1
|
Yu Q, Xu J, Li M, Xi Y, Sun H, Xie Y, Cheng Q, Li P, Chen C, Yang F, Zheng Y. Synergistic effects of ferulic acid esterase-producing lactic acid bacteria, cellulase and xylanase on the fermentation characteristics, fibre and nitrogen components and microbial community structure of Broussonetia papyrifera during ensiling. J Sci Food Agric 2024; 104:3543-3558. [PMID: 38146051 DOI: 10.1002/jsfa.13239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/21/2023] [Accepted: 12/26/2023] [Indexed: 12/27/2023]
Abstract
BACKGROUND The high fibre content of whole plants of Broussonetia papyrifera limits its efficient utilization. Ferulic acid esterase (FAE), in combination with xylanase, can effectively cleave the lignin-carbohydrate complex, promoting the function of cellulase. However, little is known about the impact of these additives on silage. To effectively utilize natural woody plant resources, FAE-producing Lactiplantibacillus plantarum RO395, xylanase (XY) and cellulase (CE) were used to investigate the dynamic fermentation characteristics, fibre and nitrogen components and microbial community structure during B. papyrifera ensiling. RESULTS Broussonetia papyrifera was either not treated (CK) or treated with FAE-producing lactic acid bacteria (LP), CE, XY, LP + CE, LP + XY or LP + CE + XY for 3, 7, 15, 30 or 60 days, respectively. In comparison with those in the CK treatment, the L. plantarum and enzyme treatments (LP + CE, LP + XY and LP + XY + CE), especially the LP + XY + CE treatment, significantly increased the lactic acid concentration and decreased the pH and the contents of acid detergent insoluble protein and NH3 -N (P < 0.05). Enzyme addition improved the degradation efficiency of lignocellulose, and a synergistic effect was observed after enzyme treatment in combination with LP; in addition, the lowest acid detergent fibre, neutral detergent fibre, hemicellulose and cellulose contents were detected after the LP + CE + XY treatment (P < 0.05). Moreover, CE, XY and LP additions significantly improved the microbial community structure, increased the relative abundance of Lactiplantibacillus and Firmicutes, and effectively inhibited undesirable bacterial (Enterobacter) growth during ensiling. CONCLUSION FAE-producing L. plantarum and the two tested enzymes exhibited synergistic effects on improving the quality of silage, which indicates that this combination can serve as an efficient method for improved B. papyrifera silage utilization. © 2023 Society of Chemical Industry.
Collapse
Affiliation(s)
- Qiang Yu
- College of Animal Science, Guizhou University, Guizhou, China
| | - Jinyi Xu
- College of Animal Science, Guizhou University, Guizhou, China
| | - Mengxin Li
- College of Animal Science, Guizhou University, Guizhou, China
| | - Yulong Xi
- College of Animal Science, Guizhou University, Guizhou, China
| | - Hong Sun
- College of Animal Science, Guizhou University, Guizhou, China
| | - Yixiao Xie
- College of Animal Science, Guizhou University, Guizhou, China
| | - Qiming Cheng
- College of Animal Science, Guizhou University, Guizhou, China
| | - Ping Li
- College of Animal Science, Guizhou University, Guizhou, China
| | - Chao Chen
- College of Animal Science, Guizhou University, Guizhou, China
| | - Fuyu Yang
- College of Animal Science, Guizhou University, Guizhou, China
| | - Yulong Zheng
- College of Animal Science, Guizhou University, Guizhou, China
| |
Collapse
|
2
|
Omori KK, Drucker CT, Okumura TLS, Carl NB, Dinn BT, Ly D, Sacapano KN, Tajii A, Owens CP. The structure of a Lactobacillus helveticus chlorogenic acid esterase and the dynamics of its insertion domain provide insights into substrate binding. FEBS Lett 2023; 597:2946-2962. [PMID: 37698360 DOI: 10.1002/1873-3468.14731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/31/2023] [Accepted: 08/20/2023] [Indexed: 09/13/2023]
Abstract
Chlorogenic acid esterases (ChlEs) are a useful class of enzymes that hydrolyze chlorogenic acid (CGA) into caffeic and quinic acids. ChlEs can break down CGA in foods to improve their sensory properties and release caffeic acid in the digestive system to improve the absorption of bioactive compounds. This work presents the structure, molecular dynamics, and biochemical characterization of a ChlE from Lactobacillus helveticus (Lh). Molecular dynamics simulations suggest that substrate access to the active site of LhChlE is modulated by two hairpin loops above the active site. Docking simulations and mutational analysis suggest that two residues within the loops, Gln145 and Lys164 , are important for CGA binding. Lys164 provides a slight substrate preference for CGA, whereas Gln145 is required for efficient turnover. This work is the first to examine the dynamics of a bacterial ChlE and provides insights on substrate binding preference and turnover in this type of enzyme.
