Ставрополь, Ставропольский край, Россия
Ставрополь, Ставропольский край, Россия
Ставрополь, Ставропольский край, Россия
Ставрополь, Россия
Ставрополь, Ставропольский край, Россия
Ставрополь, Ставропольский край, Россия
Ставрополь, Ставропольский край, Россия
Лактулоза является пребиотиком, который широко применяется в медицине и пищевой промышленности. Производство лактулозы основано на изомеризации лактозы в щелочных средах при высоких температурах. Альтернативой являются ферментативные способы, которые считаются более экологически чистыми и позволяют проводить процессы в более мягких условиях. Объектом исследования стали научные публикации по вопросам синтеза и очистки лактулозы с использованием ферментов. Для поиска информации были использованы базы данных Scopus, Web of Science, PubMed и Elibrary за период с 1978 по 2022 гг. Рассмотрели два основных пути ферментативного превращения лактозы в лактулозу: изомеризация (прямой) и трансгалактозилирование (с промежуточным гидролизом). Для первого применяют целлюлозо-2-эпимеразы, которые пока не имеют статуса безопасности и их не производят в промышленных масштабах, а побочным продуктом их реакции является эпилактоза. Для трансгалактозилирования применяют β-галактозидазы, которые имеют международный статус безопасности (GRAS) и доступны на рынке, с хорошо изученным механизмом действия. Систематизировали данные об условиях получения максимальных выходов лактулозы при использовании разных ферментов. Основными продуцентами β-галактозидаз для получения лактулозы являются дрожжи Kluyveromyces lactis и плесени Aspergillus оryzae. Выход лактулозы достигает 30 % в оптимальных условиях. Основной проблемой является необходимость внесения фруктозы. Прямой зависимости между максимальными выходами лактулозы и молярными соотношениями фруктоза:лактоза не выявлено. Применение целлобиозо-эпимераз позволяет достигать высоких выходов лактулозы (70–80 %), но для получения этих ферментов используют методы генной инженерии и мутагенеза, что ставит под сомнение их безопасность. К наиболее перспективным тенденциям развития биотехнологии лактулозы можно отнести использование вторичного молочного сырья и иммобилизованных ферментов, применение разных моделей реакторов, в т. ч. мембранных, и разработку комплексных взаимосвязанных процессов получения ферментов, конверсии лактозы в лактулозу и очистки готовых продуктов.
Лактулоза, лактоза, биоконверсия, ферменты, выход, β-галактозидаза, Kluyveromyces, Aspergillus, целлобиозо-2-эпимераза, тенденции
1. Ryabtseva SA, Khramtsov AG, Budkevich RO, Anisimov GS, Chuklo AO, Shpak MA. Physiological effects, mechanisms of action and application of lactulose. Problems of Nutrition. 2020;89(2):5-20. (In Russ.). https://doi.org/10.24411/0042-8833-2020-10012
2. Ait-Aissa A, Aider M. Lactulose: Production and use in functional food, medical and pharmaceutical applications. Practical and critical review. International Journal of Food science and Technology. 2014;49(5):1245-1253. https://doi.org/10.1111/ijfs.12465
3. Hiraishi K, Zhao F, Kurahara L-H, Li X, Yamashita T, Hashimoto T, et al. Lactulose modulates the structure of gut microbiota and alleviates colitis-associated tumorigenesis. Nutrients. 2022;14(3). https://doi.org/10.3390/nu14030649
4. Chen H-B, Su X-Y. Efficacy and safety of lactulose for the treatment of irritable bowel syndrome. Medicine. 2019;98(39). https://doi.org/10.1097/MD.0000000000017295
5. Kishor C, Ross RL, Blanchard H. Lactulose as a novel template for anticancer drug development targeting galectins. Chemical Biology and Drug Design. 2018;92(4):1801-1808. https://doi.org/10.1111/cbdd.13348
6. Karakan T, Tuohy KM, Janssen-van Solingen G. Low-dose lactulose as a prebiotic for improved gut health and enhanced mineral absorption. Frontiers in Nutrition. 2021;8. https://doi.org/10.3389/fnut.2021.672925
7. Nooshkam M, Babazadeh A, Jooyandeh H. Lactulose: Properties, technofunctional food applications, and food grade delivery system. Trends in Food Science and Technology. 2018;80:23-34. https://doi.org/10.1016/j.tifs.2018.07.028
8. Vera C, Guerrero C, Illanes A. Trends in lactose-derived bioactives: Synthesis and purification. Systems Microbiology and Biomanufacturing volume. 2022;2:393-412. https://doi.org/10.1007/s43393-021-00068-2
9. Рябцева С. А. Технология лактулозы. М.: ДеЛи принт, 2003. 232 с.
