1
|
Guang C, Du Z, Meng J, Zhu Y, Zhu Y, Mu W. Recent Progress in Physiological Significance and Biosynthesis of Lacto- N-triose II: Insights into a Crucial Biomolecule. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 39188079 DOI: 10.1021/acs.jafc.4c04284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Lacto-N-triose II (LNTri II), an important precursor for human milk oligosaccharide (HMOs) synthesis, has garnered significant attention due to its structural features and physiological properties. Composed of galactose (Gal), N-acetylglucosamine (GlcNAc), and glucose (Glc), with the chemical structure GlcNAcβ1,3Galβ1,4Glc, the distinctive structure of LNTri II confers various physiological functions such as promoting the growth of beneficial bacteria, regulating the infant immune system, and preventing certain gastrointestinal diseases. Extensive research efforts have been dedicated to elucidating efficient enzymatic synthesis pathways for LNTri II production, with particular emphasis on the transglycosylation activity of β-N-acetylhexosaminidases and the action of β-1,3-N-acetylglucosaminyltransferases. Additionally, metabolic engineering and cell factory approaches have been explored, harnessing the potential of engineered microbial hosts for the large-scale biosynthesis of LNTri II. This review summarizes the structure, derivatives, physiological effects, and biosynthesis of LNTri II.
Collapse
Affiliation(s)
- Cuie Guang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Zhihui Du
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Jiawei Meng
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Yunqi Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| |
Collapse
|
2
|
Tao M, Yang L, Zhao C, Zhang W, Zhu Y, Mu W. Efficient Biosynthesis of Lacto- N-Biose I, a Building Block of Type I Human Milk Oligosaccharides, by a Metabolically Engineered Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:5860-5866. [PMID: 38452259 DOI: 10.1021/acs.jafc.4c00153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Lacto-N-biose I (LNB), termed a Type 1 disaccharide, is an important building block of human milk oligosaccharides. It shows promising prebiotic activity by stimulating the proliferation of many gut-associated bifidobacteria and thus displays good potential in infant foods or supplements. Enzymatic and microbial approaches to LNB synthesis have been studied, almost all of which involve glycosylation of LNB phosphorylase as the final step. Herein, we report a new and easier microbial LNB synthesis strategy through the route "lactose → lacto-N-triose II (LNTri II) → lacto-N-tetraose (LNT) → LNB". A previously constructed LNT-producing Escherichia coli BL21(DE3) strain was engineered for LNB biosynthesis by introducing Bifidobacterium bifidum LnbB. LNB was efficiently produced, accompanied by lactose regeneration. Genomic integration of key pathway genes related to LNTri II and LNT synthesis was performed to enhance LNB titers. The final engineered strain produced 3.54 and 26.88 g/L LNB by shake-flask and fed-batch cultivation, respectively.
Collapse
Affiliation(s)
- Mengting Tao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Longhao Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Chunhua Zhao
- Bloomature Biotechnology Corporation, Limited, Beijing 102629, People's Republic of China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| |
Collapse
|
3
|
Zhu Y, Yang L, Zhao C, Chen Y, Zhao M, Li Z, Mu W. Microbial Synthesis of Lacto- N-fucopentaose I with High Titer and Purity by Screening of Specific Glycosyltransferase and Elimination of Residual Lacto- N-triose II and Lacto- N-tetraose. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:4317-4324. [PMID: 38364314 DOI: 10.1021/acs.jafc.3c08970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
Lacto-N-fucopentaose I (LNFP I) has recently been approved as generally recognized as safe, demonstrating its great commercial potential in the food industry. Microbial synthesis through metabolic engineering strategies is an effective approach for large-scale production of LNFP I. Biosynthesis of LNFP I requires consideration of two key points: high titer with low byproduct 2'-fucosyllactose (2'-FL) generation and high purity with low lacto-N-triose II (LNTri II) and lacto-N-tetraose (LNT) residues. Herein, α1,2-fucosyltransferase from Thermoanaerobacterium sp. RBIITD was screened from 16 selected LNFP I-producing glycosyltransferase candidates, showing the highest in vivo LNFP I productivity. Chromosomal integration of wbgO enhanced the LNFP I production by improving the precursor conversion from LNTri II to LNT. The best engineered strain produced 4.42 and 35.1 g/L LNFP I in shake-flask and fed-batch cultivation, respectively. The residual LNTri II and LNT were eliminated by further cultivation with a recombinant strain coexpressing Bifidobacterium bifidum β-N-acetylhexosaminidase and lacto-N-biosidase. A strategy for LNFP I biosynthesis with high yield and purity was finally realized, providing support for its practical application in large-scale production.