Collapse
Affiliation(s)
- Kellie K Omori
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Charles T Drucker
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Tracie L S Okumura
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Nathaniel B Carl
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Brianna T Dinn
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Destiny Ly
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Kylie N Sacapano
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Allie Tajii
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Cedric P Owens
- Department of Chemistry and Biochemistry, Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| |
Collapse
|
3
|
Siebert M, Krings U, Günther T, Fragalas A, Berger RG. Enzymatic hydrolysis of kaempferol 3-O-(2‴-O-sinapoyl-β-sophoroside), the key bitter compound of rapeseed (Brassica napus L.) protein isolate. J Sci Food Agric 2022; 102:2179-2182. [PMID: 34580868 DOI: 10.1002/jsfa.11547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 08/30/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The use of rapeseed protein for human nutrition is primarily limited by its strong bitterness, which is why the key bitter compound, kaempferol 3-O-(2‴-O-sinapoyl-β-sophoroside), is enzymatically degraded. RESULTS Mass spectrometry analyses of an extract from an untreated rapeseed protein isolate gave three signals for m/z 815 [M-H]. The predominant compound among the three compounds was confirmed as kaempferol-3-O-(2‴-O-sinapoyl-β-sophoroside). Enzymatic hydrolysis of this key bitter compound was achieved using a sinapyl ester cleaving side activity of a ferulic acid esterase (FAE) from the basidiomycete Schizophyllum commune (ScoFAE). Recombinant ferulic acid esterases from Streptomyces werraensis (SwFAE) and from Pleurotus eryngii (PeFAE) possessed better cleavage activity towards methyl sinapate but did not hydrolyze the sinapyl ester linkage of the bitter kaempferol sophoroside. CONCLUSION Kaempferol-3-O-(2‴-O-sinapoyl-β-sophoroside) was successfully degraded by enzymatic treatment with ScoFAE, which may provide a means to move the status of rapeseed protein from feed additive to food ingredient. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Collapse
Affiliation(s)
- Mareike Siebert
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University, Hannover, Germany
| | - Ulrich Krings
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University, Hannover, Germany
| | - Thorben Günther
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University, Hannover, Germany
| | | | - Ralf G Berger
- Institute of Food Chemistry, Gottfried Wilhelm Leibniz University, Hannover, Germany
| |
Collapse
|
4
|
Wei X, Wang YL, Wen BT, Liu SJ, Wang L, Sun L, Gu TY, Li Z, Bao Y, Fan SL, Zhou H, Wang F, Xin F. The α-Helical Cap Domain of a Novel Esterase from Gut Alistipes shahii Shaping the Substrate-Binding Pocket. J Agric Food Chem 2021; 69:6064-6072. [PMID: 33979121 DOI: 10.1021/acs.jafc.1c00940] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The human gut microbiota regulates nutritional metabolism, especially by encoding specific ferulic acid esterases (FAEs) to release functional ferulic acid (FA) from dietary fiber. In our previous study, we observed seven upregulated FAE genes during in vitro fecal slurry fermentation using wheat bran. Here, a 29 kDa FAE (AsFAE) from Alistipes shahii of Bacteroides was characterized and identified as the type-A FAE. The X-ray structure of AsFAE has been determined, revealing a unique α-helical domain comprising five α-helices, which was first characterized in FAEs from the gut microbiota. Further molecular docking analysis and biochemical studies revealed that Tyr100, Thr122, Tyr219, and Ile220 are essential for substrate binding and catalytic efficiency. Additionally, Glu129 and Lys130 in the cap domain shaped the substrate-binding pocket and affected the substrate preference. This is the first report on A. shahii FAE, providing a theoretical basis for the dietary metabolism in the human gut.
