Biochemical characterization of β-galactosidases and engineering of their product specificity

Huifang Yin

Biochemical characterization of β-galactosidases and engineering of their product specificity

Vertaalde titel van de bijdrage: Biochemische karakterisering van β-galactosidasen en engineering van hun productspecificiteit

Huifang Yin

Enzymologie

Onderzoeksoutput: Thesis fully internal (DIV)

1202 Downloads (Pure)

Samenvatting

De menselijke darm bevat vele triljoenen micro-organismen, met een totaal gewicht tot 2 kg. Deze darmflora is van belang voor de menselijke gezondheid; ze bevordert vertering van voedsel, produceert sommige vitaminen en helpt ziekteverwekkende bacteriën te bestrijden. Zo bevordert een gezonde darmflora de menselijke gezondheid. Prebiotica zijn speciale koolhydraten die de gezonde micro-organismen helpen te groeien die vervolgens ongezonde micro-organismen remmen, en zodoende een gezonde darmflora bevorderen. Humane melk oligosachariden (hMOS) zijn speciale prebiotica die in moedermelk zitten en sterke gezondheidsvoordelen geven aan de baby. Borstvoeding geven is echter niet voor iedereen mogelijk. In die gevallen is er de mogelijkheid flesvoeding te gebruiken om de baby te voeden. Flesvoeding is gemaakt op basis van koemelk, waar amper prebiotica in zitten. Als alternatief voor hMOS, worden galactooligosachariden (GOS) toegevoegd aan de flesvoeding, om het effect van hMOS na te bootsen. GOS zijn mengsels van koolhydraten, geproduceerd uit melk suiker door bacteriële β-galactosidase enzymen. Verschillende β-galactosidase enzymen, produceren verschillende GOS mengsels, met variatie in samenstelling en structuren, maar ook in prebiotische fucntionaliteit. Hoewel verschillende β-galactosidase enzymen en GOS mengsels bestudeerd zijn, was er nog weinig bekend over welke enzym kenmerken bepalend zijn voor de samenstelling en structuren van de GOS. Daartoe is dit onderwerp van studie in dit proefschrift, met combinaties van enzym mutagenese en gedetailleerde analyse van de gevormde producten. Er zijn eveneens nieuwe prebiotische mengsels van structuren gevormd in deze studie, die mogelijk een betere functionaliteit in flesvoeding hebben en dus de potentie hebben toepassing te vinden in de industrie.

Vertaalde titel van de bijdrage	Biochemische karakterisering van β-galactosidasen en engineering van hun productspecificiteit
Originele taal-2	English
Kwalificatie	Doctor of Philosophy
Toekennende instantie	Rijksuniversiteit Groningen
Begeleider(s)/adviseur	Dijkhuizen, Lubbert, Supervisor van Leeuwen, Sander, Co-supervisor
Datum van toekenning	25-sep.-2017
Plaats van publicatie	[Groningen]
Uitgever	University of Groningen
Gedrukte ISBN's	978-94-034-0083-9
Elektronische ISBN's	978-94-034-0082-2
Status	Published - 2017

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Title and contentsFinal publisher's version, 344 KB
Chapter 1Final publisher's version, 590 KB
Chapter 2Final publisher's version, 1,59 MB
Chapter 3Final publisher's version, 1,32 MB
Chapter 4Final publisher's version, 1,25 MB
Chapter 5Final publisher's version, 1,49 MB
Chapter 6Final publisher's version, 311 KB
Samenvatting en vooruitzichtenFinal publisher's version, 327 KB
Chinese summaryFinal publisher's version, 257 KB
AcknowledgementsFinal publisher's version, 260 KB
Complete thesisFinal publisher's version, 5,24 MB
PropositionsFinal publisher's version, 154 KB

