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Eat S, Wulansari S, Ketbot P, Waeonukul R, Pason P, Uke A, Kosugi A, Ratanakhanokchai K, Tachaapaikoon C. A novel cellobiose 2-epimerase from anaerobic halophilic Iocasia fonsfrigidae and its ability to convert lactose in fresh goat milk into epilactose. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:8529-8540. [PMID: 39392661 DOI: 10.1002/jsfa.13680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 10/12/2024]
Abstract
BACKGROUND Cellobiose 2-epimerase (CE) has received great attention due to its potential applications in the food and pharmaceutical industries. In this study, a novel CE from mesophilic anaerobic halophilic bacterium Iocasia fonsfrigidae strain SP3-1 (IfCE) was successfully expressed in Escherichia coli and characterized. RESULTS Unlike other CEs, the purified IfCE shows only epimerization activity toward β-1,4-glycosidic linkages of disaccharides, including mannobiose, cellobiose and lactose, but not for monosaccharides, β-1,4-glycosidic linkages of trisaccharides and α-1,4-glycosidic linkages of disaccharides. Only one epimerization product was obtained from the action of IfCE against mannobiose, cellobiose and lactose. Under optimum conditions, 31.0% of epilactose, a rare and low-calorie prebiotic sweetener with medicinal and pharmacological properties, was obtained from 10 mg mL-1 lactose. IfCE was highly active against lactose under NaCl concentrations up to 500 mmol L-1, possibly due to the excessive basic (arginine and lysine) and acidic (aspartic and glutamic acids) amino acid residues, which are localized on the surface of the halophilic enzyme structure. These residues may protect the enzyme from Cl- and Na+ ions from the environment, respectively. Under normal conditions, IfCE was able to convert lactose present in fresh goat milk to epilactose with a conversion yield of 31% in 10 min. In addition, IfCE has been investigated as a safe enzyme for human allergen. CONCLUSION The results suggested that IfCE is a promising candidate to increase the quality and value of milk and dairy products by converting lactose that causes digestive problems in people with lactose intolerance into epilactose. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Sokhoeun Eat
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Shinta Wulansari
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Prattana Ketbot
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Rattiya Waeonukul
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Patthra Pason
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Ayaka Uke
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Japan
| | - Akihiko Kosugi
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Japan
| | - Khanok Ratanakhanokchai
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
| | - Chakrit Tachaapaikoon
- Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
- Excellent Center of Enzyme Technology and Microbial Utilization, Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, Thailand
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Xiong S, Huang Z, Ding J, Ni D, Mu W. Improvement of cellobiose 2-epimerase expression in Bacillus subtilis for efficient bioconversion of lactose to epilactose. Int J Biol Macromol 2024; 280:136063. [PMID: 39341311 DOI: 10.1016/j.ijbiomac.2024.136063] [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: 03/21/2024] [Revised: 09/22/2024] [Accepted: 09/25/2024] [Indexed: 10/01/2024]
Abstract
Epilactose, a lactose derivative known for its prebiotic properties and potential health benefits, has garnered significant interest. Cellulose 2-epimerase (CEase) is responsible for catalyzing the conversion of lactose to epilactose. In this study, the enhancement of food-grade CEase expression in Bacillus subtilis WB600 was systematically investigated. Among seven selected epilactose-producing CEases, Rhodothermus marinus CEase (RmCE) exhibited the highest epimerization activity when expressed in B. subtilis. Translational and transcriptional regulations were employed to enhance CEase expression by screening effective N-terminal coding sequences (NCSs) and promoters. The final strain demonstrated efficient production of CEase, with epimerization activity reaching 273.6 ± 6.5 U/mL and 1255 ± 26.4 U/mL in shake-flask and fed-batch cultivation, respectively. Utilizing only 0.25 % (V/V) of the fed-batch cultivation broth for lactose biotransformation, epilactose was efficiently produced from 300 g/L of lactose within 4 h, achieving a yield of 29.5 %. These findings provide significant support for the potential industrialization of enzymatic epilactose production.
