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Msango K, Gouda MNR, Ramakrishnan B, Kumar A, Subramanian S. Variation and functional profile of gut bacteria in the scarab beetle, Anomala dimidiata, under a cellulose-enriched microenvironment. Sci Rep 2024; 14:22400. [PMID: 39333778 PMCID: PMC11437086 DOI: 10.1038/s41598-024-73417-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 09/17/2024] [Indexed: 09/30/2024] Open
Abstract
This study utilized cultivable methods and 16 S amplicon sequencing to compare taxonomic profiles and functional potential of gut bacteria in the scarab beetle, Anomola dimidiata, under cellulose-enriched conditions. Eight culturable cellulolytic gut bacteria were isolated from the midgut and hindgut of the scarab larvae, respectively. 16 S amplicon sequencing evinced that the most represented taxonomic profiles at phylum level in the fermentation chamber and midgut were Bacillota (71.62 and 56.76%), Pseudomonadota (22.66 and 36.89%) and Bacteroidota (2.7 and 2.81%). Bacillota (56.74 and 91.39%) were significantly enriched in the midgut with the addition of cellulose. In contrast, Bacillota and Psedomonadota were significantly enriched in the fermentation chamber. Carbohydrate metabolism was up-regulated in the midgut, while nitrogen and phosphorus metabolism were up-regulated in the fermentation chamber, suggesting these symbionts' possible metabolic roles to the host. An analysis of total cellulases as well as amplicon sequence variants indicated that the gut bacteria belonging to Acinetobacter, Bacillus, Brucella, Brevibacillus, Enterobacter, Lysinibacillus and Paenibacillus are involved in nutrition provisioning. These results have provided additional insights into the gut bacteria associated with cellulose digestion in A. dimidiata and created a platform for bioprospecting novel isolates to produce biomolecules for biotechnological use, besides identifying eco-friendly targets for its management.
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Affiliation(s)
- Kondwani Msango
- Insect Physiology, Molecular Biology and Microbiology Agricultural Research and Extension Trust, Private Bag 9, Lilongwe, Malawi.
- Division of Entomology, Indian Agricultural Research Institute, New Delhi, 110012, India.
| | - M N Rudra Gouda
- Division of Entomology, Indian Agricultural Research Institute, New Delhi, 110012, India
| | - B Ramakrishnan
- Division of Microbiology, Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Aundy Kumar
- Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
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2
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Nong D, Haviland ZK, Zexer N, Pfaff SA, Cosgrove DJ, Tien M, Anderson CT, Hancock WO. Single-molecule tracking reveals dual front door/back door inhibition of Cel7A cellulase by its product cellobiose. Proc Natl Acad Sci U S A 2024; 121:e2322567121. [PMID: 38648472 PMCID: PMC11067010 DOI: 10.1073/pnas.2322567121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Degrading cellulose is a key step in the processing of lignocellulosic biomass into bioethanol. Cellobiose, the disaccharide product of cellulose degradation, has been shown to inhibit cellulase activity, but the mechanisms underlying product inhibition are not clear. We combined single-molecule imaging and biochemical investigations with the goal of revealing the mechanism by which cellobiose inhibits the activity of Trichoderma reesei Cel7A, a well-characterized exo-cellulase. We find that cellobiose slows the processive velocity of Cel7A and shortens the distance moved per encounter; effects that can be explained by cellobiose binding to the product release site of the enzyme. Cellobiose also strongly inhibits the binding of Cel7A to immobilized cellulose, with a Ki of 2.1 mM. The isolated catalytic domain (CD) of Cel7A was also inhibited to a similar degree by cellobiose, and binding of an isolated carbohydrate-binding module to cellulose was not inhibited by cellobiose, suggesting that cellobiose acts on the CD alone. Finally, cellopentaose inhibited Cel7A binding at micromolar concentrations without affecting the enzyme's velocity of movement along cellulose. Together, these results suggest that cellobiose inhibits Cel7A activity both by binding to the "back door" product release site to slow activity and to the "front door" substrate-binding tunnel to inhibit interaction with cellulose. These findings point to strategies for engineering cellulases to reduce product inhibition and enhance cellulose degradation, supporting the growth of a sustainable bioeconomy.
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Affiliation(s)
- Daguan Nong
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Zachary K. Haviland
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Nerya Zexer
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Sarah A. Pfaff
- Department of Biology, Pennsylvania State University, University Park, PA16802
- Intercollege Graduate Degree Program in Plant Biology, Department of Biology, The Pennsylvania State University, University Park, PA16802
| | - Daniel J. Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Ming Tien
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA16802
| | - Charles T. Anderson
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - William O. Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
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3
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Li X, Xiang Z, Dang W, Lin Z, Wang H, Wang H, Ye D, Yao R. High-yield and scalable cellulose nanomesh preparation via dilute acid vapor and enzymatic hydrolysis-mediated nanofabrication. Carbohydr Polym 2024; 323:121370. [PMID: 37940267 DOI: 10.1016/j.carbpol.2023.121370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 11/10/2023]
Abstract
Nanocellulose has received considerable attention in diverse research fields owing to its unique nanostructure-mediated physicochemical properties. However, classical acid hydrolysis usually destroys the microstructural integrity of cellulose, leading to the violent dissociation of cellulose into low-dimensional nanofibers and limiting the formation of intact structures with high specific surface areas. Herein, we have optimized the methodology of dilute acid vapor hydrolysis combined with the enzymatic hydrolysis (DAVE) method and investigated the pore formation mechanism of cellulose nanomesh (CNM). Benefiting from the selective nano-engraving effect of hydrochloric acid vapor on the amorphous region of cellulose followed by widening of the three-dimensional nanopores using enzymatic hydrolysis, confirmed by topographic, spectroscopic, and crystallographic tests, the as-prepared CNM, significantly different from the existing nanocellulose, exhibited improved specific surface area (98.37 m2/g), high yield (88.5 %), high crystallinity (73.4 %), and excellent thermal stability (375.4 °C). The proposed DAVE approach may open a new avenue for nanocellulose manufacturing.
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Affiliation(s)
- Xiaowen Li
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China
| | - Zhongrun Xiang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China
| | - Wanting Dang
- Department of Pharmaceutical Science and Engineering, School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China
| | - Zewan Lin
- College of Light Textile Engineering and Art, Anhui Agricultural University, Hefei, Anhui 230036, China; Biomass Molecular Engineering Centre, Hefei, Anhui 230036, China
| | - Huai Wang
- Department of Pharmaceutical Science and Engineering, School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China
| | - Huiqing Wang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China.
| | - Dongdong Ye
- College of Light Textile Engineering and Art, Anhui Agricultural University, Hefei, Anhui 230036, China; Biomass Molecular Engineering Centre, Hefei, Anhui 230036, China.
| | - Risheng Yao
- Department of Pharmaceutical Science and Engineering, School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui Province 230009, China.
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4
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Ramtanon I, Berlioz-Barbier A, Remy S, Renault JH, Masle AL. A combined liquid chromatography - trapped ion mobility - tandem high-resolution mass spectrometry and multivariate analysis approach for the determination of enzymatic reactivity descriptors in biomass hydrolysates. J Chromatogr A 2023; 1706:464277. [PMID: 37573756 DOI: 10.1016/j.chroma.2023.464277] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/17/2023] [Accepted: 08/02/2023] [Indexed: 08/15/2023]
Abstract
Intermediate products such as oxygenated compounds may interfere with bioconversion kinetics of lignocellulosic biomass into bioethanol. This work presents a multidimensional approach, based on liquid chromatography (LC), trapped ion mobility spectrometry (TIMS), tandem high-resolution mass spectrometry (HRMS/MS), and multivariate analysis, for the identification of enzymatic reactivity descriptors in 22 industrial biomass samples, called hydrolysates. The first part of the study is dedicated to the improvement of the chemical diversity assessment of the hydrolysates through an original three-dimensional Van Krevelen diagram displaying the double bond equivalent (DBE) as third dimension. In a second part, the evaluation of data by multivariate data analysis allowed the discrimination of sample according to the biomass type and the level of enzymatic reactivity. In the last part, a potential descriptor of low enzymatic reactivity was selected and used in a case study. An in-depth structural analysis was performed on the feature annotated as carbohydrate derivative. Considering the intricate fragmentation spectrum exhibited by the selected feature, trapped ion mobility was employed to enhance separation prior to the HRMS/MS experiments. This final step improved data interpretation and increased the identification confidence level leading to the characterization of xylotriose, 3,5-dimethoxy-4-hydroxybenzaldehyde and 4-hydroxy-3-methoxy-cinnamaldehyde. This is the first study to present an untargeted multidimensional approach for the identification of enzymatic hydrolysis inhibitors in industrial hydrolysate samples.
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Affiliation(s)
- Ian Ramtanon
- IFP Energies nouvelles, rond-point de l'échangeur de Solaize, BP 3, 69360 Solaize, France
| | | | - Simon Remy
- Université de Reims Champagne-Ardenne, CNRS, ICMR 7312, 51097, Reims, France
| | - Jean-Hugues Renault
- Université de Reims Champagne-Ardenne, CNRS, ICMR 7312, 51097, Reims, France
| | - Agnès Le Masle
- IFP Energies nouvelles, rond-point de l'échangeur de Solaize, BP 3, 69360 Solaize, France.
