Mechanistic insights into the structure-dependant and strain-specific utilization of wheat arabinoxylan by Bifidobacterium longum.
Carbohydr Polym
; 249: 116886, 2020 Dec 01.
Article
en En
| MEDLINE
| ID: mdl-32933699
ABSTRACT
Arabinoxylan (AX), an important dietary fiber from cereal grains, is mainly metabolised in the large intestine by gut bacteria, especially bifidobacteria. This study investigated the uptake and metabolism of wheat AX by a Bifidobacterium longum strain that could grow well with AX as the sole carbon source. The bacterial growth rate showed a significant correlation to the molecular weight (MW) of AX and its acid hydrolysates. Assessment of the key AX degrading enzymes suggested that the uptake and consumption of AX involved extracellular cleavage of xylan backbone and intracellular degradation of both the backbone and the arabinose substitution. The preference for native or partially hydrolysed AX with single substitutions and a sufficiently high MW suggested the structure-dependant uptake by the bacterial cells. Genetic analysis of B. longum showed the lack of ß-xylosidase, suggesting the existence of unknown enzymes or dual/multiple-specific enzymes for hydrolysis of the non-reducing end of xylan backbone.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Triticum
/
Xilanos
/
Bifidobacterium longum
Idioma:
En
Revista:
Carbohydr Polym
Año:
2020
Tipo del documento:
Article
País de afiliación:
Hong Kong