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Affiliation(s)
- Suchun Xiong
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, China; State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zhaolin Huang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Junmei Ding
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, China.
| | - Dawei Ni
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
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Wang M, Wang L, Lyu X, Hua X, Goddard JM, Yang R. Lactulose production from lactose isomerization by chemo-catalysts and enzymes: Current status and future perspectives. Biotechnol Adv 2022; 60:108021. [PMID: 35901861 DOI: 10.1016/j.biotechadv.2022.108021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/02/2022] [Accepted: 07/17/2022] [Indexed: 11/29/2022]
Abstract
Lactulose, a semisynthetic nondigestive disaccharide with versatile applications in the food and pharmaceutical industries, has received increasing interest due to its significant health-promoting effects. Currently, industrial lactulose production is exclusively carried out by chemical isomerization of lactose via the Lobry de Bruyn-Alberda van Ekenstein (LA) rearrangement, and much work has been directed toward improving the conversion efficiency in terms of lactulose yield and purity by using new chemo-catalysts and integrated catalytic-purification systems. Lactulose can also be produced by an enzymatic route offering a potentially greener alternative to chemo-catalysis with fewer side products. Compared to the controlled trans-galactosylation by β-galactosidase, directed isomerization of lactose with high isomerization efficiency catalyzed by the most efficient lactulose-producing enzyme, cellobiose 2-epimerase (CE), has gained much attention in recent decades. To further facilitate the industrial translation of CE-based lactulose biotransformation, numerous studies have been reported on improving biocatalytic performance through enzyme mediated molecular modification. This review summarizes recent developments in the chemical and enzymatic production of lactulose. Related catalytic mechanisms are also highlighted and described in detail. Emerging techniques that aimed at advancing lactulose production, such as the boronate affinity-based technique and molecular biological techniques, are reviewed. Finally, perspectives on challenges and opportunities in lactulose production and purification are also discussed.
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Affiliation(s)
- Mingming Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China; College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong Province 266003, China; Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Lu Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China
| | - Xiaomei Lyu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China
| | - Xiao Hua
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China
| | - Julie M Goddard
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA.
| | - Ruijin Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China.
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Novel and emerging prebiotics: Advances and opportunities. ADVANCES IN FOOD AND NUTRITION RESEARCH 2021; 95:41-95. [PMID: 33745516 DOI: 10.1016/bs.afnr.2020.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Consumers are conscientiously changing their eating preferences toward healthier options, such as functional foods enriched with pre- and probiotics. Prebiotics are attractive bioactive compounds with multidimensional beneficial action on both human and animal health, namely on the gastrointestinal tract, cardiometabolism, bones or mental health. Conventionally, prebiotics are non-digestible carbohydrates which generally present favorable organoleptic properties, temperature and acidic stability, and are considered interesting food ingredients. However, according to the current definition of prebiotics, application categories other than food are accepted, as well as non-carbohydrate substrates and bioactivity at extra-intestinal sites. Regulatory issues are considered a major concern for prebiotics since a clear understanding and application of these compounds among the consumers, regulators, scientists, suppliers or manufacturers, health-care providers and standards or recommendation-setting organizations are of utmost importance. Prebiotics can be divided in several categories according to their development and regulatory status. Inulin, galactooligosaccharides, fructooligosaccharides and lactulose are generally classified as well established prebiotics. Xylooligosaccharides, isomaltooligosaccharides, chitooligosaccharides and lactosucrose are classified as "emerging" prebiotics, while raffinose, neoagaro-oligosaccharides and epilactose are "under development." Other substances, such as human milk oligosaccharides, polyphenols, polyunsaturated fatty acids, proteins, protein hydrolysates and peptides are considered "new candidates." This chapter will encompass actual information about the non-established prebiotics, mainly their physicochemical properties, market, legislation, biological activity and possible applications. Generally, there is a lack of clear demonstrations about the effective health benefits associated with all the non-established prebiotics. Overcoming this limitation will undoubtedly increase the demand for these compounds and their market size will follow the consumer's trend.