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Haataja T, Gado JE, Nutt A, Anderson NT, Nilsson M, Momeni MH, Isaksson R, Väljamäe P, Johansson G, Payne CM, Ståhlberg J. Enzyme kinetics by GH7 cellobiohydrolases on chromogenic substrates is dictated by non-productive binding: insights from crystal structures and MD simulation. FEBS J 2023; 290:379-399. [PMID: 35997626 PMCID: PMC10087753 DOI: 10.1111/febs.16602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 02/05/2023]
Abstract
Cellobiohydrolases (CBHs) in the glycoside hydrolase family 7 (GH7) (EC3.2.1.176) are the major cellulose degrading enzymes both in industrial settings and in the context of carbon cycling in nature. Small carbohydrate conjugates such as p-nitrophenyl-β-d-cellobioside (pNPC), p-nitrophenyl-β-d-lactoside (pNPL) and methylumbelliferyl-β-d-cellobioside have commonly been used in colorimetric and fluorometric assays for analysing activity of these enzymes. Despite the similar nature of these compounds the kinetics of their enzymatic hydrolysis vary greatly between the different compounds as well as among different enzymes within the GH7 family. Through enzyme kinetics, crystallographic structure determination, molecular dynamics simulations, and fluorometric binding studies using the closely related compound o-nitrophenyl-β-d-cellobioside (oNPC), in this work we examine the different hydrolysis characteristics of these compounds on two model enzymes of this class, TrCel7A from Trichoderma reesei and PcCel7D from Phanerochaete chrysosporium. Protein crystal structures of the E212Q mutant of TrCel7A with pNPC and pNPL, and the wildtype TrCel7A with oNPC, reveal that non-productive binding at the product site is the dominating binding mode for these compounds. Enzyme kinetics results suggest the strength of non-productive binding is a key determinant for the activity characteristics on these substrates, with PcCel7D consistently showing higher turnover rates (kcat ) than TrCel7A, but higher Michaelis-Menten (KM ) constants as well. Furthermore, oNPC turned out to be useful as an active-site probe for fluorometric determination of the dissociation constant for cellobiose on TrCel7A but could not be utilized for the same purpose on PcCel7D, likely due to strong binding to an unknown site outside the active site.
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Affiliation(s)
- Topi Haataja
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA.,Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Anu Nutt
- Department of Chemistry, Uppsala University, Sweden.,Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | - Nolan T Anderson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Mikael Nilsson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Majid Haddad Momeni
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Roland Isaksson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | | | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Overexpression of LAS21 in Cellulase-Displaying Saccharomyces cerevisiae for High-Yield Ethanol Production from Pretreated Sugarcane Bagasse. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8110652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The valorization of lignocellulosic feedstocks into biofuels and biochemicals has received much attention due to its environmental friendliness and sustainability. However, engineering an ideal microorganism that can both produce sufficient cellulases and ferment ethanol is highly challenging. In this study, we have tested seven different genes that are involved in glycosylphosphatidylinositol (GPI) biosynthesis and remodeling for the improvement of cellulase activity tethered on the S. cerevisiae cell surface. It was found that the overexpression of LAS21 can improve β-glucosidase activity by 48.8% compared to the original strain. Then, the three cellulase genes (cellobiohydrolase, endoglucanase, and β-glucosidase) and the LAS21 gene were co-introduced into a diploid thermotolerant S. cerevisiae strain by a multiple-round transformation approach, resulting in the cellulolytic ECBLCCE5 strain. Further optimization of the bioprocess parameters was found to enhance the ethanol yield of the ECBLCCE5 strain. Scaling up the valorization of pretreated sugarcane bagasses in a 1 L bioreactor resulted in a maximum ethanol concentration of 28.0 g/L (86.5% of theoretical yield). Our study provides a promising way to improve the economic viability of second-generation ethanol production. Moreover, the engineering of genes involved in GPI biosynthesis and remodeling can be applied to other yeast cell surface display applications.
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7
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Metaproteomics reveals enzymatic strategies deployed by anaerobic microbiomes to maintain lignocellulose deconstruction at high solids. Nat Commun 2022; 13:3870. [PMID: 35790765 PMCID: PMC9256739 DOI: 10.1038/s41467-022-31433-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/16/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractEconomically viable production of cellulosic biofuels requires operation at high solids loadings—on the order of 15 wt%. To this end we characterize Nature’s ability to deconstruct and utilize mid-season switchgrass at increasing solid loadings using an anaerobic methanogenic microbiome. This community exhibits undiminished fractional carbohydrate solubilization at loadings ranging from 30 g/L to 150 g/L. Metaproteomic interrogation reveals marked increases in the abundance of specific carbohydrate-active enzyme classes. Significant enrichment of auxiliary activity family 6 enzymes at higher solids suggests a role for Fenton chemistry. Stress-response proteins accompanying these reactions are similarly upregulated at higher solids, as are β-glucosidases, xylosidases, carbohydrate-debranching, and pectin-acting enzymes—all of which indicate that removal of deconstruction inhibitors is important for observed undiminished solubilization. Our work provides insights into the mechanisms by which natural microbiomes effectively deconstruct and utilize lignocellulose at high solids loadings, informing the future development of defined cultures for efficient bioconversion.
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Schaller KS, Molina GA, Kari J, Schiano-di-Cola C, Sørensen TH, Borch K, Peters GH, Westh P. Virtual Bioprospecting of Interfacial Enzymes: Relating Sequence and Kinetics. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kay S. Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- Department of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Gustavo Avelar Molina
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | - Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
- Department of Science and Environment, Roskilde University, Universitetsvej 1, DK-4000 Roskilde, Denmark
| | - Corinna Schiano-di-Cola
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
| | | | - Kim Borch
- Novozymes A/S, Biologiens Vej 2, DK-2800 Kgs. Lyngby, Denmark
| | - Günther H.J. Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, DK-2800 Kgs. Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800 Kgs. Lyngby, Denmark
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Min K, Kim YH, Kim J, Kim Y, Gong G, Um Y. Effect of manganese peroxidase on the decomposition of cellulosic components: Direct cellulolytic activity and synergistic effect with cellulase. BIORESOURCE TECHNOLOGY 2022; 343:126138. [PMID: 34678456 DOI: 10.1016/j.biortech.2021.126138] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/09/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Herein, it was unearthed that manganese peroxidase (MnP) from Phanerochaete chrysosporium, a lignin-degrading enzyme, is capable of not only directly decomposing cellulosic components but also boosting cellulase activity. MnP decomposes various cellulosic substrates (carboxymethyl cellulose, cellobiose [CMC], and Avicel®) and produces reducing sugars rather than oxidized sugars such as lactone and ketoaldolase. MnP with MnII in acetate buffer evolves the MnIII-acetate complex functioning as a strong oxidant, and the non-specificity of MnIII-acetate enables cellulose-decomposition. The catalytic mechanism was proposed by analyzing catalytic products derived from MnP-treated cellopentaose. Notably, MnP also boosts cellulase activity on CMC and Avicel®, even considering the cellulolytic activity of MnP itself. To the best of the authors' knowledge, this is the first report demonstrating a previously unknown fungal MnP activity in cellulose-decomposition in addition to a known delignification activity. Consequently, the results provide a promising insight for further investigation of the versatility of lignin-degrading biocatalysts.
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Affiliation(s)
- Kyoungseon Min
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research (KIER), Gwangju 61003, Republic of Korea
| | - Yong Hwan Kim
- Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jiye Kim
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yunje Kim
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Clean Energy and Chemical Engineering, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
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10
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Crooks C, Bechle NJ, St John FJ. A New Subfamily of Glycoside Hydrolase Family 30 with Strict Xylobiohydrolase Function. Front Mol Biosci 2021; 8:714238. [PMID: 34557520 PMCID: PMC8453022 DOI: 10.3389/fmolb.2021.714238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
The Acetivibrio clariflavus (basonym: Clostridium clariflavum) glycoside hydrolase family 30 cellulosomal protein encoded by the Clocl_1795 gene was highly represented during growth on cellulosic substrates. In this report, the recombinantly expressed protein has been characterized and shown to be a non-reducing terminal (NRT)-specific xylobiohydrolase (AcXbh30A). Biochemical function, optimal biophysical parameters, and phylogeny were investigated. The findings indicate that AcXbh30A strictly cleaves xylobiose from the NRT up until an α-1,2-linked glucuronic acid (GA)-decorated xylose if the number of xyloses is even or otherwise a single xylose will remain resulting in a penultimate GA-substituted xylose. Unlike recently reported xylobiohydrolases, AcXbh30A has no other detectable hydrolysis products under our optimized reaction conditions. Sequence analysis indicates that AcXbh30A represents a new GH30 subfamily. This new xylobiohydrolase may be useful for commercial production of industrial quantities of xylobiose.
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Affiliation(s)
- Casey Crooks
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, Madison, WI, United States
| | - Nathan J Bechle
- Engineering Mechanics and Remote Sensing Laboratory, Forest Products Laboratory, USDA Forest Service, Madison, WI, United States
| | - Franz J St John
- Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, Madison, WI, United States
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de Souza MF, da Silva Bon EP, da Silva AS. Production of cellulases and β-glucosidases by Trichoderma reesei Rut C30 using steam-pretreated sugarcane bagasse: an integrated approach for onsite enzyme production. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2021. [DOI: 10.1007/s43153-021-00114-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Agrawal R, Verma A, Singhania RR, Varjani S, Di Dong C, Kumar Patel A. Current understanding of the inhibition factors and their mechanism of action for the lignocellulosic biomass hydrolysis. BIORESOURCE TECHNOLOGY 2021; 332:125042. [PMID: 33813178 DOI: 10.1016/j.biortech.2021.125042] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Biorefining of lignocellulosic biomass is a relatively new concept but it has strong potential to develop and partially replace the fossil derived fuels and myriad of value products to subsequently reduce the greenhouse gas emissions. However, the energy and cost intensive process of releasing the entrapped fermentable sugars is a major challenge for its commercialization. Various factors playing a detrimental role during enzymatic hydrolysis of biomass are inherent recalcitrance of lignocellulosic biomass, expensive enzymes, sub-optimal enzyme composition, lack of synergistic activity and enzyme inhibition caused by various inhibitors. The current study investigated the mechanism of enzyme inhibition during lignocellulosic biomass saccharification especially at high solid loadings. These inhibition factors are categorized into physio-chemical factors, water-soluble and -insoluble enzyme inhibitors, oligomers and enzyme-lignin binding. Furthermore, different approaches are proposed to alleviate the challenges and improve the enzymatic hydrolysis efficiency such as supplementation with surfactants, synergistic catalytic/non-catalytic proteins, and bioprocess modifications.