10. Sitanggang AB, Drews A, Kraume M. Recent advances on prebiotic lactulose production. World Journal of Microbiology and Biotechnology. 2016;32(9). https://doi.org/10.1007/s11274-016-2103-7
11. Karim A, Aïder M. Contribution to the process development for lactulose production through complete valorization of whey permeate by using electro-activation technology versus a chemical isomerization process. ACS Omega. 2020;5(44):28831-28843. https://doi.org/10.1021/acsomega.0c04178
12. Silvério SC, Macedo EA, Teixeira JA, Rodrigues LR. Biocatalytic approaches using lactulose: End product compared with substrate. Comprehensive Reviews in Food Science and Food Safety. 2016;15(5):878-896. https://doi.org/10.1111/1541-4337.12215
13. Vera C, Illanes A. Lactose-derived nondigestible oligosaccharides and other high added-value products. In: Illanes A, Guerrero C, Vera C, Wilson L, Conejeros R, Scott F, editors. Lactose-derived prebiotics. A process perspective. Academic Press; 2016. pp. 87-110. https://doi.org/10.1016/B978-0-12-802724-0.00003-2
14. 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. Biotechnology Advances. 2022;60. https://doi.org/10.1016/j.biotechadv.2022.108021
15. Lactulose market - Global industry insights, trends, outlook and opportunity analysis, 2022-2028 [Internet]. [cited 2022 Aug 11]. Available from: https://www.coherentmarketinsights.com/market-insight/lactulose-market-590
16. Kruschitz A, Nidetzky B. Downstream processing technologies in the biocatalytic production of oligosaccharides. Biotechnology Advances. 2020;43. https://doi.org/10.1016/j.biotechadv.2020.107568
17. BRENDA [Internet]. [cited 2022 Aug 11]. Available from: https://www.brenda-enzymes.org
18. Martins GN, Ureta MM, Tymczyszyn EE, Castilho PC, Gomez-Zavaglia A. Technological aspects of the production of fructo and galacto-oligosaccharides. Enzymatic synthesis and hydrolysis. Frontiers in Nutrition. 2019;6. https://doi.org/10.3389/fnut.2019.00078
19. Ureta MM, Martins GN, Figueira O, Pire PF, Castilho PC, Gomez-Zavaglia A. Recent advances in β-galactosidase and fructosyltransferase immobilization technology. Critical Reviews in Food Science and Nutrition. 2021;61(16):2659-2690. https://doi.org/10.1080/10408398.2020.1783639
20. van den Dungen MW, Boer R, Wilms LC, Efimova Yu, Abbas HE. The safety of a Kluyveromyces lactis strain lineage for enzyme production. Regulatory Toxicology and Pharmacology. 2021;126. https://doi.org/10.1016/j.yrtph.2021.105027
21. Žolnere K, Ciproviča I. The comparison of commercially available β-galactosidases for dairy industry: Review. Research for Rural Development. 2017;1:215-222. https://doi.org/10.22616/rrd.23.2017.032
22. de Albuquerque TL, de Sousa M, e Silva NCG, Girão Neto CAC, Gonçalves LRB, Fernandez-Lafuente R, et al. β-Galactosidase from Kluyveromyces lactis: Characterization, production, immobilization and applications - A review. International Journal of Biological Macromolecules. 2021;191:881-898. https://doi.org/10.1016/j.ijbiomac.2021.09.133
23. Girão Neto CAC, e Silva NCG, de Oliveira Costa T, de Albuquerque TL, Gonçalves LRB, Fernandez-Lafuente R, et al. The β-galactosidase immobilization protocol determines its performance as catalysts in the kinetically controlled synthesis of lactulose. International Journal of Biological Macromolecules. 2021;176:468-478. https://doi.org/10.1016/j.ijbiomac.2021.02.078
24. Mayer J, Conrad J, Klaiber I, Lutz-Wahl S, Beifuss U, Fischer L. Enzymatic production and complete nuclear magnetic resonance assignment of the sugar lactulose. Journal of Agricultural and Food Chemistry. 2004;52(23):6983-6990. https://doi.org/10.1021/jf048912y
25. Mayer J, Kranz B, Fischer L. Continuous production of lactulose by immobilized thermostable b-glycosidase from Pyrococcus furiosus. Journal of Biotechnology. 2010;145(4):387-393. https://doi.org/10.1016/j.jbiotec.2009.12.017
