9 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Tfu_0580 displayed a clear activity against colloidal chitin, which is comparable to a commercial Streptomyces griseus chitinase. Enzyme activities against p-nitrophenyl β-D-N,N′,N′′-triacetylchitotriose (p-NP-(GlcNAc)3), N,N′-diacetyl-β-D-chitobioside (p-NP-(GlcNAc)2) and p-nitrophenyl N-acetyl-β-D-glucosaminide (p-NP-(GlcNAc)) showed that Tfu_0580 exhibited highest activity against p-NP-(GlcNAc)3. Further optimization of the enzyme activity conditions showed: 1) an optimum catalytic activity at pH 6.0 and 30 °C; 2) activity over broad pH (4.8–7.5) and temperature (20–55 °C); 3) stimulation of activity by the metallic ions Ca2+ and Mn2+.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, United States
| | - Stephen S Fong
- Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA, United States.,Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, United States
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Hao Z, Yang B, Jahng D. Spent coffee ground as a new bulking agent for accelerated biodrying of dewatered sludge. WATER RESEARCH 2018; 138:250-263. [PMID: 29605704 DOI: 10.1016/j.watres.2018.03.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/01/2018] [Accepted: 03/20/2018] [Indexed: 06/08/2023]
Abstract
The feasibility of using spent coffee ground (SCG) as a new bulking agent for biodrying of dewatered sludge (DS) was investigated in comparison with two other frequently-used bulking agents, air-dried sludge (AS) and sawdust (SD). Results showed that the moisture contents (MC) of 16-day DS biodrying with AS (Trial A), SCG (Trial B) and SD (Trial C) decreased from 70.14 wt%, 68.25 wt% and 71.63 wt% to 59.12 wt%, 41.35 wt% and 57.69 wt%, respectively. In case of Trial B, the MC rapidly decreased to 46.16 wt% with the highest water removal (70.87%) within 8 days because of the longest high-temperature period (5.8 days). Further studies indicated that the abundant biodegradable volatile solids (BVS) and high dissolved organic matter (DOM) contents in SCG were the main driving forces for water removal. According to pyrosequencing data, Firmicutes, most of which were recognized as thermophiles, was rapidly enriched on Day 8 and became the dominant phylum in Trial B. Four thermophilic genera, Bacillus, Ureibacillus, Geobacillus and Thermobifida, which can produce thermostable hydrolytic extracellular enzymes, were the most abundant in Trial B, indicating that these thermophilic bacteria evolved during the long high-temperature period enhanced the biodegradation of BVS in SCG. The 8-day biodried product of Trial B was demonstrated to be an excellent solid fuel with low heating value (LHV) of 9284 kJ kg-1, which was 2.1 and 1.8 times those of biodried products with AS and SD, respectively. Thus SCG was found to be an excellent bulking agent accelerating DS biodrying and producing a solid fuel with a high calorific value.
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Affiliation(s)
- Zongdi Hao
- Department of Environmental Engineering & Energy, Myongji University, 116 Myongjiro, Cheoingu, Yonginshi, Gyeonggido, 17058, Republic of Korea
| | - Benqin Yang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan, 650500, People's Republic of China
| | - Deokjin Jahng
- Department of Environmental Engineering & Energy, Myongji University, 116 Myongjiro, Cheoingu, Yonginshi, Gyeonggido, 17058, Republic of Korea.
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Rühlmann A, Groth G, Urlacher VB. Characterization of CYP154F1 from Thermobifida fusca YX and Extension of Its Substrate Spectrum by Site-Directed Mutagenesis. Chembiochem 2018; 19:478-485. [PMID: 29266604 DOI: 10.1002/cbic.201700565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 11/05/2022]
Abstract
Previous studies on cytochrome P450 monooxygenases (CYP) from family 154 reported their substrate promiscuity and high activity. Hence, herein, the uncharacterized family member CYP154F1 is described. Screening of more than 100 organic compounds revealed that CYP154F1 preferably accepts small linear molecules with a carbon chain length of 8-10 atoms. In contrast to thoroughly characterized CYP154E1, CYP154F1 has a much narrower substrate spectrum and lower activity. A structural alignment of homology models of CYP154F1 and CYP154E1 revealed few differences in the active sites of both family members. By gradual mutagenesis of the CYP154F1 active site towards those of CYP154E1, a key residue accounting for the different activities of both enzymes was identified at position 234. Substitution of T234 for large hydrophobic amino acids led to up to tenfold higher conversion rates of small substrates, such as geraniol. Replacement of T234 by small hydrophobic amino acids, valine or alanine, resulted in mutants with extended substrate spectra. These mutants are able to convert some of the larger substrates of CYP154E1, such as (E)-stilbene and (+)-nootkatone.