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Affiliation(s)
- Ruchi Agrawal
- The Energy and Resources Institute, TERI Gram, Gwal Pahari, Gurugram, Haryana, India
| | - Amit Verma
- College of Basic Science and Humanities, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar - 385506 (Banaskantha), Gujarat, India
| | - Reeta Rani Singhania
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Sunita Varjani
- Gujarat Pollution Control Board, Gandhinagar, Gujarat 382010, India
| | - Cheng Di Dong
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan
| | - Anil Kumar Patel
- Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City, Taiwan.
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13
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Differential effects of inorganic salts on cellulase kinetics in enzymatic saccharification of cellulose and lignocellulosic biomass. Bioprocess Biosyst Eng 2021; 44:2331-2344. [PMID: 34195894 DOI: 10.1007/s00449-021-02607-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/23/2021] [Indexed: 10/21/2022]
Abstract
Inorganic salt pretreatment of lignocellulosic biomass has proven to be an efficient way to increase the efficiency of enzymatic saccharification. However, it is not clear that this improvement is the result of modification of the lignocellulosic substrate after pretreatment, or removal of inhibitor, or enhancement of cellulase or a combination of these events. Therefore, this study aimed to analyze the effects of inorganic salts on kinetics of cellulase enzymes (celluclast 1.5L and accellerase 1500). Two substrates rich in cellulose content [carboxymethylcellulose (CMC), avicel (AV)] and lignocellulose substrate [sugarcane bagasse (SB)] were considered. The enzymatic saccharification was carried with and without the addition of inorganic salts (NaCl and KCl) at 0.5 M and 1.0 M concentration. The kinetic parameters, Km and Vm, were determined to mechanically understand the pattern of inhibition and enhancement of inorganic salts on enzymatic saccharification. The kinetics parameters of celluclast 1.5L and accellerase 1500 for hydrolysis of CMC and AV with NaCl showed uncompetitive inhibition. Whereas, influences of KCl on both cellulase were differentiated to function in inhibition or enhancement modes when challenged with different substrates. On the other hand, enzymatic hydrolysis efficiencies of SB using both cellulases were enhanced under addition of NaCl and KCl, by increasing Vm of celluclast 1.5L from 0.303 to 0.635 mg/mL min (0.5 M KCl) and accellerase 1500 from 0.383 to 0.719 mg/mL min (1.0 M NaCl). The details of kinetic analysis in this work revealed the mechanism of inorganic salts on cellulase kinetics to be involved in substrate modification and removal of inhibitor.
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Chang H, Wohlschlager L, Csarman F, Ruff A, Schuhmann W, Scheiblbrandner S, Ludwig R. Real-Time Measurement of Cellobiose and Glucose Formation during Enzymatic Biomass Hydrolysis. Anal Chem 2021; 93:7732-7738. [PMID: 34014659 PMCID: PMC8173519 DOI: 10.1021/acs.analchem.1c01182] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Enzymatic hydrolysis
of lignocellulosic biomass for biofuel production
relies on complex multi-enzyme ensembles. Continuous and accurate
measurement of the released key products is crucial in optimizing
the industrial degradation process and also investigating the activity
and interaction between the involved enzymes and the insoluble substrate.
Amperometric biosensors have been applied to perform continuous cellobiose
measurements during the enzymatic hydrolysis of pure cellulose powders.
The oxygen-sensitive mediators used in these biosensors restricted
their function under physiological or industrial conditions. Also,
the combined measurements of the hydrolysis products cellobiose and
glucose require a high selectivity of the biorecognition elements.
We employed an [Os(2,2′-bipyridine)2Cl]Cl-modified
polymer and cellobiose dehydrogenase to fabricate a cellobiose biosensor,
which can accurately and specifically detect cellobiose even in the
presence of oxygen and the other main product glucose. Additionally,
a glucose biosensor was fabricated to simultaneously measure glucose
produced from cellobiose by β-glucosidases. The cellobiose and
glucose biosensors work at applied potentials of +0.25 and +0.45 V
versus Ag|AgCl (3 M KCl), respectively, and can selectively detect
their substrate. Both biosensors were used in combination to monitor
the hydrolysis of pure cellulose of low crystallinity or industrial
corncob samples. The obtained results correlate with the high-performance
liquid chromatography pulsed amperometric detection analysis and demonstrate
that neither oxygen nor the presence of redox-active compounds from
the lignin fraction of the corncob interferes with the measurements.
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Affiliation(s)
- Hucheng Chang
- Biocatalysis and Biosensor Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Lena Wohlschlager
- Biocatalysis and Biosensor Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Florian Csarman
- Biocatalysis and Biosensor Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Adrian Ruff
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Stefan Scheiblbrandner
- Biocatalysis and Biosensor Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| | - Roland Ludwig
- Biocatalysis and Biosensor Laboratory, Department of Food Science and Technology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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15
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Nath P, Goyal A. Structure and dynamics analysis of multi-domain putative β-1,4-glucosidase of family 3 glycoside hydrolase (PsGH3) from Pseudopedobacter saltans. J Mol Model 2021; 27:106. [PMID: 33694107 PMCID: PMC7945971 DOI: 10.1007/s00894-021-04721-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/01/2021] [Indexed: 11/30/2022]
Abstract
Structure and conformational behaviour of a putative β-1,4-glucosidase of glycoside hydrolase family 3 (PsGH3) from Pseudopedobacter saltans was predicted by using in-silico tools. PsGH3 modeled structure constructed using Phyre2 displayed multidomain architecture comprising an N-terminal (β/α)8-fold domain followed by (α/β)6-sandwich domain, PA14 domain, and a C-terminal domain resembling an immunoglobulin fold. Ramachandran plot displayed 99.3% of amino acids in the allowed region and 0.7% residues in the disallowed region. Multiple sequence alignment (MSA) and structure superposition of PsGH3 with other homologues from GH3 family revealed the conserved residues, Asp274 and Glu624 present in loops LA and LB, respectively originating from N-terminal domain act as catalytic residues. The volume and area calculated for PsGH3 displayed a deep active-site conformation comparable with its homologues, β-1,4-glucosidases (GH3) of Kluyveromyces marxianus and Streptomyces venezuelae. Molecular dynamic (MD) simulation of PsGH3 structure for 80 ns suggested stable and compact structure. Molecular docking studies revealed deeper active site conformation of PsGH3 that could house larger cellooligosaccharides up to 7° of polymerization (DP7). The amino acid residues, Ala86, Leu88, Cys275, Pro483, Phe493, Asn417, Asn491, Pro492, and Leu495 created a binding pocket near the catalytic cleft, crucial for ligand binding. MD simulation of PsGH3 in the presence of cellooligosaccharides, viz., cellobiose and celloheptaose showed stability in terms of RMSD, Rg, and SASA values till 80 ns. The calculation of average number of hydrogen bond (H-bond), interaction energy, and binding free energy confirmed the stronger binding affinity of the larger cellooligosaccharides such as celloheptaose in the binding cavity of PsGH3.
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Affiliation(s)
- Priyanka Nath
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Arun Goyal
- Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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16
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Shibata N, Kakeshita H, Igarashi K, Takimura Y, Shida Y, Ogasawara W, Koda T, Hasunuma T, Kondo A. Disruption of alpha-tubulin releases carbon catabolite repression and enhances enzyme production in Trichoderma reesei even in the presence of glucose. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:39. [PMID: 33557925 PMCID: PMC7869464 DOI: 10.1186/s13068-021-01887-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/19/2021] [Indexed: 05/05/2023]
Abstract
BACKGROUND Trichoderma reesei is a filamentous fungus that is important as an industrial producer of cellulases and hemicellulases due to its high secretion of these enzymes and outstanding performance in industrial fermenters. However, the reduction of enzyme production caused by carbon catabolite repression (CCR) has long been a problem. Disruption of a typical transcriptional regulator, Cre1, does not sufficiently suppress this reduction in the presence of glucose. RESULTS We found that deletion of an α-tubulin (tubB) in T. reesei enhanced both the amount and rate of secretory protein production. Also, the tubulin-disrupted (ΔtubB) strain had high enzyme production and the same enzyme profile even if the strain was cultured in a glucose-containing medium. From transcriptome analysis, the ΔtubB strain exhibited upregulation of both cellulase and hemicellulase genes including some that were not originally induced by cellulose. Moreover, cellobiose transporter genes and the other sugar transporter genes were highly upregulated, and simultaneous uptake of glucose and cellobiose was also observed in the ΔtubB strain. These results suggested that the ΔtubB strain was released from CCR. CONCLUSION Trichoderma reesei α-tubulin is involved in the transcription of cellulase and hemicellulase genes, as well as in CCR. This is the first report of overcoming CCR by disrupting α-tubulin gene in T. reesei. The disruption of α-tubulin is a promising approach for creating next-generation enzyme-producing strains of T. reesei.
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Affiliation(s)
- Nozomu Shibata
- Biological Science Research, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Hiroshi Kakeshita
- Biological Science Research, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Kazuaki Igarashi
- Biological Science Research, Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi, 321-3497, Japan
| | - Yasushi Takimura
- Biological Science Research, Kao Corporation, 1334 Minato, Wakayama, Wakayama, 640-8580, Japan
| | - Yosuke Shida
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan
| | - Wataru Ogasawara
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata, 940-2188, Japan
| | - Tohru Koda
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo, 657-8501, Japan
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501, Japan
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17
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Enhanced glycolic acid yield through xylose and cellobiose utilization by metabolically engineered Escherichia coli. Bioprocess Biosyst Eng 2021; 44:1081-1091. [PMID: 33527231 DOI: 10.1007/s00449-020-02502-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/24/2020] [Indexed: 12/11/2022]
Abstract
Microbial biorefinery is a promising route toward sustainable production of glycolic acid (GA), a valuable raw material for various industries. However, inherent microbial GA production has limited substrate consumption using either D-xylose or D-glucose as carbon catabolite repression (CCR) averts their co-utilization. To bypass CCR, a GA-producing strain using D-xylose via Dahms pathway was engineered to allow cellobiose uptake. Unlike glucose, cellobiose was assimilated and intracellularly degraded without repressing D-xylose uptake. The final GA-producing E. coli strain (CLGA8) has an overexpressed cellobiose phosphorylase (cep94A) from Saccharophagus degradans 2-40 and an activated glyoxylate shunt pathway. Expression of cep94A improved GA production reaching the maximum theoretical yield (0.51 g GA g-1 xylose), whereas activation of glyoxylate shunt pathway enabled GA production from cellobiose, which further increased the GA titer (2.25 g GA L-1). To date, this is the highest reported GA yield from D-xylose through Dahms pathway in an engineered E. coli with cellobiose as co-substrate.