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title = "Biochemical characterization of β-galactosidases and engineering of their product specificity",

abstract = "The human intestine contains tens of trillions of microorganisms, and has a weight up to 2 kg. This gut microbiota is important for human health; it contributes to food digestion, produces some vitamins, and helps combating pathogenic bacteria. Therefore, a healthy and balanced gut microbiota benefits human wellbeing. Prebiotic compounds are special carbohydrates that promote growth of beneficial microorganisms which in turn inhibit harmful microorganisms, and thus stimulate a healthy gut microbiota. Human milk oligosaccharides (hMOS) are the special prebiotics that occur in mother milk and provide strong health benefits to babies. Breast feeding is not possible for every mother, however. In this case, they may choose to use infant formula to feed their babies. Infant formula is based on cow milk, which contains almost no prebiotics. As an alternative to hMOS – galactooligosaccharides (GOS), have been added into the infant formula to mimic the prebiotic functions of hMOS. GOS are carbohydrate mixtures produced by microbial β-galactosidase enzymes from milk sugar. Different β-galactosidase enzymes produce different GOS mixtures, with variations in composition, structures, and also in prebiotics functions. Although various β-galactosidase enzymes and the produced GOS mixtures have been studied, we still knew little about what enzyme features determine the GOS composition and structures produced. This topic therefore has been studied in detail in this PhD thesis, combining enzyme mutagenesis and detailed analysis of products formed. Also, this study has generated new types of prebiotics, which may have better functionality in infant nutrition for babies, and thus have potential industrial application.",

author = "Huifang Yin",

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AU - Yin, Huifang

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N2 - The human intestine contains tens of trillions of microorganisms, and has a weight up to 2 kg. This gut microbiota is important for human health; it contributes to food digestion, produces some vitamins, and helps combating pathogenic bacteria. Therefore, a healthy and balanced gut microbiota benefits human wellbeing. Prebiotic compounds are special carbohydrates that promote growth of beneficial microorganisms which in turn inhibit harmful microorganisms, and thus stimulate a healthy gut microbiota. Human milk oligosaccharides (hMOS) are the special prebiotics that occur in mother milk and provide strong health benefits to babies. Breast feeding is not possible for every mother, however. In this case, they may choose to use infant formula to feed their babies. Infant formula is based on cow milk, which contains almost no prebiotics. As an alternative to hMOS – galactooligosaccharides (GOS), have been added into the infant formula to mimic the prebiotic functions of hMOS. GOS are carbohydrate mixtures produced by microbial β-galactosidase enzymes from milk sugar. Different β-galactosidase enzymes produce different GOS mixtures, with variations in composition, structures, and also in prebiotics functions. Although various β-galactosidase enzymes and the produced GOS mixtures have been studied, we still knew little about what enzyme features determine the GOS composition and structures produced. This topic therefore has been studied in detail in this PhD thesis, combining enzyme mutagenesis and detailed analysis of products formed. Also, this study has generated new types of prebiotics, which may have better functionality in infant nutrition for babies, and thus have potential industrial application.

AB - The human intestine contains tens of trillions of microorganisms, and has a weight up to 2 kg. This gut microbiota is important for human health; it contributes to food digestion, produces some vitamins, and helps combating pathogenic bacteria. Therefore, a healthy and balanced gut microbiota benefits human wellbeing. Prebiotic compounds are special carbohydrates that promote growth of beneficial microorganisms which in turn inhibit harmful microorganisms, and thus stimulate a healthy gut microbiota. Human milk oligosaccharides (hMOS) are the special prebiotics that occur in mother milk and provide strong health benefits to babies. Breast feeding is not possible for every mother, however. In this case, they may choose to use infant formula to feed their babies. Infant formula is based on cow milk, which contains almost no prebiotics. As an alternative to hMOS – galactooligosaccharides (GOS), have been added into the infant formula to mimic the prebiotic functions of hMOS. GOS are carbohydrate mixtures produced by microbial β-galactosidase enzymes from milk sugar. Different β-galactosidase enzymes produce different GOS mixtures, with variations in composition, structures, and also in prebiotics functions. Although various β-galactosidase enzymes and the produced GOS mixtures have been studied, we still knew little about what enzyme features determine the GOS composition and structures produced. This topic therefore has been studied in detail in this PhD thesis, combining enzyme mutagenesis and detailed analysis of products formed. Also, this study has generated new types of prebiotics, which may have better functionality in infant nutrition for babies, and thus have potential industrial application.

M3 - Thesis fully internal (DIV)

SN - 978-94-034-0083-9

PB - University of Groningen

CY - [Groningen]

ER -