Collapse
Affiliation(s)
- Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| | - Longhao Yang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| | - Chunhua Zhao
- Bloomature Biotechnology Corporation, Limited, Beijing 102629, People's Republic of China
| | - Yihan Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| | - Mingli Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| | - Zeyu Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China
| |
Collapse
|
4
|
Chen L, Qin Y, Ma L, Meng D, You C. Biosynthesis of Lacto-N-biose I from starch and N-acetylglucosamine via an in vitro synthetic enzymatic biosystem. Synth Syst Biotechnol 2023; 8:555-562. [PMID: 37663063 PMCID: PMC10468323 DOI: 10.1016/j.synbio.2023.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/07/2023] [Accepted: 08/16/2023] [Indexed: 09/05/2023] Open
Abstract
Human milk oligosaccharides (HMOs) are very distinctive components in human milk and are beneficial for infant health. Lacto-N-biose I (LNB) is the core structural unit of HMOs, which could be used for the synthesis of other HMOs. In this study, an ATP-free in vitro synthetic enzymatic biosystem contained four thermostable enzymes (alpha-glucan phosphorylase from Thermococcus kodakarensis, UDP-glucose-hexose-1-phosphate uridylyltransferase from Thermotoga maritima, UDP-glucose 4-epimerase from T. maritima, lacto-N-biose phosphorylase from Clostridium thermobutyricum) were constructed for the biosynthesis of LNB from starch and N-acetylglucosamine (GlcNAc). Under the optimal conditions, 0.75 g/L and 2.23 g/L LNB was produced from 1.1 g/L and 4.4 g/L GlcNAc and excess starch, with the molar yield of 39% and 29% based on the GlcNAc concentration, respectively, confirming the feasibility of this in vitro synthetic enzymatic biosystem for LNB synthesis and shedding light on the biosynthesis of other HMOs using LNB as the core structural unit from low cost polysaccharides.
Collapse
Affiliation(s)
- Lijie Chen
- College of Bioengineering, Tianjin University of Science and Technology, Tianjin, 300457, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Yanmei Qin
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Long Ma
- College of Bioengineering, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Dongdong Meng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Chun You
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin, 300308, China
| |
Collapse
|
5
|
Yang L, Zhu Y, Zhao C, Zhao M, Tao M, Li Z, Zhang W, Mu W. Elimination of Residual Lacto- N-triose II for Lacto- N-tetraose Biosynthesis in Engineered Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:12511-12518. [PMID: 37555443 DOI: 10.1021/acs.jafc.3c03644] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Lacto-N-tetraose (LNT) is an important neutral human milk oligosaccharide (HMO) and acts as a significant core structure for complex HMO biosynthesis. We previously achieved high-yield LNT biosynthesis (57.5 g/L) using fed-batch fermentation; however, residual lacto-N-triose II (LNTri II) was also found (21.58 g/L). Here, we re-engineered an efficient LNT-producing Escherichia coli with low LNTri II accumulation using genetically stable LNTri II-producing strains with a genomic insertion of lgtA (encoding β1,3-N-acetylglucosaminyltransferase). Comparable and low titers of LNT (3.73-4.61 g/L) and LNTri II (0.33-0.63 g/L), respectively, were obtained by introducing β1,3-galactosyltransferase. To reduce residual LNTri II, the E. coli transporter gene setA was disrupted, obviously reducing the accumulation of LNTri II and LNT. Next, the gene encoding β-N-acetylhexosaminidase (BbhI) was introduced into LNT-producing strains or E. coli BL21(DE3) for single- or mixed-strain cultivation, respectively. Finally, LNT was obtained (30.13 g/L) in a cocultivation system of mixed engineered strains without undesired LNTri II.