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18
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Tavares MP, Morgan T, Gomes RF, Rodrigues MQRB, Castro-Borges W, de Rezende ST, de Oliveira Mendes TA, Guimarães VM. Secretomic insight into the biomass hydrolysis potential of the phytopathogenic fungus Chrysoporthe cubensis. J Proteomics 2021; 236:104121. [PMID: 33540065 DOI: 10.1016/j.jprot.2021.104121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/17/2020] [Accepted: 01/12/2021] [Indexed: 12/13/2022]
Abstract
The phytopathogenic fungus Chrysoporthe cubensis has a great capacity to produce highly efficient enzymes for the hydrolysis of lignocellulosic biomass. The bioinfosecretome of C. cubensis was identified by computational predictions of secreted proteins combined with protein analysis using 1D-LC-MS/MS. The in silico secretome predicted 562 putative genes capable of encoding secreted proteins, including 273 CAZymes. Proteomics analysis confirmed the existence of 313 proteins, including 137 CAZymes classified as Glycosyl Hydrolases (GH), Polysaccharide Lyases (PL), Carbohydrate Esterases (CE) and Auxiliary Activities enzymes (AA), which indicates the presence of classical and oxidative cellulolytic mechanisms. The enzymes diversity in the extract shows fungal versatility to act in complex biomasses. This study provides an insight into the lignocellulose-degradation mechanisms by C. cubensis and allows the identification of the enzymes that are potentially useful in improving industrial process of bioconversion of lignocellulose. SIGNIFICANCE: Chrysoporthe cubensis is an important deadly canker pathogen of commercially cultivated Eucalyptus species. The effective depolymerisation of the recalcitrant plant cell wall performed by this fungus is closely related to its high potential of lignocellulolytic enzymes secretion. Since the degradation of biomass occurs in nature almost exclusively by enzyme secretion systems, it is reasonable to suggest that the identification of C. cubensis lignocellulolytic enzymes is relevant in contributing to new sustainable alternatives for industrial solutions. As far as we know, this work is the first accurate proteomic evaluation of the enzymes secreted by this species of fungus. The integration of the gel-based proteomic approach, the bioinformatic prediction of the secretome and the analyses of enzymatic activity are powerful tools in the evaluation of biotechnological potential of C. cubensis in producing carbohydrate-active enzymes. In addition, analysis of the C. cubensis secretome grown in wheat bran draws attention to this plant pathogen and its extracellular enzymatic machinery, especially regarding the identification of promising new enzymes for industrial applications. The results from this work allowed for explanation and reinforce previous research that revealed C. cubensis as a strong candidate to produce enzymes to hydrolyse sugarcane bagasse and similar substrates.
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Affiliation(s)
- Murillo Peterlini Tavares
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Túlio Morgan
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Riziane Ferreira Gomes
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | | | - William Castro-Borges
- Department of Biological Science, Universidade Federal de Ouro Preto, Campus Universitário Morro do Cruzeiro, Ouro Preto, MG 35400-000, Brazil
| | - Sebastião Tavares de Rezende
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Tiago Antônio de Oliveira Mendes
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil
| | - Valéria Monteze Guimarães
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Av. PH Rolfs, s/n, Viçosa, MG 36570-900, Brazil.
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19
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da Silva AS, Espinheira RP, Teixeira RSS, de Souza MF, Ferreira-Leitão V, Bon EPS. Constraints and advances in high-solids enzymatic hydrolysis of lignocellulosic biomass: a critical review. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:58. [PMID: 32211072 PMCID: PMC7092515 DOI: 10.1186/s13068-020-01697-w] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 03/11/2020] [Indexed: 05/22/2023]
Abstract
The industrial production of sugar syrups from lignocellulosic materials requires the conduction of the enzymatic hydrolysis step at high-solids loadings (i.e., with over 15% solids [w/w] in the reaction mixture). Such conditions result in sugar syrups with increased concentrations and in improvements in both capital and operational costs, making the process more economically feasible. However, this approach still poses several technical hindrances that impact the process efficiency, known as the "high-solids effect" (i.e., the decrease in glucan conversion yields as solids load increases). The purpose of this review was to present the findings on the main limitations and advances in high-solids enzymatic hydrolysis in an updated and comprehensive manner. The causes for the rheological limitations at the onset of the high-solids operation as well as those influencing the "high-solids effect" will be discussed. The subject of water constraint, which results in a highly viscous system and impairs mixing, and by extension, mass and heat transfer, will be analyzed under the perspective of the limitations imposed to the action of the cellulolytic enzymes. The "high-solids effect" will be further discussed vis-à-vis enzymes end-product inhibition and the inhibitory effect of compounds formed during the biomass pretreatment as well as the enzymes' unproductive adsorption to lignin. This review also presents the scientific and technological advances being introduced to lessen high-solids hydrolysis hindrances, such as the development of more efficient enzyme formulations, biomass and enzyme feeding strategies, reactor and impeller designs as well as process strategies to alleviate the end-product inhibition. We surveyed the academic literature in the form of scientific papers as well as patents to showcase the efforts on technological development and industrial implementation of the use of lignocellulosic materials as renewable feedstocks. Using a critical approach, we expect that this review will aid in the identification of areas with higher demand for scientific and technological efforts.
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Affiliation(s)
- Ayla Sant’Ana da Silva
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Roberta Pereira Espinheira
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Ricardo Sposina Sobral Teixeira
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Marcella Fernandes de Souza
- Laboratory of Analytical Chemistry and Applied Ecochemistry, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Viridiana Ferreira-Leitão
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Elba P. S. Bon
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
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20
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Wang H, Lin X, Li S, Lin J, Xie C, Liu D, Yao D. Rational molecular design for improving digestive enzyme resistance of beta-glucosidase from Trichoderma viride based on inhibition of bound state formation. Enzyme Microb Technol 2019; 133:109465. [PMID: 31874695 DOI: 10.1016/j.enzmictec.2019.109465] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 11/18/2022]
Abstract
Beta-glucosidase (BGL1) is widely used in animal feed industries. However, degradation caused by digestive enzymes in the intestine hampers its application. Improving the resistance of feed enzymes against proteases is crucial in livestock farming. To improve the resistance of beta-glucosidase against pepsin and trypsin, a rational molecular design based on the inhibition of bound-state formation and secondary design was developed. The strategy includes: (1) prediction of the interaction surface of the pepsin-BGL1 complex structure, (2) prediction of key amino acids affecting the formation of the complex, (3) optimization of pepsin-resistant mutants by structural evaluation, (4) secondary molecular design based on pepsin-resistant mutants, and optimization of pepsin and trypsin-resistant mutants. Two BGL1 protein mutants (BGL1Q627C and BGL1Q627C/R543H/R646W) were constructed, and then mutated and wild-type BGL1s were expressed in Pichia pastoris. The half-life of BGL1Q627C and BGL1Q627C/R543H/R646W were 1.36 and 1.51 times that of the wild type upon pepsin exposure, respectively. For trypsin resistance, the half-life were 0.93 and 1.53 times that of the wild type, respectively. Compare to those of the wild type, most of the basic enzymatic properties of both mutants were not significantly changed except for increased Michaelis constants. The rational design method can be used as a guide for modifying other feed enzymes.
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Affiliation(s)
- Hao Wang
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; Department of Bioengineering, Jinan University, Guangzhou City, Guangdong Province, 510632, China
| | - Xiangna Lin
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; National Engineering Research Center of Genetic Medicine, Guangzhou City, Guangdong Province, 510632, China
| | - Shuang Li
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; Department of Bioengineering, Jinan University, Guangzhou City, Guangdong Province, 510632, China
| | - Jianlin Lin
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China
| | - Chunfang Xie
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; Department of Bioengineering, Jinan University, Guangzhou City, Guangdong Province, 510632, China
| | - Daling Liu
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; Department of Bioengineering, Jinan University, Guangzhou City, Guangdong Province, 510632, China.
| | - Dongsheng Yao
- Institute of Microbial Biotechnology, Jinan University, Guangzhou City, Guangdong Province, 510632, China; National Engineering Research Center of Genetic Medicine, Guangzhou City, Guangdong Province, 510632, China.
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21
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Røjel N, Kari J, Sørensen TH, Borch K, Westh P. pH profiles of cellulases depend on the substrate and architecture of the binding region. Biotechnol Bioeng 2019; 117:382-391. [PMID: 31631319 DOI: 10.1002/bit.27206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/09/2019] [Accepted: 10/13/2019] [Indexed: 01/06/2023]
Abstract
Understanding the pH effect of cellulolytic enzymes is of great technological importance. In this study, we have examined the influence of pH on activity and stability for central cellulases (Cel7A, Cel7B, Cel6A from Trichoderma reesei, and Cel7A from Rasamsonia emersonii). We systematically changed pH from 2 to 7, temperature from 20°C to 70°C, and used both soluble (4-nitrophenyl β- d-lactopyranoside [pNPL]) and insoluble (Avicel) substrates at different concentrations. Collective interpretation of these data provided new insights. An unusual tolerance to acidic conditions was observed for both investigated Cel7As, but only on real insoluble cellulose. In contrast, pH profiles on pNPL were bell-shaped with a strong loss of activity both above and below the optimal pH for all four enzymes. On a practical level, these observations call for the caution of the common practice of using soluble substrates for the general characterization of pH effects on cellulase activity. Kinetic modeling of the experimental data suggested that the nucleophile of Cel7A experiences a strong downward shift in pKa upon complexation with an insoluble substrate. This shift was less pronounced for Cel7B, Cel6A, and for Cel7A acting on the soluble substrate, and we hypothesize that these differences are related to the accessibility of water to the binding region of the Michaelis complex.
