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Lian D, Zhuang S, Shui C, Zheng S, Ma Y, Sun Z, Porras-Domínguez JR, Öner ET, Liang M, Van den Ende W. Characterization of inulolytic enzymes from the Jerusalem artichoke-derived Glutamicibacter mishrai NJAU-1. Appl Microbiol Biotechnol 2022; 106:5525-5538. [PMID: 35896838 DOI: 10.1007/s00253-022-12088-6] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/17/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
The rhizosphere context of inulin-accumulating plants, such as Jerusalem artichoke (Helianthus tuberosus), is an ideal starting basis for the discovery of inulolytic enzymes with potential for bio fructose production. We isolated a Glutamicibacter mishrai NJAU-1 strain from this context, showing exo-inulinase activity, releasing fructose from fructans. The growth conditions (pH 9.0; 15 °C) were adjusted, and the production of inulinase by Glutamicibacter mishrai NJAU-1 increased by 90% (0.32 U/mL). Intriguingly, both levan and inulin, but not fructose and sucrose, induced the production of exo-inulinase activity. Two exo-inulinase genes (inu1 and inu2) were cloned and heterologously expressed in Pichia pastoris. While INU2 preferentially hydrolyzed longer inulins, the smallest fructan 1-kestose appeared as the preferred substrate for INU1, also efficiently degrading nystose and sucrose. Active site docking studies with GFn- and Fn-type small inulins (G is glucose, F is fructose, and n is the number of β (2-1) bound fructose moieties) revealed subtle substrate differences between INU1 and INU2. A possible explanation about substrate specificity and INU's protein structure is then suggested. KEY POINTS: • A Glutamicibacter mishrai strain harbored exo-inulinase activity. • Fructans induced the inulolytic activity in G. mishrai while the inulolytic activity was optimized at pH 9.0 and 15 °C. • Two exo-inulinases with differential substrate specificity were characterized.
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Affiliation(s)
- Dan Lian
- Jiangsu Key Lab of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Shuo Zhuang
- Jiangsu Key Lab of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Chen Shui
- Jiangsu Key Lab of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Shicheng Zheng
- Jiangsu Key Lab of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yanhong Ma
- Institute of Agro-Product Processing, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China
| | - Zongjiu Sun
- College of Grassland and Environmental Sciences, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang, China
| | - Jaime R Porras-Domínguez
- Laboratory of Molecular Plant Biology and KU Leuven Plant Institute, KU Leuven, Kasteelpark Arenberg 31, 3001, Louvain, Belgium
| | - Ebru Toksoy Öner
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, 34722, Turkey
| | - Mingxiang Liang
- Jiangsu Key Lab of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
| | - Wim Van den Ende
- Laboratory of Molecular Plant Biology and KU Leuven Plant Institute, KU Leuven, Kasteelpark Arenberg 31, 3001, Louvain, Belgium
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Huang Y, Li L, Chi Y, Sha Y, Wang R, Xu Z, Xu X, Li S, Gao Z, Xu H. Fusion and secretory expression of an exo-inulinase and a d-allulose 3-epimerase to produce d-allulose syrup from inulin. J Sci Food Agric 2021; 101:693-702. [PMID: 32700446 DOI: 10.1002/jsfa.10682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 04/12/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND This study developed a feasible catalytic method for d-allulose syrup production using a fusion enzyme, either in free or immobilized form, through hydrolysis of inulin extracted from Jerusalem artichoke tubers. RESULTS d-Allulose 3-epimerase (DAE) was actively expressed in secretory form by fusing with the extracellular exo-inulinase CSCA in Escherichia coli BL21 (DE3). The best linker ligating the two enzymes was a flexible peptide containing 12 residues (GSAGSAAGSGEF). At 55 °C and pH 8.0, and as with the addition of 1 mmol L-1 Mn2+ , the CSCA-linkerE-DAE fusion enzyme obtained through high cell-density cultivation displayed a maximal exo-inulinase