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Xiao Y, Chen Q, Guang C, Zhang W, Mu W. An overview on biological production of functional lactose derivatives. Appl Microbiol Biotechnol 2019; 103:3683-3691. [DOI: 10.1007/s00253-019-09755-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/30/2022]
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Chen Q, Xiao Y, Zhang W, Zhang T, Jiang B, Stressler T, Fischer L, Mu W. Current research on cellobiose 2-epimerase: Enzymatic properties, mechanistic insights, and potential applications in the dairy industry. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2018.09.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Park AR, Kim JS, Jang SW, Park YG, Koo BS, Lee HC. Rational modification of substrate binding site by structure-based engineering of a cellobiose 2-epimerase in Caldicellulosiruptor saccharolyticus. Microb Cell Fact 2017; 16:224. [PMID: 29233137 PMCID: PMC5726027 DOI: 10.1186/s12934-017-0841-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/06/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Lactulose, a synthetic disaccharide, has received increasing interest due to its role as a prebiotic, specifically proliferating Bifidobacilli and Lactobacilli and enhancing absorption of calcium and magnesium. The use of cellobiose 2-epimerase (CE) is considered an interesting alternative for industrial production of lactulose. CE reversibly converts D-glucose residues into D-mannose residues at the reducing end of unmodified β-1,4-linked oligosaccharides, including β-1,4-mannobiose, cellobiose, and lactose. Recently, a few CE 3D structure were reported, revealing mechanistic details. Using this information, we redesigned the substrate binding site of CE to extend its activity from epimerization to isomerization. RESULTS Using superimposition with 3 known CE structure models, we identified 2 residues (Tyr114, Asn184) that appeared to play an important role in binding epilactose. We modified these residues, which interact with C2 of the mannose moiety, to prevent epimerization to epilactose. We found a Y114E mutation led to increased release of a by-product, lactulose, at 65 °C, while its activity was low at 37 °C. Notably, this phenomenon was observed only at high temperature and more reliably when the substrate was increased. Using Y114E, isomerization of lactose to lactulose was investigated under optimized conditions, resulting in 86.9 g/l of lactulose and 4.6 g/l of epilactose for 2 h when 200 g/l of lactose was used. CONCLUSION These results showed that the Y114E mutation increased isomerization of lactose, while decreasing the epimerization of lactose. Thus, a subtle modification of the active site pocket could extend its native activity from epimerization to isomerization without significantly impairing substrate binding. While additional studies are required to scale this to an industrial process, we demonstrated the potential of engineering this enzyme based on structural analysis.
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Affiliation(s)
- Ah-Reum Park
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Jin-Sook Kim
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Seung-Won Jang
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Young-Gyun Park
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Bong-Seong Koo
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea
| | - Hyeon-Cheol Lee
- ForBioKorea Co., Ltd., Gasan digital 2-ro, Geumcheon-gu, Seoul, Republic of Korea.
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Kuschel B, Seitl I, Glück C, Mu W, Jiang B, Stressler T, Fischer L. Hidden Reaction: Mesophilic Cellobiose 2-Epimerases Produce Lactulose. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:2530-2539. [PMID: 28252294 DOI: 10.1021/acs.jafc.6b05599] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Lactulose (4-O-β-d-galactopyranosyl-d-fructofuranose) is a prebiotic sugar derived from the milk sugar lactose (4-O-β-d-galactopyranosyl-d-glucopyranose). In our study we observed for the first time that known cellobiose 2-epimerases (CEs; EC 5.1.3.11) from mesophilic microorganisms were generally able to catalyze the isomerization reaction of lactose into lactulose. Commonly, CEs catalyze the C2-epimerization of d-glucose and d-mannose moieties at the reducing end of β-1,4-glycosidic-linked oligosaccharides. Thus, epilactose (4-O-β-d-galactopyranosyl-d-mannopyranose) is formed with lactose as substrate. So far, only four CEs, exclusively from thermophilic microorganisms, have been reported to additionally catalyze the isomerization reaction of lactose into lactulose. The specific isomerization activity of the seven CEs in this study ranged between 8.7 ± 0.1 and 1300 ± 37 pkat/mg. The results indicate that very likely all CEs are able to catalyze both the epimerization as well as the isomerization reaction, whereby the latter is performed at a comparatively much lower reaction rate.