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Affiliation(s)
- Nanna Røjel
- Department of Science and Environment (INM), Roskilde University, Roskilde, Denmark.,Present address: Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, DK-2800, Kgs. Lyngby, Denmark
| | - Jeppe Kari
- Department of Science and Environment (INM), Roskilde University, Roskilde, Denmark.,Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | | | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
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22
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Kari J, Christensen SJ, Andersen M, Baiget SS, Borch K, Westh P. A practical approach to steady-state kinetic analysis of cellulases acting on their natural insoluble substrate. Anal Biochem 2019; 586:113411. [PMID: 31520594 DOI: 10.1016/j.ab.2019.113411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 10/26/2022]
Abstract
Measurement of steady-state rates (vSS) is straightforward in standard enzymology with soluble substrate, and it has been instrumental for comparative biochemical analyses within this area. For insoluble substrate, however, experimental values of vss remain controversial, and this has strongly limited the amount and quality of comparative analyses for cellulases and other enzymes that act on the surface of an insoluble substrate. In the current work, we have measured progress curves over a wide range of conditions for two cellulases, TrCel6A and TrCel7A from Trichoderma reesei, acting on their natural, insoluble substrate, cellulose. Based on this, we consider practical compromises for the determination of experimental vSS values, and propose a basic protocol that provides representative reaction rates and is experimentally simple so that larger groups of enzymes and conditions can be readily assayed with standard laboratory equipment. We surmise that the suggested experimental approach can be useful in comparative biochemical studies of cellulases; an area that remains poorly developed.
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Affiliation(s)
- Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark
| | - Stefan Jarl Christensen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | - Morten Andersen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | | | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark.
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23
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A biochemical comparison of fungal GH6 cellobiohydrolases. Biochem J 2019; 476:2157-2172. [DOI: 10.1042/bcj20190185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/14/2019] [Accepted: 07/16/2019] [Indexed: 02/02/2023]
Abstract
AbstractCellobiohydrolases (CBHs) from glycoside hydrolase family 6 (GH6) make up an important part of the secretome in many cellulolytic fungi. They are also of technical interest, particularly because they are part of the enzyme cocktails that are used for the industrial breakdown of lignocellulosic biomass. Nevertheless, functional studies of GH6 CBHs are scarce and focused on a few model enzymes. To elucidate functional breadth among GH6 CBHs, we conducted a comparative biochemical study of seven GH6 CBHs originating from fungi living in different habitats, in addition to one enzyme variant. The enzyme sequences were investigated by phylogenetic analyses to ensure that they were not closely related phylogenetically. The selected enzymes were all heterologously expressed in Aspergillus oryzae, purified and thoroughly characterized biochemically. This approach allowed direct comparisons of functional data, and the results revealed substantial variability. For example, the adsorption capacity on cellulose spanned two orders of magnitude and kinetic parameters, derived from two independent steady-state methods also varied significantly. While the different functional parameters covered wide ranges, they were not independent since they changed in parallel between two poles. One pole was characterized by strong substrate interactions, high adsorption capacity and low turnover number while the other showed weak substrate interactions, poor adsorption and high turnover. The investigated enzymes essentially defined a continuum between these two opposites, and this scaling of functional parameters raises interesting questions regarding functional plasticity and evolution of GH6 CBHs.
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Siqueira GA, Dias IKR, Arantes V. Exploring the action of endoglucanases on bleached eucalyptus kraft pulp as potential catalyst for isolation of cellulose nanocrystals. Int J Biol Macromol 2019; 133:1249-1259. [PMID: 31047930 DOI: 10.1016/j.ijbiomac.2019.04.162] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/22/2019] [Accepted: 04/22/2019] [Indexed: 10/26/2022]
Abstract
Cellulose nanocrystals (CNCs) is a high-value and emerging bionanomaterial with an increasing number of applications. The action of endoglucanases (EGs) from fungal and bacterial sources belonging to three glycosyl hydrolase (GH) families were investigated on bleached eucalyptus kraft pulp as potential catalysts to prepare CNC. Fungal GH7EG was the most efficient in hydrolysis and fiber fragmentation without altering crystallinity and crystallite size. Fiber fragmentation promoted by fungal GH45EG was similar to that observed for GH7EG, although it released a smaller amount of sugar. Bacterial GH5EG resulted in very low hydrolysis yield and practically did not fragment the fibers, resulting in a hydrolysis residue with characteristics very similar to the initial material. GH45EG was the only EG that affected the crystallinity and crystallite size and also the only enzyme capable of isolating nanoparticles. The isolated nanoparticles had very narrow width distribution range of 6-10 nm and length distribution range of 400-600 nm. Supplementation of β-glucosidase and conventional mechanical refining as a pretreatment did not improve the release of nanoparticles. Despite catalyzing the same biochemical reaction, different EGs displayed very distinct action during hydrolysis. The reported strong binding of GH45EG's CBM to the cellulose and the lack of increased accessibility of the enzyme to new substrate likely allowed continuous hydrolysis of the few fibers available, resulting in the isolation of cellulose nanoparticles.
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Affiliation(s)
- Germano A Siqueira
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
| | - Isabella K R Dias
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
| | - Valdeir Arantes
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
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Binod P, Gnansounou E, Sindhu R, Pandey A. Enzymes for second generation biofuels: Recent developments and future perspectives. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2018.06.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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26
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Functional characterisation of cellobiohydrolase I (Cbh1) from Trichoderma virens UKM1 expressed in Aspergillus niger. Protein Expr Purif 2019; 154:52-61. [DOI: 10.1016/j.pep.2018.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/12/2018] [Accepted: 09/20/2018] [Indexed: 11/20/2022]
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Geronimo I, Ntarima P, Piens K, Gudmundsson M, Hansson H, Sandgren M, Payne CM. Kinetic and molecular dynamics study of inhibition and transglycosylation in Hypocrea jecorina family 3 β-glucosidases. J Biol Chem 2019; 294:3169-3180. [PMID: 30602567 DOI: 10.1074/jbc.ra118.007027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Indexed: 01/09/2023] Open
Abstract
β-Glucosidases enhance enzymatic biomass conversion by relieving cellobiose inhibition of endoglucanases and cellobiohydrolases. However, the susceptibility of these enzymes to inhibition and transglycosylation at high glucose or cellobiose concentrations severely limits their activity and, consequently, the overall efficiency of enzyme mixtures. We determined the impact of these two processes on the hydrolytic activity of the industrially relevant family 3 β-glucosidases from Hypocrea jecorina, HjCel3A and HjCel3B, and investigated the underlying molecular mechanisms through kinetic studies, binding free energy calculations, and molecular dynamics (MD) simulations. HjCel3B had a 7-fold higher specificity for cellobiose than HjCel3A but greater tendency for glucose inhibition. Energy decomposition analysis indicated that cellobiose has relatively weak electrostatic interactions with binding site residues, allowing it to be easily displaced by glucose and free to inhibit other hydrolytic enzymes. HjCel3A is, thus, preferable as an industrial β-glucosidase despite its lower activity caused by transglycosylation. This competing pathway to hydrolysis arises from binding of glucose or cellobiose at the product site after formation of the glycosyl-enzyme intermediate. MD simulations revealed that binding is facilitated by hydrophobic interactions with Trp-37, Phe-260, and Tyr-443. Targeting these aromatic residues for mutation to reduce substrate affinity at the product site would therefore potentially mitigate transglycosidic activity. Engineering improved variants of HjCel3A and other structurally similar β-glucosidases would have a significant economic effect on enzymatic biomass conversion in terms of yield and production cost as the process can be consequently conducted at higher substrate loadings.
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Affiliation(s)
- Inacrist Geronimo
- From the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Patricia Ntarima
- the Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium, and
| | - Kathleen Piens
- the Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium, and
| | - Mikael Gudmundsson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Henrik Hansson
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Mats Sandgren
- the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
| | - Christina M Payne
- From the Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, .,the Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, 750 07 Uppsala, Sweden
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Xin D, Chen X, Wen P, Zhang J. Insight into the role of α-arabinofuranosidase in biomass hydrolysis: cellulose digestibility and inhibition by xylooligomers. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:64. [PMID: 30949240 PMCID: PMC6429694 DOI: 10.1186/s13068-019-1412-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 03/15/2019] [Indexed: 05/05/2023]
Abstract
BACKGROUND α-l-Arabinofuranosidase (ARA), a debranching enzyme that can remove arabinose substituents from arabinoxylan and arabinoxylooligomers (AXOS), promotes the hydrolysis of the arabinoxylan fraction of biomass; however, the impact of ARA on the overall digestibility of cellulose is controversial. In this study, we investigated the effects of the addition of ARA on cellulase hydrolytic action. RESULTS We found that approximately 15% of the xylan was converted into AXOS during the hydrolysis of aqueous ammonia-pretreated corn stover and that this AXOS fraction was approximately 12% substituted with arabinose. The addition of ARA removes a portion of the arabinose decoration, but the resulting less-substituted AXOS inhibited cellulase action much more effectively; showing an increase of 45.7%. Kinetic experiments revealed that AXOS with a lower degree of arabinose substitution showed stronger affinity for the active site of cellobiohydrolase, which could be the mechanism of increased inhibition. CONCLUSIONS Our findings strongly suggest that the ratio of ARA and other xylanases should be carefully selected to avoid the strong inhibition caused by the less-substituted AXOS during the hydrolysis of arabinoxylan-containing biomass. This study advances our understanding of the inhibitory mechanism of xylooligomers and provides critical new insights into the relationship of ARA addition and cellulose digestibility.
