Glycoside hydrolase family 32 enzymes from Bombella spp. catalyze the formation of high-molecular weight fructans from sucrose.

Autor:	Härer L; Chair of Microbiology, Technical University of Munich, Gregor-Mendel-Straße 4, 85354 Freising, Germany., Ernst L; Institute of Chemistry, Division of Food Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120 Halle (Saale), Germany., Bechtner J; Department of Food Science-Food Technology, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark., Wefers D; Institute of Chemistry, Division of Food Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 2, 06120 Halle (Saale), Germany., Ehrmann MA; Chair of Microbiology, Technical University of Munich, Gregor-Mendel-Straße 4, 85354 Freising, Germany.
Jazyk:	angličtina
Zdroj:	Journal of applied microbiology [J Appl Microbiol] 2023 Nov 01; Vol. 134 (11).
DOI:	10.1093/jambio/lxad268
Abstrakt:	Aims: Acetic acid bacteria of the genus Bombella have not been reported to produce exopolysaccharides (EPS). In this study, the formation of fructans by B. apis TMW 2.1884 and B. mellum TMW 2.1889 was investigated. Methods and Results: Out of eight strains from four different Bombella species, only B. apis TMW 2.1884 and B. mellum TMW 2.1889 showed EPS formation with 50 g l-1 sucrose as substrate. Both EPS were identified as high-molecular weight (HMW) polymers (106-107 Da) by asymmetric flow field-flow fractionation coupled to multi angle laser light scattering and UV detecors (AF4-MALLS/UV) and high performance size exclusion chromatography coupled to MALLS and refractive index detectors (HPSEC-MALLS/RI) analyses. Monosaccharide analysis via trifluoroacetic acid hydrolysis showed that both EPS are fructans. Determination of glycosidic linkages by methylation analysis revealed mainly 2,6-linked fructofuranose (Fruf) units with additional 2,1-linked Fruf units (10%) and 2,1,6-Fruf branched units (7%). No glycoside hydrolase (GH) 68 family genes that are typically associated with the formation of HMW fructans in bacteria could be identified in the genomes. Through heterologous expression in Escherichia coli Top10, an enzyme of the GH32 family could be assigned to the catalysis of fructan formation. The identified fructosyltransferases could be clearly differentiated phylogenetically and structurally from other previously described bacterial fructosyltransferases. Conclusions: The formation of HMW fructans by individual strains of the genus Bombella is catalyzed by enzymes of the GH32 family. Analysis of the fructans revealed an atypical structure consisting of 2,6-linked Fruf units as well as 2,1-linked Fruf units and 2,1,6-Fruf units. (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)
Databáze:	MEDLINE
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