26. Chen Q, Xiao Y, Zhang W, Zhang T, Jiang B, Stressler T, et al. Current research on cellobiose 2-epimerase: Enzymatic properties, mechanistic insights, and potential applications in the dairy industry. Trends in Food Science and Technology. 2018;82:167-176. https://doi.org/10.1016/j.tifs.2018.09.009
27. Chen Q, Xiao Y, Wu Y. Characteristics of cellobiose 2-epimerase and its application in enzymatic production of lactulose and epilactose. In: Mu W, Zhang W, Chen Q, editors. Novel enzymes for functional carbohydrates production. From scientific research to application in health food industry. Singapore: Springer; 2021. pp. 105-123. https://doi.org/10.1007/ 978-981-3 3-6021-1
28. Kuschel B, Seitl I, Glück C, Mu W, Orcid, Jiang B, Stressle T, et al. Hidden reaction: Mesophilic cellobiose-2-epimerases producelactulose. Journal of Agricultural and Food Chemistry. 2017;65(12):2530-2539. https://doi.org/10.1021/acs.jafc.6b05599
29. Park A-R, Kim J-S, Jang S-W, Park Y-G, Koo B-S, Lee H-C. Rational modification of substrate binding site by structure based engineering of a cellobiose-2-epimerase in Caldicellulosiruptor saccharolyticus. Microbial Cell Factories. 2017;16(1). https://doi.org/10.1186/s12934-017-0841-3
30. Shen Q, Zhang Y, Yang R, Pan S, Dong J, Fan Y, et al. Enhancement of isomerization activity and lactulose production of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus. Food Chemistry. 2016;207:60-67. https://doi.org/10.1016/j.foodchem.2016.02.067
31. Wang L, Gu J, Feng Y, Wang M, Tong Y, Liu Y, et al. Enhancement of the isomerization activity and thermostability of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus by exchange of a flexible loop. Journal of Agricultural and Food Chemistry. 2021;69(6):1907-1915. https://doi.org/10.1021/acs.jafc.0c07073
32. Chen Q, Levin R, Zhang W, Zhang T, Jiang B, Stressler T, et al. Characterization of a novel cellobiose 2-epimerase from thermophilic Caldicellulosiruptor obsidiansis for lactulose production. Journal of the Science of Food and Agriculture. 2017;97(10):3095-3105. https://doi.org/10.1002/jsfa.8148
33. Chen Q, Wu Y, Huang Z, Zhang W, Mu W. Molecular characterization of a mesophilic cellobiose 2-epimerase that maintains a high catalytic efficiency at low temperatures. Journal of Agricultural and Food Chemistry. 2021;69(29):8268-8275. https://doi.org/10.1021/acs.jafc.1c02025
34. Gu J, Yang R, Hua X, Zhang W, Zhao W. Adsorption-based immobilization of Caldicellulosiruptor saccharolyticus cellobiose 2-epimerase on Bacillus subtilis spores. Biotechnology and Applied Biochemistry. 2015;62(2):237-244. https://doi.org/10.1002/bab.1262
35. Kim J-E, Kim Y-S, Kang L-W, Oh D-K. Characterization of a recombinant cellobiose 2-epimerase from Dictyoglomus turgidum that epimer izes and isomer izes β-1,4 and α-1,4-gluco-oligosacchar ides. Biotechnology Letters. 2012;34(11):2061-2068. https://doi.org/10.1007/s10529-012-0999-z
36. Kim Y-S, Kim J-E, Oh D-K. Borate enhances the production of lactulose from lactose by cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus. Bioresource Technology. 2013;128:809-812. https://doi.org/10.1016/j.biortech.2012.10.060
37. Rentschler E, Schuh K, Krewinkel M, Baur C, Claaßen W, Meyer S, et al. Enzymatic production of lactulose and epilactose in milk. Journal of Dairy Science. 2015;98(10):6767-6775. https://doi.org/10.3168/jds.2015-9900
38. Panesar PS, Kumari S. Lactulose: Production, purification and potential applications. Biotechnology Advances. 2011;29(6):940-948. https://doi.org/10.1016/j.biotechadv.2011.08.008
39. Wang H, Yang R, Hua X, Zhao W, Zhang W. Enzymatic production of lactulose and 1-lactulose: Current state and perspectives. Applied Microbiology and Biotechnology. 2013;97(14):6167-6180. https://doi.org/10.1007/s00253-013-4998-3
40. Vaheri M, Kaupinnen V. The formation of lactulose (4-O-β-galactopyranosylfructose) by β-galactosidase. Acta Pharmaceutica Fennica. 1978;87:75-83.