Collapse
Affiliation(s)
- Longhao Yang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Chunhua Zhao
- Bloomature Biotechnology Co., Ltd., Beijing 102629, China
| | - Mingli Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Mengting Tao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zeyu Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China
| |
Collapse
|
6
|
Zhao M, Zhu Y, Wang H, Xu W, Zhang W, Mu W. An Overview of Sugar Nucleotide-Dependent Glycosyltransferases for Human Milk Oligosaccharide Synthesis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:12390-12402. [PMID: 37552889 DOI: 10.1021/acs.jafc.3c02895] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Human milk oligosaccharides (HMOs) have received increasing attention because of their special effects on infant health and commercial value as the new generation of core components in infant formula. Currently, large-scale production of HMOs is generally based on microbial synthesis using metabolically engineered cell factories. Introduction of the specific glycosyltransferases is essential for the construction of HMO-producing engineered strains in which the HMO-producing glycosyltransferases are generally sugar nucleotide-dependent. Four types of glycosyltransferases have been used for typical glycosylation reactions to synthesize HMOs. Soluble expression, substrate specificity, and regioselectivity are common concerns of these glycosyltransferases in practical applications. Screening of specific glycosyltransferases is an important research topic to solve these problems. Molecular modification has also been performed to enhance the catalytic activity of various HMO-producing glycosyltransferases and to improve the substrate specificity and regioselectivity. In this article, various sugar nucleotide-dependent glycosyltransferases for HMO synthesis were overviewed, common concerns of these glycosyltransferases were described, and the future perspectives of glycosyltransferase-related studies were provided.
Collapse
Affiliation(s)
- Mingli Zhao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Hao Wang
- Bloomage Biotechnology Corp., Ltd., Jinan, Shandong 250010, People's Republic of China
| | - Wei Xu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| |
Collapse
|
7
|
Liao Y, Wu J, Li Z, Wang J, Yuan L, Lao C, Chen X, Yao J. Metabolic Engineering of Escherichia coli for High-Level Production of Lacto- N-neotetraose and Lacto- N-tetraose. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37467490 DOI: 10.1021/acs.jafc.3c02997] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Lacto-N-neotetraose (LNnT) and lacto-N-tetraose (LNT) are important oligosaccharides found in breast milk and are commonly used as nutritional supplements in infant formula. We used metabolic engineering techniques to optimize the modified Escherichia coli BL21 star (DE3) strain for efficient synthesis of LNnT and LNT using β-1,4-galactosyltransferase (HpgalT) from Helicobacter pylori and β-1,3-galactosyltransferase (SewbdO) from Salmonella enterica subsp. salamae serovar, respectively. Further, we optimized the expression of three key genes, lgtA, galE, and HpgalT (SewbdO), to synthesize LNnT or LNT and deleted several genes (ugd, ushA, agp, wcaJ, otsA, and wcaC) to block competition in the UDP-galactose synthesis pathway. The optimized strain produced LNnT or LNT with a titer of 22.07 or 48.41 g/L, respectively, in a supplemented batch culture, producing 0.41 or 0.73 g/L/h, respectively. The strategies used in this study contribute to the development of cell factories for high-level LNnT and LNT and their derivatives.