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Affiliation(s)
- Beatrice Kuschel
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim , Garbenstrasse 25, D-70599, Stuttgart, Germany
| | - Ines Seitl
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim , Garbenstrasse 25, D-70599, Stuttgart, Germany
| | - Claudia Glück
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim , Garbenstrasse 25, D-70599, Stuttgart, Germany
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Bo Jiang
- State Key Laboratory of Food Science and Technology, Jiangnan University , Wuxi, Jiangsu 214122, China
| | - Timo Stressler
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim , Garbenstrasse 25, D-70599, Stuttgart, Germany
| | - Lutz Fischer
- Department of Biotechnology and Enzyme Science, Institute of Food Science and Biotechnology, University of Hohenheim , Garbenstrasse 25, D-70599, Stuttgart, Germany
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Reaction investigation of lactulose-producing cellobiose 2-epimerases under operational relevant conditions. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2016.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Yoshihara A, Kozakai T, Shintani T, Matsutani R, Ohtani K, Iida T, Akimitsu K, Izumori K, Gullapalli PK. Purification and characterization of d-allulose 3-epimerase derived from Arthrobacter globiformis M30, a GRAS microorganism. J Biosci Bioeng 2016; 123:170-176. [PMID: 27713017 DOI: 10.1016/j.jbiosc.2016.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/09/2016] [Accepted: 09/10/2016] [Indexed: 10/20/2022]
Abstract
An enzyme that catalyzes C-3 epimerization between d-fructose and d-allulose was found in Arthrobacter globiformis strain M30. Arthrobacter species have long been used in the food industry and are well-known for their high degree of safety. The enzyme was purified by ion exchange and hydrophobic interaction chromatographies and characterized as a d-allulose 3-epimerase (d-AE). The molecular weight of the purified enzyme was estimated to be 128 kDa with four identical subunits. The enzyme showed maximal activity and thermostability in the presence of Mg2+. The optimal pH and temperature for enzymatic activity were 7.0-8.0 and 70°C, respectively. The enzyme was immobilized to ion exchange resin whereupon it was stable for longer periods than the free enzyme when stored at below 10°C. In the column reaction, the enzyme activity also maintained stability for more than 4 months. Under these conditions, 215 kg of d-allulose produced per liter immobilized enzyme, and this was the highest production yield of d-allulose reported so far. These highly stable properties suggest that this enzyme represents an ideal candidate for the industrial production of d-allulose.
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Affiliation(s)
- Akihide Yoshihara
- Rare Sugar Research Center, Kagawa University, 2393 Ikenobe, Miki 761-0795, Kagawa, Japan
| | - Taro Kozakai
- Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki 761-0795, Kagawa, Japan
| | - Tomoya Shintani
- Matsutani Chemical Industry Co., Ltd, 5-3 Kita-Itami, Itami 664-8508, Hyogo, Japan
| | - Ryo Matsutani
- Matsutani Chemical Industry Co., Ltd, 5-3 Kita-Itami, Itami 664-8508, Hyogo, Japan
| | - Kouhei Ohtani
- Matsutani Chemical Industry Co., Ltd, 5-3 Kita-Itami, Itami 664-8508, Hyogo, Japan
| | - Tetsuo Iida
- Matsutani Chemical Industry Co., Ltd, 5-3 Kita-Itami, Itami 664-8508, Hyogo, Japan
| | - Kazuya Akimitsu
- Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki 761-0795, Kagawa, Japan
| | - Ken Izumori
- Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki 761-0795, Kagawa, Japan
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Kuschel B, Riemer F, Pfost D, Conrad J, Losch C, Claaßen W, Beifuß U, Weiss J, Mu W, Jiang B, Stressler T, Fischer L. Large-scale purification of epilactose using a semi-preparative HPLC system. Eur Food Res Technol 2016. [DOI: 10.1007/s00217-016-2752-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Wang M, Hua X, Yang R, Shen Q. Immobilization of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus on commercial resin Duolite A568. FOOD BIOSCI 2016. [DOI: 10.1016/j.fbio.2016.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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13
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Saburi W. Functions, structures, and applications of cellobiose 2-epimerase and glycoside hydrolase family 130 mannoside phosphorylases. Biosci Biotechnol Biochem 2016; 80:1294-305. [PMID: 27031293 DOI: 10.1080/09168451.2016.1166934] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Carbohydrate isomerases/epimerases are essential in carbohydrate metabolism, and have great potential in industrial carbohydrate conversion. Cellobiose 2-epimerase (CE) reversibly epimerizes the reducing end d-glucose residue of β-(1→4)-linked disaccharides to d-mannose residue. CE shares catalytic machinery with monosaccharide isomerases and epimerases having an (α/α)6-barrel catalytic domain. Two histidine residues act as general acid and base catalysts in the proton abstraction and addition mechanism. β-Mannoside hydrolase and 4-O-β-d-mannosyl-d-glucose phosphorylase (MGP) were found as neighboring genes of CE, meaning that CE is involved in β-mannan metabolism, where it epimerizes β-d-mannopyranosyl-(1→4)-d-mannose to β-d-mannopyranosyl-(1→4)-d-glucose for further phosphorolysis. MGPs form glycoside hydrolase family 130 (GH130) together with other β-mannoside phosphorylases and hydrolases. Structural analysis of GH130 enzymes revealed an unusual catalytic mechanism involving a proton relay and the molecular basis for substrate and reaction specificities. Epilactose, efficiently produced from lactose using CE, has superior physiological functions as a prebiotic oligosaccharide.
