Characterization of a glucansucrase from Lactobacillus reuteri E81 and production of malto-oligosaccharides

Authors: ISPIRLI, HÜMEYRA - Yildiz Technical University; YÜZER, MUSTAFA O - Bayburt University; Skory, Christopher - Chris; COLQUHOUN, IAN J - The Quadram Institute Bioscience; SAGDIÇ, OSMAN - Yildiz Technical University; DERTLI, ENES - Bayburt University

Submitted to: Biocatalysis and Biotransformation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2019
Publication Date: 5/7/2019
Citation: Ispirli, H., Yüzer, M., Skory, C.D., Colquhoun, I., Sagdiç, O., Dertli, E. 2019. Characterization of a glucansucrase from Lactobacillus reuteri E81 and production of malto-oligosaccharides. Biocatalysis and Biotransformation. 37:6, 421-430.. https://doi.org/10.1080/10242422.2019.1593969.
DOI: https://doi.org/10.1080/10242422.2019.1593969

Interpretive Summary: Certain bacteria used in fermented foods produce an enzyme called glucansucrase that are able to produce polymers of glucose, called glucan, from cane or beet sugars that contribute to the quality of many types of food. In addition, glucansucrases are important in the production of short sugar chains, called oligosaccharides that are used as prebiotics for improved intestinal health. In this study, we identified a novel glucansucrase from a bacterium isolated from a traditional Turkish sourdough. This enzyme was shown to be stable with high temperatures and could more efficiently produce glucan and oligosaccharides than many other previously described enzymes. These findings may help us to understand the role of glucansucrases for the production of different glucans and oligosaccharides with potentially important roles in the food industry as food stabilizing agents or prebiotics.

Technical Abstract: Glucansucrases, which can be produced by different Lactic Acid Bacteria (LAB), catalyze the synthesis of a-glucans with different structures and properties using sucrose as substrate. In this study, a novel glucansucrase (GTFA) from Lactobacillus reuteri E81 was identified and heterogously expressed. Alignments of GtfA with other glucansucrases revealed its novelty and a putative 3D model structure was obtained. The biochemical properties of the truncated enzyme without the N-terminal variable region, GtfA-'N, was characterized. The Km and Vmax were found to be 7.5 mM and 1.49 IU/mg, respectively and it showed optimum activities at pH 7 and at 50°C. The GtfA-'N produced in vitro an a-glucan with (a1'3) and (a1'6) glycosidic linkages using sucrose as the substrate. Importantly, GtfA-'N synthesized DP = 10 oligosaccharides using sucrose and maltose as the donor and acceptor sugars, respectively, as detected by TLC, HPLC, LC-MS and NMR analysis.