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Affiliation(s)
- Ansgar Rühlmann
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Georg Groth
- Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
| | - Vlada B Urlacher
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany
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Abstract
Cellulose deconstruction is achieved in nature through two main enzymatic paradigms, i.e., free enzymes and enzymatic complexes (called cellulosomes). Gaining insights into the mechanism of action and synergy among the different cellulases is of high interest, notably in the field of renewable energy, and specifically, for the conversion of cellulosic biomass to soluble sugars, en route to biofuels. In this context, designer cellulosomes are artificially assembled, chimaeric protein complexes that are used as a tool to comparatively study cellulose degradation by different enzymatic paradigms, and could also serve to improve cellulose deconstruction. Various molecular biology techniques are employed in order to design and engineer the various components of designer cellulosomes. In this chapter, we describe the cloning processes through which the appropriate modules are selected and assembled at the molecular level.
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Affiliation(s)
- Amaranta Kahn
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
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31
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Setter-Lamed E, Moraïs S, Stern J, Lamed R, Bayer EA. Modular Organization of the Thermobifida fusca Exoglucanase Cel6B Impacts Cellulose Hydrolysis and Designer Cellulosome Efficiency. Biotechnol J 2017; 12. [PMID: 28901714 DOI: 10.1002/biot.201700205] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/06/2017] [Indexed: 11/09/2022]
Abstract
Cellulose deconstruction can be achieved by three distinct enzymatic paradigms: free enzymes, multifunctional enzymes, and self-assembled, multi-enzyme complexes (cellulosomes). To study their comparative efficiency, the simple and efficient cellulolytic system of the aerobic bacterium, Thermobifida fusca, is developed as an enzymatic model. In previous studies, most of its cellulases are successfully converted to the cellulosomal mode and exhibited high cellulolytic activities, except for Cel6B, a key exoglucanase of the T. fusca enzymatic system. Here, the impact of the modular organization of Cel6B on enzymatic activity is investigated. The position of the cellulose-binding module (CBM), its family and linker segment are shown to affect activity. Surprisingly, exchange of the native family-2 CBM to family-3 generates an increase in Cel6B activity on cellulosic substrates. Conversion of Cel6B to the cellulosomal mode by fusing a cohesin to the catalytic module enables formation of divalent enzyme complexes with dockerin-bearing enzymes. The resultant pseudo-cellulosomes, containing Cel6B combined with endoglucanase Cel5A, exhibits enhanced enzymatic activity, compared to mixtures of wild-type enzymes or bifunctional enzymes, unlike similar pseudo-cellulosomes containing endoglucanase Cel6A or proccessive endoglucanase Cel9A. Insight into the different enzymatic paradigms benefits ongoing development of efficient cellulolytic systems for conversion of plant-derived biomass into valuable sugars. NOVELTY STATEMENT The protein engineering of the modular arrangement of a key exoglucanase from a highly cellulolytic bacterium, Thermobifida fusca, served to explore and compare three major enzymatic paradigms for cellulose degradation. This approach revealed highly active chimaeric forms of the exoglucanase that act in synergy together with a potent endoglucanase in bifunctional enzymes or divalent pseudo-cellulosome-like complexes. Such engineered enzymes could be further integrated into larger enzymatic complexes, thereby providing a significant step forward towards conversion of the entire T. fusca free cellulolytic system into the cellulosomal modex and the enhanced conversion of cellulosic biomass into soluble sugars.
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Affiliation(s)
- Eva Setter-Lamed
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sarah Moraïs
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johanna Stern
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Israel
| | - Edward A Bayer
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel
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32
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Lewin GR, Carlos C, Chevrette MG, Horn HA, McDonald BR, Stankey RJ, Fox BG, Currie CR. Evolution and Ecology of Actinobacteria and Their Bioenergy Applications. Annu Rev Microbiol 2017; 70:235-54. [PMID: 27607553 DOI: 10.1146/annurev-micro-102215-095748] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ancient phylum Actinobacteria is composed of phylogenetically and physiologically diverse bacteria that help Earth's ecosystems function. As free-living organisms and symbionts of herbivorous animals, Actinobacteria contribute to the global carbon cycle through the breakdown of plant biomass. In addition, they mediate community dynamics as producers of small molecules with diverse biological activities. Together, the evolution of high cellulolytic ability and diverse chemistry, shaped by their ecological roles in nature, make Actinobacteria a promising group for the bioenergy industry. Specifically, their enzymes can contribute to industrial-scale breakdown of cellulosic plant biomass into simple sugars that can then be converted into biofuels. Furthermore, harnessing their ability to biosynthesize a range of small molecules has potential for the production of specialty biofuels.
