-
1.
Production of HMOs using microbial hosts - from cell engineering to large scale production.
Bych, K, Mikš, MH, Johanson, T, Hederos, MJ, Vigsnæs, LK, Becker, P
Current opinion in biotechnology. 2019;:130-137
Abstract
Human Milk Oligosaccharides (HMOs) constitute an important, highly abundant part of mothers' milk delivering many health benefits to the neonate. Until recently, limited availability of HMOs has prevented their use in infant nutrition and impeded research into their biological effects. The shift from chemical synthesis to biotechnological manufacturing has made them accessible in quantities and at prices that are within reach for commercial applications, including infant formula. It accelerated the studies in the field of pre-clinical and clinical HMO biology. This review gives a short overview of HMO manufacturing from the design and optimization of the microbial cell factory and the production of HMOs in the industrial fermentation process to the purification in the downstream process necessary to obtain a final product. Moreover, the transition from chemistry to biotechnology and the current regulatory landscape and commercialization progress are briefly reviewed.
-
2.
Synthesis of Human Milk Oligosaccharides: Protein Engineering Strategies for Improved Enzymatic Transglycosylation.
Zeuner, B, Teze, D, Muschiol, J, Meyer, AS
Molecules (Basel, Switzerland). 2019;(11)
Abstract
Human milk oligosaccharides (HMOs) signify a unique group of oligosaccharides in breast milk, which is of major importance for infant health and development. The functional benefits of HMOs create an enormous impetus for biosynthetic production of HMOs for use as additives in infant formula and other products. HMO molecules can be synthesized chemically, via fermentation, and by enzymatic synthesis. This treatise discusses these different techniques, with particular focus on harnessing enzymes for controlled enzymatic synthesis of HMO molecules. In order to foster precise and high-yield enzymatic synthesis, several novel protein engineering approaches have been reported, mainly concerning changing glycoside hydrolases to catalyze relevant transglycosylations. The protein engineering strategies for these enzymes range from rationally modifying specific catalytic residues, over targeted subsite -1 mutations, to unique and novel transplantations of designed peptide sequences near the active site, so-called loop engineering. These strategies have proven useful to foster enhanced transglycosylation to promote different types of HMO synthesis reactions. The rationale of subsite -1 modification, acceptor binding site matching, and loop engineering, including changes that may alter the spatial arrangement of water in the enzyme active site region, may prove useful for novel enzyme-catalyzed carbohydrate design in general.
-
3.
Exit Gluten-Free and Enter Low FODMAPs: A Novel Dietary Strategy to Reduce Gastrointestinal Symptoms in Athletes.
Lis, DM
Sports medicine (Auckland, N.Z.). 2019;(Suppl 1):87-97
-
-
Free full text
-
Abstract
Exercise-associated physiological disturbances alter gastrointestinal function and integrity. These alterations may increase susceptibility to dietary triggers, namely gluten and a family of short-chain carbohydrates known as FODMAPs (fermentable oligo-, di-, monosaccharides and polyols). A recent surge in the popularity of gluten-free diets (GFDs) among athletes without celiac disease has been exacerbated by unsubstantiated commercial health claims and high-profile athletes citing this diet to be the secret to their success. Up to 41% of athletes at least partially adhere to a GFD diet, with the belief that gluten avoidance improves exercise performance and parameters influencing performance, particularly gastrointestinal symptoms (GIS). In contrast to these beliefs, seminal work investigating the effects of a GFD in athletes without celiac disease has demonstrated no beneficial effect of a GFD versus a gluten-containing diet on performance, gastrointestinal health, inflammation, or perceptual wellbeing. Interestingly, the subsequent reduction in FODMAPs concurrent with the elimination of gluten-containing grains may actually be the factors affecting GIS improvement, not gluten. Pre-existent in the gastrointestinal tract or ingested during exercise, the osmotic and gas-producing effects of variably absorbed FODMAPs may trigger or increase the magnitude of exercise-associated GIS. Research using FODMAP reduction to address gastrointestinal issues in clinically healthy athletes is emerging as a promising strategy to reduce exercise-associated GIS. Applied research and practitioners merging clinical and sports nutrition methods will be essential for the effective use of a low FODMAP approach to tackle the multifactorial nature of gastrointestinal disturbances in athletes.
-
4.
Non-digestible carbohydrates in infant formula as substitution for human milk oligosaccharide functions: Effects on microbiota and gut maturation.