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Affiliation(s)
- Donglin Xin
- College of Forestry, Northwest A&F University, 3 Taicheng Road, Yangling, 712100 Shaanxi China
| | - Xiang Chen
- College of Forestry, Northwest A&F University, 3 Taicheng Road, Yangling, 712100 Shaanxi China
| | - Peiyao Wen
- College of Forestry, Northwest A&F University, 3 Taicheng Road, Yangling, 712100 Shaanxi China
| | - Junhua Zhang
- College of Forestry, Northwest A&F University, 3 Taicheng Road, Yangling, 712100 Shaanxi China
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29
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Cellobiose fermentation by Saccharomyces cerevisiae: Comparative analysis of intra versus extracellular sugar hydrolysis. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Zhang P, Chen M, Duan Y, Huang R, Su R, Qi W, Thielemans W, He Z. Real-Time Adsorption of Exo- and Endoglucanases on Cellulose: Effect of pH, Temperature, and Inhibitors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13514-13522. [PMID: 30372079 DOI: 10.1021/acs.langmuir.8b02260] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Effective regulation of cellulase adsorption is key to improving the efficiencies of the two major bottlenecks of lignocellulose hydrolysis and cellulase recovery. In this work, we investigated the effect of inhibitors, pH, and temperature on the adsorption of exo- and endoglucanases (Cel7A and Cel7B, respectively) on cellulose using quartz crystal microgravimetry with dissipation. The addition of glucose and cellobiose can both inhibit the hydrolysis activity of Cel7A, whereas only cellobiose can inhibit that of Cel7B. Notably, the adsorption was favored by acidic conditions (pH ≤ 4.8) and low temperature, whereas alkaline conditions (pH 9 and 10) facilitated enzyme desorption, which is useful to guide the process of cellulase recovery. The adsorption and hydrolysis activity of Cel7A and Cel7B were both higher at 45 °C than at 25 °C. These findings pave the way to effective regulation of cellulase adsorption and thus improve lignocellulose conversion and cellulase recovery.
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Affiliation(s)
| | | | | | | | - Rongxin Su
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072 , PR China
| | - Wei Qi
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072 , PR China
| | - Wim Thielemans
- Renewable Materials and Nanotechnology Group, Department of Chemical Engineering , KU Leuven , Campus Kortrijk, Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
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Alves LDF, Meleiro LP, Silva RN, Westmann CA, Guazzaroni ME. Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome. Front Microbiol 2018; 9:2556. [PMID: 30420843 PMCID: PMC6215845 DOI: 10.3389/fmicb.2018.02556] [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: 06/07/2018] [Accepted: 10/08/2018] [Indexed: 11/13/2022] Open
Abstract
Beta-glucosidases are key enzymes involved in lignocellulosic biomass degradation for bioethanol production, which complete the final step during cellulose hydrolysis by converting cellobiose into glucose. Currently, industry requires enzymes with improved catalytic performance or tolerance to process-specific parameters. In this sense, metagenomics has become a powerful tool for accessing and exploring the biochemical biodiversity present in different natural environments. Here, we report the identification of a novel β-glucosidase from metagenomic DNA isolated from soil samples enriched with decaying plant matter from a Secondary Atlantic Forest region. For this, we employed a functional screening approach using an optimized and synthetic broad host-range vector for library production. The novel β-glucosidase – named Lfa2 – displays three GH3-family conserved domains and conserved catalytic amino acids D283 and E487. The purified enzyme was most active in pH 5.5 and at 50°C, and showed hydrolytic activity toward several pNP synthetic substrates containing β-glucose, β-galactose, β-xylose, β-fucose, and α-arabinopyranose, as well as toward cellobiose. Lfa2 showed considerable glucose tolerance, exhibiting an IC50 of 300 mM glucose and 30% of remaining activity in 600 mM glucose. In addition, Lfa2 retained full or slightly enhanced activity in the presence of several metal ions. Further, β-glucosidase activity was increased by 1.7-fold in the presence of 10% (v/v) ethanol, a concentration that can be reached in conventional fermentation processes. Similarly, Lfa2 showed 1.7-fold enhanced activity at high concentrations of 5-hydroxymethyl furfural, one of the most important cellulase inhibitors in pretreated sugarcane bagasse hydrolysates. Moreover, the synergistic effect of Lfa2 on Bacillus subtilis GH5-CBM3 endoglucanase activity was demonstrated by the increased production of glucose (1.6-fold). Together, these results indicate that β-glucosidase Lfa2 is a promissory enzyme candidate for utilization in diverse industrial applications, such as cellulosic biomass degradation or flavor enhancement in winemaking and grape processing.
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Affiliation(s)
- Luana de Fátima Alves
- Department of Biochemistry and Immunology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Luana Parras Meleiro
- Department of Chemistry, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Roberto N Silva
- Department of Biochemistry and Immunology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Cauã Antunes Westmann
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Luo C, Li Y, Liao H, Yang Y. De novo transcriptome assembly of the bamboo snout beetle Cyrtotrachelus buqueti reveals ability to degrade lignocellulose of bamboo feedstock. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:292. [PMID: 30386429 PMCID: PMC6204003 DOI: 10.1186/s13068-018-1291-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/15/2018] [Indexed: 05/27/2023]
Abstract
BACKGROUND The bamboo weevil Cyrtotrachelus buqueti, which is considered a pest species, damages bamboo shoots via its piercing-sucking mode of feeding. C. buqueti is well known for its ability to transform bamboo shoot biomass into nutrients and energy for growth, development and reproduction with high specificity and efficacy of bioconversion. Woody bamboo is a perennial grass that is a potential feedstock for lignocellulosic biomass because of its high growth rate and lignocellulose content. To verify our hypothesis that C. buqueti efficiently degrades bamboo lignocellulose, we assessed the bamboo lignocellulose-degrading ability of this insect through RNA sequencing for identifying a potential route for utilisation of bamboo biomass. RESULTS Analysis of carbohydrate-active enzyme (CAZyme) family genes in the developmental transcriptome of C. buqueti revealed 1082 unigenes, including 55 glycoside hydrolases (GH) families containing 309 GHs, 51 glycosyltransferases (GT) families containing 329 GTs, 8 carbohydrate esterases (CE) families containing 174 CEs, 6 polysaccharide lyases (PL) families containing 11 PLs, 8 auxiliary activities (AA) families containing 131 enzymes with AAs and 17 carbohydrate-binding modules (CBM) families containing 128 CBMs. We used weighted gene co-expression network analysis to analyse developmental RNA sequencing data, and 19 unique modules were identified in the analysis. Of these modules, the expression of MEyellow module genes was unique and the module included numerous CAZyme family genes. CAZyme genes in this module were divided into two groups depending on whether gene expression was higher in the adult/larval stages or in the egg/pupal stages. Enzyme assays revealed that cellulase activity was highest in the midgut whereas lignin-degrading enzyme activity was highest in the hindgut, consistent with findings from intestinal gene expression studies. We also analysed the expression of CAZyme genes in the transcriptome of C. buqueti from two cities and found that several genes were also assigned to CAZyme families. The insect had genes and enzymes associated with lignocellulose degradation, the expression of which differed with developmental stage and intestinal region. CONCLUSION Cyrtotrachelus buqueti exhibits lignocellulose degradation-related enzymes and genes, most notably CAZyme family genes. CAZyme family genes showed differences in expression at different developmental stages, with adults being more effective at cellulose degradation and larvae at lignin degradation, as well as at different regions of the intestine, with the midgut being more cellulolytic than the hindgut. This degradative system could be utilised for the bioconversion of bamboo lignocellulosic biomass.
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Affiliation(s)
- Chaobing Luo
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, College of Life Science, Leshan Normal University, No. 778, Riverside Road, Central District, Leshan, 614000 China
| | - Yuanqiu Li
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, College of Life Science, Leshan Normal University, No. 778, Riverside Road, Central District, Leshan, 614000 China
- College of Food and Biological Engineering, Xihua University, Chengdu, China
| | - Hong Liao
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, College of Life Science, Leshan Normal University, No. 778, Riverside Road, Central District, Leshan, 614000 China
| | - Yaojun Yang
- Bamboo Diseases and Pests Control and Resources Development Key Laboratory of Sichuan Province, College of Life Science, Leshan Normal University, No. 778, Riverside Road, Central District, Leshan, 614000 China
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Christensen SJ, Kari J, Badino SF, Borch K, Westh P. Rate‐limiting step and substrate accessibility of cellobiohydrolase Cel6A from
Trichoderma reesei. FEBS J 2018; 285:4482-4493. [DOI: 10.1111/febs.14668] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 09/11/2018] [Accepted: 09/28/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Stefan J. Christensen
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | - Silke F. Badino
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials Department of Science and Environment Roskilde University Denmark
- Department of Biotechnology and Biomedicine Technical University of Denmark Lyngby Denmark
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35
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Haldar D, Gayen K, Sen D. Enumeration of monosugars’ inhibition characteristics on the kinetics of enzymatic hydrolysis of cellulose. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.06.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Rabinovich ML, Melnik MS, Herner ML, Voznyi YV, Vasilchenko LG. Predominant Nonproductive Substrate Binding by Fungal Cellobiohydrolase I and Implications for Activity Improvement. Biotechnol J 2018; 14:e1700712. [PMID: 29781240 DOI: 10.1002/biot.201700712] [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: 11/21/2017] [Revised: 05/08/2018] [Indexed: 12/20/2022]
Abstract
Enzymatic conversion of the most abundant renewable source of organic compounds, cellulose to fermentable sugars is attractive for production of green fuels and chemicals. The major component of industrial enzyme systems, cellobiohydrolase I from Hypocrea jecorina (Trichoderma reesei) (HjCel7A) processively splits disaccharide units from the reducing ends of tightly packed cellulose chains. HjCel7A consists of a catalytic domain (CD) and a carbohydrate-binding module (CBM) separated by a linker peptide. A tunnel-shaped substrate-binding site in the CD includes nine subsites for β-d-glucose units, seven of which (-7 to -1) precede the catalytic center. Low catalytic activity of Cel7A is the bottleneck and the primary target for improvement. Here it is shown for the first time that, in spite of much lower apparent kcat of HjCel7A at the hydrolysis of β-1,4-glucosidic linkages in the fluorogenic cellotetra- and -pentaose compared to the structurally related endoglucanase I (HjCel7B), the specificity constants (catalytic efficiency) kcat /Km for both enzymes are almost equal in these reactions. The observed activity difference appears from strong nonproductive substrate binding by HjCel7A, particularly significant for MU-β-cellotetraose (MUG4 ). Interaction of substrates with the subsites -6 and -5 proximal to the nonconserved Gln101 residue in HjCel7A decreases Km,ap by >1500 times. HjCel7A can be nonproductively bound onto cellulose surface with Kd ≈2-9 nM via CBM and CD that captures six terminal glucose units of cellulose chain. Decomposition of this nonproductive complex can determine the rate of cellulose conversion. MUG4 is a promising substrate to select active cellobiohydrolase I variants with reduced nonproductive substrate binding.