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Affiliation(s)
- Gina R Lewin
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Camila Carlos
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Marc G Chevrette
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Heidi A Horn
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706;
| | - Bradon R McDonald
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Robert J Stankey
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
| | - Brian G Fox
- Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726.,Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin-Madison, Wisconsin 53706; .,Department of Energy Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Wisconsin 53726
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Ding CQ, Li KR, Duan YX, Jia SR, Lv HX, Bai H, Zhong C. Study on community structure of microbial consortium for the degradation of viscose fiber wastewater. BIORESOUR BIOPROCESS 2017; 4:31. [PMID: 28748136 PMCID: PMC5502227 DOI: 10.1186/s40643-017-0159-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/30/2017] [Indexed: 12/03/2022] Open
Abstract
Background Enrichment culture was applied to obtain microbial consortium from activated sludge samples collected from biodegradation system, a chemical fiber plant in Hebei Province, China. Bacterial composition and community dynamic variation were assessed employing denaturing gradient gel electrophoresis fingerprinting technology based on amplified 16S rRNA genes in the entire process of enrichment culture for viscose fiber wastewater. Results Four bacteria named as VF01, VF02, VF03, and VF04 were isolated from the microbial consortium adopting the spray-plate method. The DNA bands of these four bacteria were corresponded to the predominant DNA bands in the electrophoresis pattern. VF01, VF02, VF03, and VF04 were phylogenetically closed to Bacillus licheniformis, Bacillus subtilis, Paracoccus tibetensis, and Pseudomonas sp. by sequence analysis, respectively. The degradation effects for CODCr of single isolated strain, mixed strains, and microbial consortium (VF) originally screened from viscose fiber wastewater were determined. The degradation ability was as follows: microbial consortium (VF) > mixed strains > single isolated strain. Microbial consortium (VF) showed the optimum degradation rate of CODCr of 87% on 14th day. Degradation of pollutants sped up by bio-augmentation of four strains. The molecular weight distribution of organic matter showed that viscose fiber wastewater contained a certain amount of large molecular organic matter, which could be decomposed into smaller molecular substances by microbial consortium (VF). Conclusions The microbial consortium (VF) obtained from enrichment culture exhibited great potential for CODCr degradation. The screened strains had bio-augmentation functions and the addition of a mixture of four bacteria could speed up the degradation rate of pollutants.
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Affiliation(s)
- Chao-Qun Ding
- Key Laboratory of Industrial Fermentation Microbiology, (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457 People's Republic of China
| | - Kun-Rong Li
- Key Laboratory of Industrial Fermentation Microbiology, (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457 People's Republic of China
| | - Yun-Xia Duan
- Tianjin Academy of Environmental Sciences, Tianjin, 300191 China
| | - Shi-Ru Jia
- Key Laboratory of Industrial Fermentation Microbiology, (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457 People's Republic of China
| | - He-Xin Lv
- Key Laboratory of Industrial Fermentation Microbiology, (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457 People's Republic of China
| | - He Bai
- CNOOC Ener Tech Beijing Research Institute of Engineering & Technology for Safety & Environmental Protection, Tianjin, 300457 China
| | - Cheng Zhong
- Key Laboratory of Industrial Fermentation Microbiology, (Ministry of Education), Tianjin University of Science & Technology, Tianjin, 300457 People's Republic of China
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Kumar H, Nguyen QT, Binda C, Mattevi A, Fraaije MW. Isolation and characterization of a thermostable F 420:NADPH oxidoreductase from Thermobifida fusca. J Biol Chem 2017; 292:10123-10130. [PMID: 28411200 DOI: 10.1074/jbc.m117.787754] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 04/07/2017] [Indexed: 12/23/2022] Open
Abstract
F420H2-dependent enzymes reduce a wide range of substrates that are otherwise recalcitrant to enzyme-catalyzed reduction, and their potential for applications in biocatalysis has attracted increasing attention. Thermobifida fusca is a moderately thermophilic bacterium and holds high biocatalytic potential as a source for several highly thermostable enzymes. We report here on the isolation and characterization of a thermostable F420: NADPH oxidoreductase (Tfu-FNO) from T. fusca, the first F420-dependent enzyme described from this bacterium. Tfu-FNO was heterologously expressed in Escherichia coli, yielding up to 200 mg of recombinant enzyme per liter of culture. We found that Tfu-FNO is highly thermostable, reaching its highest activity at 65 °C and that Tfu-FNO is likely to act in vivo as an F420 reductase at the expense of NADPH, similar to its counterpart in Streptomyces griseus We obtained the crystal structure of FNO in complex with NADP+ at 1.8 Å resolution, providing the first bacterial FNO structure. The overall architecture and NADP+-binding site of Tfu-FNO were highly similar to those of the Archaeoglobus fulgidus FNO (Af-FNO). The active site is located in a hydrophobic pocket between an N-terminal dinucleotide binding domain and a smaller C-terminal domain. Residues interacting with the 2'-phosphate of NADP+ were probed by targeted mutagenesis, indicating that Thr-28, Ser-50, Arg-51, and Arg-55 are important for discriminating between NADP+ and NAD+ Interestingly, a T28A mutant increased the kinetic efficiency >3-fold as compared with the wild-type enzyme when NADH is the substrate. The biochemical and structural data presented here provide crucial insights into the molecular recognition of the two cofactors, F420 and NAD(P)H by FNO.