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Affiliation(s)
- Wataru Saburi
- a Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
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Krewinkel M, Kaiser J, Merz M, Rentschler E, Kuschel B, Hinrichs J, Fischer L. Novel cellobiose 2-epimerases for the production of epilactose from milk ultrafiltrate containing lactose. J Dairy Sci 2015; 98:3665-78. [DOI: 10.3168/jds.2015-9411] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/10/2015] [Indexed: 01/22/2023]
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Zhang Y, Zheng Q, Zhang J, Zhang H. Insights into the epimerization activities of RaCE and pAGE: the quantum mechanics/molecular mechanics simulations. RSC Adv 2015. [DOI: 10.1039/c5ra14091a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Ruminococcus albus cellobiose 2-epimerase (RaCE) and N-acetyl-d-glucosamine 2-epimerase from porcine kidney (pAGE) belong to the AGE superfamily and have a detectable AGE activity.
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Affiliation(s)
- Yulai Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Qingchuan Zheng
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Jilong Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
| | - Hongxing Zhang
- State Key Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- People's Republic of China
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Jaito N, Saburi W, Odaka R, Kido Y, Hamura K, Nishimoto M, Kitaoka M, Matsui H, Mori H. Characterization of a thermophilic 4-O-β-D-mannosyl-D-glucose phosphorylase from Rhodothermus marinus. Biosci Biotechnol Biochem 2014; 78:263-70. [PMID: 25036679 DOI: 10.1080/09168451.2014.882760] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
4-O-β-D-Mannosyl-D-glucose phosphorylase (MGP), found in anaerobes, converts 4-O-β-D-mannosyl-D-glucose (Man-Glc) to α-D-mannosyl phosphate and D-glucose. It participates in mannan metabolism with cellobiose 2-epimerase (CE), which converts β-1,4-mannobiose to Man-Glc. A putative MGP gene is present in the genome of the thermophilic aerobe Rhodothermus marinus (Rm) upstream of the gene encoding CE. Konjac glucomannan enhanced production by R. marinus of MGP, CE, and extracellular mannan endo-1,4-β-mannosidase. Recombinant RmMGP catalyzed the phosphorolysis of Man-Glc through a sequential bi-bi mechanism involving ternary complex formation. Its molecular masses were 45 and 222 kDa under denaturing and nondenaturing conditions, respectively. Its pH and temperature optima were 6.5 and 75 °C, and it was stable between pH 5.5-8.3 and below 80 °C. In the reverse reaction, RmMGP had higher acceptor preferences for 6-deoxy-D-glucose and D-xylose than R. albus NE1 MGP. In contrast to R. albus NE1 MGP, RmMGP utilized methyl β-D-glucoside and 1,5-anhydro-D-glucitol as acceptor substrates.
