title: Trophic Interactions of Infant Bifidobacteria andEubacterium halliiduring L-Fucose and Fucosyllactose Degradation.
abstract: Fucosyllactoses (2'- or 3'-FL) account for up to 20% of human milk oligosaccharides (HMOs). Infant bifidobacteria, such asBifidobacterium longumsubsp.infantis, utilize the lactose moiety to form lactate and acetate, and metabolize L-fucose to 1,2-propanediol (1,2-PD).Eubacterium halliiis a common member of the adult gut microbiota that can produce butyrate from lactate and acetate, and convert 1,2-PD to propionate. Recently, a Swiss cohort study identifiedE. halliias one of the first butyrate producers in the infant gut. However, the global prevalence ofE. halliiand its role in utilization of HMO degradation intermediates remains unexplored. Fecal 16S rRNA gene libraries (n= 857) of humans of all age groups from Venezuela, Malawi, Switzerland, and the USA were screened for the occurrence ofE. hallii. Single and co-culture experiments ofB. longumsubsp.infantisandE. halliiwere conducted in modified YCFA containing acetate and glucose, L-fucose, or FL.Bifidobacteriumspp. (n= 56) of different origin were screened for the ability to metabolize L-fucose. Relative abundance ofE. halliiwas low (10-5-10-3%) during the first months but increased and reached adult levels (0.01-10%) at 5-10 years of age in all four populations. In single culture,B. longumsubsp.infantisgrew in the presence of all three carbohydrates whileE. halliiwas metabolically active only with glucose. In co-cultureE. halliialso grew with L-fucose or FL. In co-cultures grown with glucose, acetate, and glucose were consumed and nearly equimolar proportions of formate and butyrate were formed.B. longumsubsp.infantisused L-fucose and produced 1,2-PD, acetate and formate in a ratio of 1:1:1, while 1,2-PD was used byE. halliito form propionate.E. halliiconsumed acetate, lactate and 1,2-PD released byB. longumsubsp.infantisfrom FL, and produced butyrate, propionate, and formate. BesideB. longumsubsp.infantis, Bifidobacterium breve, and a strain ofB. longumsubsp.suiswere able to utilize L-fucose. This study identified a trophic interaction of infantbifidobacteriaandE. halliiduring L-fucose degradation, and pointed atE. halliias a metabolically versatile species that occurs in infants and utilizes intermediates of bifidobacterial HMO fermentation.
authors.affiliation: Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zurich Zurich, Switzerland.
authors.forename: Clarissa
authors.initials: C
authors.lastname: Schwab
authors.affiliation: Department of Biosystems Science and Engineering, ETH ZurichBasel, Switzerland; Scientific IT Services, ETH ZurichBasel, Switzerland; Swiss Institute of BioinformaticsBasel, Switzerland.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Ruscheweyh
authors.affiliation: Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH ZurichZurich, Switzerland; Department of Microbiology, Nutrition, and Dietetics, Czech University of Life Sciences PraguePrague, Czechia.
authors.forename: Vera
authors.initials: V
authors.lastname: Bunesova
authors.affiliation: Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zurich Zurich, Switzerland.
authors.forename: Van Thanh
authors.initials: VT
authors.lastname: Pham
authors.affiliation: Department of Biosystems Science and Engineering, ETH ZurichBasel, Switzerland; Swiss Institute of BioinformaticsBasel, Switzerland.
authors.forename: Niko
authors.initials: N
authors.lastname: Beerenwinkel
authors.affiliation: Laboratory of Food Biotechnology, Department of Health Sciences and Technology, ETH Zurich Zurich, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lacroix
keywords: Eubacterium hallii; bifidobacterium; fucose; fucosyllactose; trophic interactions