Collapse
Affiliation(s)
- Yingxue Liao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Jinyong Wu
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Huainan New Energy Research Center, Institute of Plasma Physics, Chinese Academy of Sciences, Huainan 232000, China
| | - Zhongkui Li
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Jin Wang
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Lixia Yuan
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Caiwen Lao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China
| | - Xiangsong Chen
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Huainan New Energy Research Center, Institute of Plasma Physics, Chinese Academy of Sciences, Huainan 232000, China
| | - Jianming Yao
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| |
Collapse
|
8
|
Meng J, Zhu Y, Wang H, Cao H, Mu W. Biosynthesis of Human Milk Oligosaccharides: Enzyme Cascade and Metabolic Engineering Approaches. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:2234-2243. [PMID: 36700801 DOI: 10.1021/acs.jafc.2c08436] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Human milk oligosaccharides (HMOs) have unique beneficial effects for infants and are considered as the new gold standard for premium infant formula. They are a collection of unconjugated glycans, and more than 200 distinct structures have been identified. Generally, HMOs are enzymatically produced by elongation and/or modification from lactose via stepwise glycosylation. Each glycosylation requires a specific glycosyltransferase (GT) and the corresponding nucleotide sugar donor. In this review, the typical HMO-producing GTs and the one-pot multienzyme modules for generating various nucleotide sugar donors are introduced, the principles for designing the enzyme cascade routes for HMO synthesis are described, and the important metabolic engineering strategies for mass production of HMOs are also reviewed. In addition, the future research directions in biotechnological production of HMOs were prospected.
Collapse
Affiliation(s)
- Jiawei Meng
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Hao Wang
- Bloomage Biotechnology Corporation, Limited, Jinan, Shandong 250010, People's Republic of China
| | - Hongzhi Cao
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong 266003, People's Republic of China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| |
Collapse
|
9
|
Zhu Y, Zhang J, Zhang W, Mu W. Recent progress on health effects and biosynthesis of two key sialylated human milk oligosaccharides, 3'-sialyllactose and 6'-sialyllactose. Biotechnol Adv 2023; 62:108058. [PMID: 36372185 DOI: 10.1016/j.biotechadv.2022.108058] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 10/25/2022] [Accepted: 11/06/2022] [Indexed: 11/13/2022]
Abstract
Human milk oligosaccharides (HMOs), the third major solid component in breast milk, are recognized as the first prebiotics for health benefits in infants. Sialylated HMOs are an important type of HMOs, accounting for approximately 13% of total HMOs. 3'-Sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) are two simplest sialylated HMOs. Both SLs display promising prebiotic effects, especially in promoting the proliferation of bifidobacteria and shaping the gut microbiota. SLs exhibit several health effects, including antiadhesive antimicrobial ability, antiviral activity, prevention of necrotizing enterocolitis, immunomodulatory activity, regulation of intestinal epithelial cell response, promotion of brain development, and cognition improvement. Both SLs have been approved as "Generally Recognized as Safe" by the American Food and Drug Administration and are commercially added to infant formula. The biosynthesis of SLs using enzymatic or microbial approaches has been widely studied. The enzymatic synthesis of SLs can be realized by two types of enzymes, sialidases with trans-sialidase activity and sialyltransferases. Microbial synthesis can be achieved by the multiple recombinant bacteria in one-pot reaction, which express the enzymes involved in SL synthesis pathways separately or in combination, or by metabolically engineered strains in a fermentation process. In this article, the physiological properties of 3'-SL and 6'-SL are summarized in detail and the biosynthesis of these SLs via enzymatic and microbial synthesis is comprehensively reviewed.