Akkerman, R, Faas, MM, de Vos, P
Critical reviews in food science and nutrition. 2019;(9):1486-1497
Abstract
Human milk (HM) is the golden standard for nutrition of newborn infants. Human milk oligosaccharides (HMOs) are abundantly present in HM and exert multiple beneficial functions, such as support of colonization of the gut microbiota, reduction of pathogenic infections and support of immune development. HMO-composition is during lactation continuously adapted by the mother to accommodate the needs of the neonate. Unfortunately, for many valid reasons not all neonates can be fed with HM and are either totally or partly fed with cow-milk derived infant formulas, which do not contain HMOs. These cow-milk formulas are supplemented with non-digestible carbohydrates (NDCs) that have functional effects similar to that of some HMOs, since production of synthetic HMOs is challenging and still very expensive. However, NDCs cannot substitute all HMO functions. More efficacious NDCs may be developed and customized for specific groups of neonates such as pre-matures and allergy prone infants. Here current knowledge of HMO functions in the neonate in view of possible replacement of HMOs by NDCs in infant formulas is reviewed. Furthermore, methods to expedite identification of suitable NDCs and structure/function relationships are reviewed as in vivo studies in babies are impossible.
-
5.
Varied Pathways of Infant Gut-Associated Bifidobacterium to Assimilate Human Milk Oligosaccharides: Prevalence of the Gene Set and Its Correlation with Bifidobacteria-Rich Microbiota Formation.
Sakanaka, M, Gotoh, A, Yoshida, K, Odamaki, T, Koguchi, H, Xiao, JZ, Kitaoka, M, Katayama, T
Nutrients. 2019;(1)
Abstract
The infant's gut microbiome is generally rich in the Bifidobacterium genus. The mother's milk contains natural prebiotics, called human milk oligosaccharides (HMOs), as the third most abundant solid component after lactose and lipids, and of the different gut microbes, infant gut-associated bifidobacteria are the most efficient in assimilating HMOs. Indeed, the fecal concentration of HMOs was found to be negatively correlated with the fecal abundance of Bifidobacterium in infants. Given these results, two HMO molecules, 2'-fucosyllactose and lacto-N-neotetraose, have recently been industrialized to fortify formula milk. As of now, however, our knowledge about the HMO consumption pathways in infant gut-associated bifidobacteria is still incomplete. The recent studies indicate that HMO assimilation abilities significantly vary among different Bifidobacterium species and strains. Therefore, to truly maximize the effects of prebiotic and probiotic supplementation in commercialized formula, we need to understand HMO consumption behaviors of bifidobacteria in more detail. In this review, we summarized how different Bifidobacterium species/strains are equipped with varied gene sets required for HMO assimilation. We then examined the correlation between the abundance of the HMO-related genes and bifidobacteria-rich microbiota formation in the infant gut through data mining analysis of a deposited fecal microbiome shotgun sequencing dataset. Finally, we shortly described future perspectives on HMO-related studies.
-
6.
Lignocellulose derived functional oligosaccharides: production, properties, and health benefits.
Bhatia, L, Sharma, A, Bachheti, RK, Chandel, AK
Preparative biochemistry & biotechnology. 2019;(8):744-758
Abstract
Lignocellulosic biomass (LB) is the renewable feedstock for the production of fuel/energy, feed/food, chemicals, and materials. LB could also be the versatile source of the functional oligosaccharides, which are non-digestible food ingredients having numerous applications in food, cosmetics, pharmaceutical industries, and others. The burgeoning functional food demand is expected to be more than US$440 billion in 2022. Because of higher stability at low pH and high temperature, oligosaccharides stimulate the growth of prebiotic bifidobacteria and lactic acid bacteria. Xylooligosaccharides (XOS) are major constituents of oligosaccharides consisting of 2-7 xylose monomeric units linked via β-(1,4)-linkages. XOS can be obtained from various agro-residues by thermochemical pretreatment, enzymatic or chemoenzymatic methods. While thermochemical methods are fast, reproducible, enzymatic methods are substrate specific, costly, and produce minimum side products. Enzymatic methods are preferred for the production of food grade and pharmaceutically important oligosaccharides. XOS are potent prebiotics having antioxidant properties and enhance the bio-adsorption of calcium and improving bowel functions, etc. LB can cater to the increasing demand of oligosaccharides because of their foreseeable amount and the advancements in technology to recover oligosaccharides. This paper summarizes the methods for oligosaccharides production from LB, classification, and benefits of oligosaccharides on human health.
-
7.
Prebiotic Oligosaccharides Prepared by Enzymatic Degradation of Dietary Fibers in Rice Grains.
Kyu, MT, Dar, B, Aye, SS, Matsuda, T
Journal of nutritional science and vitaminology. 2019;(Supplement):S143-S147
Abstract
Rice are consumed mainly as polished rice grains. In the threshing and polishing processes of paddy rice, a considerable amount of husk and bran are separated as by-products. Rice bran is utilized for oil production, whereas rice husk as well as straw is not fully utilized. Defatted rice bran is rich in proteins and non-digestible polysaccharides, while husk and straw consist mainly of plant cell wall components, including cellulose, hemicellulose and pectin. Such non-digestible polysaccharides function in gastrointestinal lumen as dietary fiber, though physiological functions and their application are limited. Non-digestible oligosaccharides have recently been interested as prebiotics from a viewpoint of health benefit via utilization by intestinal microbiota. A diversity of non-digestible polysaccharides in rice bran and husk are good and ecological sources for production of both prebiotic and potentially prebiotic oligosaccharides. In this review, we summarize non-digestible polysaccharides constituting cell wall of rice grains including husk and degradation of the polysaccharides into oligo- and monosaccharides by microbial glycoside hydrolases. Prebiotic potential of such oligosaccharides derived from rice non-digestible polysaccharides are also introduced. Finally, our recent attempt for effective production of cello-oligosaccharides by regulated enzymatic degradation is briefly described.