Collapse
Affiliation(s)
- Xue Wei
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yu-Lu Wang
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bo-Ting Wen
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shu-Jun Liu
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Luyao Wang
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Lichao Sun
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tian-Yi Gu
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zhen Li
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yuming Bao
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Shi-Long Fan
- Key Laboratory of Ministry of Education for Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Huan Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Fengzhong Wang
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fengjiao Xin
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| |
Collapse
|
5
|
Xie Y, Guo J, Li W, Wu Z, Yu Z. Effects of Ferulic Acid Esterase-Producing Lactic Acid Bacteria and Storage Temperature on the Fermentation Quality, In Vitro Digestibility and Phenolic Acid Extraction Yields of Sorghum ( Sorghum bicolor L.) Silage. Microorganisms 2021; 9:114. [PMID: 33418910 DOI: 10.3390/microorganisms9010114] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/29/2020] [Accepted: 01/03/2021] [Indexed: 11/22/2022] Open
Abstract
Two lactic acid bacteria (LAB) strains with different ferulic acid esterase (FAE) activities were isolated: Lactobacillus farciminis (LF18) and Lactobacillus plantarum (LP23). The effects of these strains on the fermentation quality, in vitro digestibility and phenolic acid extraction yields of sorghum (Sorghum bicolor L.) silage were studied at 20, 30 and 40 °C. Sorghum was ensiled with no additive (control), LF18 or LP23 for 45 days. At 40 °C, the lactic acid content decreased, whereas the ammonia nitrogen (NH3-N) content significantly increased (p < 0.05). At all three temperatures, the inoculants significantly improved the lactic acid contents and reduced the NH3-N contents (p < 0.05). Neither LP23 nor LF18 significantly improved the digestibility of sorghum silages (p > 0.05). The LP23 group exhibited higher phenolic acid extraction yields at 30 °C (p < 0.05), and the corresponding yields of the LF18 and control groups were improved at 40 °C (p < 0.05). FAE-producing LABs might partially ameliorate the negative effects of high temperature and improve the fermentation quality of sorghum silage. The screened FAE-producing LABs could be candidate strains for preserving sorghum silage at high temperature, and some further insights into the relationship between FAE-producing LABs and ensiling temperatures were obtained.
Collapse
|
6
|
Lau T, Harbourne N, Oruña-Concha MJ. Optimization of enzyme-assisted extraction of ferulic acid from sweet corn cob by response surface methodology. J Sci Food Agric 2020; 100:1479-1485. [PMID: 31756272 DOI: 10.1002/jsfa.10155] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 11/07/2019] [Accepted: 11/20/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Sweet corn cob (SCC), an agricultural by-product of the corn-processing industry, contains more than 80% insoluble bound ferulic acid (FA). Extraction of these bound phenolics can be achieved through chemical or enzymatic hydrolysis; however, the shift towards greener chemistry has raised awareness about the use of enzymatic hydrolysis. In the present study, the ability of ferulic acid esterase (FAE) and xylanase (XY) to catalyze the hydrolysis of FA from SCC was investigated. Response surface methodology (RSM), based on a five-level, four-factor central composite rotatable design (CCRD), was used to establish the optimum conditions for enzymatic hydrolysis of FA from SCC. Sweet corn cob was treated with a combination of FAE and XY at various concentrations (FAE: 0.00 to 0.04 U/g; XY: 0.00 to 18 093.5 U/g), temperatures (45 to 65 °C), and pH levels (pH 4.5 to 6.5). RESULTS The optimum extraction conditions predicted by the model were: FAE concentration of 0.02 U/g, XY concentration of 3475.3 U/g, extraction pH of 4.5, and an extraction temperature of 45 °C. CONCLUSION Under these conditions, the experimental yield of FA was 1.69 ± 0.02 g kg-1 of SCC, which is in agreement with the value predicted by the model. © 2019 Society of Chemical Industry.