activity of 21.8 U mg-1 and resulted in a yield of 6.3 g L-1 d-allulose and 39.2 g L-1 d-fructose using 60 g L-1 inulin as the raw material. Catechol-modified alginate with titanium ions (Alg(Ti)PDA) was found to be a promising immobilization material for the fusion enzyme. After conversion for 8 days, the Alg(Ti)PDA-immobilized CSCA-linkerE-DAE (8 U g-1 ) completed 24 reaction cycles and retained over 80% of its original activity. Each reaction obtained an average of 19.8 g L-1 d-allulose and 32.7 g L-1 D-fructose from 60 g L-1 inulin. CONCLUSION This study shed light on a feasible and cost-effective approach for the production of syrup containing d-allulose and D-fructose with inulin as the raw material via the use of a CSCA and DAE fusion enzyme. This syrup is of added value as a functional sweetener. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Yueyuan Huang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Liangfei Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Yaowei Chi
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Yuanyuan Sha
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Rui Wang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Zheng Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan, China
| | - Xiaoqi Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Zhen Gao
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
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Ma J, Li Q, Tan H, Jiang H, Li K, Zhang L, Shi Q, Yin H. Unique N-glycosylation of a recombinant exo-inulinase from Kluyveromyces cicerisporus and its effect on enzymatic activity and thermostability. J Biol Eng 2019; 13:81. [PMID: 31737090 PMCID: PMC6844067 DOI: 10.1186/s13036-019-0215-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 10/16/2019] [Indexed: 01/05/2023] Open
Abstract
Background Inulinase can hydrolyze polyfructan into high-fructose syrups and fructoligosaccharides, which are widely used in food, the medical industry and the biorefinery of Jerusalem artichoke. In the present study, a recombinant exo-inulinase (rKcINU1), derived from Kluyveromyces cicerisporus CBS4857, was proven as an N-linked glycoprotein, and the removal of N-linked glycan chains led to reduced activity. Results Five N-glycosylation sites with variable high mannose-type oligosaccharides (Man3–9GlcNAc2) were confirmed in the rKcINU1. The structural modeling showed that all five glycosylation sites (Asn-362, Asn-370, Asn-399, Asn-467 and Asn-526) were located at the C-terminus β-sandwich domain, which has been proven to be more conducive to the occurrence of glycosylation modification than the N-terminus domain. Single-site N-glycosylation mutants with Asn substituted by Gln were obtained, and the Mut with all five N-glycosylation sites removed was constructed, which resulted in the loss of all enzyme activity. Interestingly, the N362Q led to an 18% increase in the specific activity against inulin, while a significant decrease in thermostability (2.91 °C decrease in Tm) occurred, and other single mutations resulted in the decrease in the specific activity to various extents, among which N467Q demonstrated the lowest enzyme activity. Conclusion The increased enzyme activity in N362Q, combined with thermostability testing, 3D modeling, kinetics data and secondary structure analysis, implied that the N-linked glycan chains at the Asn-362 position functioned negatively, mainly as a type of steric hindrance toward its adjacent N-glycans to bring rigidity. Meanwhile, the N-glycosylation at the other four sites positively regulated enzyme activity caused by altered substrate affinity by means of fine-tuning the β-sandwich domain configuration. This may have facilitated the capture and transfer of substrates to the enzyme active cavity, in a manner quite similar to that of carbohydrate binding modules (CBMs), i.e. the chains endowed the β-sandwich domain with the functions of CBM. This study discovered a unique C-terminal sequence which is more favorable to glycosylation, thereby casting a novel view for glycoengineering of enzymes from fungi via redesigning the amino acid sequence at the C-terminal domain, so as to optimize the enzymatic properties.