Collapse
Affiliation(s)
- Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jiameng Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
| |
Collapse
|
10
|
Zhang W, Vervoort J, Pan J, Gao P, Zhu H, Wang X, Zhang Y, Chen B, Liu Y, Li Y, Pang X, Zhang S, Jiang S, Lu J, Lyu J. Comparison of twelve human milk oligosaccharides in mature milk from different areas in China in the Chinese Human Milk Project (CHMP) study. Food Chem 2022; 395:133554. [PMID: 35830777 DOI: 10.1016/j.foodchem.2022.133554] [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: 08/25/2021] [Revised: 05/27/2022] [Accepted: 06/20/2022] [Indexed: 12/16/2022]
Abstract
Human milk oligosaccharides (HMOs) act as a vital role in the development of infant's gut microbiome and immune function. This study aimed to measure 12 oligosaccharides in milk from Chinese donors (n = 203), and evaluated the influences of multiple factors on the HMOs profiles. The results indicated that concentrations of 6'-sialyllactose were the highest among 12 oligosaccharides (2.31 ± 0.81 g/L). HMOs concentrations varied depending on geographical location. Latitude was observed to be related to concentrations of Lacto-N-neohexaose, lacto-N-fucopentaose III, 3'-sialyllactose (r = -0.67, r = +0.63 and r = +0.50, respectively). Environmental factors like seasons correlated with lacto-N-difucohexaose Ⅱ, Lacto-N-neohexaose and 2'-fucosyllactose (r = -0.47, r = -0.4, r = -0.35, respectively). Several HMOs concentrations were correlated with maternal diet. As a consequence, the HMOs profiles measured were influenced by geographical, environmental, maternal anthropometric as well as dietary factors.
Collapse
Affiliation(s)
- Wenyuan Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China; Laboratory of Biochemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Jacques Vervoort
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China; Laboratory of Biochemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Jiancun Pan
- Feihe Research Institute, Heilongjiang Feihe Dairy Co., Ltd, Beijing, China; PKUHSC-China Feihe Joint Research Institute of Nutrition and Healthy Lifespan Development, Xueyuan Road 38, Haidian, Beijing 100083, China
| | - Peng Gao
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Huiquan Zhu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Xiaodan Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Yumeng Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Baorong Chen
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Ying Liu
- Feihe Research Institute, Heilongjiang Feihe Dairy Co., Ltd, Beijing, China; PKUHSC-China Feihe Joint Research Institute of Nutrition and Healthy Lifespan Development, Xueyuan Road 38, Haidian, Beijing 100083, China
| | - Yuanyuan Li
- Feihe Research Institute, Heilongjiang Feihe Dairy Co., Ltd, Beijing, China; PKUHSC-China Feihe Joint Research Institute of Nutrition and Healthy Lifespan Development, Xueyuan Road 38, Haidian, Beijing 100083, China
| | - Xiaoyang Pang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Shuwen Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China
| | - Shilong Jiang
- Feihe Research Institute, Heilongjiang Feihe Dairy Co., Ltd, Beijing, China; PKUHSC-China Feihe Joint Research Institute of Nutrition and Healthy Lifespan Development, Xueyuan Road 38, Haidian, Beijing 100083, China.
| | - Jing Lu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China; Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center for Food Additives, School of Food and Health, Beijing Technology and Business University, Beijing, China.
| | - Jiaping Lyu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Science, Beijing, China.
| |
Collapse
|
11
|
Liu Y, Zhu Y, Wang H, Wan L, Zhang W, Mu W. Strategies for Enhancing Microbial Production of 2'-Fucosyllactose, the Most Abundant Human Milk Oligosaccharide. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11481-11499. [PMID: 36094047 DOI: 10.1021/acs.jafc.2c04539] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Human milk oligosaccharides (HMOs), a group of structurally diverse unconjugated glycans in breast milk, act as important prebiotics and have plenty of unique health effects for growing infants. 2'-Fucosyllactose (2'-FL) is the most abundant HMO, accounting for approximately 30%, among approximately 200 identified HMOs with different structures. 2'-FL can be enzymatically produced by α1,2-fucosyltransferase, using GDP-l-fucose as donor and lactose as acceptor. Metabolic engineering strategies have been widely used for enhancement of GDP-l-fucose supply and microbial production of 2'-FL with high productivity. GDP-l-fucose supply can be enhanced by two main pathways, including de novo and salvage pathways. 2'-FL-producing α1,2-fucosyltransferases have widely been identified from various microorganisms. Metabolic pathways for 2'-FL synthesis can be basically constructed by enhancing GDP-l-fucose supply and introducing α1,2-fucosyltransferase. Various strategies have been attempted to enhance 2'-FL production, such as acceptor enhancement, donor enhancement, and improvement of the functional expression of α1,2-fucosyltransferase. In this review, current progress in GDP-l-fucose synthesis and bacterial α1,2-fucosyltransferases is described in detail, various metabolic engineering strategies for enhancing 2'-FL production are comprehensively reviewed, and future research focuses in biotechnological production of 2'-FL are suggested.