41. Lee Y-J, Kim CS, Oh D-K. Lactulose production by beta-galactosidase in permeabilized cells of Kluyveromyces lactis. Applied Microbiology and Biotechnology. 2004;64(4):787-793. https://doi.org/10.1007/s00253-003-1506-1
42. Adamczak M, Charubin D, Bednarski W. Influence of reaction medium composition on enzymatic synthesis of galactooligosaccharides and lactulose from lactose concentrates prepared from whey permeate. Chemical Papers. 2009;63:111-116. https://doi.org/10.2478/s11696-009-0010-1
43. Fattahi H, Zokaee F, Bonakdarpour B, Hashemi SA, Khatami SH. Enzymatic synthesis of lactulose by commercial β-galactosidase from Klyveromyces lactis. Afinidad. 2010;67(546):149-153.
44. Hua X, Yang R, Zhang W, Fei Y, Jin Z, Jiang B. Dual-enzymatic synthesis of lactulose in organic-aqueous two-phase media. Food Research International. 2010;43(3):716-722. https://doi.org/10.1016/j.foodres.2009.11.008
45. Guerrero C, Vera C, Plou F, Illanes A. Influence of reaction conditions on the selectivity of the synthesis of lactulose with microbial b-galactosidases. Journal of Molecular Catalysis B: Enzymatic. 2011;72(3-4):206-212. https://doi.org/10.1016/j.molcatb.2011.06.007
46. Shen Q, Yang R, Hua X, Ye F, Wang H, Zhao W, et al. Enzymatic synthesis and identification of oligosaccharides obtained by transgalactosylation of lactose in the presence of fructose using b-galactosidase from Kluyveromyces lactis. Food Chemistry. 2012;135(3):1547-1554. https://doi.org/10.1016/j.foodchem.2012.05.115
47. Song YS, Shin HY, Lee JY, Park C, Kim SW. β-Galactosidaseimmobilised microreactor fabricated using a novel technique for enzyme immobilisation and its application for continuous synthesis of lactulose. Food Chemistry. 2012;133(3):611-617. https://doi.org/10.1016/j.foodchem.2012.01.096
48. Song YS, Suh YJ, Park C, Kim SW. Improvement of lactulose synthesis through optimization of reaction conditions with immobilized β-galactosidase. Korean Journal of Chemical Engineering. 2013;30(1):160-165. https://doi.org/10.1007/s11814-012-0105-1
49. Song YS, Lee HU, Park C, Kim SW. Batch and continuous synthesis of lactulose from whey lactose by immobilized β-galactosidase. Food Chemistry. 2013;136(2):689-694. https://doi.org/10.1016/j.foodchem.2012.08.074
50. Hua X, Yang R, Shen Q, Ye F, Zhang W, Zhao W. Production of 1-lactulose and lactulose using commercial β-galactosidase from Kluyveromyces lactis in the presence of fructose. Food Chemistry. 2013;137(1-4):1-7. https://doi.org/10.1016/j.foodchem.2012.10.003
51. Khatami S, Ashtiani FZ, Bonakdarpour B, Mehrdad M. The enzymatic production of lactulose via transglycosylation in conventional and non-conventional media. International Dairy Journal. 2014;34(1):74-79. https://doi.org/10.1016/j.idairyj.2013.07.010
52. Sitanggang AB, Drews A, Kraume M. Continuous synthesis of lactulose in an enzymatic membrane reactor reduces lactulose secondary hydrolysis. Bioresource Technology. 2014;167:108-115. https://doi.org/10.1016/j.biortech.2014.05.124
53. Sitanggang AB, Drews A, Kraume M. Rapid transgalactosylation towards lactulose synthesis in a small scale enzymatic membrane reactor (EMR). Chemical Engineering Transactions. 2014;38:19-24. https://doi.org/10.3303/CET1438004
54. Sitanggang AB, Drews A, Kraume M. Influences of operating conditions on continuous lactulose synthesis in an enzymatic membrane reactor system: A basis prior to long-term operation. Journal of Biotechnology. 2015;203:89-96. https://doi.org/10.1016/j.jbiotec.2015.03.016
55. Guerrero C, Vera C, Conejeros R, Illanes A. Transgalactosylation and hydrolytic activities of commercial preparations of β-galactosidase for the synthesis of prebiotic carbohydrates. Enzyme and Microbial Technology. 2015;70:9-17. https://doi.org/10.1016/j.enzmictec.2014.12.006