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Affiliation(s)
- Nongluck Jaito
- a Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
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Krewinkel M, Gosch M, Rentschler E, Fischer L. Epilactose production by 2 cellobiose 2-epimerases in natural milk. J Dairy Sci 2014; 97:155-61. [DOI: 10.3168/jds.2013-7389] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 09/14/2013] [Indexed: 11/19/2022]
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Fujiwara T, Saburi W, Inoue S, Mori H, Matsui H, Tanaka I, Yao M. Crystal structure of Ruminococcus albus cellobiose 2-epimerase: structural insights into epimerization of unmodified sugar. FEBS Lett 2013; 587:840-6. [PMID: 23462136 DOI: 10.1016/j.febslet.2013.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/31/2013] [Accepted: 02/01/2013] [Indexed: 10/27/2022]
Abstract
Enzymatic epimerization is an important modification for carbohydrates to acquire diverse functions attributable to their stereoisomers. Cellobiose 2-epimerase (CE) catalyzes interconversion between d-glucose and d-mannose residues at the reducing end of β-1,4-linked oligosaccharides. Here, we solved the structure of Ruminococcus albus CE (RaCE). The structure of RaCE showed strong similarity to those of N-acetyl-D-glucosamine 2-epimerase and aldose-ketose isomerase YihS with a high degree of conservation of residues around the catalytic center, although sequence identity between them is low. Based on structural comparison, we found that His184 is required for RaCE activity as the third histidine added to two essential histidines in other sugar epimerases/isomerases. This finding was confirmed by mutagenesis, suggesting a new catalytic mechanism for CE involving three histidines.
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Affiliation(s)
- Takaaki Fujiwara
- Graduate School of Life Science, Hokkaido University, Kita-ku, Sapporo, Japan
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Mu W, Li Q, Fan C, Zhou C, Jiang B. Recent advances on physiological functions and biotechnological production of epilactose. Appl Microbiol Biotechnol 2013; 97:1821-7. [DOI: 10.1007/s00253-013-4687-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 12/23/2012] [Accepted: 12/27/2012] [Indexed: 01/09/2023]
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Kawahara R, Saburi W, Odaka R, Taguchi H, Ito S, Mori H, Matsui H. Metabolic mechanism of mannan in a ruminal bacterium, Ruminococcus albus, involving two mannoside phosphorylases and cellobiose 2-epimerase: discovery of a new carbohydrate phosphorylase, β-1,4-mannooligosaccharide phosphorylase. J Biol Chem 2012; 287:42389-99. [PMID: 23093406 DOI: 10.1074/jbc.m112.390336] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ruminococcus albus is a typical ruminal bacterium digesting cellulose and hemicellulose. Cellobiose 2-epimerase (CE; EC 5.1.3.11), which converts cellobiose to 4-O-β-D-glucosyl-D-mannose, is a particularly unique enzyme in R. albus, but its physiological function is unclear. Recently, a new metabolic pathway of mannan involving CE was postulated for another CE-producing bacterium, Bacteroides fragilis. In this pathway, β-1,4-mannobiose is epimerized to 4-O-β-D-mannosyl-D-glucose (Man-Glc) by CE, and Man-Glc is phosphorolyzed to α-D-mannosyl 1-phosphate (Man1P) and D-glucose by Man-Glc phosphorylase (MP; EC 2.4.1.281). Ruminococcus albus NE1 showed intracellular MP activity, and two MP isozymes, RaMP1 and RaMP2, were obtained from the cell-free extract. These enzymes were highly specific for the mannosyl residue at the non-reducing end of the substrate and catalyzed the phosphorolysis and synthesis of Man-Glc through a sequential Bi Bi mechanism. In a synthetic reaction, RaMP1 showed high activity only toward D-glucose and 6-deoxy-D-glucose in the presence of Man1P, whereas RaMP2 showed acceptor specificity significantly different from RaMP1. RaMP2 acted on D-glucose derivatives at the C2- and C3-positions, including deoxy- and deoxyfluoro-analogues and epimers, but not on those substituted at the C6-position. Furthermore, RaMP2 had high synthetic activity toward the following oligosaccharides: β-linked glucobioses, maltose, N,N'-diacetylchitobiose, and β-1,4-mannooligosaccharides. Particularly, β-1,4-mannooligosaccharides served as significantly better acceptor substrates for RaMP2 than D-glucose. In the phosphorolytic reactions, RaMP2 had weak activity toward β-1,4-mannobiose but efficiently degraded β-1,4-mannooligosaccharides longer than β-1,4-mannobiose. Consequently, RaMP2 is thought to catalyze the phosphorolysis of β-1,4-mannooligosaccharides longer than β-1,4-mannobiose to produce Man1P and β-1,4-mannobiose.
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Affiliation(s)
- Ryosuke Kawahara
- Research Faculty of Agriculture, Hokkaido University, N-9, W-9, Sapporo 060-8589, Japan
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