Collapse
Affiliation(s)
- Yuanlin Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Hao Wang
- Bloomage Biotechnology Corp., Ltd., Jinan, Shandong 250010, People's Republic of China
| | - Li Wan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China
| |
Collapse
|
12
|
Zhang P, Zhu Y, Li Z, Zhang W, Guang C, Mu W. Designing a Highly Efficient Biosynthetic Route for Lacto- N-Neotetraose Production in Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:9961-9968. [PMID: 35938974 DOI: 10.1021/acs.jafc.2c04416] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recently, the biosynthesis of human milk oligosaccharides (HMOs) has been attracting increasing attention. Lacto-N-neotetraose (LNnT) is one of the most important neutral-core HMOs with promising health effects for infants. It has received Generally Recognized as Safe (GRAS) status and is the second HMO commercially added in infant formula after 2'-fucosyllactose. In previous studies, a series of engineered Escherichia coli strains have been constructed and optimized to produce high titers of precursor lacto-N-triose II. On the basis of these strains, LNnT-producing strains were constructed by overexpressing the β1,4-galactosyltransferase-encoding gene from Aggregatibacter actinomycetemcomitans NUM4039 (Aa-β1,4-GalT). Interestingly, an appreciable LNnT titer was obtained by weakening the metabolic flux of the UDP-GlcNAc pathway and simply overexpressing the essential genes lgtA, galE, and Aa-β1,4-GalT in lacZ-, wecB-, and nagB-deleted E. coli. Subsequently, LNnT synthesis was optimized through balancing the expression of these three biosynthetic enzymes. The optimized strain produced LNnT with an extracellular titer of 12.1 g/L in fed-batch cultivation, with the productivity and specific yield of 0.25 g/L·h and 0.27 g/g dry cell weight, respectively.
Collapse
Affiliation(s)
- Pan Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zeyu Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Cuie Guang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| |
Collapse
|
13
|
Li Z, Zhu Y, Zhang P, Zhang W, Mu W. Pathway Optimization and Uridine 5'-Triphosphate Regeneration for Enhancing Lacto- N-Tetraose Biosynthesis in Engineered Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:7727-7735. [PMID: 35723433 DOI: 10.1021/acs.jafc.2c02426] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recently, human milk oligosaccharides (HMOs) have attracted increasing attention and display great commercial importance, especially for the infant formula industry. Lacto-N-tetraose (LNT) is an important neutral HMO commercially added in infant formula and a core structure for synthesizing complex HMOs. Previously, a novel LNT-generating β-1,3-galactosyltransferase from Pseudogulbenkiania ferrooxidans was identified and used for construction of an LNT-producing engineered Escherichia coli. In this work, LNT biosynthesis was further enhanced by pathway optimization and uridine 5'-triphosphate (UTP) regeneration. The main strategies included genomic integration of UDP-glucose 4-epimerase-encoding gene, fine-tuning of the LNT pathway-related genes, blocking of competitive pathways related to UDP-galactose, and overexpression of UTP supply related genes. The maximal LNT titer reached 6.16 and 57.5 g/L by shake-flask and fed-batch fermentation, respectively.