56. De Albuquerque TL, Gomes SDL, D’Almeida AP, Fernandez-Lafuente R, Gonçalves LRB, Rocha MVP. Immobilization of β-galactosidase in glutaraldehyde-chitosan and its application to the synthesis of lactulose using cheese whey as feedstock. Process Biochemistry. 2018;73:65-73. https://doi.org/10.1016/j.procbio.2018.08.010
57. Schmidt CM, Nedele A-K, Hinrichs J. Enzymatic generation of lactulose in sweet and acid whey: Feasibility study for the scale up towards robust processing. Food and Bioproducts Processing. 2020;119:329-336. https://doi.org/10.1016/j.fbp.2019.11.015
58. Schmidt CM, Balinger F, Conrad J, Günther J, Beifuss U, Hinrichs J. Enzymatic generation of lactulose in sweet and acid whey: Optimization of feed composition and structural elucidation of 1-lactulose. Food Chemistry. 2020;305. https://doi.org/10.1016/j.foodchem.2019.125481
59. de Freitas MFM, Hortêncio LC, de Albuquerque TL, Rocha MVP, Gonçalves LRB. Simultaneous hydrolysis of cheese whey and lactulose production catalyzed by beta-galactosidase from Kluyveromyces lactis NRRL Y1564. Bioprocess and Biosystems Engineering. 2020;43(4):711-722. https://doi.org/10.1007/s00449-019-02270-y
60. Guerrero C, Vera C, Araya E, Conejeros R, Illanes A. Repeated-batch operation for the synthesis of lactulose with β-galactosidase immobilized by aggregation and crosslinking. Bioresource Technology. 2015;190:122-131. https://doi.org/10.1016/j.biortech.2015.04.039
61. Sitanggang AB, Drews A, Kraume M. Development of a continuous membrane reactor process for enzyme-catalyzed lactulose synthesis. Biochemical Engineering Journal. 2016;109:65-80. https://doi.org/10.1016/j.bej.2016.01.006
62. Guerrero C, Vera C, Illanes A. Synthesis of lactulose in batch and repeated-batch operation with immobilized β-galactosidase in different agarose functionalized supports. Bioresource Technology. 2017;230:56-66. https://doi.org/10.1016/j.biortech.2017.01.037
63. Guerrero C, Vera C, Serna N, Illanes A. Immobilization of Aspergillus oryzae β-galactosidase in an agarose matrix functionalized by four different methods and application to the synthesis of lactulose. Bioresource Technology. 2017;232:53-63. https://doi.org/10.1016/j.biortech.2017.02.003
64. Guerrero C, Valdivia F, Ubilla C, Ramírez N, Gómez M, Aburto C, et al. Continuous enzymatic synthesis of lactulose in packed-bed reactor with immobilized Aspergillus oryzae β-galactosidase. Bioresource Technology. 2019;278:296-302. https://doi.org/10.1016/j.biortech.2018.12.018
65. Ubilla C, Ramírez N, Valdivia F, Vera C, Illanes A, Guerrero C. Synthesis of lactulose in continuous stirred tank reactor with β-galactosidase of Apergillus oryzae immobilized in monofunctional glyoxyl agarose support. Frontiers in Bioengineering and Biotechnology. 2020;8. https://doi.org/10.3389/fbioe.2020.00699
66. Guerrero C, Aburto C, Suarez S, Vera C, Illanes A. Improvements in the production of Aspergillus oryzae β-galactosidase crosslinked aggregates and their use in repeated-batch synthesis of lactulose. International Journal of Biological Macromolecules. 2020;142:452-462. https://doi.org/10. 1016/j.ijbiomac.2019.09.117
67. Serey M, Vera C, Guerrero C, Illanes A. Immobilization of Aspergillus oryzae β-galactosidase in cation functionalized agarose matrix and its application in the synthesis of lactulose. International Journal of Biological Macromolecules. 2021;167:1564-1574. https://doi.org/10.1016/j.ijbiomac.2020.11.110
68. Ramírez N, Ubilla C, Campos J, Valencia F, Aburto C, Vera C, et al. Enzymatic production of lactulose by fed-batch and repeated fed-batch reactor. Bioresource Technology. 2021;341. https://doi.org/10.1016/j.biortech.2021.125769
69. Zimmer FC, Souza AHP, Silveira AFC, Santos MR, Matsushita M, Souza NE, et al. Application of factorial design for optimization of the synthesis of lactulose obtained from whey permeate. Journal of the Brazilian Chemical Society. 2017;28(12):2326-2333. https://doi.org/10.21577/0103-5053.20170083