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Affiliation(s)
- Hemant Kumar
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Quoc-Thai Nguyen
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Scuola Universitaria Superiore IUSS Pavia, Piazza della Vittoria 15, 27100 Pavia, Italy.,Faculty of Pharmacy, University of Medicine and Pharmacy, Ho Chi Minh City, 41 Dinh Tien Hoang St., Ben Nghe Ward, District 1, Ho Chi Minh City, Vietnam, and
| | - Claudia Binda
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Andrea Mattevi
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy
| | - Marco W Fraaije
- From the Molecular Enzymology Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands,
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Genome-Scale Modeling of Thermophilic Microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016. [PMID: 27913830 DOI: 10.1007/10_2016_45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Thermophilic microorganisms are of increasing interest for many industries as their enzymes and metabolisms are highly efficient at elevated temperatures. However, their metabolic processes are often largely different from their mesophilic counterparts. These differences can lead to metabolic engineering strategies that are doomed to fail. Genome-scale metabolic modeling is an effective and highly utilized way to investigate cellular phenotypes and to test metabolic engineering strategies. In this review we chronicle a number of thermophilic organisms that have recently been studied with genome-scale models. The microorganisms spread across archaea and bacteria domains, and their study gives insights that can be applied in a broader context than just the species they describe. We end with a perspective on the future development and applications of genome-scale models of thermophilic organisms.
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Chen CY, Lee CC, Chen HS, Yang CH, Wang SP, Wu JH, Meng M. Modification of lignin in sugarcane bagasse by a monocopper hydrogen peroxide-generating oxidase from Thermobifida fusca. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Jiang X, Zhou X, Liu Q, Zheng L, Yu N, Li W. Expression of Acidothermus cellulolyticus thermostable cellulases in tobacco and rice plants. BIOTECHNOL BIOTEC EQ 2016. [DOI: 10.1080/13102818.2016.1236671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Xiran Jiang
- Department of Biomedical Engineering, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian, PR China
| | - Xiaoya Zhou
- Molecular Medicine and Chemistry Laboratory Foundation College, Jining Medical University, Jining, PR China
| | - Qi Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai, PR China
| | - Lulu Zheng
- Department of Environmental Science and Engineering, Fudan University, Shanghai, PR China
| | - Ning Yu
- The First Clinical College, Liaoning University of Traditional Chinese Medicine, Shenyang, PR China
| | - Wenli Li
- School of Life Science and Medicine, Dalian University of Technology, Panjin, PR China
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Gaber Y, Mekasha S, Vaaje-Kolstad G, Eijsink VG, Fraaije MW. Characterization of a chitinase from the cellulolytic actinomycete Thermobifida fusca. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1253-1259. [DOI: 10.1016/j.bbapap.2016.04.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/22/2016] [Accepted: 04/20/2016] [Indexed: 01/19/2023]
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Deng Y, Lin J, Mao Y, Zhang X. Systematic analysis of an evolved Thermobifida fusca muC producing malic acid on organic and inorganic nitrogen sources. Sci Rep 2016; 6:30025. [PMID: 27424527 PMCID: PMC4948018 DOI: 10.1038/srep30025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/27/2016] [Indexed: 12/21/2022] Open
Abstract
Thermobifida fusca is a thermophilic actinobacterium. T. fusca muC obtained by adaptive evolution preferred yeast extract to ammonium sulfate for accumulating malic acid and ammonium sulfate for cell growth. We did transcriptome analysis of T. fusca muC on Avicel and cellobiose with addition of ammonium sulfate or yeast extract, respectively by RNAseq. The transcriptional results indicate that ammonium sulfate induced the transcriptions of the genes related to carbohydrate metabolisms significantly more than yeast extract. Importantly, Tfu_2487, encoding histidine-containing protein (HPr), didn’t transcribe on yeast extract at all, while it transcribed highly on ammonium sulfate. In order to understand the impact of HPr on malate production and cell growth of the muC strain, we deleted Tfu_2487 to get a mutant strain: muCΔ2487, which had 1.33 mole/mole-glucose equivalent malate yield, much higher than that on yeast extract. We then developed an E. coli-T. fusca shuttle plasmid for over-expressing HPr in muCΔ2487, a strain without HPr background, forming the muCΔ2487S strain. The muCΔ2487S strain had a much lower malate yield but faster cell growth than the muC strain. The results of both mutant strains confirmed that HPr was the key regulatory protein for T. fusca’s metabolisms on nitrogen sources.