Collapse
Affiliation(s)
- Tiffany Lau
- Department of Food and Nutritional Sciences, University of Reading, Reading, UK
| | - Niamh Harbourne
- UCD Institute of Food and Health, School of Agricultural and Food Science, University College Dublin, Dublin, Ireland
| | | |
Collapse
|
7
|
Holck J, Fredslund F, Møller MS, Brask J, Krogh KBRM, Lange L, Welner DH, Svensson B, Meyer AS, Wilkens C. A carbohydrate-binding family 48 module enables feruloyl esterase action on polymeric arabinoxylan. J Biol Chem 2019; 294:17339-17353. [PMID: 31558605 DOI: 10.1074/jbc.ra119.009523] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/17/2019] [Indexed: 12/25/2022] Open
Abstract
Feruloyl esterases (EC 3.1.1.73), belonging to carbohydrate esterase family 1 (CE1), hydrolyze ester bonds between ferulic acid (FA) and arabinose moieties in arabinoxylans. Recently, some CE1 enzymes identified in metagenomics studies have been predicted to contain a family 48 carbohydrate-binding module (CBM48), a CBM family associated with starch binding. Two of these CE1s, wastewater treatment sludge (wts) Fae1A and wtsFae1B isolated from wastewater treatment surplus sludge, have a cognate CBM48 domain and are feruloyl esterases, and wtsFae1A binds arabinoxylan. Here, we show that wtsFae1B also binds to arabinoxylan and that neither binds starch. Surface plasmon resonance analysis revealed that wtsFae1B's Kd for xylohexaose is 14.8 μm and that it does not bind to starch mimics, β-cyclodextrin, or maltohexaose. Interestingly, in the absence of CBM48 domains, the CE1 regions from wtsFae1A and wtsFae1B did not bind arabinoxylan and were also unable to catalyze FA release from arabinoxylan. Pretreatment with a β-d-1,4-xylanase did enable CE1 domain-mediated FA release from arabinoxylan in the absence of CBM48, indicating that CBM48 is essential for the CE1 activity on the polysaccharide. Crystal structures of wtsFae1A (at 1.63 Å resolution) and wtsFae1B (1.98 Å) revealed that both are folded proteins comprising structurally-conserved hydrogen bonds that lock the CBM48 position relative to that of the CE1 domain. wtsFae1A docking indicated that both enzymes accommodate the arabinoxylan backbone in a cleft at the CE1-CBM48 domain interface. Binding at this cleft appears to enable CE1 activities on polymeric arabinoxylan, illustrating an unexpected and crucial role of CBM48 domains for accommodating arabinoxylan.
Collapse
Affiliation(s)
- Jesper Holck
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kongens Lyngby, Denmark
| | - Folmer Fredslund
- Enzyme Engineering and Structural Biology, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, DK-2800 Kongens Lyngby, Denmark
| | - Marie S Møller
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kongens Lyngby, Denmark
| | - Jesper Brask
- Novozymes A/S, Biologiens Vej 2, DK-2800 Kongens Lyngby, Denmark
| | | | - Lene Lange
- LLa-Bioeconomy, Research and Advisory, Karensgade 5, DK-2500 Valby, Denmark
| | - Ditte H Welner
- Enzyme Engineering and Structural Biology, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, DK-2800 Kongens Lyngby, Denmark
| | - Birte Svensson
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kongens Lyngby, Denmark
| | - Anne S Meyer
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kongens Lyngby, Denmark
| | - Casper Wilkens
- Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800 Kongens Lyngby, Denmark
| |
Collapse
|
8
|
Chakraborty D, Kaur B, Obulisamy K, Selvam A, Wong JWC. Agrowaste to vanillin conversion by a natural Pediococcus acidilactici strain BD16. Environ Technol 2017; 38:1823-1834. [PMID: 27734757 DOI: 10.1080/09593330.2016.1237556] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 09/11/2016] [Indexed: 06/06/2023]
Abstract
Owing to its flavoring, antimicrobial, antioxidant and anticarcinogenic nature, vanillin is widely used in foods, beverages, perfumes and pharmaceutical products. Ferulic acid (FA) is an important precursor of vanillin which is abundant in cereals like maize, rice and wheat and sugar beet. A major drawback of microbial vanillin production from FA is the degradation and biotransformation of toxic vanillin to other phenolic derivatives. The present study is undertaken to explore microbial vanillin production from FA precursor rice bran by employing vanillin-resistant Pediococcus acidilactici BD16, a natural lactic acid bacteria isolate. Extracellular, intracellular and cellular vanillin dehydrogenase activity was found least, which was minimized vanillin degradation, and the strain resists more than 5 g L-1 vanillin in the medium. A metabolomics approach was followed for the detection of FA, vanillin and other metabolites generated during fermentation of rice bran medium. A metabolic pathway was also predicted for vanillin biosynthesis. Approximately 1.06 g L-1 of crude vanillin was recovered from rice-bran-containing medium and this further offers scope for the industrial utilization of the organism and its genetic manipulation to enhance production of biovanillin.