70. Illanes A. Whey upgrading by enzyme biocatalysis. Electronic Journal of Biotechnology. 2011;14(6).
71. Shen Q, Zhang Y, Yang R, Hua X, Zhang W, Zhao W. Thermostability enhancement of cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus by site-directed mutagenesis. Journal of Molecular Catalysis B: Enzymatic. 2015;120:158-164. https://doi.org/10.1016/j.molcatb.2015.07.007
72. Karim A, Gerliani N, Aïder M. Kluyveromyces marxianus: An emerging yeast cell factory for applications in food and biotechnology. International Journal of Food Microbiology. 2020;333. https://doi.org/10.1016/j.ijfoodmicro.2020.108818
73. Lyutova LV, Naumov GI, Shnyreva AV, Naumova ES. Molecular polymorphism of β-galactosidase LAC4 genes in dairy and natural strains of Kluyveromyces yeasts. Molecular Biology. 2021;55(1):75-85. (In Russ.). https://doi.org/10.31857/S0026898421010109
74. Naumova ES, Sadykova AZ, Michailova YuV, Naumov GI. Polymorphism of lactose genes in the dairy yeasts Kluyveromyces marxianus, potential probiotic microorganisms. Microbiology. 2017;86(3):335-343. (In Russ.). https://doi.org/10.7868/S0026365617030144
75. Ryabtseva SA, Skripnyuk AA, Kotova AA, Khramtsov AG, Rodnaya AB, Lodygin AD, et al. Method for combined enzyme beta-galactosidase production. Russia Patent Ru 2622078C1. 2017.
76. Panesar PS, Kumari S, Panesar R. Potential applications of immobilized β-galactosidase in food processing industries. Enzyme Research. 2010;2010. https://doi.org/10.4061/2010/473137
77. Córdova A, Henríquez P, Nuñez H, Rico-Rodriguez F, Guerrero C, Astudillo-Castro C, et al. Recent advances in the application of enzyme processing assisted by ultrasound in agri-foods: A review. Catalysts. 2022;12(1). https://doi.org/10.3390/catal12010107
78. Geciova J, Bury D, Jelen P. Methods for disruption of microbial cells for potential use in the dairy industry - A review. International Dairy Journal. 2002;12(6):541-553. https://doi.org/10.1016/S0958-6946(02)00038-9
79. Ajisaka K, Nishida H, Fujimoto H. Use of an activated carbon column for the synthesis of disaccharides by use of a reverse hydrolysis activity of β-galactosidase. Biotechnology Letters. 1987;9:387-392.
80. Kim Y-S, Park C-S, Oh D-K. Lactulose production from lactose and fructose by a thermostable β-galactosidase from Sulfolobus solfataricus. Enzyme and Microbial Technology. 2006;39(4):903-908. https://doi.org/10.1016/j.enzmictec.2006.01.023
81. Hashem AM, Ismail SAE, Helmy WA, El-Mohamady Y, Abou-Romia R. Factors affecting the production of lactulose by Lactobacillus acidophilus NRRL 4495 β-galactosidase and its biological activity. Malaysian Journal of Microbiology. 2013;9(1):1-6. https://doi.org/10.21161/mjm.43612
82. Wang H, Yan R, Hua X, Zhang W, Zhao W. An approach for lactulose production using the cotx-mediatedspore-displayed β-galactosidase as a biocatalyst. Journal of Microbiology and Biotechnology. 2016;26(7):1267-1277. https://doi.org/10.4014/jmb.1602.02036
83. Letsididi R, Hassanin HAM, Koko MYF, Zhang T, Jiang B, Mu W. Lactulose production by a thermostable glycoside hydrolase from the hyperthermophilic archaeon Caldivirga maquilingensis IC-167. Journal of the Science of Food and Agriculture. 2018;98(3):928-937. https://doi.org/10.1002/jsfa.8539
84. Montanari G, Zambonelli C, Grazia L, Benevelli M, and Chiavari C. Release of β-galactosidase from Lactobacilli. Food Technology and Biotechnology. 2000;38(2):129-133.