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Affiliation(s)
- Yu Deng
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.,The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jia Lin
- College of Life Science, North China University of Science and Technology, Tangshan 063000, China
| | - Yin Mao
- National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.,The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Xiaojuan Zhang
- School of pharmaceutical science, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
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Tóth Á, Barna T, Szabó E, Elek R, Hubert Á, Nagy I, Nagy I, Kriszt B, Táncsics A, Kukolya J. Cloning, Expression and Biochemical Characterization of Endomannanases from Thermobifida Species Isolated from Different Niches. PLoS One 2016; 11:e0155769. [PMID: 27223892 PMCID: PMC4880297 DOI: 10.1371/journal.pone.0155769] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/03/2016] [Indexed: 11/19/2022] Open
Abstract
Thermobifidas are thermotolerant, compost inhabiting actinomycetes which have complex polysaccharide hydrolyzing enzyme systems. The best characterized enzymes of these hydrolases are cellulases from T. fusca, while other important enzymes especially hemicellulases are not deeply explored. To fill this gap we cloned and investigated endomannanases from those reference strains of the Thermobifida genus, which have published data on other hydrolases (T. fusca TM51, T. alba CECT3323, T. cellulosilytica TB100T and T. halotolerans YIM90462T). Our phylogenetic analyses of 16S rDNA and endomannanase sequences revealed that T. alba CECT3323 is miss-classified; it belongs to the T. fusca species. The cloned and investigated endomannanases belong to the family of glycosyl hydrolases 5 (GH5), their size is around 50 kDa and they are modular enzymes. Their catalytic domains are extended by a C-terminal carbohydrate binding module (CBM) of type 2 with a 23–25 residues long interdomain linker region consisting of Pro, Thr and Glu/Asp rich repetitive tetrapeptide motifs. Their polypeptide chains exhibit high homology, interdomain sequence, which don’t show homology to each other, but all of them are built up from 3–6 times repeated tetrapeptide motifs) (PTDP-Tc, TEEP-Tf, DPGT-Th). All of the heterologously expressed Man5A enzymes exhibited activity only on mannan. The pH optima of Man5A enzymes from T. halotolerans, T. cellulosilytica and T. fusca are slightly different (7.0, 7.5 and 8.0, respectively) while their temperature optima span within the range of 70–75°C. The three endomannanases exhibited very similar kinetic performances on LBG-mannan substrate: 0.9–1.7mM of KM and 80–120 1/sec of turnover number. We detected great variability in heat stability at 70°C, which was influenced by the presence of Ca2+. The investigated endomannanases might be important subjects for studying the structure/function relation behind the heat stability and for industrial applications to hemicellulose degradation.
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Affiliation(s)
- Ákos Tóth
- Department of Applied and Environmental Microbiology, National Agricultural Research and Innovation Centre, Budapest, Hungary
| | - Terézia Barna
- Department of Genetics and Applied Microbiology, University of Debrecen, Hungary
| | - Erna Szabó
- Department of Genetics and Applied Microbiology, University of Debrecen, Hungary
| | - Rita Elek
- Department of Genetics and Applied Microbiology, University of Debrecen, Hungary
| | - Ágnes Hubert
- Department of Molecular Structural Biology, Max Planck Institute for Biochemistry, Martinsried, Germany
| | - István Nagy
- Department of Molecular Structural Biology, Max Planck Institute for Biochemistry, Martinsried, Germany
| | - István Nagy
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Balázs Kriszt
- Department of Environmental Protection and Environmental Safety, Szent István University, Gödöllő, Hungary
| | - András Táncsics
- Regional University Center of Excellence in Environmental Industry, Szent István University, Gödöllő, Hungary
| | - József Kukolya
- Department of Applied and Environmental Microbiology, National Agricultural Research and Innovation Centre, Budapest, Hungary
- * E-mail:
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Karim Z, Afrin S, Husain Q, Danish R. Necessity of enzymatic hydrolysis for production and functionalization of nanocelluloses. Crit Rev Biotechnol 2016; 37:355-370. [PMID: 27049593 DOI: 10.3109/07388551.2016.1163322] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Nanocellulose (NC) from cellulosic biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. They still suffer, however, some drawbacks. The challenges are the exploration of raw materials, scaling, recovery of chemicals utilized for the production or functionalization and most important is toxic behavior that hinders them from implementing in medical/pharmaceutical field. This review emphasizes the structural behavior of cellulosic biomass and biological barriers for enzyme interactions, which are pertinent to understand the enzymatic hydrolysis of cellulose for the production of NCs. Additionally, the enzymatic catalysis for the modification of solid and NC is discussed. The utility of various classes of enzymes for introducing desired functional groups on the surface of NC has been further examined. Thereafter, a green mechanistic approach is applied for understanding at molecular level.