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Affiliation(s)
- Mikhail L Rabinovich
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Maria S Melnik
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Mikhail L Herner
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Yakov V Voznyi
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Lilia G Vasilchenko
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
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Badino SF, Kari J, Christensen SJ, Borch K, Westh P. Direct kinetic comparison of the two cellobiohydrolases Cel6A and Cel7A from Hypocrea jecorina. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1739-1745. [DOI: 10.1016/j.bbapap.2017.08.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/25/2017] [Accepted: 08/14/2017] [Indexed: 01/17/2023]
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Single-cell Protein and Xylitol Production by a Novel Yeast Strain Candida intermedia FL023 from Lignocellulosic Hydrolysates and Xylose. Appl Biochem Biotechnol 2017; 185:163-178. [PMID: 29098561 PMCID: PMC5937888 DOI: 10.1007/s12010-017-2644-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/19/2017] [Indexed: 11/06/2022]
Abstract
Yeasts are good candidates to utilize the hydrolysates of lignocellulose, the most abundant bioresource, for bioproducts. This study aimed to evaluate the efficiencies of single-cell protein (SCP) and xylitol production by a novel yeast strain, Candida intermedia FL023, from lignocellulosic hydrolysates and xylose. This strain efficiently assimilated hexose, pentose, and cellubiose for cell mass production with the crude protein content of 484.2 g kg−1 dry cell mass. SCP was produced by strain FL023 using corncob hydrolysate and urea as the carbon and nitrogen sources with the dry cell mass productivity 0.86 g L−1 h−1 and the yield of 0.40 g g−1 sugar. SCP was also produced using NaOH-pretreated Miscanthus sinensis straw and corn steep liquor as the carbon and nitrogen sources through simultaneous saccharification and fermentation with the dry cell productivity of 0.23 g L−1 h−1 and yield of 0.17 g g−1 straw. C. intermedia FL023 was tolerant to 0.5 g L−1 furfural, acetic acid, and syringaldehyde in xylitol fermentation and produced 45.7 g L−1 xylitol from xylose with the productivity of 0.38 g L−1 h−1 and the yield of 0.57 g g−1 xylose. This study provides feasible methods for feed and food additive production from the abundant lignocellulosic bioresources.
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Druzhinina IS, Kubicek CP. Genetic engineering of Trichoderma reesei cellulases and their production. Microb Biotechnol 2017; 10:1485-1499. [PMID: 28557371 PMCID: PMC5658622 DOI: 10.1111/1751-7915.12726] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/11/2017] [Accepted: 04/11/2017] [Indexed: 11/26/2022] Open
Abstract
Lignocellulosic biomass, which mainly consists of cellulose, hemicellulose and lignin, is the most abundant renewable source for production of biofuel and biorefinery products. The industrial use of plant biomass involves mechanical milling or chipping, followed by chemical or physicochemical pretreatment steps to make the material more susceptible to enzymatic hydrolysis. Thereby the cost of enzyme production still presents the major bottleneck, mostly because some of the produced enzymes have low catalytic activity under industrial conditions and/or because the rate of hydrolysis of some enzymes in the secreted enzyme mixture is limiting. Almost all of the lignocellulolytic enzyme cocktails needed for the hydrolysis step are produced by fermentation of the ascomycete Trichoderma reesei (Hypocreales). For this reason, the structure and mechanism of the enzymes involved, the regulation of their expression and the pathways of their formation and secretion have been investigated in T. reesei in considerable details. Several of the findings thereby obtained have been used to improve the formation of the T. reesei cellulases and their properties. In this article, we will review the achievements that have already been made and also show promising fields for further progress.
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Affiliation(s)
- Irina S. Druzhinina
- Microbiology GroupResearch Area Biochemical TechnologyInstitute of Chemical, Environmental and Biological EngineeringTU WienViennaAustria
| | - Christian P. Kubicek
- Microbiology GroupResearch Area Biochemical TechnologyInstitute of Chemical, Environmental and Biological EngineeringTU WienViennaAustria
- Present address:
Steinschötelgasse 7Wien1100Austria
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40
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Xiros C, Studer MH. A Multispecies Fungal Biofilm Approach to Enhance the Celluloyltic Efficiency of Membrane Reactors for Consolidated Bioprocessing of Plant Biomass. Front Microbiol 2017; 8:1930. [PMID: 29067006 PMCID: PMC5641325 DOI: 10.3389/fmicb.2017.01930] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 09/21/2017] [Indexed: 01/06/2023] Open
Abstract
The constraints and advantages in cellulolytic enzymes production by fungal biofilms for a consolidated bioconversion process were investigated during this study. The biofilm cultivations were carried out in reactors designed for consolidated bioprocessing Multispecies Biofilm Membrane reactors, (MBM) where an aerobic fungal biofilm produces the lignocellulolytic enzymes while a fermenting microorganism forms the fermentation product at anaerobic conditions. It was shown that although mycelial growth was limited in the MBM reactors compared to submerged cultivations, the secretion of cellulolytic enzymes per cell dry weight was higher. When Trichoderma reesei was used as the sole enzyme producer, cellobiose accumulated in the liquid medium as the result of the deficiency of β-glucosidase in the fungal secretome. To enhance β-glucosidase activity, T. reesei was co-cultivated with A. phoenicis which is a β-glucosidase overproducer. The two fungi formed a multispecies biofilm which produced a balanced cellulolytic cocktail for the saccharification of plant biomass. The mixed biofilm reached a 2.5 fold increase in β-glucosidase production, compared to the single T. reesei biofilm. The enzymatic systems of single and mixed biofilms were evaluated regarding their efficiency on cellulosic substrates degradation. Washed solids from steam pretreated beechwood, as well as microcrystalline cellulose were used as the substrates. The enzymatic system of the multispecies biofilm released four times more glucose than the enzymatic system of T. reesei alone from both substrates and hydrolyzed 78 and 60% of the cellulose content of washed solids from beechwood and microcrystalline cellulose, respectively.
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Affiliation(s)
- Charilaos Xiros
- Laboratory for Bioenergy and Biochemicals, School of Agricultural, Forest and Food Sciences, Bern University of Applied Sciences, Bern, Switzerland
| | - Michael H Studer
- Laboratory for Bioenergy and Biochemicals, School of Agricultural, Forest and Food Sciences, Bern University of Applied Sciences, Bern, Switzerland
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41
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Promising cellulolytic fungi isolates for rice straw degradation. J Microbiol 2017; 55:711-719. [DOI: 10.1007/s12275-017-6282-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/12/2017] [Accepted: 08/07/2017] [Indexed: 10/18/2022]
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42
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Mithra M, Padmaja G. Strategies for enzyme saving during saccharification of pretreated lignocellulo-starch biomass: effect of enzyme dosage and detoxification chemicals. Heliyon 2017; 3:e00384. [PMID: 28831456 PMCID: PMC5553344 DOI: 10.1016/j.heliyon.2017.e00384] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/22/2017] [Accepted: 08/07/2017] [Indexed: 11/25/2022] Open
Abstract
Two strategies leading to enzyme saving during saccharification of pretreated lignocellulo-starch biomass (LCSB) was investigated which included reducing enzyme dosage by varying their levels in enzyme cocktails and enhancing the fermentable sugar yield in enzyme-reduced systems using detoxification chemicals. Time course release of reducing sugars (RS) during 24-120 h was significantly higher when an enzyme cocktail containing full dose of cellulase (16 FPU/g cellulose) along with half dose each of xylanase (1.5 mg protein/g hemicelluloses) and Stargen (12.5 μl/g biomass) was used to saccharify conventional dilute sulphuric acid (DSA) pretreated biomass compared to a parallel system where only one-fourth the dose of the latter two enzymes was used. The reduction in RS content in the 120 h saccharified mash to the extent of 3-4 g/L compared to the system saccharified with full complement of the three enzymes could be overcome considerably by supplementing the system (half dose of two enzymes) with detoxification chemical mix incorporating Tween 20, PEG 4000 and sodium borohydride. Microwave (MW)-assisted DSA pretreated biomass on saccharification with enzyme cocktail having full dose of cellulase and half dose of Stargen along with detoxification chemicals gave significantly higher RS yield than DSA pretreated system saccharified using three enzymes. The study showed that xylanase could be eliminated during saccharification of MW-assisted DSA pretreated biomass without affecting RS yield when detoxification chemicals were also supplemented. The Saccharification Efficiency and Overall Conversion Efficiency were also high for the MW-assisted DSA pretreated biomass. Since whole slurry saccharifcation of pretreated biomass is essential to conserve fermentable sugars in LCSB saccharification, detoxification of soluble inhibitors is equally important as channelling out of insoluble lignin remaining in the residue. As one of the major factors contributing to the cost of ethanol production from LCSB is the cost of enzymes, appropriate modification of enzyme cocktail based on the composition of the pretreated biomass coupled with effective detoxification of the slurry would be a promising approach towards cost reduction.