-
8.
Microbial production of sialic acid and sialylated human milk oligosaccharides: Advances and perspectives.
Zhang, X, Liu, Y, Liu, L, Li, J, Du, G, Chen, J
Biotechnology advances. 2019;(5):787-800
Abstract
Sialic acids (SAs) are important functional sugars, and monomers of sialylated human milk oligosaccharides (sialylated HMOs or sialyllactoses), which are crucial for improving infant development and can facilitate infant brain development, maintain brain health, and enhance immunity. The most common form of SA is N-acetylneuraminic acid (NeuAc), and the main forms of sialyllactoses are 6'-sialyllactose (6'-SL) and 3'-sialyllactose (3'-SL). As functional food additive, the demand for NeuAc and sialyllactoses will continuously increase due to their wide and important fields of application. However, NeuAc and sialyllactoses produced by traditional extraction methods are inefficient and may cause allergen contamination, and cannot keep up with the rapidly increasing market demand. Therefore, the production of NeuAc and sialyllactoses by sustainable biotechnological methods have attracted increasing attention. In particular, the development of metabolic engineering and synthetic biology techniques and strategies have promoted efficient biosynthesis of NeuAc and sialyllactoses. In this review, we first discussed the application of NeuAc and sialyllactoses. Secondly, metabolic engineering and protein engineering-fueled progress of whole-cell catalysis and de novo synthesis of NeuAc and sialyllactoses were systematically summarized and compared. Furthermore, challenges of efficient microbial production of NeuAc and sialyllactoses as well as strategies for overcoming the challenges were discussed, such as clustered regularly interspaced short palindromic repeats interference (CRISPRi)-aided identification of key precursor transport pathways, synergistically debottleneck of kinetic and thermodynamic limits in synthetic pathways, and dynamic regulation of metabolic pathways for balancing cell growth and production. We hope this review can further facilitate the understanding of limiting factors that hampered efficient production of sialic acid and sialyllactoses, as well as contribute to the development of strategies for the construction of efficient production hosts for high-level production of sialic acid and sialyllactose based on synthetic biology tools and strategies.
-
9.
Dietary Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs) and Gastrointestinal Disease.
Vakil, N
Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2018;(4):468-475
Abstract
FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Dietary modification of FODMAPs has been shown to have significant effects on the physiology of the gastrointestinal tract and improves symptoms of abdominal pain, distention, and bloating in patients with irritable bowel syndrome. Structured withdrawal and reintroduction of FODMAPs supervised by a dietitian is the optimal practice for dietary FODMAP modification in irritable bowel syndrome. FODMAPs are present in enteral feeding formulas and may have a role in diarrhea and bloating in tube-fed patients. Emerging areas of research include the effects of dietary modification of FODMAPs on the microbiome, micronutrient absorption, and caloric intake. FODMAP dietary modification is an emerging area in other gastrointestinal disorders and is of relevance to all practicing dietitians.
-
10.
Human Milk Oligosaccharides as Promising Antivirals.
Morozov, V, Hansman, G, Hanisch, FG, Schroten, H, Kunz, C
Molecular nutrition & food research. 2018;(6):e1700679
Abstract
Human milk oligosaccharides (HMOs) are diverse unconjugated carbohydrates that are highly abundant in human breast milk. These glycans are investigated in the context of exhibiting multiple functions in infant growth and development. They seem to provide protection against infectious diseases, including a number of poorly manageable viral infections. Although the potential mechanism of the HMO antiviral protection is rather broad, much of the current experimental work has focused on studying of HMO antiadhesive properties. HMOs may mimic structures of viral receptors and block adherence to target cells, thus preventing infection. Still, the potential of HMOs as a source for new antiviral drugs is relatively unexploited. This can be partly attributed to the extreme complexity of the virus-carbohydrate interactions and technical difficulties in HMO isolation, characterization, and manufacturing procedures. Fortunately, we are currently entering a period of major technological advances that have enabled deeper insights into carbohydrate mediated viral entry, rational selection of HMOs as anti-entry inhibitors, and even evaluation of individual synthetic HMO structures. Here, we provide an up-to-date review on glycan binding studies for rotaviruses, noroviruses, influenza viruses, and human immunodeficiency viruses. We also discuss the preventive and therapeutic potential of HMOs as anti-entry inhibitors and address challenges on the route from fundamental studies to clinical trials.