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Affiliation(s)
- Junyan Ma
- 1Natural Products and Glyco-Biotechnology Research Group, Liaoning Province Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China.,2Liaoning Province Key Laboratory of Bio-Organic Chemistry, Dalian University, Dalian, 116622 China
| | - Qian Li
- 2Liaoning Province Key Laboratory of Bio-Organic Chemistry, Dalian University, Dalian, 116622 China
| | - Haidong Tan
- 1Natural Products and Glyco-Biotechnology Research Group, Liaoning Province Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
| | - Hao Jiang
- 3Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
| | - Kuikui Li
- 1Natural Products and Glyco-Biotechnology Research Group, Liaoning Province Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
| | - Lihua Zhang
- 3Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
| | - Quan Shi
- 3Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
| | - Heng Yin
- 1Natural Products and Glyco-Biotechnology Research Group, Liaoning Province Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 China
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Garuba EO, Abiodun, Onilude A. Immobilization of thermostable exo-inulinase from mutant thermophilic Aspergillus tamarii-U4 using kaolin clay and its application in inulin hydrolysis. J Genet Eng Biotechnol 2018; 16:341-346. [PMID: 30733744 PMCID: PMC6353754 DOI: 10.1016/j.jgeb.2018.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 03/16/2018] [Accepted: 03/31/2018] [Indexed: 11/16/2022]
Abstract
In this study, attempts were made to immobilize purified exo-inulinase from mutant thermophic Aspergillus tamarii-U4 onto Kaolinite clay by covalent bonding cross-linked with glutaraldehyde with an immobilization yield of 66% achieved. The free and immobilized inulinases were then characterized and characterization of the enzymes revealed that temperature and pH optima for the activity of the free and immobilized enzymes were both 65 °C and pH 4.5 respectively. The free inulinase completely lost its activity after incubation at 65 °C for 6 h while the immobilized inulinase retained 16.4% of its activity under the same condition of temperature and incubation time. The estimated kinetic parameters Km and Vmax for the free inulinase as estimated from Lineweaver-Burk plots were 0.39 mM and 4.21 µmol/min for the free inulinase and 0.37 mM and 4.01 µmol/min for the immobilized inulinase respectively. Inulin at 2.5% (w/v) and a flow rate of 0.1 mL was completely hydrolysed for 10 days at 60 °C in a continuous packed bed column and the operational stability of the system revealed that the half-life of the immobilized inulinase was 51 days. These properties make the immobilized exo-inulinase from Aspergillus tamarii-U4 a potential candidate for the production of fructose from inulin hydrolysis.
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Affiliation(s)
- Emmanuel O Garuba
- Microbial Physiology and Biochemistry Laboratory, Department of Microbiology, University of Ibadan, Nigeria
| | - Abiodun
- Microbial Physiology and Biochemistry Laboratory, Department of Microbiology, University of Ibadan, Nigeria
| | - A Onilude
- Microbial Physiology and Biochemistry Laboratory, Department of Microbiology, University of Ibadan, Nigeria
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Shi N, Mao W, He X, Chi Z, Chi Z, Liu G. Co-expression of Exo-inulinase and Endo-inulinase Genes in the Oleaginous Yeast Yarrowia lipolytica for Efficient Single Cell Oil Production from Inulin. Appl Biochem Biotechnol 2017; 185:334-346. [PMID: 29150774 DOI: 10.1007/s12010-017-2659-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [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: 10/06/2017] [Accepted: 11/13/2017] [Indexed: 12/30/2022]
Abstract
Yarrowia lipolytica is a promising platform for the single cell oil (SCO) production. In this study, a transformant X+N8 in which exo- and endo-inulinase genes were co-expressed could produce an inulinase activity of 124.33 U/mL within 72 h. However, the inulinase activity of a transformant X2 carrying a single exo-inulinase gene was only 47.33 U/mL within 72 h. Moreover, the transformant X+N8 could accumulate 48.13% (w/w) SCO from inulin and the cell dry weight reached 13.63 g/L within 78 h, which were significantly higher than those of the transformant X2 (41.87% (w/w) and 11.23 g/L) under the same conditions. In addition, inulin hydrolysis and utilization of the transformant X+N8 were also more efficient than those of the transformant X2 during the fermentation process. These results demonstrated that the co-expression of the exo- and endo-inulinase genes significantly enhanced the SCO production from inulin due to the improvement of the inulinase activity and the synergistic action of exo- and endo-inulinase. Besides, over 95.01% of the fatty acids from the transformant X+N8 were C16-C18, especially C18:1 (53.10%), suggesting that the fatty acids could be used as feedstock for biodiesel production.
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Affiliation(s)
- Nianci Shi
- College of Marine Life Science, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China
| | - Weian Mao
- College of Marine Life Science, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China
| | - Xiaoxia He
- Qingdao Entry-Exit Inspection and Quarantine Bureau, Qingdao, 266002, China
| | - Zhe Chi
- College of Marine Life Science, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China
| | - Zhenming Chi
- College of Marine Life Science, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China
| | - Guanglei Liu
- College of Marine Life Science, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China.
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