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Affiliation(s)
- Zoheb Karim
- a Division of Materials Science , Composite Centre Sweden, Luleå University of Technology , Luleå , Sweden
| | - Sadaf Afrin
- b Department of Chemistry, Faculty of Sciences , Aligarh Muslim University , Aligarh , UP , India
| | - Qayyum Husain
- c Department of Biochemistry, Faculty of Life Sciences , Aligarh Muslim University , Aligarh , UP , India
| | - Rehan Danish
- d Infinity Vacuum Technology , Geomdan Techpart Geomdangondan-Ro 26, Buk-Gu , Daegu , Korea
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Abstract
Designer cellulosomes consist of chimeric cohesin-bearing scaffoldins for the controlled incorporation of recombinant dockerin-containing enzymes. The largest designer cellulosome reported to date is a chimeric scaffoldin that contains 6 cohesins. This scaffoldin represented a technical limit of sorts, since adding another cohesin proved problematic, owing to resultant low expression levels, instability (cleavage) of the scaffoldin polypeptide, and limited numbers of available cohesin-dockerin specificities—the hallmark of designer cellulosomes. Nevertheless, increasing the number of enzymes integrated into designer cellulosomes is critical, in order to further enhance degradation of plant cell wall material. Adaptor scaffoldins comprise an intermediate type of scaffoldin that can both incorporate various enzymes and attach to an additional scaffoldin. Using this strategy, we constructed an efficient form of adaptor scaffoldin that possesses three type I cohesins for enzyme integration, a single type II dockerin for interaction with an additional scaffoldin, and a carbohydrate-binding module for targeting to the cellulosic substrate. In parallel, we designed a hexavalent scaffoldin capable of connecting to the adaptor scaffoldin by the incorporation of an appropriate type II cohesin. The resultant extended designer cellulosome comprised 8 recombinant enzymes—4 xylanases and 4 cellulases—thereby representing a potent enzymatic cocktail for solubilization of natural lignocellulosic substrates. The contribution of the adaptor scaffoldin clearly demonstrated that proximity between the two scaffoldins and their composite set of enzymes is crucial for optimized degradation. After 72 h of incubation, the performance of the extended designer cellulosome was determined to be approximately 70% compared to that of native cellulosomes. Plant cell wall residues represent a major source of renewable biomass for the production of biofuels such as ethanol via breakdown to soluble sugars. The natural microbial degradation process, however, is inefficient for achieving cost-effective processes in the conversion of plant-derived biomass to biofuels, either from dedicated crops or human-generated cellulosic wastes. The accumulation of the latter is considered a major environmental pollutant. The development of designer cellulosome nanodevices for enhanced plant cell wall degradation thus has major impacts in the fields of environmental pollution, bioenergy production, and biotechnology in general. The findings reported in this article comprise a true breakthrough in our capacity to produce extended designer cellulosomes via synthetic biology means, thus enabling the assembly of higher-order complexes that can supersede the number of enzymes included in a single multienzyme complex.
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Zhang L, Zhang H, Wang Z, Chen G, Wang L. Dynamic changes of the dominant functioning microbial community in the compost of a 90-m(3) aerobic solid state fermentor revealed by integrated meta-omics. BIORESOURCE TECHNOLOGY 2016; 203:1-10. [PMID: 26720133 DOI: 10.1016/j.biortech.2015.12.040] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 06/05/2023]
Abstract
The dynamic changes in the composition and function of both bacterial and fungal communities over time and at various depths in the compost of a 90-m(3) industrial-scale fermentor were explored using integrated meta-omics. The microbial communities in the middle layer (1.2m) of the compost developed a stable and simple structure over time, which was mainly composed of Thermobifida, Bacillus, Thermomyces and Aspergillus. According to the metaproteomic results, the bacterial community was more focused on cellulose degradation, characterized by 44% of the cellulases that were secreted by Thermobifida, while the fungal community was more likely to degrade hemicellulose, mainly via Thermomyces and Aspergillus. The results revealed that, under artificial control of the temperature and oxygen concentration, the efficiency of organic waste degradation was greatly increased and the fermentation cycle was shortened to 11 days.