Collapse
Affiliation(s)
- Zeyu Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Pan Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| |
Collapse
|
14
|
Zhang P, Zhu Y, Li Z, Zhang W, Mu W. Recent Advances on Lacto- N-neotetraose, a Commercially Added Human Milk Oligosaccharide in Infant Formula. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:4534-4547. [PMID: 35385279 DOI: 10.1021/acs.jafc.2c01101] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Human milk oligosaccharides (HMOs) act as the important prebiotics and display many unique health effects for infants. Lacto-N-neotetraose (LNnT), an abundant HMO, attracts increasing attention because of its unique beneficial effects to infants and great commercial importance. It occurs in all groups of human milk, but the concentration generally decreases gradually with the lactation period. It has superior prebiotic property for infants, and its other health effects have also been verified, including being immunomodulatory, anti-inflammatory, preventing necrotizing enterocolitis, antiadhesive antimicrobials, antiviral activity, and promoting maturation of intestinal epithelial cells. Safety evaluation and clinical trial studies suggest that LNnT is safe and well-tolerant for infants. It has been commercially added as a functional ingredient in infant formula. LNnT can be synthesized via chemical, enzymatic, or cell factory approachs, among which the metabolic engineering-based cell factory synthesis is considered to be the most practical and effective. In this article, the occurrence and physiological effects of LNnT were reviewed in detail, the safety evaluation and regulation status of LNnT were described, various approaches to LNnT synthesis were comprehensively summarized and compared, and the future perspectives of LNnT-related studies were provided.
Collapse
Affiliation(s)
- Pan Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zeyu Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| |
Collapse
|
15
|
Chen G, Wu H, Zhu Y, Wan L, Zhang W, Mu W. Glycosyltransferase from Bacteroides gallinaceum Is a Novel α-1,3-Fucosyltransferase that Can Be Used for 3-Fucosyllactose Production In Vivo by Metabolically Engineered Escherichia coli. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:1934-1942. [PMID: 34989571 DOI: 10.1021/acs.jafc.1c06719] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
As one of the attractive fucosylated human milk oligosaccharides, the biological production of 3-fucosyllactose (3-FL) has received great attention, as it exhibits many excellent physiological functions for infants. In this work, a novel 3-FL-producing α-1,3-fucosyltransferase (α1,3-FucT) named FutM2 from Bacteroides gallinaceum was first selected from nine potential candidates in the NCBI database. Then, a highly 3-FL-producing engineered Escherichia coli strain was constructed by modular pathway enhancement including the GDL-l-fucose precursor supply by overexpressing manC, manB, gmd, and wcaG (CBGW), and the 3-FL synthesis pathway by introducing B. gallinaceum FutM2. Finally, a titer of 20.3 g L-1 and productivity of 0.40 g L-1 h-1 of 3-FL were achieved in the 3-L bioreactor by engineered E. coli (ΔlacZΔwcaJ) harboring pCDF-CBGW and pET-futM2. Our study provided a novel α1,3-FucT from B. gallinaceum that could be used for 3-FL production, presenting an efficient microbial cell factory platform to de novo synthesize 3-FL from glycerol.
Collapse
Affiliation(s)
- Geng Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Hao Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
- School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, China
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Li Wan
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, Jiangsu 214122, China
| |
Collapse
|
16
|
Hu D, Wu H, Zhu Y, Zhang W, Mu W. Engineering Escherichia coli for highly efficient production of lacto-N-triose II from N-acetylglucosamine, the monomer of chitin. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:198. [PMID: 34625117 PMCID: PMC8501739 DOI: 10.1186/s13068-021-02050-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/29/2021] [Indexed: 05/05/2023]
Abstract
BACKGROUND Lacto-N-triose II (LNT II), an important backbone for the synthesis of different human milk oligosaccharides, such as lacto-N-neotetraose and lacto-N-tetraose, has recently received significant attention. The production of LNT II from renewable carbon sources has attracted worldwide attention from the perspective of sustainable development and green environmental protection. RESULTS In this study, we first constructed an engineered E. coli cell factory for producing LNT II from N-acetylglucosamine (GlcNAc) feedstock, a monomer of chitin, by introducing heterologous β-1,3-acetylglucosaminyltransferase, resulting in a LNT II titer of 0.12 g L-1. Then, lacZ (lactose hydrolysis) and nanE (GlcNAc-6-P epimerization to ManNAc-6-P) were inactivated to further strengthen the synthesis of LNT II, and the titer of LNT II was increased to 0.41 g L-1. To increase the supply of UDP-GlcNAc, a precursor of LNT II, related pathway enzymes including GlcNAc-6-P deacetylase, glucosamine synthase, and UDP-N-acetylglucosamine pyrophosphorylase, were overexpressed in combination, optimized, and modulated. Finally, a maximum titer of 15.8 g L-1 of LNT II was obtained in a 3-L bioreactor with optimal enzyme expression levels and β-lactose and GlcNAc feeding strategy. CONCLUSIONS Metabolic engineering of E. coli is an effective strategy for LNT II production from GlcNAc feedstock. The titer of LNT II could be significantly increased by modulating the gene expression strength and blocking the bypass pathway, providing a new utilization for GlcNAc to produce high value-added products.