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Affiliation(s)
| | - G. Padmaja
- Division of Crop Utilization, ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India
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43
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Synergies in coupled hydrolysis and fermentation of cellulose using a Trichoderma reesei enzyme preparation and a recombinant Saccharomyces cerevisiae strain. World J Microbiol Biotechnol 2017; 33:140. [DOI: 10.1007/s11274-017-2308-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/01/2017] [Indexed: 11/27/2022]
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44
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An YX, Zong MH, Hu SQ, Li N. Effect of residual lignins present in cholinium ionic liquid-pretreated rice straw on the enzymatic hydrolysis of cellulose. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2016.12.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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45
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Badino SF, Christensen SJ, Kari J, Windahl MS, Hvidt S, Borch K, Westh P. Exo-exo synergy between Cel6A and Cel7A fromHypocrea jecorina: Role of carbohydrate binding module and the endo-lytic character of the enzymes. Biotechnol Bioeng 2017; 114:1639-1647. [DOI: 10.1002/bit.26276] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Silke F. Badino
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Stefan J. Christensen
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Michael S. Windahl
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
- Novozymes A/S; Bagsvaerd Denmark
| | - Søren Hvidt
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
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46
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Hu BB, Zhu MJ. Enhanced hydrogen production and biological saccharification from spent mushroom compost by Clostridium thermocellum 27405 supplemented with recombinant β-glucosidases. INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2017; 42:7866-7874. [DOI: 10.1016/j.ijhydene.2017.01.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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47
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Production of ethanol from steam exploded triticale straw in a simultaneous saccharification and fermentation process. Process Biochem 2017. [DOI: 10.1016/j.procbio.2016.11.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Bulakhov AG, Volkov PV, Rozhkova AM, Gusakov AV, Nemashkalov VA, Satrutdinov AD, Sinitsyn AP. Using an Inducible Promoter of a Gene Encoding Penicillium verruculosum Glucoamylase for Production of Enzyme Preparations with Enhanced Cellulase Performance. PLoS One 2017; 12:e0170404. [PMID: 28107425 PMCID: PMC5249098 DOI: 10.1371/journal.pone.0170404] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/04/2017] [Indexed: 02/05/2023] Open
Abstract
Background Penicillium verruculosum is an efficient producer of highly active cellulase multienzyme system. One of the approaches for enhancing cellulase performance in hydrolysis of cellulosic substrates is to enrich the reaction system with β -glucosidase and/or accessory enzymes, such as lytic polysaccharide monooxygenases (LPMO) displaying a synergism with cellulases. Results Genes bglI, encoding β-glucosidase from Aspergillus niger (AnBGL), and eglIV, encoding LPMO (formerly endoglucanase IV) from Trichoderma reesei (TrLPMO), were cloned and expressed by P. verruculosum B1-537 strain under the control of the inducible gla1 gene promoter. Content of the heterologous AnBGL in the secreted multienzyme cocktails (hBGL1, hBGL2 and hBGL3) varied from 4 to 10% of the total protein, while the content of TrLPMO in the hLPMO sample was ~3%. The glucose yields in 48-h hydrolysis of Avicel and milled aspen wood by the hBGL1, hBGL2 and hBGL3 preparations increased by up to 99 and 80%, respectively, relative to control enzyme preparations without the heterologous AnBGL (at protein loading 5 mg/g substrate for all enzyme samples). The heterologous TrLPMO in the hLPMO preparation boosted the conversion of the lignocellulosic substrate by 10–43%; however, in hydrolysis of Avicel the hLPMO sample was less effective than the control preparations. The highest product yield in hydrolysis of aspen wood was obtained when the hBGL2 and hLPMO preparations were used at the ratio 1:1. Conclusions The enzyme preparations produced by recombinant P. verruculosum strains, expressing the heterologous AnBGL or TrLPMO under the control of the gla1 gene promoter in a starch-containing medium, proved to be more effective in hydrolysis of a lignocellulosic substrate than control enzyme preparations without the heterologous enzymes. The enzyme composition containing both AnBGL and TrLPMO demonstrated the highest performance in lignocellulose hydrolysis, providing a background for developing a fungal strain capable to express both heterologous enzymes simultaneously.
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Affiliation(s)
- Alexander G. Bulakhov
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
| | - Pavel V. Volkov
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
| | - Aleksandra M. Rozhkova
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
- Department of Chemistry, M.V.Lomonosov Moscow State University, Moscow, Russia
- * E-mail:
| | - Alexander V. Gusakov
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
- Department of Chemistry, M.V.Lomonosov Moscow State University, Moscow, Russia
| | - Vitaly A. Nemashkalov
- G.K.Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow region, Russia
| | - Aidar D. Satrutdinov
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
| | - Arkady P. Sinitsyn
- Federal Research Centre «Fundamentals of Biotechnology», Russian Academy of Sciences, Moscow, Russia
- Department of Chemistry, M.V.Lomonosov Moscow State University, Moscow, Russia
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Willis JD, Grant JN, Mazarei M, Kline LM, Rempe CS, Collins AG, Turner GB, Decker SR, Sykes RW, Davis MF, Labbe N, Jurat-Fuentes JL, Stewart CN. The TcEG1 beetle ( Tribolium castaneum) cellulase produced in transgenic switchgrass is active at alkaline pH and auto-hydrolyzes biomass for increased cellobiose release. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:230. [PMID: 29213306 PMCID: PMC5707894 DOI: 10.1186/s13068-017-0918-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/28/2017] [Indexed: 05/17/2023]
Abstract
BACKGROUND Genetically engineered biofuel crops, such as switchgrass (Panicum virgatum L.), that produce their own cell wall-digesting cellulase enzymes would reduce costs of cellulosic biofuel production. To date, non-bioenergy plant models have been used in nearly all studies assessing the synthesis and activity of plant-produced fungal and bacterial cellulases. One potential source for cellulolytic enzyme genes is herbivorous insects adapted to digest plant cell walls. Here we examine the potential of transgenic switchgrass-produced TcEG1 cellulase from Tribolium castaneum (red flour beetle). This enzyme, when overproduced in Escherichia coli and Saccharomyces cerevisiae, efficiently digests cellulose at optima of 50 °C and pH 12.0. RESULTS TcEG1 that was produced in green transgenic switchgrass tissue had a range of endoglucanase activity of 0.16-0.05 units (µM glucose release/min/mg) at 50 °C and pH 12.0. TcEG1 activity from air-dried leaves was unchanged from that from green tissue, but when tissue was dried in a desiccant oven (46 °C), specific enzyme activity decreased by 60%. When transgenic biomass was "dropped-in" into an alkaline buffer (pH 12.0) and allowed to incubate at 50 °C, cellobiose release was increased up to 77% over non-transgenic biomass. Saccharification was increased in one transgenic event by 28%, which had a concurrent decrease in lignin content of 9%. Histological analysis revealed an increase in cell wall thickness with no change to cell area or perimeter. Transgenic plants produced more, albeit narrower, tillers with equivalent dry biomass as the control. CONCLUSIONS This work describes the first study in which an insect cellulase has been produced in transgenic plants; in this case, the dedicated bioenergy crop switchgrass. Switchgrass overexpressing the TcEG1 gene appeared to be morphologically similar to its non-transgenic control and produced equivalent dry biomass. Therefore, we propose TcEG1 transgenics could be bred with other transgenic germplasm (e.g., low-lignin lines) to yield new switchgrass with synergistically reduced recalcitrance to biofuel production. In addition, transgenes for other cell wall degrading enzymes may be stacked with TcEG1 in switchgrass to yield complementary cell wall digestion features and complete auto-hydrolysis.
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Affiliation(s)
- Jonathan D. Willis
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Joshua N. Grant
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Mitra Mazarei
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lindsey M. Kline
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
| | - Caroline S. Rempe
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996 USA
| | - A. Grace Collins
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Geoffrey B. Turner
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Stephen R. Decker
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Robert W. Sykes
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Mark F. Davis
- The National Research Energy Laboratory, Golden, CO 80401 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Nicole Labbe
- Center for Renewable Carbon, University of Tennessee, Knoxville, TN 37996 USA
| | - Juan L. Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996 USA
| | - C. Neal Stewart
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
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50
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Hydrolysis of model cellulose films by cellulosomes: Extension of quartz crystal microbalance technique to multienzymatic complexes. J Biotechnol 2016; 241:42-49. [PMID: 27838255 DOI: 10.1016/j.jbiotec.2016.11.008] [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: 06/02/2016] [Revised: 10/07/2016] [Accepted: 11/08/2016] [Indexed: 11/23/2022]
Abstract
Bacterial cellulosomes contain highly efficient complexed cellulases and have been studied extensively for the production of lignocellulosic biofuels and bioproducts. A surface measurement technique, quartz crystal microbalance with dissipation (QCM-D), was extended for the investigation of real-time binding and hydrolysis of model cellulose surfaces from free fungal cellulases to the cellulosomes of Clostridium thermocellum (Ruminiclostridium thermocellum). In differentiating the activities of cell-free and cell-bound cellulosomes, greater than 68% of the cellulosomes in the crude cell broth were found to exist unattached to the cell across multiple growth stages. The initial hydrolysis rate of crude cell broth measured by QCM was greater than that of cell-free cellulosomes, but the corresponding frequency drop (a direct measure of the mass of enzyme adsorbed to the film) of crude cell broth was less than that of the cell-free cellulosomes, consistent with the underestimation of the cell mass adsorbed using QCM. Inhibition of hydrolysis by cellobiose (0-10g/L), which is similar for crude cell broth and cell-free cellulosomes, demonstrates the sensitivity of the QCM to environmental perturbations of multienzymatic complexes. QCM measurements using multienzymatic complexes may be used to screen and optimize hydrolysis conditions and to develop mechanistic, surface-based models of enzymatic cellulose deconstruction.
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