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Affiliation(s)
- Lili Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Huaiqiang Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | | | - Guanjun Chen
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China
| | - Lushan Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, China.
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Saini A, Aggarwal NK, Sharma A, Yadav A. Actinomycetes: A Source of Lignocellulolytic Enzymes. Enzyme Res 2015; 2015:279381. [PMID: 26793393 PMCID: PMC4697097 DOI: 10.1155/2015/279381] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/01/2015] [Indexed: 01/17/2023] Open
Abstract
Lignocellulose is the most abundant biomass on earth. Agricultural, forest, and agroindustrial activities generate tons of lignocellulosic wastes annually, which present readily procurable, economically affordable, and renewable feedstock for various lignocelluloses based applications. Lignocelluloses are the focus of present decade researchers globally, in an attempt to develop technologies based on natural biomass for reducing dependence on expensive and exhaustible substrates. Lignocellulolytic enzymes, that is, cellulases, hemicellulases, and lignolytic enzymes, play very important role in the processing of lignocelluloses which is prerequisite for their utilization in various processes. These enzymes are obtained from microorganisms distributed in both prokaryotic and eukaryotic domains including bacteria, fungi, and actinomycetes. Actinomycetes are an attractive microbial group for production of lignocellulose degrading enzymes. Various studies have evaluated the lignocellulose degrading ability of actinomycetes, which can be potentially implemented in the production of different value added products. This paper is an overview of the diversity of cellulolytic, hemicellulolytic, and lignolytic actinomycetes along with brief discussion of their hydrolytic enzyme systems involved in biomass modification.
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Affiliation(s)
- Anita Saini
- Department of Microbiology, Kurukshetra University, Kurukshetra, Haryana 136119, India
| | - Neeraj K. Aggarwal
- Department of Microbiology, Kurukshetra University, Kurukshetra, Haryana 136119, India
| | - Anuja Sharma
- Department of Microbiology, Kurukshetra University, Kurukshetra, Haryana 136119, India
| | - Anita Yadav
- Department of Biotechnology, Kurukshetra University, Kurukshetra, Haryana 136119, India
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Stockinger LW, Eide KB, Dybvik AI, Sletta H, Vårum KM, Eijsink VG, Tøndervik A, Sørlie M. The effect of the carbohydrate binding module on substrate degradation by the human chitotriosidase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1494-501. [DOI: 10.1016/j.bbapap.2015.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/29/2015] [Accepted: 06/23/2015] [Indexed: 11/25/2022]
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Systematic analysis of intracellular mechanisms of propanol production in the engineered Thermobifida fusca B6 strain. Appl Microbiol Biotechnol 2015; 99:8089-100. [PMID: 26227414 DOI: 10.1007/s00253-015-6850-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/30/2015] [Accepted: 07/15/2015] [Indexed: 10/23/2022]
Abstract
Thermobifida fusca is a moderately thermophilic actinobacterium naturally capable of utilizing lignocellulosic biomass. The B6 strain of T. fusca was previously engineered to produce 1-propanol directly on lignocellulosic biomass by expressing a bifunctional butyraldehyde/alcohol dehydrogenase (adhE2). To characterize the intracellular mechanisms related to the accumulation of 1-propanol, the engineered B6 and wild-type (WT) strains were systematically compared by analysis of the transcriptome and intracellular metabolome during exponential growth on glucose, cellobiose, and Avicel. Of the 18 known cellulases in T. fusca, 10 cellulase genes were transcriptionally expressed on all three substrates along with three hemicellulases. Transcriptomic analysis of cellodextrin and cellulose transport revealed that Tfu_0936 (multiple sugar transport system permease) was the key enzyme regulating the uptake of sugars in T. fusca. For both WT and B6 strains, it was found that growth in oxygen-limited conditions resulted in a blocked tricarboxylic acid (TCA) cycle caused by repressed expression of Tfu_1925 (aconitate hydratase). Further, the transcriptome suggested a pathway for synthesizing succinyl-CoA: oxaloacetate to malate (by malate dehydrogenase), malate to fumarate (by fumarate hydratase), and fumarate to succinate (by succinate dehydrogenase/fumarate reductase) which was ultimately converted to succinyl-CoA by succinyl-CoA synthetase. Both the transcriptome and the intracellular metabolome confirmed that 1-propanol was produced through succinyl-CoA, L-methylmalonyl-CoA, D-methylmalonyl-CoA, and propionyl-CoA in the B6 strain.