Collapse
Affiliation(s)
- Duoduo Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Hao Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
| | - Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, Jiangsu, China.
| |
Collapse
|
17
|
Zhu Y, Li Z, Luo G, Wu H, Zhang W, Mu W. Metabolic Engineering of Escherichia coli for Efficient Biosynthesis of Lacto- N-tetraose Using a Novel β-1,3-Galactosyltransferase from Pseudogulbenkiania ferrooxidans. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11342-11349. [PMID: 34436880 DOI: 10.1021/acs.jafc.1c04059] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Human milk oligosaccharides (HMOs) attract considerable interest in recent years because of their particular role in infant health. Lacto-N-tetraose (LNT), one of the most abundant HMOs, has been commercially added in the infant formula as a functional fortifier. In this study, a novel LNT-producing β-1,3-galactosyltransferase (β-1,3-GalT) from Pseudogulbenkiania ferrooxidans was screened from 14 putative candidates, and a highly LNT-producing metabolically engineered Escherichia coli strain was constructed based on a previously constructed lacto-N-triose II (LNT II)-producing strain, by strengthening UDP-galactose synthesis and introduction of P. ferrooxidans β-1,3-GalT. The engineered strain produced 3.11 and 25.49 g/L LNT in shake-flask and fed-batch cultivation, with the molar conversion ratio of LNT II to LNT of 88.15 and 85.09%, respectively. The productivity and specific yield of LNT in fed-batch cultivation were measured to be 0.61 g/L·h and 0.76 g/g dry cell weight, respectively. To the best of our knowledge, it is the highest LNT yield ever reported.
Collapse
Affiliation(s)
- Yingying Zhu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Zeyu Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Guocong Luo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Hao Wu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wenli Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wanmeng Mu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China
- International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| |
Collapse
|
18
|
Efficient biosynthesis of lacto-N-neotetraose by a novel β-1,4-galactosyltransferase from Aggregatibacter actinomycetemcomitans NUM4039. Enzyme Microb Technol 2021; 153:109912. [PMID: 34670186 DOI: 10.1016/j.enzmictec.2021.109912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/16/2021] [Accepted: 09/01/2021] [Indexed: 01/03/2023]
Abstract
Lacto-N-neotetraose (LNnT) is a unique tetrasaccharide naturally occurring in human milk, as an important member of human milk oligosaccharides. Because of promising beneficial effects, it has been commercially added as a functional fortifier in infant formula. β-1,4-Galactosyltransferase (β-1,4-GalT) catalyzes LNnT biosynthesis from uridine 5'-diphospho-galactose (UDP-Gal) to lacto-N-triose II (LNT II). There have been only two LNnT-producing bacterial β-1,4-GalTs, including the ones from Neisseria meningitidis and Histophilus somni. In this study, a novel LNnT-producing β-1,4-GalT was identified from Aggregatibacter actinomycetemcomitans. The enzyme was easily overexpressed in E. coli in soluble form. It displayed much higher transglycosylation versus hydrolysis activity, indicating its great potential in LNnT biosynthesis. The enzyme produced 13 mM LNnT from 20 mM LNT II and 60 mM UDP-Gal, with the yield of 65 % on LNT II and very low level of UDP-Gal hydrolysis. Therefore, it could be considered as a good candidate for the practical LNnT production.
Collapse
|