85. Tang L, Li Z, Dong X, Yang R, Zhang J, Mao Z. Lactulose biosynthesis by β-galactosidase from a newly isolated Arthrobacter sp. Journal of Industrial Microbiology and Biotechnology. 2011;38(3):471-476. https://doi.org/10.1007/s10295-010-0897-0
86. Lorenzen PChr, Breiter J, Clawin-Rädecker I, Dau A. A novel bi-enzymatic system for lactose conversion. International Journal of Food Science and Technology. 2013;48(7):1396-1403. https://doi.org/10.1111/ijfs.12101
87. Song Y-S, Lee H-U, Park C, Kim S-W. Optimization of lactulose synthesis from whey lactose by immobilized β-galactosidase and glucose isomerase. Carbohydrate Research. 2013;369:1-5. https://doi.org/10.1016/j.carres.2013.01.002
88. Sato H, Saburi W, Ojima T, Taguchi H, Mori H, Matsui H. Immobilization of a thermostable cellobiose 2-epimerase from Rhodothermus marinus JCM9785 and continuous production of epilactose. Bioscience, Biotechnology, and Biochemistry. 2012;76(8):1584-1587. https://doi.org/10.1271/bbb.120284
89. Kim Y-S, Oh D-K. Lactulose production from lactose as a single substrate by a thermostable cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus. Bioresource Technology. 2012;104:668-672. https://doi.org/10.1016/j.biortech.2011.11.016
90. Wu L, Xu C, Li S, Liang J, Xu H, Xu Z. Efficient production of lactulose from whey powder by cellobiose 2-epimerase in an enzymatic membrane reactor. Bioresource Technology. 2017;233:305-312. https://doi.org/10.1016/j.biortech.2017.02.089
91. Wang M, Wang H, Feng Y, Xu Q, Admassu H, Yang R, et al. Preparation and characterization of sugar-assisted cross-linked enzyme aggregates (CLEAs) of recombinant cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus (CsCE). Journal of Agricultural and Food Chemistry. 2018;66(29):7712-7721. https://doi.org/10.1021/acs.jafc.8b02333
92. Xiao Y, Chen Q, Shakhnovich EI, Zhang W, Mu W. Simulation-guided enzyme discovery: A new microbial source of cellobiose 2-epimerase. International Journal of Biological Macromolecules. 2019;139:1002-1008. https://doi.org/10.1016/j.ijbiomac.2019.08.075
93. Botelho VA, Mateus M, Petrus JCC, de Pinho MN. Membrane bioreactor for simultaneous synthesis and fractionation of oligosaccharides. Membranes. 2022;12(2). https://doi.org/10.3390/membranes12020171
94. Maráz A, Kovács Z, Benjamins E, Pázmándi M. Recent developments in microbial production of high-purity galacto-oligosaccharides. World Journal of Microbiology and Biotechnology. 2022;38(6). https://doi.org/10.1007/s11274-022-03279-4
95. Julio-Gonzalez LC, Hernandez-Hernandez O, Moreno FJ, Olano A, Corzo N. High-yield purification of commercial lactulose syrup. Separation and Purification Technology. 2019;224:475-480. https://doi.org/10.1016/j.seppur.2019.05.053
96. Guerrero C, Vera C, Illanes A. Selective bioconversion with yeast for the purification of raw lactulose and transgalactosylated oligosaccharides. International Dairy Journal. 2018;81:131-137. https://doi.org/10.1016/j.idairyj.2018.02.003
97. Huang Z, Huang L, Xing G, Xu X, Tu C, Dong M. Effect of co-fermentation with lactic acid bacteria and K. marxianus on physicochemical and sensory properties of goat milk. Foods. 2020;9(3). https://doi.org/10.3390/foods9030299
98. Wilson L, Illanes A, Ottone C, Romero O. Co-immobilized carrier-free enzymes for lactose upgrading. Current Opinion in Green and Sustainable Chemistry. 2021;33. https://doi.org/10.1016/j.cogsc.2021.100553