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Hamre AG, Jana S, Holen MM, Mathiesen G, Väljamäe P, Payne CM, Sørlie M. Thermodynamic Relationships with Processivity in Serratia marcescens Family 18 Chitinases. J Phys Chem B 2015; 119:9601-13. [PMID: 26154587 DOI: 10.1021/acs.jpcb.5b03817] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The enzymatic degradation of recalcitrant polysaccharides is accomplished by synergistic enzyme cocktails of glycoside hydrolases (GHs) and accessory enzymes. Many GHs are processive which means that they remain attached to the substrate in between subsequent hydrolytic reactions. Chitinases are GHs that catalyze the hydrolysis of chitin (β-1,4-linked N-acetylglucosamine). Previously, a relationship between active site topology and processivity has been suggested while recent computational efforts have suggested a link between the degree of processivity and ligand binding free energy. We have investigated these relationships by employing computational (molecular dynamics (MD)) and experimental (isothermal titration calorimetry (ITC)) approaches to gain insight into the thermodynamics of substrate binding to Serratia marcescens chitinases ChiA, ChiB, and ChiC. We show that increased processive ability indeed corresponds to more favorable binding free energy and that this likely is a general feature of GHs. Moreover, ligand binding in ChiB is entropically driven; in ChiC it is enthalpically driven, and the enthalpic and entropic contributions to ligand binding in ChiA are equal. Furthermore, water is shown to be especially important in ChiA-binding. This work provides new insight into oligosaccharide binding, getting us one step closer to understand how GHs efficiently degrade recalcitrant polysaccharides.
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Affiliation(s)
- Anne Grethe Hamre
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Suvamay Jana
- ‡Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Matilde Mengkrog Holen
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Geir Mathiesen
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
| | - Priit Väljamäe
- §Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Christina M Payne
- ‡Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Morten Sørlie
- †Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. 5003, N-1432 Ås, Norway
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Stern J, Kahn A, Vazana Y, Shamshoum M, Moraïs S, Lamed R, Bayer EA. Significance of relative position of cellulases in designer cellulosomes for optimized cellulolysis. PLoS One 2015; 10:e0127326. [PMID: 26024227 PMCID: PMC4449128 DOI: 10.1371/journal.pone.0127326] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/13/2015] [Indexed: 11/23/2022] Open
Abstract
Degradation of cellulose is of major interest in the quest for alternative sources of renewable energy, for its positive effects on environment and ecology, and for use in advanced biotechnological applications. Due to its microcrystalline organization, celluose is extremely difficult to degrade, although numerous microbes have evolved that produce the appropriate enzymes. The most efficient known natural cellulolytic system is produced by anaerobic bacteria, such as C. thermocellum, that possess a multi-enzymatic complex termed the cellulosome. Our laboratory has devised and developed the designer cellulosome concept, which consists of chimaeric scaffoldins for controlled incorporation of recombinant polysaccharide-degrading enzymes. Recently, we reported the creation of a combinatorial library of four cellulosomal modules comprising a basic chimaeric scaffoldin, i.e., a CBM and 3 divergent cohesin modules. Here, we employed selected members of this library to determine whether the position of defined cellulolytic enzymes is important for optimized degradation of a microcrystalline cellulosic substrate. For this purpose, 10 chimaeric scaffoldins were used for incorporation of three recombinant Thermobifida fusca enzymes: the processive endoglucanase Cel9A, endoglucanase Cel5A and exoglucanase Cel48A. In addition, we examined whether the characteristic properties of the T. fusca enzymes as designer cellulosome components are unique to this bacterium by replacing them with parallel enzymes from Clostridium thermocellum. The results support the contention that for a given set of cellulosomal enzymes, their relative position within a scaffoldin can be critical for optimal degradation of microcrystaline cellulosic substrates.
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Affiliation(s)
- Johanna Stern
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Amaranta Kahn
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Yael Vazana
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Melina Shamshoum
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Sarah Moraïs
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Raphael Lamed
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Edward A. Bayer
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
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Deng Y, Zhang X. DtxR, an iron-dependent transcriptional repressor that regulates the expression of siderophore gene clusters in Thermobifida fusca. FEMS Microbiol Lett 2015; 362:1-6. [DOI: 10.1093/femsle/fnu053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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50
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Production of butyric acid by a cellulolytic actinobacterium Thermobifida fusca on cellulose. Biochem Eng J 2014. [DOI: 10.1016/j.bej.2014.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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