Collapse
Affiliation(s)
- Debkumar Chakraborty
- a Sino-Forest Applied Research Centre for Pearl River Delta Environment , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
- b Department of Biology , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
| | - Baljinder Kaur
- c Department of Biotechnology , Punjabi University , Patiala , India
| | - Karthikeyan Obulisamy
- a Sino-Forest Applied Research Centre for Pearl River Delta Environment , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
- b Department of Biology , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
| | - Ammaiyappan Selvam
- a Sino-Forest Applied Research Centre for Pearl River Delta Environment , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
- b Department of Biology , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
| | - Jonathan W C Wong
- a Sino-Forest Applied Research Centre for Pearl River Delta Environment , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
- b Department of Biology , Hong Kong Baptist University , Kowloon Tong , Hong Kong SAR , People's Republic of China
| |
Collapse
|
9
|
Gruninger RJ, Cote C, McAllister TA, Abbott DW. Contributions of a unique β-clamp to substrate recognition illuminates the molecular basis of exolysis in ferulic acid esterases. Biochem J 2016; 473:839-49. [PMID: 27026397 DOI: 10.1042/BJ20151153] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/18/2016] [Indexed: 11/17/2022]
Abstract
Lignocellulosic biomass is a promising renewable resource; however, deconstruction of this material is still the rate-limiting step. Major obstacles in the biocatalytic turnover of lignocellulose are ester-linked decorations that prevent access to primary structural polysaccharides. Enzymes targeting these esters represent promising biotools for increasing bioconversion efficiency. Ruminant livestock are unique in their ability to degrade lignocellulose through the action of their gut microbiome. The anaerobic fungi (phylum Neocallimastigomycota) are key members of this ecosystem that express a large repertoire of carbohydrate-active enzymes (CAZymes) with little sequence identity with characterized CAZymes [Lombard, Golaconda, Drula, Coutinho and Henrissat (2014) Nucleic Acids Res. 42: , D490-D495]. We have identified a carbohydrate esterase family 1 (CE1) ferulic acid esterase (FAE) belonging to Anaeromyces mucronatus(AmCE1/Fae1a), and determined its X-ray structure in both the presence [1.55 Å (1 Å=0.1 nm)] and absence (1.60 Å) of ferulic acid. AmCE1 adopts an α/β-hydrolase fold that is structurally conserved with bacterial FAEs, and possesses a unique loop, termed the β-clamp, that encloses the ligand. Isothermal titration calorimetry reveals that substrate binding is driven by enthalpic contributions, which overcomes a large entropic penalty. A comparative analysis of AmCE1 with related enzymes has uncovered the apparent structural basis for differential FAE activities targeting cross-linking ferulic acid conjugates compared with terminal decorations. Based on comparisons to structurally characterized FAEs, we propose that the β-clamp may define the structural basis of exolytic activities in FAEs. This provides a structure-based tool for predicting exolysis and endolysis in CE1. These insights hold promise for rationally identifying enzymes tailored for bioconversion of biomass with variations in cell wall composition.
Collapse
|
10
|
Badhan A, Jin L, Wang Y, Han S, Kowalczys K, Brown DCW, Ayala CJ, Latoszek-Green M, Miki B, Tsang A, McAllister T. Expression of a fungal ferulic acid esterase in alfalfa modifies cell wall digestibility. Biotechnol Biofuels 2014; 7:39. [PMID: 24650274 PMCID: PMC3999942 DOI: 10.1186/1754-6834-7-39] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Accepted: 02/21/2014] [Indexed: 05/17/2023]
Abstract
BACKGROUND Alfalfa (Medicago sativa) is an important forage crop in North America owing to its high biomass production, perennial nature and ability to fix nitrogen. Feruloyl esterase (EC 3.1.1.73) hydrolyzes ester linkages in plant cell walls and has the potential to further improve alfalfa as biomass for biofuel production. RESULTS In this study, faeB [GenBank:AJ309807] was synthesized at GenScript and sub-cloned into a novel pEACH vector containing different signaling peptides to target type B ferulic acid esterase (FAEB) proteins to the apoplast, chloroplast, endoplasmic reticulum and vacuole. Four constructs harboring faeB were transiently expressed in Nicotiana leaves, with FAEB accumulating at high levels in all target sites, except chloroplast. Stable transformed lines of alfalfa were subsequently obtained using Agrobacterium tumefaciens (LBA4404). Out of 136 transgenic plants regenerated, 18 independent lines exhibited FAEB activity. Subsequent in vitro digestibility and Fourier transformed infrared spectroscopy (FTIR) analysis of FAEB-expressing lines showed that they possessed modified cell wall morphology and composition with a reduction in ester linkages and elevated lignin content. Consequently, they were more recalcitrant to digestion by mixed ruminal microorganisms. Interestingly, delignification by alkaline peroxide treatment followed by exposure to a commercial cellulase mixture resulted in higher glucose release from transgenic lines as compared to the control line. CONCLUSION Modifying cell wall crosslinking has the potential to lower recalcitrance of holocellulose, but also exhibited unintended consequences on alfalfa cell wall digestibility due to elevated lignin content. The combination of efficient delignification treatment (alkaline peroxide) and transgenic esterase activity complement each other towards efficient and effective digestion of transgenic lines.
Collapse
Affiliation(s)
- Ajay Badhan
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada
| | - Long Jin
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada
| | - Yuxi Wang
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada
| | - Shuyou Han
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
| | - Katarzyna Kowalczys
- Canadian Centre for Agri-Food Research in Health and Medicine, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Daniel CW Brown
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
- Canadian Centre for Agri-Food Research in Health and Medicine, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Carlos Juarez Ayala
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
| | - Marysia Latoszek-Green
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
| | - Brian Miki
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
| | - Adrian Tsang
- Biology Department, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Tim McAllister
- Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403 1st Avenue South, Lethbridge, AB T1J 4B1, Canada
| |
Collapse
|
11
|
Abstract
The combustion of fossil-derived fuels has a significant impact on atmospheric carbon dioxide (CO(2)) levels and correspondingly is an important contributor to anthropogenic global climate change. Plants have evolved photosynthetic mechanisms in which solar energy is used to fix CO(2) into carbohydrates. Thus, combustion of biofuels, derived from plant biomass, can be considered a potentially carbon neutral process. One of the major limitations for efficient conversion of plant biomass to biofuels is the recalcitrant nature of the plant cell wall, which is composed mostly of lignocellulosic materials (lignin, cellulose, and hemicellulose). The heteropolymer xylan represents the most abundant hemicellulosic polysaccharide and is composed primarily of xylose, arabinose, and glucuronic acid. Microbes have evolved a plethora of enzymatic strategies for hydrolyzing xylan into its constituent sugars for subsequent fermentation to biofuels. Therefore, microorganisms are considered an important source of biocatalysts in the emerging biofuel industry. To produce an optimized enzymatic cocktail for xylan deconstruction, it will be valuable to gain insight at the molecular level of the chemical linkages and the mechanisms by which these enzymes recognize their substrates and catalyze their reactions. Recent advances in genomics, proteomics, and structural biology have revolutionized our understanding of the microbial xylanolytic enzymes. This review focuses on current understanding of the molecular basis for substrate specificity and catalysis by enzymes involved in xylan deconstruction.
Collapse
Affiliation(s)
- Dylan Dodd
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | | |
Collapse
|